CHAPMAN EDWARD (GB)
COLLIS ANDREW JOHN (GB)
FUERST DOUGLAS E (US)
HOSFORD JOSEPH (GB)
MACDERMAID CHRISTOPHER M (US)
MATHY GRÉGORY (BE)
MORRISON JAMES PATRICK (US)
WO1995030009A2 | 1995-11-09 | |||
WO1994010291A1 | 1994-05-11 | |||
WO2020260475A1 | 2020-12-30 | |||
WO1994010291A1 | 1994-05-11 | |||
WO2018057031A1 | 2018-03-29 | |||
WO2015082978A1 | 2015-06-11 | |||
WO2014016374A1 | 2014-01-30 | |||
WO2008153541A1 | 2008-12-18 | |||
WO2009143457A2 | 2009-11-26 | |||
WO2012080369A1 | 2012-06-21 |
US20190134128A1 | 2019-05-09 | |||
US4436727A | 1984-03-13 | |||
US4877611A | 1989-10-31 | |||
US4866034A | 1989-09-12 | |||
US4912094A | 1990-03-27 | |||
GB2220211A | 1990-01-04 |
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Claims 1. A method for making a product saponin, said method comprising the steps of: (i) providing a plant cell culture extract comprising saponins; and (ii) enzymatically converting a starting saponin from the plant cell culture extract to a product saponin. 2. A method for making a product saponin, said method comprising the steps of: (i) culturing plant cells capable of synthesizing saponins under conditions leading to the synthesis of saponins; (ii) recovering saponins from the plant cell culture; and (iii) enzymatically converting a starting saponin from the recovered saponins to the product saponin. 3. A method for making a product saponin, said method comprising the steps of: (i) culturing plant cells capable of synthesizing saponins under conditions leading to the synthesis of saponins; (ii) enzymatically converting a starting saponin from the synthesized saponins to the product saponin; and (iii) recovering saponins from the plant cell culture. 4. A method for increasing the amount of a product saponin obtainable from a plant cell culture, said method comprising the steps of: (i) culturing plant cells capable of synthesizing saponins under conditions leading to the synthesis of saponins; (ii) recovering saponins from the plant cell culture; and (iii) enzymatically converting a starting saponin from the recovered saponins to the product saponin. 5. A method for increasing the amount of a product saponin obtainable from a plant cell culture, said method comprising the steps of: (i) culturing plant cells capable of synthesizing saponins under conditions leading to the synthesis of saponins; (ii) enzymatically converting a starting saponin from the synthesized saponins to the product saponin; and (iii) recovering saponins from the plant cell culture. 6. A method for reducing the amount of a starting saponin obtainable from a plant cell culture, said method comprising the following steps of: (i) culturing plant cells capable of synthesizing saponins under conditions leading to the synthesis of saponins; (ii) recovering saponins; and (iii) enzymatically converting the starting saponin from the recovered saponins to a product saponin. 7. A method for reducing the amount of a starting saponin obtainable from a plant cell culture, said method comprising the following steps of: (i) culturing plant cells capable of synthesizing saponins under conditions leading to the synthesis of saponins; (ii) enzymatically converting a starting saponin from the synthesized saponins to the product saponin; and (iii) recovering saponins from the plant cell culture. 8. A method for producing saponins by plant cell culture, said method comprising the steps of: (i) culturing plant cells capable of synthesizing saponins under conditions leading to the synthesis of saponins; and (ii) recovering saponins, wherein the yield of a product saponin is increased by enzymatically converting a starting saponin from recovered saponins to the product saponin. 9. The method according to any one of claims 1 to 8, wherein the saponins are quillaic acid glycosides. 10. The method according to any one of claims 1 to 9, wherein the plant cell culture extract or the plant cells are from Quillaja saponaria. 11. The method according to claim 10, wherein the starting saponin is a QS-18 family component. 12. The method according to claim 10, wherein the starting saponin is a desglucosyl-QS-17 family component. 13. The method according to claim 10, wherein the starting saponin is a QS-17 family component. 14. The method according to claim 10, wherein the starting saponin is a desarabinofuranosyl- QS-18 family component. 15. The method according to claim 10, wherein the starting saponin is an acetylated desglucosyl-QS-17 family component. 16. The method according to claim 11 or 12, wherein the product saponin is a QS-21 family component. 17. The method according to claim 13, wherein the product saponin is a QS-18 family component. 18. The method according to claim 13, wherein the product saponin is a desglucosyl-QS-17 family component. 19. The method according to claim 14, wherein the product saponin is a desarabinofuranosyl- QS-21 family component. 20. The method according to claim 15, wherein the product saponin is an acetylated QS-21 family component. 21. The method according to any one of claims 1 to 20, wherein a single starting saponin is converted to a single product saponin. 22. The method according to any one of claims 1 to 20, wherein a plurality of starting saponins is converted to a plurality of product saponins. 23. The method according to any one of claims 1 to 22, wherein the enzymatic conversion involves the removal of a beta-glucose residue by a glucosidase. 24. The method according to claim 23, wherein the glucosidase comprises, such as consists of, an amino acid sequence according to SEQ ID No.262, 208, 63, 229, 250, 5, 101, 207, 169, 247, 302, 324, 319, 9, 240, 325, 338, 850, 879, 868, 826, 804, 888, 881, 891, 816, 827, 857, 853, 842, 814, 886, 885, 838, 829, 808, 828, 870, 873, 844, 882, 874, 825, 824, 823, 810, 894, 849, 803, 890, 841, 832, 830, 845, 871, 837, 883 or 809 or functional variants thereof. 25. The method according to any one of claims 1 to 24, wherein the enzymatic conversion involves the removal of an alpha-rhamnose residue by a rhamnosidase. 26. The method according to claim 25, wherein the rhamnosidase comprises, such as consists of, an amino acid sequence according to SEQ ID No.992, 1003, 1052, 1073, 1017, 1055, 1075, 1001, 1007, 1061, 1079, 1027, 1039, 1041, 989, 1053, 1018, 1066, 1082, 1076, 993, 1077, 1046, 1015, 1063, 1054, 1074, 1067 or 1033, or functional variants thereof. 27. A saponin prepared by the method of any one of claims 1 to 26. 28. Use of a saponin prepared by the method of any one of claims 1 to 26 in the manufacture of an adjuvant. 29. An adjuvant composition comprising a saponin according to claim 27. 30. An immunogenic composition comprising a saponin according to claim 27, and an antigen or a polynucleotide encoding an antigen. 31. A kit of parts comprising: (i) a saponin according to claim 27, and (ii) an antigen or a polynucleotide encoding an antigen. |
and/or QS-182164 A V2 (i.e. xylose isomer): ; - ‘QS-182150 B component’, being triterpenoid glycosides having a m/z of 2150 with negative mode electrospray mass spectrometry. The QS-182150 B component corresponds to the B-isomer xylose chemotype structures B4a (apiose isomer) and B6a (xylose isomer) characterised in Nyberg 2000 and Nyberg 2003. The QS-182150 B component may consist of QS-182150 B V1 (i.e. apiose isomer):
and/or QS-182150 B V2 (i.e. xylose isomer): - ‘QS-182018 B component’, being triterpenoid glycosides having a m/z of 2018 with negative mode electrospray mass spectrometry. The QS-182018 B component corresponds to the B-isomer xylose chemotype structure B2a characterised in Nyberg 2000 and Nyberg 2003. The QS-182018 B component may consist of QS-182018 B: - ‘QS-182164 B component’, being triterpenoid glycosides having a m/z of 2164 with negative mode electrospray mass spectrometry. The QS-182164 B corresponds to the B-isomer rhamnose chemotype structures B3a (apiose isomer) and B5a (xylose isomer). The QS-182164 B component may consist of QS-182164 B V1 (i.e. apiose isomer):
and/or QS-182164 B V2 (i.e. xylose isomer): - desglucosyl-QS-17 family components (i.e. triterpenoid glycosides having alpha-O- rhamnosylation at the C2 position of the arabinofuranose moiety of QS-21 family components but lacking the glycosylation of QS-17 family components), such as: - ‘desglucosyl-QS-172134 A component’, being triterpenoid glycosides having a m/z of 2134 with negative mode electrospray mass spectrometry. The desglucosyl-QS-172134 A component is believed to be identified in Kite 2004 as Peak 75 and corresponds to A-isomers of the xylose chemotype. The desglucosyl-QS-172134 A component may consist of desglucosyl-QS-172134 A V1 (i.e. apiose isomer): and/or desglucosyl-QS-172134 A V2 (i.e. xylose isomer): - ‘desglucosyl-QS-172002 A component’, being triterpenoid glycosides having a m/z of 2002 with negative mode electrospray mass spectrometry. The desglucosyl-QS-172002 A component corresponds to the A-isomer xylose chemotype and may consist of desglucosyl-QS-172002 A: - ‘desglucosyl-QS-172148 A component’, being triterpenoid glycosides having a m/z of 2148 with negative mode electrospray mass spectrometry. The desglucosyl-QS-172148 A component is believed to be identified in Kite 2004 as Peaks 70 and 72 and corresponds to the A-isomer rhamnose chemotype. The desglucosyl-QS-172148 A component may consist of desglucosyl-QS-172148 A V1 (i.e. apiose isomer): and/or desglucosyl-QS-172148 A V2 (i.e. xylose isomer):
- ‘desglucosyl-QS-172134 B component’, being triterpenoid glycosides having a m/z of 2134 with negative mode electrospray mass spectrometry. The desglucosyl-QS-172134 B component is believed to be identified in Kite 2004 as Peak 67 and corresponds to B-isomers of the xylose chemotype. The desglucosyl-QS-172134 B component may consist of desglucosyl-QS-172134 B V1 (i.e. apiose isomer): and/or desglucosyl-QS-172134 B V2 (i.e. xylose isomer):
- ‘desglucosyl-QS-172002 B component’, being triterpenoid glycosides having a m/z of 2002 with negative mode electrospray mass spectrometry. The desglucosyl-QS-172002 B component corresponds to the B-isomer of the xylose chemotype and may consist of desglucosyl-QS-172002 B: - ‘desglucosyl-QS-172148 B component’, being triterpenoid glycosides having a m/z of 2148 with negative mode electrospray mass spectrometry. The desglucosyl-QS-172148 B component is believed to be identified in Kite 2004 as Peak 65 and corresponds to B-isomers of the rhamnose chemotype. The desglucosyl-QS-172148 B component may consist of desglucosyl-QS-172148 B V1 (i.e. apiose isomer): and/or desglucosyl-QS-172148 B V2 (i.e. xylose isomer): - QS-17 family components (i.e. triterpenoid glycosides having beta-O- glucopyranosylation at the C3 position of the L-rhamnose moiety and alpha-O- rhamnosylation at the C2 position of the arabinofuranose moiety of QS-21 family components), such as: - ‘QS-172296 A component’, being the triterpenoid glycosides identified as part of the QS-17 main peak in Fig.2 and having a m/z of 2296 with negative mode electrospray mass spectrometry. The QS-172296 A component is believed to be identified in Kite 2004 as Peak 59 and corresponds to the A-isomers of xylose chemotype structure QS-III. The QS-172296 A component may consist of QS-17 2296 A V1 (i.e. apiose isomer): and/or QS-172296 A V2 (i.e. xylose isomer): - ‘QS-172164 A component’, being the triterpenoid glycosides identified as part of the QS-17 main peak in Fig.2 and having a m/z of 2164 with negative mode electrospray mass spectrometry. The QS-172164 A component is believed to be identified in Kite 2004 as Peak 58 and corresponds to the A-isomer xylose chemotype. The QS-172164 A component may consist of QS-172164 A: - ‘QS-172310 A component’, being the triterpenoid glycosides identified as part of the QS-17 main peak in Fig.2 and having a m/z of 2310 with negative mode electrospray mass spectrometry. The QS-172310 A component is believed to be identified in Kite 2004 as Peak 57 and corresponds to A-isomers of the rhamnose chemotype. The QS-172310 A component may consist of QS-17 2310 A V1 (i.e. apiose isomer):
and/or QS-172310 A V2 (i.e. xylose isomer): - ‘QS-172296 B component’, being triterpenoid glycosides having a m/z of 2296 with negative mode electrospray mass spectrometry. The QS-172296 B component corresponds to the B-isomers of xylose chemotype structure QS-III in Kite 2004. The QS-172296 B component may consist of QS-172296 B V1 (i.e. apiose isomer):
and/or QS-172296 B V2 (i.e. xylose isomer): - ‘QS-172164 B component’, being triterpenoid glycosides having a m/z of 2164 with negative mode electrospray mass spectrometry. The QS-172164 B component corresponds to the B-isomer xylose chemotype. The QS-172164 B component and may consist of QS-172164 B:
- ‘QS-172310 B component’, being triterpenoid having a m/z of 2310 with negative mode electrospray mass spectrometry. The QS-172310 B component corresponds to B-isomers of the rhamnose chemotype. The QS-172310 B component may consist of QS-172310 B V1 (i.e. apiose isomer): and/or QS-172310 B V2 (i.e. xylose isomer); - desarabinofuranosyl-QS-18 family components (i.e. triterpenoid glycosides having beta-O-glucopyranosylation at the C3 position of the L-rhamnose moiety and but lacking the arabinofuranose moiety of QS-21 family components). The desarabinofuranosyl-QS- 18 family components are present in relatively low amounts in extracts, meaning that they have not been subjected to detailed characterisation. Desarabinofuranosyl-QS-18 family components can be challenging to isolate from QS-21 family components. Desarabinofuranosyl-QS-18 family components include: - desarabinofuranosyl-QS-182018 A component (i.e. triterpenoid glycosides identified as part of the ‘2018 Peak’ in Fig.6). Suitably the desarabinofuranosyl- QS-182018 A component in the UPLC-UV/MS methods described herein has a retention time of approximately 4.5 min, the primary component of the peak having a m/z of 2018 with negative mode electrospray mass spectrometry. The desarabinofuranosyl-QS-182018 A component may also be identified in the UPLC-UV methods described herein with a retention time of approximately 5.8 min. The desarabinofuranosyl-QS-182018 A component is believed to be identified in Kite 2004 as Peak 90 and corresponds to A-isomers of the xylose chemotype. Putative structures have been identified for the primary desarabinofuranosyl-QS-182018 A components using MS/MS. The desarabinofuranosyl-QS-182018 A component may consist of desarabinofuranosyl-QS-182018 A V1 (i.e. apiose isomer):
Exact Mass: 201793 and/or desarabinofuranosyl-QS-182018 A V2 (i.e. xylose isomer): - desarabinofuranosyl-QS-181886 A component (i.e. triterpenoid glycosides identified as part of the ‘2018 Peak’ in Fig.6). Suitably the desarabinofuranosyl- QS-181886 A component in the UPLC-UV/MS methods described herein has a retention time of approximately 4.5 min and a m/z of 1886 with negative mode electrospray mass spectrometry. The desarabinofuranosyl-QS-181886 A component and corresponds to the A-isomer xylose chemotype may also be identified in the UPLC-UV methods described herein with a retention time of approximately 5.8 min. The desarabinofuranosyl-QS-181886 A component may consist of:
- desarabinofuranosyl-QS-182032 A component (i.e. triterpenoid glycosides identified as part of the ‘2018 Peak’ in Fig.6). Suitably the desarabinofuranosyl- QS-182032 A component in the UPLC-UV/MS methods described herein has a retention time of approximately 4.5 min and a m/z of 2032 with negative mode electrospray mass spectrometry. The desarabinofuranosyl-QS-182032 A component corresponds to A-isomers of the rhamnose chemotype and may also be identified in the UPLC-UV methods described herein with a retention time of approximately 5.8 min. The desarabinofuranosyl-QS-182032 A component may consist of desarabinofuranosyl-QS-182032 A V1 (i.e. apiose isomer): and/or desarabinofuranosyl-QS-182032 A V2 (i.e. xylose isomer):
- desarabinofuranosyl-QS-182018 B component (i.e. triterpenoid glycosides having a m/z of 2018 with negative mode electrospray mass spectrometry). The desarabinofuranosyl-QS-182018 B component corresponds to B-isomers of the xylose chemotype. Desarabinofuranosyl-QS-182018 B component may consist of desarabinofuranosyl-QS-182018 B V1 (i.e. apiose isomer): and/or desarabinofuranosyl-QS-182018 B V2 (i.e. xylose isomer):
- desarabinofuranosyl-QS-181886 B component (i.e. triterpenoid glycosides identified having a m/z of 1886 with negative mode electrospray mass spectrometry). The desarabinofuranosyl-QS-181886 B component corresponds to the B-isomer xylose chemotype. The desarabinofuranosyl-QS-181886 B component may consist of: - desarabinofuranosyl-QS-182032 B component (i.e. triterpenoid glycosides having a m/z of 2032 with negative mode electrospray mass spectrometry). The desarabinofuranosyl-QS-182032 B component corresponds to B-isomers of the rhamnose chemotype. The desarabinofuranosyl-QS-182032 B component may consist of desarabinofuranosyl-QS-182032 B V1 (i.e. apiose isomer):
and/or desarabinofuranosyl-QS-182032 B V2 (i.e. xylose isomer): - acetylated desglucosyl-QS-17 family components (i.e. triterpenoid glycosides having alpha-O-rhamnosylation at the C2 position of the arabinofuranose moiety and acetylation of the C3 position of the fucose of QS-21 family components), such as: - ‘acetylated desglucosyl-QS-172176 A component’, being triterpenoid glycosides having a m/z of 2176 with negative mode electrospray mass spectrometry. The acetylated desglucosyl-QS-172176 A component corresponds to A-isomers of the xylose chemotype. The acetylated desglucosyl- QS-172176 A component may consist of acetylated desglucosyl-QS-172176 A V1 (i.e. apiose isomer): and/or acetylated desglucosyl-QS-172176 A V2 (i.e. xylose isomer): - ‘acetylated desglucosyl-QS-172044 A component’, being triterpenoid glycosides having m/z of 2044 with negative mode electrospray mass spectrometry. The acetylated desglucosyl-QS-172044 A component corresponds to the A-isomer xylose chemotype. The acetylated desglucosyl-QS- 172044 A component may consist of acetylated desglucosyl-QS-172044 A:
- ‘acetylated desglucosyl-QS-172190 A component’, being triterpenoid glycosides having a m/z of 2190 with negative mode electrospray mass spectrometry. The acetylated desglucosyl-QS-172190 A corresponds to the A- isomer rhamnose chemotype. The acetylated desglucosyl-QS-172190 A component may consist of acetylated desglucosyl-QS-172190 A V1 (i.e. apiose isomer): and/or acetylated desglucosyl-QS-172190 A V2 (i.e. xylose isomer):
Starting saponins of direct relevance to the engineered glucosidase polypeptides for use in the methods of the invention are those having cleavable glucose residues, nevertheless, the engineered glucosidase polypeptides may be utilised in conjunction with additional enzymes capable of cleaving other sugar residues. Particular starting saponins of relevance to the engineered glucosidase polypeptides include: - QS-18 family components; - QS-17 family components; and - desarabinofuranosyl-QS-18 family components. Starting saponins of direct relevance to the engineered rhamnosidase polypeptides for use in the methods of the invention are those having cleavable rhamnose residues, nevertheless, the engineered rhamnosidase polypeptides may be utilised in conjunction with additional enzymes capable to cleaving other sugar residues. Particular starting saponins of relevance to the engineered rhamnosidase polypeptides include: - desglucosyl-QS-17 family components; - QS-17 family components; and - acetylated desglucosyl-QS-17 family components. The methods of the present invention enzymatically modify a starting saponin obtained from a plant cell culture to provide a product saponin (i.e. a saponin resulting from an enzymatic modification). The product saponin may be a naturally occurring saponin (i.e. a steroid or terpenoid glycoside found in nature, though the product saponin is itself obtained by the methods of the invention) or an artificially created saponin (i.e. a steroid or terpenoid glycoside not found in nature). In some embodiments, the product saponin is a steroid glycoside. In other embodiments, the product saponin is a terpenoid glycoside, especially a triterpenoid glycoside. Naturally occurring product saponins may be saponins synthesized by plant cells cultured in vitro that originate from plants that produce saponins, such as the plants described below. Naturally occurring product saponins include those obtainable from, such as obtained from, an in vitro plant cell culture originating from the genera Gypsophilia, Saponaria, such as the Saponaria vaccaria species, or Saponaria officinalis species, or Quillaja (Bomford, 1992). Especially of interest are product saponins obtainable from an in vitro plant cell culture originating from Quillaja species. Particular product saponins of interest include those obtained from an in vitro plant cell culture originating from Quillaja brasiliensis or Quillaja saponaria. In one embodiment, the product saponin is obtained from an in vitro plant cell culture originating from Quillaja saponaria. In one embodiment, the product saponin is obtained from an in vitro plant cell culture originating from Quillaja brasiliensis. In certain embodiments, the product saponin is a quillaic acid glycoside. Product saponins obtainable from a culture of plant cells originating from Quillaja saponaria include: - QS-18 family components (i.e. triterpenoid glycosides having beta-O- glucopyranosylation at the C3 position of the L-rhamnose moiety of QS-21 family components), such as: - ‘QS-182150 A component’. The QS-182150 A component may consist of QS- 182150 A V1 (i.e. apiose isomer):
and/or QS-182150 A V2 (i.e. xylose isomer): - ‘QS-182018 A component’. The QS-182018 A component may consist of QS-5 18 2018 A:
- ‘QS-182164 A component’. The QS-182164 A component may consist of QS- 18 2164 A V1 (i.e. apiose isomer): 5 and/or QS-182164 A V2 (i.e. xylose isomer):
- ‘QS-182150 B component’. The QS-182150 B component may consist of QS- 18 2150 B V1 (i.e. apiose isomer): 5 and/or QS-182150 B V2 (i.e. xylose isomer):
- ‘QS-182018 B component’. The QS-182018 B component may consist of QS- 18 2018 B: 5 - ‘QS-182164 B component’. The QS-182164 B component may consist of QS- 18 2164 B V1 (i.e. apiose isomer):
and/or QS-182164 B V2 (i.e. xylose isomer): - desglucosyl-QS-17 family components (i.e. triterpenoid glycosides having alpha-O- rhamnosylation at the C2 position of the arabinofuranose moiety of QS-21 family components), such as: - ‘desglucosyl-QS-172134 A component’. The desglucosyl-QS-172134 A component may consist of desglucosyl-QS-172134 A V1 (i.e. apiose isomer): and/or desglucosyl-QS-172134 A V2 (i.e. xylose isomer): - ‘desglucosyl-QS-172002 A component’. The desglucosyl-QS-172002 A component may consist of desglucosyl-QS-172002 A:
- ‘desglucosyl-QS-172148 A component’. The desglucosyl-QS-172148 A component may consist of desglucosyl-QS-172148 A V1 (i.e. apiose isomer): and/or desglucosyl-QS-172148 A V2 (i.e. xylose isomer):
- ‘desglucosyl-QS-172134 B component’. The desglucosyl-QS-172134 B component may consist of desglucosyl-QS-172134 B V1 (i.e. apiose isomer): and/or desglucosyl-QS-172134 B V2 (i.e. xylose isomer):
- ‘desglucosyl-QS-172002 B component’. The desglucosyl-QS-172002 B component may consist of desglucosyl-QS-172002 B: - ‘desglucosyl-QS-172148 B component’. The desglucosyl-QS-172148 B component may consist of desglucosyl-QS-172148 B V1 (i.e. apiose isomer):
and/or desglucosyl-QS-172148 B V2 (i.e. xylose isomer): - QS-21 family components, such as: - ‘QS-211988 A component’, being the triterpenoid glycosides identified as part of the QS-21 main peak in Fig. 6 and having a m/z of 1988 with negative mode electrospray mass spectrometry. Suitably the QS-211988 A component in the UPLC-UV/MS methods described herein has a retention time of approximately 4.4 min and a m/z of 1988 with negative mode electrospray mass spectrometry. The QS-211988 A component is believed to be identified in Kite 2004 as Peak 88 and corresponds to the A-isomer xylose chemotype structures S6 (apiose isomer) and S4 (xylose isomer) characterised in Nyberg 2000 and Nyberg 2003. The QS-21 1988 A component may consist of QS-211988 A V1 (i.e. apiose isomer): and QS-211988 A V2 (i.e. xylose isomer): - ‘QS-211856 A component’, being the triterpenoid glycosides identified as part of the QS-21 main peak in Fig. 6 and having a m/z of 1856 with negative mode electrospray mass spectrometry. Suitably the QS-211856 A component in the UPLC-UV/MS methods described herein has a retention time of approximately 4.4 min and a m/z of 1856 with negative mode electrospray mass spectrometry. The QS-211856 A component is believed to be identified in Kite 2004 as Peak 86 and corresponds to the A-isomer xylose chemotype structure S2 characterised in Nyberg 2000 and Nyberg 2003. The QS-211856 A component may consist of: . - ‘QS-212002 A component’, being the triterpenoid glycosides identified as part of the QS-21 main peak in Fig.6 and having a m/z of 2002 with negative mode electrospray mass spectrometry. Suitably the QS-212002 A component in the UPLC-UV/MS methods described herein has a retention time of approximately 4.4 min and a m/z of 2002 with negative mode electrospray mass spectrometry. The QS-212002 A component is believed to be identified in Kite 2004 as Peak 85 and corresponds to the A-isomer rhamnose chemotype of structures S3 and S5 characterised in Nyberg 2000 and Nyberg 2003. The QS-212002 A component may consist of QS-212002 A V1 (i.e. apiose isomer):
and QS-212002 A V2 (i.e. xylose isomer): - ‘QS-211988 B component’, being the triterpenoid glycosides identified as part of the B-isomer peak in Fig. 6 and having a m/z of 1988 with negative mode electrospray mass spectrometry. Suitably the QS-211988 B component in the UPLC-UV/MS methods described herein has a retention time of approximately 4.0 min and a m/z of 1988 with negative mode electrospray mass spectrometry. The QS-21 1988 B component corresponds to the B-isomer xylose chemotype structures S6a (apiose isomer) and S4a (xylose isomer) characterised in Nyberg 2000 and Nyberg 2003. The QS-211988 B component may consist of QS-211988 B V1 (i.e. apiose isomer): and QS-211988 B V2 (i.e. xylose isomer): - ‘QS-211856 B component’, being the triterpenoid glycosides identified as part of the B-isomer peak in Fig. 6 and having a m/z of 1856 with negative mode electrospray mass spectrometry. The QS-211856 B component corresponds to the B-isomer xylose chemotype structure S2a characterised in Nyberg 2000 and Nyberg 2003. The QS-211856 B component may consist of: - ‘QS-212002 B component’, being the triterpenoid glycosides having a m/z of 2002 with negative mode electrospray mass spectrometry. The QS-212002 B component corresponds to the B-isomer rhamnose chemotype of structures S3a and S5a characterised in Nyberg 2000 and Nyberg 2003. The QS-212002 B component may consist of QS-212002 B component V1 (i.e. apiose isomer):
and QS-212002 B V2 (i.e. xylose isomer): - desarabinofuranosyl-QS-21 family components (i.e. triterpenoid glycosides lacking the arabinofuranose moiety of QS-21 family components). The desarabinofuranosyl-QS-21 family components are present in relatively low amounts in extracts, meaning that they have not been subjected to detailed characterisation. Desarabinofuranosyl-QS-21 family components include: - desarabinofuranosyl-QS-211856 A component (i.e. triterpenoid glycosides identified as part of the ‘Lyophilization Peak’ in Fig.6). Suitably the desarabinofuranosyl-QS-211856 A component in the UPLC-UV/MS methods described herein has a retention time of approximately 4.7 min, the primary component of the peak having a m/z of 1856 with negative mode electrospray mass spectrometry. The desarabinofuranosyl-QS-211856 A component is believed to be identified in Kite 2004 as Peak 96. Putative structures have been identified for the primary desarabinofuranosyl-QS-211856 A components using MS/MS. The desarabinofuranosyl-QS-211856 A component may consist of desarabinofuranosyl-QS-211856 A V1 (i.e. apiose isomer): and/or desarabinofuranosyl-QS-211856 A V2 (i.e. xylose isomer): - desarabinofuranosyl-QS-211712 A component (i.e. triterpenoid glycosides identified as part of the ‘Lyophilization Peak’ in Fig.6). Suitably the desarabinofuranosyl-QS-211712 A component in the UPLC-UV/MS methods described herein has a retention time of approximately 4.7 min and a m/z of 1712 with negative mode electrospray mass spectrometry. The desarabinofuranosyl- QS-211712 A component may consist of desarabinofuranosyl-QS-211712 A: - desarabinofuranosyl-QS-211870 A component, i.e. triterpenoid glycosides having a m/z of 1870 with negative mode electrospray mass spectrometry. The desarabinofuranosyl-QS-211870 A component may consist of desarabinofuranosyl-QS-211870 A V1 (i.e. apiose isomer): and/or desarabinofuranosyl-QS-211870 A V2 (i.e. xylose isomer):
- desarabinofuranosyl-QS-211856 B component, i.e. triterpenoid glycosides having a m/z of 1856 with negative mode electrospray mass spectrometry. The desarabinofuranosyl-QS-211856 B component may consist of desarabinofuranosyl-QS-211856 B V1 (i.e. apiose isomer): and/or desarabinofuranosyl-QS-211856 B V2 (i.e. xylose isomer):
- desarabinofuranosyl-QS-211712 B component, i.e. triterpenoid glycosides having a m/z of 1712 with negative mode electrospray mass spectrometry. The desarabinofuranosyl-QS-211712 B component may consist of desarabinofuranosyl-QS-211712 B: - desarabinofuranosyl-QS-211870 B component, i.e. triterpenoid glycosides having a m/z of 1870 with negative mode electrospray mass spectrometry. The desarabinofuranosyl-QS-211870 B component may consist of desarabinofuranosyl-QS-211870 B V1 (i.e. apiose isomer):
and/or desarabinofuranosyl-QS-211870 B V2 (i.e. xylose isomer): - acetylated QS-21 family components (i.e. triterpenoid glycosides having acetylation of the C3 position of the fucose of QS-21 family components), such as: - ‘acetylated QS-212030 A component’, being triterpenoid glycosides having a m/z of 2030 with negative mode electrospray mass spectrometry. The acetylated QS-212030 A corresponds to the A-isomer xylose chemotype. The acetylated QS-212030 A component may consist of acetylated QS-212030 A V1 (i.e. apiose isomer):
and/or acetylated QS-212030 A V2 (i.e. xylose isomer): - ‘acetylated QS-211898 A component’, being triterpenoid glycosides having a m/z of 1898 with negative mode electrospray mass spectrometry. The acetylated QS-211898 A corresponds to the A-isomer xylose chemotype. The acetylated QS-211898 A component may consist of acetylated QS-211898 A:
- ‘acetylated QS-212044 A component’, being triterpenoid glycosides having a m/z of 2044 with negative mode electrospray mass spectrometry. The acetylated QS-212044 A corresponds to A-isomers of the rhamnose chemotype. The acetylated QS-212044 A component may consist of acetylated QS-212044 A V1 (i.e. apiose isomer): and/or acetylated QS-212044 A V2 (i.e. xylose isomer): Product saponins of direct relevance to the engineered glucosidase polypeptides for use in the methods of the invention are those where a glucose residue has been cleaved relative to a starting saponin. Nevertheless, the engineered glucosidase polypetides may be utilised in conjunction with additional enzymes capable to cleaving other sugar residues. Particular product saponins of relevance to the engineered glucosidase polypeptides include: - desglucosyl-QS-17 family components; - QS-21 family components; and - desarabinofuranosyl-QS-21 family components. Product saponins of direct relevance to the engineered rhamnosidase polypeptides for use in the methods of the invention are those where a rhamnose residue has been cleaved relative to a starting saponin. Nevertheless, the engineered rhamnosidase polypeptides may be utilised in conjunction with additional enzymes capable to cleaving other sugar residues. Particular product saponins of relevance to the engineered rhamnosidase polypeptides include: - QS-18 family components; - QS-21 family components; and - acetylated QS-21 family components. The term ‘QS-18 family components’ as used herein means the xylose chemotype QS- 182150 component (A and B isomers, and apiose and xylose isomers: QS-182150 A V1, QS- 182150 A V2, QS-182150 B V1 and QS-182150 B V2), the xylose chemotype QS-182018 component (A and B isomers: QS-182018 A and QS-182018 B), the rhamnose chemotype QS-182164 component (A and B isomers, and apiose and xylose isomers: QS-182164 A V1, QS-182164 A V2, QS-182164 B V1 and QS-182164 B V2). The term ‘desglucosyl-QS-17 family components’ as used herein means the xylose chemotype desglucosyl-QS-172134 component (A and B isomers, and apiose and xylose isomers: desglucosyl-QS-172134 A V1, desglucosyl-QS-172134 A V2, desglucosyl-QS-17 2134 B V1 and desglucosyl-QS-172134 B V2), the xylose chemotype desglucosyl-QS-172002 component (A and B isomers: desglucosyl-QS-172002 A and desglucosyl-QS-172002 B), the rhamnose chemotype desglucosyl-QS-172148 component (A and B isomers, and apiose and xylose isomers: desglucosyl-QS-172148 A V1, desglucosyl-QS-172148 A V2, desglucosyl-QS- 172148 B V1 and desglucosyl-QS-172148 B V2). The term ‘QS-17 family components’ as used herein means the xylose chemotype QS- 172296 component (A and B isomers, and apiose and xylose isomers: QS-172296 A V1, QS- 172296 A V2, QS-172296 B V1 and QS-172296 B V2), the xylose chemotype QS-172164 component (A and B isomers: QS-172164 A and QS-172164 B), the rhamnose chemotype QS-172310 component (A and B isomers, and apiose and xylose isomers: QS-172310 A V1, QS-172310 A V2, QS-172310 B V1 and QS-172310 B V2). The term ‘QS-21 family components’ as used herein means the xylose chemotype QS- 211988 component (A and B isomers, and apiose and xylose isomers: QS-211988 A V1, QS- 211988 A V2, QS-211988 B V1 and QS-211988 B V2), the xylose chemotype QS-211856 component (A and B isomers: QS-211856 A and QS-211856 B), the rhamnose chemotype QS-212002 component (A and B isomers, and apiose and xylose isomers: QS-212002 A V1, QS-212002 A V2, QS-212002 B V1 and QS-212002 B V2). The term ‘desarabinofuranosyl-QS-18 family components’ as used herein means the xylose chemotype desarabinofuranosyl-QS-182018 component (A and B isomers, and apiose and xylose isomers: desarabinofuranosyl-QS-182018 A V1, desarabinofuranosyl-QS-182018 A V2, desarabinofuranosyl-QS-182018 B V1 and desarabinofuranosyl-QS-182018 B V2), the xylose chemotype desarabinofuranosyl-QS-181886 component (A and B isomers: desarabinofuranosyl-QS-181886 A and desarabinofuranosyl-QS-181886 B), the rhamnose chemotype desarabinofuranosyl-QS-182032 component (A and B isomers, and apiose and xylose isomers: desarabinofuranosyl-QS-182032 A V1, desarabinofuranosyl-QS-182032 A V2, desarabinofuranosyl-QS-182032 B V1 and desarabinofuranosyl-QS-182032 B V2). The term ‘acetylated desglucosyl-QS-17 family components’ as used herein means xylose chemotype acetylated desglucosyl-QS-172176 component (apiose and xylose isomers: acetylated desglucosyl-QS-172176 A V1 and acetylated desglucosyl-QS-172176 A V2), the xylose chemotype acetylated desglucosyl-QS-172044 A component, the rhamnose chemotype acetylated desglucosyl-QS-172190 component (apiose and xylose isomers: acetylated desglucosyl-QS-172190 A V1 and acetylated desglucosyl-QS-172190 A V2). The term ‘desarabinofuranosyl-QS-21 family components’ as used herein means xylose chemotype desarabinofuranosyl-QS-211856 component (A and B isomers, and apiose and xylose isomers: desarabinofuranosyl-QS-211856 A V1, desarabinofuranosyl-QS-211856 A V2, desarabinofuranosyl-QS-211856 B V1 and desarabinofuranosyl-QS-211856 B V2), the xylose chemotype desarabinofuranosyl-QS-211712 component (A and B isomers: desarabinofuranosyl-QS-211712 A and desarabinofuranosyl-QS-211712 B), the rhamnose chemotype desarabinofuranosyl-QS-211870 component (A and B isomers, and apiose and xylose isomers: desarabinofuranosyl-QS-211870 A V1, desarabinofuranosyl-QS-211870 A V2, desarabinofuranosyl-QS-211870 B V1 and desarabinofuranosyl-QS-211870 B V2). The term ‘acetylated QS-21 family components’ as used herein means xylose chemotype acetylated QS-212030 component (apiose and xylose isomers: acetylated QS-21 2030 A V1 and acetylated QS-212030 A V2), the xylose chemotype acetylated QS-211898 A component, the rhamnose chemotype acetylated QS-212044 component (apiose and xylose isomers: acetylated QS-212044 A V1 and acetylated QS-212044 A V2). Plant cell culture The term ‘plant cell culture’ is to be understood as the in vitro culture of any plant tissues or any plant cells derived from any tissue from plants producing saponins, such as e.g. plants described and referred to earlier. Tissues or cells from the plant cell culture are capable of synthesizing saponins. The term ‘capable of synthesizing saponins’, in the sense of the present invention, refers to the ability of cells to synthesize and produce saponins. Depending on different factors, such as e.g. the origin of the plant cell culture, the cell culture conditions, saponin synthesis and production thereof may require to be triggered. The term ‘under conditions leading to the synthesis of saponins’, in the sense of the present invention, refers to conditions triggering and resulting into the effective synthesis of saponins and production thereof. A plant cell culture in the sense of the present invention may be obtained and generated according to any known method. Lambert et al. (2011) provides a review on in vitro cultures of saponin-producing plants in general. WO 94/10291 (incorporated herein by reference) discloses how to obtain an in vitro culture of plant cells originating from Quillaja saponaria species that are capable of synthesizing and producing saponins. Methods for culturing plant cells, and general culture conditions for plant cells are known in the art. Conventional culture media known for plant cell culture, such as e.g. classical Murashige and Skoog (MS) medium, White’s medium, or Linsmaler & Skoog's medium can be used in the methods of the invention. These media typically contain at least one or more macronutrients, e.g. selected from NH4NO3, KNO3, CaCl2, MgSO4, KH2PO4, NH4Cl, or KCl; at least one or more micronutrients, e.g. selected from KI, H3BO3, MnSO4, ZnS04, Na2MoO4, CuSO4, CoCl2, DeSO4, or Na2EDTA; at least one or more vitamins, e.g. selected from myoinisotol, nicotinic acid, pyrodixine-HCl, or thiamine-HCl, for example at a total concentration between 0.01 and 3 g/L, such as between 50 and 150 mg/L; at least one or more amino acids, such as glycine; at least one or more carbon source, e.g. selected from sucrose, glucose or fructose; and at least one or more plant hormone, e.g. selected from one or more cytokinins, or one or more auxins, such as 2,4-D and/or NAA. Plant cells used in the methods of the invention may originate from different tissues or organs of a given plant body, e.g. primordia, leaves, stems, hairy roots, internodes, cambium, whether cultured in suspension in a liquid medium or on a solid medium, e.g. calli. In one embodiment, the plant cells used in the method of the invention originate from the cambium, e.g. are cambial meristematic cells (CMC). In an alternative embodiment, the plant cells originate from hairy roots. Plant cells used in the methods of the invention may be a callus, e.g. deriving from the cambium of the plant. A “callus” is typically defined as a cluster of dedifferentiated cells cultured on solidified medium. Callus generation may be achieved from any plant tissue explant by any method known to the skilled person, e.g. the methods described in WO 94/10291, in US 2019/0134128 or in WO 15/082978. In brief, tissue explants from a plant of a small size may be surface sterilized, e.g. by washing thoroughly with clean water, using a disinfectant such as hypochlorite, using wett agents, such as Tween or Triton, using antibiotics and/or using anti- fungal agents. Surface sterilized explants are then, typically, laid on the surface of solidified medium, such as agar, and incubated in a sterile environment, until a mass of undifferentiated cells grows (typically between 2 to 12 weeks, e.g.8 weeks) in proximity to the plant source material. Calli may be gradually purified and further propagated by means of repeating the similar solid medium-culturing, that is, by inoculating fresh solid medium by turns with small pieces of callus formed in the previous solid medium-culturing, e.g. every 4 weeks. Callus culture conditions including media components, such as MS media, pH ranges, carbon sources, nitrogen sources, macro-salts and micro-salts, vitamins and growth regulators are well known in the art. Calli thus formed and refined on the solid medium by subculture may be inoculated into a liquid medium and cultured so as to obtain a suspension cell culture. The terms “suspension plant culture” and “suspension of plant cells” are interchangeable and refer to an in vitro culture of plant cells dispersed in a liquid medium and grown in suspension. In one embodiment, the plant cells for use in the methods of the invention are grown in suspension in a liquid medium. To obtain plant cells into a suspension culture, cells are for example removed from a callus and transferred to sterile culture vessels containing nutrient culture medium. It is appreciated that optimized media for suspension cell lines may differ from the optimum for callus. It is within the ambit of the skilled person to determine suitable and optimal culture media. The transition from a callus to suspension cell cultures is also known to the skilled person (described e.g. in WO 94/10291 or US 2019/0134128). Suspension culture conditions including media components, pH ranges, carbon sources, nitrogen sources, macro-salts and micro-salts, vitamins and growth regulators are well known in the art, e.g. classical MS media. Once initiated and adapted to growth in suspension, suspension cells may be sub-cultured or propagated, for example by dilution, e.g. every 4 weeks. Saponin synthesis by the plant cells used in the methods of the invention (i.e. capable of synthesizing saponins) may be optimized by eliciting the cells with an elicitor. Suitable elicitors for use in the methods of the invention are monococarboxylic compound-type elicitors, such as 5-chlorosalicyclic acid, salicyclic acid, acetylsalicyclic acid, a methyl ester, e.g. methyl jasmonate (MeJa), or the chemically synthesized 2-HEJ. In one embodiment, the elicitor is MeJa. While the concentration of elicitors is typically referred to by reference to the volume of the culture medium, an alternative way to define the concentration is by reference to the PCV %. The term “PCV” stands for Packed Cell Volume and refers to the volume occupied by cells in culture medium. It may be calculated as follows: PCV (%) = (volume of cell pellet/volume of sample) × 100. A suitable range of an elicitor, e.g. MeJa is from 0.5 to 10 µM/PCV %. Elicitors may be added directly to the culture medium. Alternatively, the culture medium may be replaced with a culture medium including the elicitor(s). Elicitation duration may be adjusted, depending on the plant cells under consideration. It is within the ambit of the skilled person to determine the optimal duration. Suitably, the elicitation may take place between 1 to 14 days, more suitably between 2 to 10 days, and even more suitably, between 3 to 8 days. Alternatively, or additionally, to elicitation, saponin synthesis by the plant cells used in the method of the invention may be further optimized by depleting the cells in nitrogen, e.g. prior to elicitation. Nitrogen depletion means reducing the level of any source of nitrogen present in the culture medium. Suitably, e.g. prior to elicitation, the cell culture medium of the cells is removed and replaced with a culture medium containing no source of nitrogen. Suitable ranges for the duration of nitrogen depletion (prior to elicitation) are from 1 to 9 days, suitably, from 2 to 7 days, and more suitably from 3 to 6 days. Elicitation and/or nitrogen depletion are non-limiting examples of ‘conditions leading to the synthesis of saponins’ in the sense of the present invention. Saponins synthesized by the plant cells used in the methods of the invention may either be extracellularly secreted into the culture medium and/or remain located intracellularly. Accordingly, a starting saponin intended to be enzymatically modified, or converted, in the sense of the present invention, may be included in the cell culture medium. In other words, the cell culture medium of plant cells capable of synthesizing saponins may be used as starting material, and subject to enzymatic treatment. In some embodiments, glycosidases are added to the culture medium, optionally after nitrogen has been depleted from the culture medium as described earlier and/or cells have been elicited with an elicitor as described earlier. Alternatively, a starting saponin intended to be enzymatically modified, or converted, in the sense of the present invention, may be recovered from the intracellular content of the plant cells. For example, the plant cells may be lysed (by any known in the art technique) and the resulting intracellular content be subject to enzymatic treatment. In the sense of the present invention, the term ‘plant cell culture extract’ is to be understood as any extract, or material, obtained from an in vitro plant cell culture, that includes saponins, whether synthesized saponins and/or recovered saponins, including the starting saponin and/or the product saponin. For example, a plant cell culture extract may be the plant cells, or the plant cells that have been lysed. A plant cell culture extract may be crude, or partially or wholly purified. A plant cell culture extract may be obtained from the genera Gypsophilia, Saponaria, such as Saponaria vaccaria or Saponaria officinalis or Quillaja (Bomford, 1992), such as a plant cell culture extract obtained from Quillaja species. Particular plant cell culture extracts include that obtained from Quillaja brasiliensis or Quillaja saponaria. In one embodiment, the plant cell culture extract is obtained from Quillaja saponaria. In one embodiment, the plant cell culture extract is obtained from Quillaja brasiliensis. The term ‘recover’ is to be understood as collecting saponins, for example saponins synthesized by the plant cells or the plant cell culture. Saponins may be recovered from the culture medium. Alternatively, saponins may be recovered from the plant cells, e.g. by extraction. Any known extraction method is suitable (e.g. as described in WO 94/10291), using non- aqueous polar solvents, extraction using an acid medium or a basic medium, or extraction by mechanically disrupting the plant cells, such as by ball milling, sonication. Alternatively, saponins may be extracted by freezing the cell pellet (resulting in cell lysis) obtained after centrifugation of the cell culture. Suitably, the cell pellet is frozen at -20°C, and more suitably at -70°C, e.g. at least for 24 hours. Extraction may be performed using water or lower alcohols (e.g. methanol or ethanol) as solvents, including mixtures thereof. In one embodiment, the starting saponin is obtained by aqueous extraction (e.g. using solvent comprising at least 80% v/v water, especially at least 90% v/v water, such as at least 95% v/v water). In one embodiment, the starting saponin is obtained by methanol extraction (e.g. using solvent comprising at least 80% v/v methanol, especially at least 90% v/v methanol, such as at least 95% v/v methanol). In one embodiment, the starting saponin is obtained by ethanol extraction (e.g. using solvent comprising at least 80% v/v ethanol, especially at least 90% v/v ethanol, such as at least 95% v/v ethanol). In one embodiment, the starting saponin is obtained by methanol/ethanol extraction (e.g. using solvent comprising at least 20% v/v methanol, especially at least 30% v/v methanol, such as at least 40% v/v methanol and at least 20% ethanol, especially at least 30% v/v ethanol, such as at least 40% v/v ethanol). In one embodiment, the starting saponin is obtained by water/ethanol extraction (e.g. using solvent comprising at least 20% v/v water, especially at least 30% v/v water, such as at least 40% v/v water and at least 20% ethanol, especially at least 30% v/v ethanol, such as at least 40% v/v ethanol. In one embodiment, the starting saponin is obtained by water/methanol extraction (e.g. using solvent comprising at least 20% v/v water, especially at least 30% v/v water, such as at least 40% v/v water and at least 20% methanol, especially at least 30% v/v methanol, such as at least 40% v/v methanol). Methods of the invention may be applied to starting saponin in a range of contexts. A starting saponin may be in the form of a minor component in a saponin-containing composition (ignoring solvents, if any), such as a minor component in a plant cell culture extract. A starting saponin may be in the form of a major component in a saponin containing composition, such as a major component in a plant cell culture extract. A starting saponin may be in the form of a minor component in a processed, such as partially purified, plant cell culture extract. A starting saponin may be in the form of a major component in a processed, such as partially purified, plant cell culture extract. In some embodiments, the starting saponin is substantially purified at the time of enzymatic modification. In further embodiments, the starting saponin is included in a crude material, such as a crude plant cell culture extract. Purification refers to the isolation of a component from other components. Partial purification therefore means the isolation of a component, to some degree, from other components. Substantial purification means the substantial isolation of a component from other components, such as wherein the component comprises at least 50% w/w, especially as at least 70%, particularly at least 80%, for example at least 90% of the component content (50%, 70%, 80% and 90% purity, respectively). Partial purification, in relation to a plant cell culture extract, means the isolation of the starting saponin, to some degree, from other extracted components. Substantially purified, in relation to a plant cell culture extract, means the substantial isolation of the starting saponin from other extracted components, such as wherein the starting saponin comprises at least 50% w/w, especially as at least 70%, particularly at least 80%, for example at least 90% of the extracted component content. Partial or substantial purification can be undertaken through various means including chromatography, filtration over semi-permeable membranes, treatment with selective adsorbants such as polyvinylpolypyrrolidone (PVPP) and the like. Although a starting saponin may be a specific chemical entity, in many circumstances involving saponins obtained by extraction, a plurality of starting saponins may be present, these being enzymatically modified to provide their corresponding product saponins. As mentioned above for individual saponins, the invention may be applied to a plurality of starting saponins in a range of contexts mutatis mutandis. A plurality of starting saponins comprising related starting saponins may undergo equivalent enzymatic modification concurrently. A plurality of starting saponins comprising distinguishable starting saponins may undergo different enzymatic modifications concurrently (in the presence of more than one enzyme) or in series (sequential treatment with separate enzymes). A plurality of starting saponins may contain both related and distinguishable starting saponins. Methods of the invention may be applied to a starting saponin in the form of a component of: - crude plant cell culture extract, such as water and/or lower alcohol extract, especially aqueous cell extract; - partially purified plant cell culture extract, such as water and/or lower alcohol plant cell culture extract, especially aqueous plant cell culture extract; - PVPP treated plant cell culture extract, such as PVPP treated water and/or lower alcohol plant cell culture extract, especially PVPP treated aqueous plant cell culture extract; - Plant cell culture fraction equivalent to Quil A; - Plant cell culture fraction equivalent to Fraction A; - Plant cell culture fraction equivalent to Fraction B (see Nyberg 2003); - Plant cell culture fraction equivalent to Fraction C; - QS-7 fraction; - QS-17 fraction; - QS-18 fraction; or - QS-21 fraction. Methods of the invention may be applied to a starting saponin in a composition: - QS-7 family components and QS-18 family components; - QS-7 family components and QS-17 family components; - QS-17 family components and QS-18 family components; - QS-7 family components, QS-17 family components and QS-18 family components. As with other QS families, the QS-7 family components contain a plurality of related structures including xylose and rhamnose chemotypes, xylose and apiose isomers, A and B isomers:
. Certain QS-7 family components may lack glucose, or the rhamnose attached to the beta-D-fuc. Enzymatic modifications The present invention provides the enzymatic modification of saponins obtained from an in vitro plant cell culture. Enzymatic modifications envisaged in the present invention include the conversion of a starting saponin into a product saponin by the removal of one or more sugar residues from the starting saponin. Suitably, the enzymatic modifications envisaged in the present invention are the conversion of a starting saponin into a product saponin by the removal of one or more sugar residues from the starting saponin. In certain embodiments, the enzymatic modification involves the removal of a single sugar residue i.e. removal of a terminal sugar residue (‘exo’ action) from a starting saponin. In other embodiments, enzymatic conversion involves the removal of a plurality of sugar residues from a starting saponin i.e. cleavage at a saccharide linkage other than in a terminal location (‘endo’ action), resulting in removal of a plurality of sugar residues (such as 2, 3 or 4 sugar residues) attached through said saccharide linkage. Particular sugar residues which may be removed comprise (such as consist of): - glucose, in particular a terminal glucose, especially a beta-glucose, such as a beta- glucose from a quillaic acid glycoside, for example the beta-D-glucose residue highlighted below:
- rhamnose, in particular a terminal rhamnose, especially an alpha-rhamnose, such as an alpha-rhamnose from a quillaic acid glycoside, for example the alpha-L-rhamnose residues highlighted below: in particular
Particular single sugar enzymatic conversions of interest include: - QS-18 family components to QS-21 family components, such as: o QS-182150 component (i.e. QS-182150 A and/or QS-182150 B) to QS-21 1988 component, such as: • QS-182150 A component to QS-211988 A component, such as: • QS-182150 A V1 to QS-211988 A V1 • QS-182150 A V2 to QS-211988 A V2 • QS-182150 B component to QS-211988 B component, such as: • QS-182150 B V1 to QS-211988 B V1 • QS-182150 B V2 to QS-211998 B V2 • QS-182150 V1 component (i.e. QS-182150 A V1 and/or QS-182150 B V1) to QS-211988 V1 component, such as: • QS-182150 A V1 to QS-211988 A V1 • QS-182150 B V1 to QS-211988 B V1 • QS-182150 V2 component (i.e. QS-182150 A V2 and/or QS-182150 B V2) to QS-211988 V2 component, such as: • QS-182150 A V2 to QS-211988 A V2 • QS-182150 B V2 to QS-211988 B V2 o QS-182018 component (i.e. QS-182018 A and/or QS-182018 B) to QS-21 1856 component, such as: • QS-182018 A component to QS-211856 A component • QS-182018 B component to QS-211856 B component o QS-182164 component (i.e. QS-182164 A and/or QS-182164 B) to QS-21 2002 component, such as: • QS-182164 A component to QS-212002 A component, such as: • QS-182164 A V1 to QS-212002 A V1 • QS-182164 A V2 to QS-212002 A V2 • QS-182164 B component to QS-212002 B component, such as: • QS-182164 B V1 to QS-212002 B V1 • QS-182164 B V2 to QS-212002 B V2 • QS-182164 V1 component (i.e. QS-182164 A V1 and/or QS-182164 B V1) to QS-212002 V1 component, such as: • QS-182164 A V1 to QS-212002 A V1 • QS-182164 B V1 to QS-212002 B V1 • QS-182164 V2 component (i.e. QS-182164 A V2 and/or QS-182164 B V2) to QS-212002 V2 component, such as: • QS-182164 A V2 to QS-212002 A V2 • QS-182164 B V2 to QS-212002 B V2 - desglucosyl-QS-17 family components to QS-21 family components, such as: o desglucosyl-QS-172134 component (i.e. desglucosyl-QS-172134 A and/or desglucosyl-QS-172134 B) to QS-211988 component, such as: • desglucosyl-QS-172134 A component to QS-211988 A component, such as: • desglucosyl-QS-172134 A V1 to QS-211988 A V1 • desglucosyl-QS-172134 A V2 to QS-211988 A V2 • desglucosyl-QS-172134 B component to QS-211988 B component, such as: • desglucosyl-QS-172134 B V1 to QS-211988 B V1 • desglucosyl-QS-172134 B V2 to QS-211988 B V2 • desglucosyl-QS-172134 V1 component (i.e. desglucosyl-QS-172134 A V1 and/or desglucosyl-QS-172134 B V1) to QS-211988 V1 component, such as: • desglucosyl-QS-172134 A V1 to QS-211988 A V1 • desglucosyl-QS-172134 B V1 to QS-211988 B V1 • desglucosyl-QS-172134 V2 component (i.e. desglucosyl-QS-172134 A V2 and/or desglucosyl-QS-172134 B V2) to QS-211988 V2 component, such as: • desglucosyl-QS-172134 A V2 to QS-211988 A V2 • desglucosyl-QS-172134 B V2 to QS-211988 B V2 o desglucosyl-QS-172002 component (i.e. desglucosyl-QS-172002 A and/or desglucosyl-QS-172002 B) to QS-211856 component, such as: • desglucosyl-QS-172002 A component to QS-211856 A component • desglucosyl-QS-172002 B component to QS-211856 B component o desglucosyl-QS-172148 component (i.e. desglucosyl-QS-172148 A and/or desglucosyl-QS-172148 B) to QS-212002 component, such as: • desglucosyl-QS-172148 A component to QS-212002 A component, such as: • desglucosyl-QS-172148 A V1 to QS-212002 A V1 • desglucosyl-QS-172148 A V2 to QS-212002 A V2 • desglucosyl-QS-172148 B component to QS-212002 B component, such as: • desglucosyl-QS-172148 B V1 to QS-212002 B V1 • desglucosyl-QS-172148 B V2 to QS-212002 B V2 • desglucosyl-QS-172134 V1 component (i.e. desglucosyl-QS-172134 A V1 and/or desglucosyl-QS-172134 B V1) to QS-211988 V1 component, such as: • desglucosyl-QS-172148 A V1 to QS-212002 A V1 • desglucosyl-QS-172148 B V1 to QS-212002 B V1 • desglucosyl-QS-172134 V2 component (i.e. desglucosyl-QS-172134 A V2 and/or desglucosyl-QS-172134 B V2) to QS-211988 V1 component, such as: • desglucosyl-QS-172148 A V2 to QS-212002 A V2 • desglucosyl-QS-172148 B V2 to QS-212002 B V2 - QS-17 family components to QS-18 family components, such as: o QS-172296 component (i.e. QS-172296 A and/or QS-172296 B) to QS-18 2150 component, such as: • QS-172296 A component to QS-182150 A component, such as: • QS-172296 A V1 to QS-182150 A V1 • QS-172296 A V2 to QS-182150 A V2 • QS-172296 B component to QS-182150 B component, such as: • QS-172296 B V1 to QS-182150 B V1 • QS-172296 B V2 to QS-182150 B V2 • QS-172296 V1 component (i.e. QS-172296 A V1 and/or QS-172296 B V1) to QS-182150 V1 component, such as: • QS-172296 A V1 to QS-182150 A V1 • QS-172296 B V1 to QS-182150 B V1 • QS-172296 V2 component (i.e. QS-172296 A V2 and/or QS-172296 B V1) to QS-182150 V2 component, such as: • QS-172296 A V2 to QS-182150 A V2 • QS-172296 B V2 to QS-182150 B V2 o QS-172164 component (i.e. QS-172164 A and/or QS-172164 B) to QS-18 2018 component, such as: • QS-172164 A component to QS-182018 A component • QS-172164 B component to QS-182018 B component o QS-172310 component (i.e. QS-172310 A and/or QS-172310 B) to QS-18 2164 component, such as: • QS-172310 A component to QS-182164 A component, such as: • QS-172310 A V1 to QS-182164 A V1 • QS-172310 A V2 to QS-182164 A V2 • QS-172310 B component to QS-182164 B component, such as: • QS-172310 B V1 to QS-182164 B V1 • QS-172310 B V2 to QS-182164 B V2 • QS-172310 V1 component (i.e. QS-172310 A V1 and/or QS-172310 B V1) to QS-182164 V1 component, such as: • QS-172310 A V1 to QS-182164 A V1 • QS-172310 B V1 to QS-182164 B V1 • QS-172310 V2 component (i.e. QS-172310 A V2 and/or QS-172310 B V2) to QS-182164 V2 component, such as: • QS-172310 A V2 to QS-182164 A V2 • QS-172310 B V2 to QS-182164 B V2 - QS-17 family components to desglucosyl-QS-17 family components, such as: o QS-172296 component (i.e. QS-172296 A and/or QS-172296 B) to desglucosyl-QS-172134 component, such as: • QS-172296 A component to desglucosyl-QS-172134 A component, such as: • QS-172296 A V1 to desglucosyl-QS-172134 A V1 • QS-172296 A V2 to desglucosyl-QS-172134 A V2 • QS-172296 B component to desglucosyl-QS-172134 B component, such as: • QS-172296 B V1 to desglucosyl-QS-172134 B V1 • QS-172296 B V2 to desglucosyl-QS-172134 B V2 • QS-172296 V1 component (i.e. QS-172296 A V1 and/or QS-172296 B V1) to desglucosyl-QS-172134 V1 component, such as: • QS-172296 A V1 to desglucosyl-QS-172134 A V1 • QS-172296 B V1 to desglucosyl-QS-172134 B V1 • QS-172296 V2 component (i.e. QS-172296 A V2 and/or QS-172296 B V1) to desglucosyl-QS-172134 V2 component, such as: • QS-172296 A V2 to desglucosyl-QS-172134 A V2 • QS-172296 B V2 to desglucosyl-QS-172134 B V2 o QS-172164 component (i.e. QS-172164 A and/or QS-172164 B) to desglucosyl-QS-172002 component, such as: • QS-172164 A component to desglucosyl-QS-172002 A • QS-172164 B component to desglucosyl-QS-172002 B o QS-172310 component (i.e. QS-172310 A and/or QS-172310 B) to desglucosyl-QS-172148 component, such as: • QS-172310 A component to desglucosyl-QS-172148 A component, such as: • QS-172310 A V1 to desglucosyl-QS-172148 A V1 • QS-172310 A V2 to desglucosyl-QS-172148 A V2 • QS-172310 B component to QS-21, such as: • QS-172310 B V1 to desglucosyl-QS-172148 B V1 • QS-172310 B V2 to desglucosyl-QS-172148 B V2 • QS-172310 V1 component (i.e. QS-172310 A V1 and/or QS-172310 B V1) to desglucosyl-QS-172148 V1 component, such as: • QS-172310 A V1 to desglucosyl-QS-172148 A V1 • QS-172310 B V1 to desglucosyl-QS-172148 B V1 • QS-172310 V2 component (i.e. QS-172310 A V2 and/or QS-172310 B V2) to desglucosyl-QS-172148 V2 component, such as: • QS-172310 A V2 to desglucosyl-QS-172148 A V2 • QS-172310 B V2 to desglucosyl-QS-172148 B V2 Other single sugar enzymatic conversions of interest include: - desarabinofuranosyl-QS-18 family components to desarabinofuranosyl-QS-21 family components, such as: o desarabinofuranosyl-QS-182018 component (i.e. desarabinofuranosyl-QS- 182018 A and/or desarabinofuranosyl-QS-182018 B) to desarabinofuranosyl-QS-211856 component, such as: • desarabinofuranosyl-QS-182018 A component to desarabinofuranosyl-QS-211856 A component, such as: • desarabinofuranosyl-QS-182018 A V1 to desarabinofuranosyl-QS-211856 A V1 • desarabinofuranosyl-QS-182018 A V2 to desarabinofuranosyl-QS-211856 A V2 • desarabinofuranosyl-QS-182018 B component to desarabinofuranosyl-QS-211856 B component, such as: • desarabinofuranosyl-QS-182018 B V1 to desarabinofuranosyl-QS-211856 B V1 • desarabinofuranosyl-QS-182018 B V2 to desarabinofuranosyl-QS-211856 B V2 • desarabinofuranosyl-QS-182018 V1 component (i.e. desarabinofuranosyl-QS-182018 A V1 and/or desarabinofuranosyl- QS-182018 B V1) to desarabinofuranosyl-QS-211856 V1 component, such as: • desarabinofuranosyl-QS-182018 A V1 to desarabinofuranosyl-QS-211856 A V1 • desarabinofuranosyl-QS-182018 B V1 to desarabinofuranosyl-QS-211856 B V1 • desarabinofuranosyl-QS-182018 V2 component (i.e. desarabinofuranosyl-QS-182018 A V2 and/or desarabinofuranosyl- QS-182018 B V2) to desarabinofuranosyl-QS-211856 V2 component, such as: • desarabinofuranosyl-QS-182018 A V2 to desarabinofuranosyl-QS-211856 A V2 • desarabinofuranosyl-QS-182018 B V2 to desarabinofuranosyl-QS-211856 B V2 desarabinofuranosyl-QS-181886 component (i.e. desarabinofuranosyl-QS- 181886 A and/or desarabinofuranosyl-QS-181886 B) to desarabinofuranosyl-QS-211712 component, such as: • desarabinofuranosyl-QS-181886 A component to desarabinofuranosyl-QS-211712 A • desarabinofuranosyl-QS-181886 B component to desarabinofuranosyl-QS-211712 B o desarabinofuranosyl-QS-182032 component (i.e. desarabinofuranosyl-QS- 182032 A and/or desarabinofuranosyl-QS-182032 B) to desarabinofuranosyl-QS-211870 component, such as: • desarabinofuranosyl-QS-182032 A component to desarabinofuranosyl-QS-211870 A component, such as: • desarabinofuranosyl-QS-182032 A V1 to desarabinofuranosyl-QS-211870 A V1 • desarabinofuranosyl-QS-182032 A V2 to desarabinofuranosyl-QS-211870 A V2 • desarabinofuranosyl-QS-182032 B component to QS-21, such as: • desarabinofuranosyl-QS-182032 B V1 to desarabinofuranosyl-QS-211870 B V1 • QS-17 desarabinofuranosyl-QS-182032 B V2 to desarabinofuranosyl-QS-211870 B V2 • desarabinofuranosyl-QS-182032 V1 component (i.e. desarabinofuranosyl-QS-182032 A V1 and/or desarabinofuranosyl- QS-182032 B V1) to desarabinofuranosyl-QS-211870 V1 component, such as: • desarabinofuranosyl-QS-182032 A V1 to desarabinofuranosyl-QS-211870 A V1 • desarabinofuranosyl-QS-182032 B V1 to desarabinofuranosyl-QS-211870 B V1 • desarabinofuranosyl-QS-182032 V2 component (i.e. desarabinofuranosyl-QS-182032 A V2 and/or desarabinofuranosyl- QS-182032 B V2) to desarabinofuranosyl-QS-211870 V2 component, such as: • desarabinofuranosyl-QS-182032 A V2 to desarabinofuranosyl-QS-211870 A V2 • desarabinofuranosyl-QS-182032 B V2 to desarabinofuranosyl-QS-211870 B V2 - acetylated desglucosyl-QS-17 components to acetylated QS-21 family components, such as: o acetylated desglucosyl-QS-172176 A to acetylated QS-212030 A, such as: • acetylated desglucosyl-QS-172176 A V1 to acetylated QS-212030 A V1 • acetylated desglucosyl-QS-172176 A V2 to acetylated QS-212030 A V2 o acetylated desglucosyl-QS-172044 A to acetylated QS-211898 A component o acetylated desglucosyl-QS-172190 A to acetylated QS-212044 A, such as: • acetylated desglucosyl-QS-172190 A V1 to acetylated QS-212044 A V1 • acetylated desglucosyl-QS-172190 A V2 to acetylated QS-212044 A V2. Enzymatic conversions may be applied to a single starting saponin or a plurality of starting saponins in parallel. It will be appreciated that a process may comprise or consist of the conversions specified above, depending on the composition of the starting material and the enzymes used. Furthermore, while a process may be limited to the use of a single enzyme intended to remove a particular sugar residue or group of sugar residues from (i) a single starting saponin, (ii) a family of starting saponins, or (iii) from a plurality of families of starting saponins; processes may also use a plurality of enzymes intended to remove a plurality of sugar residues from (i) a single starting saponin, (ii) a family of starting saponins, or (iii) from a plurality of families of starting saponins. Processes involving multiple enzymes may be undertaken in series (i.e. a single enzyme is applied to saponin material at any time) or in parallel (i.e. more than one enzyme is applied to saponin material at any time, such as two or three enzymes, in particular two enzymes), or combinations thereof. Processes involving the removal of multiple sugar residues may involve the removal of single (but different) sugar residues from multiple starting saponins and/or the removal of multiple sugar residues from particular starting saponins (such as 2, 3 or 4 residues, in particular 2 or 3, especially 2 residues). Removal of multiple sugar residues from particular starting saponins may involve any combination of removal of single residues and/or removal of a plurality of residues in a single cleavage. Exemplary processes may comprise (such as consist of) the removal of glucose and rhamnose, in particular an alpha-rhamnose residue and a beta-glucose residue, such as the alpha-L-rhamnose residue and the beta-D-glucose residue from quillaic acid glycosides: Particular multi-sugar enzymatic conversions of interest include: - QS-17 family components to QS-21 family components, such as: o QS-172296 component (i.e. QS-172296 A and/or QS-172296 B) to QS-21 1988 component, such as: • QS-172296 A component to QS-211988 A component, such as: • QS-172296 A V1 to QS-211988 A V1 • QS-172296 A V2 to QS-211988 A V2 • QS-172296 B component to QS-211988 B component, such as: • QS-172296 B V1 to QS-211988 B V1 • QS-172296 B V2 to QS-211988 B V2 • QS-172296 V1 component (i.e. QS-172296 A V1 and/or QS-172296 B V1) to QS-211988 V1 component, such as: • QS-172296 A V1 to QS-211988 A V1 • QS-172296 B V1 to QS-211988 B V1 • QS-172296 V2 component (i.e. QS-172296 A V2 and/or QS-172296 B V2) to QS-211988 V2 component, such as: • QS-172296 A V2 to QS-211988 A V2 • QS-172296 B V2 to QS-211988 B V2 o QS-172164 component (i.e. QS-172164 A and/or QS-172164 B) to QS-21 1856 component, such as: • QS-172164 A component to QS-211856 A component • QS-172164 B component to QS-211856 B component o QS-172310 component (i.e. QS-172310 A and/or QS-172310 B) to QS-21 2002 component, such as: • QS-172310 A component to QS-212002 A component, such as: • QS-172310 A V1 to QS-212002 A V1 • QS-172310 A V2 to QS-212002 A V2 • QS-172310 B component to QS-212002 B component, such as: • QS-172310 B V1 to QS-212002 B V1 • QS-172310 B V2 to QS-212002 B V2 • QS-172310 V1 component (i.e. QS-172310 A V1 and/or QS-172310 B V1) to QS-212002 V1, such as: • QS-172310 A V1 to QS-212002 A V1 • QS-172310 B V1 to QS-212002 B V1 • QS-172310 V2 component (i.e. QS-172310 A V2 and/or QS-172310 B V2) to QS-212002 V2, such as: • QS-172310 A V2 to QS-212002 A V2 ^ QS-172310 B V2 to QS-212002 B V2. Plant cell culture extracts may contain complex mixtures of saponin components and consequently may experience a plurality of conversions when multiple enzymes are present. For example, a starting mixture containing QS-17, QS-18 and desglucosyl-QS-17 components which is treated with an appropriate beta-glucosidase and alpha-rhamnosidase in parallel may undergo conversions including: - QS-18 family components to QS-21 family components, especially QS-182150 component to QS-211988 component; - desglucosyl-QS-17 family components to QS-21 family components, especially desglucosyl-QS-172134 component to QS-211988 component; - QS-17 family components to desglucosyl-QS-17 family components to QS-21 components, especially QS-172296 component to desglucosyl-QS-172134 component to QS-211988 component; and - QS-17 family components to QS-18 family components to QS-21 family components, especially QS-172296 component to QS-182150 component to QS-211988 component. Enzyme selection Extensive protein or DNA databases of natural and artificial glycosidases are available. Candidate enzymes may be selected and screened to assess suitability for achieving a particular conversion under particular reaction conditions. Suitability of an enzyme will depend on a number of factors including: - target sugar (e.g. glucose, rhamnose) - target sugar anomer (alpha or beta); - target sugar enantiomer (D or L); - target sugar location (endo or exo); and - target sugar environment (e.g. chemical/physical, impacting accessibility and reactivity). Additional factors which facilitate effective conversions include: - rate of conversion; - environmental sensitivity - including pH, temperature, substrate, product and contaminant concentration tolerance; and - specificity for target sugar, including in respect of other sugar residues, other anomers, other sugar residue locations, and between different residues of the same sugar anomer and location within a substrate (if multiple such residues are present). Those skilled in the art will appreciate that the level and type of specificity required of an enzyme will depend on the objective to be achieved and the general circumstances. Conversion of QS-18 family components to QS-21 family components requires an enzyme demonstrating beta exo glucosidase activity. Conversion of QS-17 family components to desglucosyl-QS-17 family components requires an enzyme demonstrating beta exo glucosidase activity. Conversion of desglucosyl-QS-17 family components to QS-21 family components requires an enzyme demonstrating alpha exo rhamnosidase activity. Conversion of QS-17 family components to QS-18 family components requires an enzyme demonstrating alpha exo rhamnosidase activity. It may be noted that many Quillaja saponaria starting saponins of interest contain only one glucose residue. Many Quillaja saponaria starting saponins of interest contain a plurality of rhamnose residues, therefore selectivity for specific rhamnose residues is of greater importance practically. For example, conversion of desglucosyl-QS-17 family components to QS-21 components or QS-17 family components to QS-18 family components requires specificity for exo-rhamnosidase action over endo-rhamnosidase action. Furthermore, rhamnosidase specificity for the alpha-O-rhamnosylation at the C2 position of the arabinofuranose moiety over other terminal rhamnose residues (e.g. in the rhamnose chemotype components) may also be desirable. In certain embodiments it may be desirable to remove the terminal rhamnose from rhamnose chemotype components (alone or in conjunction with any alpha-O-rhamnosylation at the C2 position of the arabinofuranose moiety), to better facilitate their chromatographic separation from xylose chemotype components. In one embodiment, enzymatic conversion is carried out by a single enzyme. The single enzyme may be a glucosidase, in particular a beta exo glucosidase. A single enzyme glucosidase may be an engineered glucosidase polypeptide described in the present invention. Alternatively, the single enzyme is a rhamnosidase, in particular an alpha exo rhamnosidase. A single enzyme rhamnosidase may be an engineered rhamnosidase polypeptide described in the present invention. Preferred enzymes are those which efficiently enzymatically convert a starting saponin(s) to the desired product saponin(s) while demonstrating limited or no undesired conversion(s) of other saponin components present. In one embodiment, enzymatic conversion to enzymatic is carried out by more than one enzyme, such as by two or three enzymes, especially by two enzymes. Enzymatic modification (or conversion) by more than one enzyme may involve sequential/series enzymatic modification. Alternatively, enzymatic modification (or conversion) by more than one enzyme may involve concurrent/parallel enzymatic modification. Enzymatic modification (or conversion) by at least three enzymes may involve a combination of sequential/series (modification by one enzyme) and concurrent/parallel (modification by at least two other enzymes) enzymatic modification, in any order. Where a plurality of enzymes are provided, these may be as distinct proteins or may be in the form of one or more fusion proteins. An enzyme of interest is a glucosidase, such as a beta exo glucosidase. A glucosidase may be an engineered glucosidase polypeptide of the present invention. Another enzyme of interest is a rhamnosidase, such as an alpha exo rhamnosidase. A rhamnosidase may an engineered rhamnosidase polypeptide of the present invention. Enzyme combinations of interest include those comprising, such as consisting of, a glucosidase and a rhamnosidase, in particular a beta exo glucosidase and an alpha exo rhamnosidase. Enzymatic modification involving a glucosidase and a rhamnosidase, in particular a beta exo glucosidase and an alpha exo rhamnosidase, may be undertaken: sequentially with glucosidase (e.g. beta exo glucosidase) followed by rhamnosidase (e.g. alpha exo rhamnosidase), sequentially with rhamnosidase (e.g. alpha exo rhamnosidase) followed by glucosidase (e.g. beta exo glucosidase) or, conveniently, concurrently with both glucosidase (e.g. beta exo glucosidase) and rhamnosidase (e.g. alpha exo rhamnosidase). Particular enzyme combinations of interest are those comprising, such as consisting of, an engineered glucosidase of the present invention and an engineered rhamnosidase polypeptide of the present invention. Enzymes utilised will typically be of external origin to saponin material i.e. not naturally found within the source of saponins obtained by extraction. Enzymes may be native, i.e. naturally occurring glycosidases, or alternatively may be non-naturally occurring glycosidases. In one embodiment, a glucosidase enzyme is a naturally occurring glucosidase (e.g. exo glucosidase, such as beta exo glucosidase). In a second embodiment, a glucosidase enzyme is a non-naturally occurring glucosidase (e.g. exo glucosidase, such as beta exo glucosidase). In one embodiment, a rhamnosidase enzyme is a naturally occurring rhamnosidase (e.g. exo rhamnosidase, such as alpha exo rhamnosidase). In a second embodiment a rhamnosidase enzyme is a non-naturally occurring rhamnosidase (e.g. exo rhamnosidase, such as alpha exo rhamnosidase). Enzymes may be modified relative to a reference enzyme (‘engineered’). Point mutations, either singly or in combination, introduced by engineering may provide benefits such as increased activity, increased specificity, increased stability, increased expression or other the like. Assays to confirm the properties of the enzymes are well known to those skilled in the field. For example, activity may be quantified by methods such as those shown in the examples (see Examples 4 to 7) or by analogous methods. Different enzymes may show different sensitivity to environmental conditions, such as pH, temperature, substrate concentration, product concentration, solvent composition, presence of contaminants and the like. Such parameters may be taken into consideration during screening of candidate enzymes for the desired activity. Candidate enzymes having beta glucosidase activity include those in EC3.2.1.21. Beta exo glucosidases of interest include those described in Table 7, especially SEQ ID Nos.262, 208, 63, 229, 250, 5, 101, 207, 169, 247, 302, 324, 319, 9, 240, 325 and 338, and functional variants thereof. Particular beta exo glucosidases of interest include SEQ ID Nos. 262, 208, 63, 229, 250, 5, 101, 207, 169, 247, 302, 324 and 319, and functional variants thereof, such as SEQ ID Nos.262, 208, 63, 229, 250, 5, 101 and 207, and functional variants thereof. Another group of beta exo glucosidases of interest include those described in Table 9, especially SEQ ID Nos.850, 879, 868, 826, 804, 888, 881, 891, 816, 827, 857, 853, 842, 814, 886, 885, 838, 829, 808, 828, 870, 873, 844, 882, 874, 825, 824, 823, 810, 894, 849, 803, 890, 841, 832, 830, 845, 871, 837, 883 and 809, and functional variants thereof. Particular beta exo glucosidases of interest include SEQ ID Nos.850, 879, 868, 826, 804, 888, 881, 891, 816, 827, 857, 853, 842, 814, 886, 885, 838, 829, 808, 828, 870, 873, 844, 882, 874, 825, 824, 823, 810, 894, 849, 803, 890 and 841, and functional variants thereof, such as SEQ ID Nos.850, 879, 868, 826, 804, 888, 881, 891, 816, 827, 857, 853, 842, 814, 886, 885, 838, 829, 808, 828, 870, 873, 844, 882, 874, 825, 824, 823, 810 and 894, and functional variants thereof. SEQ ID No.262, and functional variants thereof, are particularly desirable beta exo glucosidases. In one embodiment the beta exo glucosidase comprises, such as consists of: (i) SEQ ID.262; or (ii) a functional variant thereof having at least 80% identity to SEQ ID.262, especially at least 90%, in particular at least 95%, such as at least 96%, at least 97%, at least 98%, for example at least 99% identity; or (iii) a functional fragment of at least 100, especially at least 200, particularly at least 300, such as at least 400, for example at least 500 contiguous amino acids of SEQ ID.262. Candidate enzymes having alpha rhamnosidase activity include those in EC3.2.1.40. Alpha exo rhamnosidases of interest include SEQ ID Nos.992, 1003, 1052, 1073, 1017, 1055, 1075, 1001, 1007, 1061, 1079, 1027, 1039, 1041, 989, 1053, 1018, 1066, 1082, 1076, 993, 1077, 1046, 1015, 1063, 1054, 1074, 1067 and 1033, and functional variants thereof. Particular alpha exo rhamnosidases of interest include SEQ ID Nos.992, 1003, 1052, 1073, 1017, 1055, 1075, 1001, 1007, 1061, 1079, 1027, 1039, 1041, 989, 1053, 1018, 1066, 1082, 1076, 993 and 1077, and functional variants thereof, such as SEQ ID Nos.992, 1003, 1052, 1073, 1017, 1055, 1075, 1001, 1007, 1061, 1079, 1027, 1039, 1041 and 989, and functional variants thereof. SEQ ID No.1017, and functional variants thereof, are particularly desirable exo rhamnosidases. In one embodiment, the alpha exo rhamnosidase comprises, such as consists of: (i) SEQ ID.1017; or (ii) a functional variant thereof having at least 80% identity to SEQ ID. 1017, especially at least 90%, in particular at least 95%, such as at least 96%, at least 97%, at least 98%, for example at least 99% identity; or (iii) a functional fragment of at least 100, especially at least 200, particularly at least 300, such as at least 400, for example at least 500 contiguous amino acids of SEQ ID.1017. Functional variants of interest in the present application include those comprising, such as consisting of: (i) a sequence having at least 80% identity to the reference sequence, especially at least 90%, in particular at least 95%, such as at least 96%, at least 97%, at least 98%, for example at least 99% identity; or (ii) a fragment of at least 100, especially at least 200, particularly at least 300, such as at least 400, for example at least 500 contiguous amino acids of the reference sequence. Certain desirable functional variants of interest include those comprising, such as consisting of, a sequence having 1 to 20 additions, deletions and/or substitutions relative to the reference sequence, especially 1 to 15 additions, deletions and/or substitutions, particularly 1 to 10 additions, deletions and/or substitutions, such as 1 to 5 additions, deletions and/or substitutions. The degree of sequence identity may be determined using by the homology alignment algorithm of Needleman and Wunsch, the ClustalW program or the BLASTP algorithm, using default settings. An algorithm using global alignment (Needleman and Wunsch) is preferred. “Percentage of sequence identity,” “percent identity,” and “percent identical” are used herein to refer to comparisons between polynucleotide sequences or polypeptide sequences, and are determined by comparing two optimally aligned sequences over a comparison window, wherein the portion of the polynucleotide or polypeptide sequence in the comparison window may comprise additions or deletions (i.e., gaps) as compared to the reference sequence for optimal alignment of the two sequences. The percentage is calculated by determining the number of positions at which either the identical nucleic acid base or amino acid residue occurs in both sequences or a nucleic acid base or amino acid residue is aligned with a gap to yield the number of matched positions, dividing the number of matched positions by the total number of positions in the window of comparison and multiplying the result by 100 to yield the percentage of sequence identity. Determination of optimal alignment and percent sequence identity is performed using the BLAST and BLAST 2.0 algorithms (see, e.g., Altschul, 1990; Altschul, 1997). Software for performing BLAST analyses is publicly available through the National Center for Biotechnology Information website. Briefly, the BLAST analyses involve first identifying high scoring sequence pairs (HSPs) by identifying short words of length W in the query sequence, which either match or satisfy some positive-valued threshold score T when aligned with a word of the same length in a database sequence. T is referred to as, the neighborhood word score threshold (Altschul, supra). These initial neighborhood word hits act as seeds for initiating searches to find longer HSPs containing them. The word hits are then extended in both directions along each sequence for as far as the cumulative alignment score can be increased. Cumulative scores are calculated using, for nucleotide sequences, the parameters M (reward score for a pair of matching residues; always >0) and N (penalty score for mismatching residues; always<0). For amino acid sequences, a scoring matrix is used to calculate the cumulative score. Extension of the word hits in each direction are halted when: the cumulative alignment score falls off by the quantity X from its maximum achieved value; the cumulative score goes to zero or below, due to the accumulation of one or more negative- scoring residue alignments; or the end of either sequence is reached. The BLAST algorithm parameters W, T, and X determine the sensitivity and speed of the alignment. The BLASTN program (for nucleotide sequences) uses as defaults a word length (W) of 11, an expectation (E) of 10, M=5, N=-4, and a comparison of both strands. For amino acid sequences, the BLASTP program uses as defaults a wordlength (W) of 3, an expectation (E) of 10, and the BLOSUM62 scoring matrix (see Henikoff, 1989). Numerous other algorithms are available that function similarly to BLAST in providing percent identity for two sequences. Optimal alignment of sequences for comparison can be conducted, e.g., by the local homology algorithm of Smith, 1981, by the homology alignment algorithm of Needleman, 1970, by the search for similarity method of Pearson, 1988, by computerized implementations of these algorithms (GAP, BESTFIT, FASTA, and TFASTA in the GCG Wisconsin Software Package), or by visual inspection (see generally, Current Protocols in Molecular Biology, 1995)). Additionally, determination of sequence alignment and percent sequence identity can employ the BESTFIT or GAP programs in the GCG Wisconsin Software package (Accelrys, Madison WI), using default parameters provided. The ClustalW program is also suitable for determining identity. Modestobacter marinus glucosidase (Uniparc reference UPI000260A2FA, Uniprot reference I4EYD5 – SEQ ID No.262 herein) is a naturally occurring glucosidase demonstrating beta exo glucosidase activity and, for example, is capable of the conversion of QS-18 family components to QS-21 family components. Despite its potent activity, the present inventors have found that the properties of wild type Modestobacter marinus glucosidase may be altered by the introduction of one or more mutations. The present invention describes an engineered glucosidase polypeptide for use in the methods of the invention comprising, such as consisting of, an amino acid sequence that is at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to the amino acid sequence of SEQ ID No.262, or a functional fragment thereof, wherein the engineered glucosidase polypeptide includes at least one residue substitution from: F44Y; V60L; G117A; F170N; V263G or V263L; N351H or N351Q; A355H, A355I, A355L, A355M, A355R, A355T or A355W; A356P; R357A, R357C, R357K, R357M or R357Q; G362C; T365A, T365N or T365S; L367C; V394R; V395Y; Q396E, Q396G, Q396N, Q396P, Q396R, Q396S or Q396Y; F430W; R435F; V438T; V440F; F442M or F442Q; G444T; A473F or A473R; L474C, L474I or L474V; I475F; L492C, L492G, L492H, L492I, L492N, L492Q, L492V, L492W or L492Y; Q493F or Q493H; P494H or P494I; S495I, S495K or S495Q; G496P or G496W; D498A, D498E, D498F, D498I, D498K, D498L, D498N, D498P, D498R, D498S, D498T or D498V; A502R; M504G or M504R; L507A or L507R; T508M; L529M; F535P; A536D or A536E; A537R; F541A, F541I, F541L, F541M or F541V; L542I; Q543G or Q543L; E547L; and Y585W. The glucosidases will contain one to forty-two of the substitutions, such as two, three, four, five, six, seven, eight, nine, ten, eleven, twelve, thirteen, fourteen, fifteen, sixteen, seventeen, eighteen, nineteen, twenty, twenty-one, twenty-two, twenty-three, twenty-four, twenty-five, twenty-six to thirty or thirty-one to forty-three substitutions. The present invention also describes an engineered glucosidase polypeptide for use in the methods of the invention comprising, such as consisting of, an amino acid sequence that is at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to the amino acid sequence of SEQ ID No.262, or a functional fragment thereof, wherein the engineered glucosidase polypeptide includes at least one residue substitution from: F44Y; V263L; N351H; A355H, A355M or A355W; R357M; T365N; L367C; Q396R; V438T; F442Q; L474C; I475F; L492V, L492N or L492H, M504R; L507R; and F541I. The glucosidases will contain one, two, three, four, five, six, seven, eight, nine, ten, eleven, twelve, thirteen, fourteen, fifteen or all sixteen substitutions. The engineered glucosidase polypeptide may comprise, such as consist of, an amino acid sequence that is at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to the amino acid sequence of SEQ ID No.262, or a functional fragment thereof, wherein the engineered glucosidase polypeptide includes at least one residue substitution from: F44Y, V263L, A355W, R357M, T365N, L367C, Q396R, F442Q, L474C, I475F and F541I. Suitably the engineered glucosidase polypeptide comprises, such as consists of, an amino acid sequence that is at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to the amino acid sequence of SEQ ID No.262, or a functional fragment thereof, wherein the engineered glucosidase polypeptide includes the residue substitutions: F44Y, V263L, A355W, R357M, T365N, L367C, Q396R, F442Q, L474C, I475F and F541I. The present invention describes a polypeptide for use in the methods of the invention comprising an amino acid sequence of sequence of SEQ ID No.262 with one to twenty-five mutations selected from the list consisting of: (i) F44Y (ii) V263L (iii) N351H (iv) A355H, A355I, A355L, A355M, A355R, A355T or A355W (v) A356P (vi) R357M (vii) T365N (viii) L367C (ix) F442Q (x) G443D (xi) A473F (xii) L474C (xiii) I475F (xiv) L492H, L492N, L492V (xv) P494I (xvi) G496P (xvii) D498P (xviii) M504R (xix) L507R (xx) F535P (xxi) A537R (xxii) F541I (xxiii) L542I (xxiv) E547L and (xxv) E588K. Variant glucosidases will contain one, two, three, four, five, six, seven, eight, nine, ten, eleven, twelve, thirteen, fourteen, fifteen, sixteen, seventeen, eighteen, nineteen, twenty, twenty-one, twenty-two, twenty-three, twenty-four or all twenty-five mutations. In some embodiments, an engineered glucosidase is not a polypeptide comprising an amino acid sequence of sequence of SEQ ID No.262 with one to twenty-five mutations selected from the list consisting of: (i) F44Y (ii) V263L (iii) N351H (iv) A355H, A355I, A355L, A355M, A355R, A355T or A355W (v) A356P (vi) R357M (vii) T365N (viii) L367C (ix) F442Q (x) G443D (xi) A473F (xii) L474C (xiii) I475F (xiv) L492H, L492N, L492V (xv) P494I (xvi) G496P (xvii) D498P (xviii) M504R (xix) L507R (xx) F535P (xxi) A537R (xxii) F541I (xxiii) L542I (xxiv) E547L and (xxv) E588K. The above-mentioned engineered glucosidase polypeptides may also be referred to herein as examples of ‘variant glucosidases’. A variant glucosidase may contain F44Y. A variant glucosidase may contain V60L. A variant glucosidase may contain G117A. A variant glucosidase may contain F170N. A variant glucosidase may contain V263G or V263L, in particular V263L. A variant glucosidase may contain N351H or N351Q, in particular N351H. A variant glucosidase may contain A355H, A355I, A355L, A355M, A355R, A355T or A355W. In some embodiments, a variant glucosidase contains A355H. In some embodiments a variant glucosidase contains A355I. In some embodiments a variant glucosidase contains A355L. In some embodiments, a variant glucosidase contains A355M. In some embodiments a variant glucosidase contains A355R. In some embodiments a variant glucosidase contains A355T. In some embodiments, a variant glucosidase contains A355W. A variant glucosidase may contain A356P. A variant glucosidase may contain R357A, R357C, R357K, R357M or R357Q, in particular R357M. A variant glucosidase may contain G362C. A variant glucosidase may contain T365A, T365N or T365S, in particular T365N. A variant glucosidase may contain L367C. A variant glucosidase may contain V394R. A variant glucosidase may contain V395Y. A variant glucosidase may contain Q396E, Q396G, Q396N, Q396P, Q396R, Q396S or Q396Y, in particular Q396R. A variant glucosidase may contain F430W. A variant glucosidase may contain R435F. A variant glucosidase may contain V438T. A variant glucosidase may contain V440F. A variant glucosidase may contain F442M or F442Q, in particular F442Q. A variant glucosidase may contain G443D. A variant glucosidase may contain G444T. A variant glucosidase may contain A473F or A473R, in particular A473F. A variant glucosidase may contain L474C, L474I or L474V, in particular L474C. A variant glucosidase may contain I475F. A variant glucosidase may contain L492C, L492G, L492H, L492I, L492N, L492Q, L492V, L492W or L492Y, in particular L492H, L492N, L492V. In some embodiments a variant glucosidase contains L492H. In some embodiments, a variant glucosidase contains L492N. In some embodiments a variant glucosidase contains L492V. A variant glucosidase may contain Q493F or Q493H. A variant glucosidase may contain P494H or P494I, in particular P494I. A variant glucosidase may contain S495I, S495K or S495Q. A variant glucosidase may contain G496P or G496W, in particular G496P. A variant glucosidase may contain D498A, D498E, D498F, D498I, D498K, D498L, D498N, D498P, D498R, D498S, D498T or D498V, in particular D498P. A variant glucosidase may contain A502R. A variant glucosidase may contain M504G or M504R, in particular M504R. A variant glucosidase may contain L507A or L507R, in particular L507R. A variant glucosidase may contain T508M. A variant glucosidase may contain L529M. A variant glucosidase may contain F535P. A variant glucosidase may contain A536D or A536E. A variant glucosidase may contain A537R. A variant glucosidase may contain F541A, F541I, F541L, F541M or F541V, in particular F541I. A variant glucosidase may contain L542I. A variant glucosidase may contain Q543G or Q543L. A variant glucosidase may contain E547L. A variant glucosidase may contain Y585W. A variant glucosidase may contain E588K. Variant glucosidases may comprise R357M, T365N, A473F, L474C and I475F. Variant glucosidases may comprise F44Y, R357M, T365N, F442Q, A473F, L474C and I475F. Variant glucosidases may comprise F44Y, V263L, R357M, T365N, F442Q, A473F, L474C, I475F and F541I. Variant glucosidases may comprise F44Y, V263L, A355W, R357M, T365N, L367C, Q396R, F442Q, L474C, I475F and F541I. Variant glucosidases may comprise F44Y, V263L, R357M, T365N, F442Q, L474C, I475F, F541I and zero to seventeen mutations selected from the list consisting of: (iii) N351H (iv) A355H, A355I, A355L, A355M, A355R, A355T or A355W (v) A356P (viii) L367C (x) G443D (xi) A473F (xiv) L492H, L492N, L492V (xv) P494I (xvi) G496P (xvii) D498P (xviii) M504R (xix) L507R (xx) F535P (xxi) A537R (xxiii) L542I (xxiv) E547L and (xxv) E588K. A variant glucosidase may comprise a “tag,” a sequence of amino acids that allows for the isolation and/or identification of the polypeptide. For example, adding an affinity tag can be useful in purification. Exemplary affinity tags that can be used include histidine (HIS) tags (e.g. hexa histidine-tag, or 6XHis-Tag), FLAG-TAG, and HA tags. Tags may be located N-terminally or C-terminally and may be directly connected or attached via a linking sequence. SEQ ID No.1177 provides a sequence for an exemplary 6XHis-Tag with linker sequence which may be N-terminally attached. SEQ ID No.1178 provides a sequence for an exemplary 6XHis-Tag with linker sequence which may be C-terminally attached. In certain embodiments, the tags used herein are removable, e.g., removal by chemical agents or by enzymatic means, once they are no longer needed, e.g., after the polypeptide has been purified. A variant glucosidase may comprise 1000 residues or fewer, especially 950 residues or fewer, in particular 900 residues or fewer, such as 850 residues or fewer. A variant glucosidase may consist of an amino acid sequence of SEQ ID No.262 with one to twenty-five mutations selected from the list consisting of: (i) F44Y (ii) V263L (iii) N351H (iv) A355H, A355I, A355L, A355M, A355R, A355T or A355W (v) A356P (vi) R357M (vii) T365N (viii) L367C (ix) F442Q (x) G443D (xi) A473F (xii) L474C (xiii) I475F (xiv) L492H, L492N, L492V (xv) P494I (xvi) G496P (xvii) D498P (xviii) M504R (xix) L507R (xx) F535P (xxi) A537R (xxii) F541I (xxiii) L542I (xxiv) E547L and (xxv) E588K. Variant glucosidases desirably demonstrate a FIOP (Fold Improvement Over Parent) relative to SEQ ID No.262 of at least 1.05, especially at least 2, in particular at least 10, such as at least 50. FIOP may be determined by the methods described in Example 4. Kribbella flavida rhamnosidase (Uniparc reference UPI00019BDB13, Uniprot reference D2PMT5 – SEQ ID No.1017 herein) is a naturally occurring rhamnosidase demonstrating alpha exo rhamnosidase activity and, for example, is capable of the conversion of desglucosyl-QS-17 family components to QS-21 family components. Despite its potent activity, the present inventors have found that the properties of wild type Kribbella flavida rhamnosidase may be altered by the introduction of one or more mutations. The present application describes an engineered rhamnosidase polypeptide for use in the method of the invention comprising, such as consisting of, an amino acid sequence that is at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to the amino acid sequence of SEQ ID No.1017, or a functional fragment thereof, wherein the engineered rhamnosidase polypeptide includes at least one residue substitution from: (i) A56C (ii) A143P (iii) Q181H, Q181R or Q181S (iv) L214M (v) G215S (vi) F216M (vii) G218D or G218N (viii) K219G (ix) A238M (x) T252Y (xi) T311W (xii) V326C (xiii) G357C (xiv) S369C, S369I, S369K or S369M (xv) I487M, I487Q or I487V (xvi) K492N (xvii) V499T (xviii) G508S (xix) R543C (xx) L557Y (xxi) G634A (xxii) S635N (xxiii) A690C and (xxiv) Q921H. Consequently, the present invention provides a polypeptide comprising an amino acid sequence of sequence of SEQ ID No.1017 with one to twenty-four mutations selected from the list consisting of: (i) A56C (ii) A143P (iii) Q181H, Q181R or Q181S (iv) L214M (v) G215S (vi) F216M (vii) G218D or G218N (viii) K219G (ix) A238M (x) T252Y (xi) T311W (xii) V326C (xiii) G357C (xiv) S369C, S369I, S369K or S369M (xv) I487M, I487Q or I487V (xvi) K492N (xvii) V499T (xviii) G508S (xix) R543C (xx) L557Y (xxi) G634A (xxii) S635N (xxiii) A690C and (xxiv) Q921H. Such polypeptides may be referred to herein as ‘variant rhamnosidases’. Variant rhamnosidases will contain one, two, three, four, five, six, seven, eight, nine, ten, eleven, twelve, thirteen, fourteen, fifteen, sixteen, seventeen, eighteen, nineteen, twenty, twenty-one, twenty-two, twenty-three or all twenty-four mutations. A variant rhamnosidase may contain A56C. A variant rhamnosidase may contain A143P. A variant rhamnosidase may contain Q181H, Q181R or Q181S. In some embodiments a variant rhamnosidase contains Q181H. In some embodiments a variant rhamnosidase contains Q181R. In some embodiments a variant rhamnosidase contains Q181S. A variant rhamnosidase may contain L214M. A variant rhamnosidase may contain G215S. A variant rhamnosidase may contain F216M. A variant rhamnosidase may contain G218D or G218N. In some embodiments a variant rhamnosidase contains G218D. In some embodiments a variant rhamnosidase contains G218N. A variant rhamnosidase may contain K219G. A variant rhamnosidase may contain A238M. A variant rhamnosidase may contain T252Y. A variant rhamnosidase may contain T311W. A variant rhamnosidase may contain V326C. A variant rhamnosidase may contain G357C. A variant rhamnosidase may contain S369C, S369I, S369K or S369M. In some embodiments a variant rhamnosidase contains S369C. In some embodiments, a variant rhamnosidase contains S369I. In some embodiments, a variant rhamnosidase contains S369K. In some embodiments a variant rhamnosidase contains S369M. A variant rhamnosidase may contain I487M, I487Q or I487V. In some embodiments a variant rhamnosidase contains I487M. In some embodiments, a variant rhamnosidase contains I487Q. In some embodiments a variant rhamnosidase contains I487V. A variant rhamnosidase may contain K492N. A variant rhamnosidase may contain V499T. A variant rhamnosidase may contain G508S. A variant rhamnosidase may contain R543C. A variant rhamnosidase may contain L557Y. A variant rhamnosidase may contain G634A. A variant rhamnosidase may contain S635N. A variant rhamnosidase may contain A690C. A variant rhamnosidase may contain Q921H. Variant rhamnosidases may comprise A143P, L214M, K219G and Q921H. Variant rhamnosidases may comprise A143P, L214M, K219G, G357C and Q921H. Variant rhamnosidases may comprise A143P, L214M, G215S, G218N, K219G, G357C, G508S, G634A and Q921H. Variant rhamnosidases may comprise A143P, L214M, G215S, G218D, K219G, G357C, G508S, G634A, A690C and Q921H. Variant rhamnosidases may comprise A143P, L214M, G215S, K219G, G357C, G508S, G634A and Q921H and one to sixteen mutations selected from the list consisting of: (i) A56C (iii) Q181H, Q181R or Q181S (vi) F216M (vii) G218D or G218N (ix) A238M (x) T252Y (xi) T311W (xii) V326C (xiv) S369C, S369I, S369K or S369M (xv) I487M, I487Q or I487V (xvi) K492N (xvii) V499T (xix) R543C (xx) L557Y (xxii) S635N and (xxiii) A690C. Variant rhamnosidases may comprise A143P, L214M, G215S, K219G, G357C, G508S, G634A, Q921H, G218D or G218N, and one to fifteen mutations selected from the list consisting of: (i) A56C (iii) Q181H, Q181R or Q181S (vi) F216M (ix) A238M (x) T252Y (xi) T311W (xii) V326C (xiv) S369C, S369I, S369K or S369M (xv) I487M, I487Q or I487V (xvi) K492N (xvii) V499T (xix) R543C (xx) L557Y (xxii) S635N and (xxiii) A690C. A variant rhamnosidase may comprise a “tag,” a sequence of amino acids that allows for the isolation and/or identification of the polypeptide. For example, adding an affinity tag can be useful in purification. Exemplary affinity tags that can be used include histidine (HIS) tags (e.g. hexa histidine-tag, or 6XHis-Tag), FLAG-TAG, and HA tags. Tags may be located N-terminally or C-terminally and may be directly connected or attached via a linking sequence. SEQ ID No.1177 provides a sequence for an exemplary 6XHis-Tag with linker sequence which may be N-terminally attached. SEQ ID No.1178 provides a sequence for an exemplary 6XHis-Tag with linker sequence which may be C-terminally attached. In certain embodiments, the tags used herein are removable, e.g. removal by chemical agents or by enzymatic means, once they are no longer needed, e.g. after the polypeptide has been purified. A variant rhamnosidase may comprise 1100 residues or fewer, especially 1050 residues or fewer, in particular 1000 residues or fewer, such as 950 residues or fewer. A variant rhamnosidase may consist of an amino acid sequence of SEQ ID No.1017 with one to twenty-four mutations selected from the list consisting of: (i) A56C (ii) A143P (iii) Q181H, Q181R or Q181S (iv) L214M (v) G215S (vi) F216M (vii) G218D or G218N (viii) K219G (ix) A238M (x) T252Y (xi) T311W (xii) V326C (xiii) G357C (xiv) S369C, S369I, S369K or S369M (xv) I487M, I487Q or I487V (xvi) K492N (xvii) V499T (xviii) G508S (xix) R543C (xx) L557Y (xxi) G634A (xxii) S635N (xxiii) A690C and (xxiv) Q921H. Variant rhamnosidases desirably demonstrate a FIOP relative to SEQ ID No.1017 of at least 1.05, especially at least 2, in particular at least 10, such as at least 50. FIOP may be determined by the methods described in Example 4. Function, in respect of functional variants, requires that the glycosidase activity is not notably reduced as a result of sequence variation, typically at least 50% of glycosidase activity, especially at least 75% activity, particularly at least 90%, such as at least 100% activity is maintained for at least one saponin modification reaction under at least one set of conditions (activity being determined by rate of modification of starting saponin to product saponin). Variants may be created with the intention of improving the glycosidase in some manner (e.g. conversion rate; specificity, which may be increased or reduced depending on needs; tolerance to environmental conditions, such as pH, substrate concentration, product concentration, other contaminants and the like; stability, thermal or chemical; production, such as facilitating expression or purification of the glycosidase either pre- or post-saponin modification). Variants need not be improved in all respects and may simply demonstrate a different balance of characteristics relative to the reference sequence. Glycosidases will typically be 2000 amino acids or fewer, such as 1500 amino acids or fewer. Suitably, glycosidases are soluble. Glycosidases may be immobilised, such as by attachment to solid (e.g. polymer) particles. Immobilisation of glycosidases may facilitate separation from a reaction mixture, improve thermal stability and/or tolerance to environmental conditions. Glycosidases may comprise a “tag,” a sequence of amino acids that allows for the isolation and/or identification of the polypeptide. For example, adding an affinity tag can be useful in purification. Exemplary affinity tags that can be used include histidine (HIS) tags (e.g., hexa histidine-tag, or 6XHis-Tag), FLAG-TAG, and HA tags. Tags may be located N-terminally or C-terminally and may be directly connected or attached via a linking sequence. SEQ ID No. 1177 provides a sequence for an exemplary 6XHis-Tag with linker sequence which may be N- terminally attached. SEQ ID No.1178 provides a sequence for an exemplary 6XHis-Tag with linker sequence which may be C-terminally attached. Reaction conditions Any suitable reaction conditions may be used. Optimal conditions will depend on a range of factors including the identity of the starting saponin, product saponin, enzyme utilised and the like. The reaction requires treatment of a starting saponin(s) with a glycosidase(s). Appropriate glycosidases may be added to a saponin-containing composition, such as e.g. a plant cell culture extract as described therein, in a range of forms such as solution (typically aqueous), suspension (typically aqueous) or solid. Suitably, glycosidases may be added directly into the culture medium of plant cells capable of synthesizing saponins. Saponins may then be recovered from the culture medium and/or the intracellular content of the cells. Alternatively, glycosidases may be added to a plant cell culture extract as described herein. In one embodiment, glycosidases are added to the cells which have been previously lysed by freezing. Saponins may then be recovered by extraction. Glycosidases may be in a purified, partially purified (such as clarified cell lysate) or unpurified form (crude cell lysate or unlysed cells). The use of partially purified or unpurified forms may be of interest when source cells (e.g. recombinant host cells, such as E. coli) express the enzyme to an extent that desired activity sufficiently exceeds any deleterious impact arising from other host cell contaminants. Desirably the glycosidase(s) are added in the form of clarified lysates. Glycosidases may be freshly prepared (e.g. clarified lysate) or taken from storage, such as thawed frozen liquid (e.g. clarified lysate) or reconstituted dried material (e.g. freeze-dried clarified lysate). Where a plurality of glycosidases is used in parallel, these will typically be expressed in different host cells to ensure adequate process control. A plurality of glycosidases used in parallel may be added together or separately (in the same or different forms). Glycosidases may be produced using a protein secretion system, such as Bacillus lichenformis. The weight of a glycosidase present may be in the range of 0.0001 mg to 25 mg per ml, especially 0.0001 mg to 5 mg per ml, in particular 0.0001 mg to 1 mg per ml, such as 0.001 mg to 0.5 mg per ml. When provided in the form of dried clarified lysate, the weight of a glycosidase present may be in the range of 0.01 mg to 100 mg of lysate per ml, especially 0.01 mg to 30 mg per ml, in particular 0.01 mg to 5 mg per ml, such as 0.01 mg to 1 mg per ml. Any appropriate pH may be used, though typically between pH 4 to 9, especially pH 5 to 8, and in particular pH 5.5 to 7.5 such as pH 5.5 to 6.5. Where a plurality of glycosidases is used in series, each enzymatic modification may be undertaken at a different pH though for convenience they may be undertaken at the same pH. Buffers may be used to aid control of the pH. Suitable buffers and appropriate concentrations may be obtained from standard sources. Inorganic salt buffers are typically used, such as potassium phosphate, sodium phosphate, potassium acetate, sodium acetate, potassium citrate, sodium citrate and the like. A suitable buffer concentration may be 10 mM to 500 mM, especially 25 mM to 250 mM and in particular 50 mM to 100 mM. Buffer concentrations of about 50 mM, such as 50 mM or about 100 mM, such as 100 mM, may be used. Any appropriate temperature may be used, though typically between 10 degC (10°C) to 60 degC (60°C), especially 15 degC (15°C) to 50 degC (50°C), in particular 15 degC (15°C) to 45 degC (45°C), such as 20 degC (20°C) to 42 degC (42°C). An appropriate time such that the reaction proceeds sufficiently is usually up to 10 days, especially up to 5 days, in particular up to 3 days. Desirably the enzyme and reaction conditions are chosen such that the reaction proceeds sufficiently in a period of up to 2 days, especially up to 1 day, in particular up to 18 hrs, such as 12 hrs, for example up to 6 hrs. The reaction will be undertaken in a suitable solvent, typically water or an aqueous solution with water miscible co-solvent(s) such as methanol, ethanol, n-propanol, i-propanol, tetrahydrofuran, ethylene glycol, glycerol,1,3-propanediol or acetonitrile. Any co-solvent(s) should be present in amounts which are not excessively deleterious to the reaction proceeding, such as 50% or less v/v, especially 20% or less, in particular 10% or less, such as 5% or less, for example 2% or less (in total). The reaction may be homogeneous or heterogeneous, monophasic, bi-phasic or multiphasic with particulates, dispersed solids in suspension and/or colloidal micelles present. Desirably the reaction will be monophasic. The starting saponins may be present at a concentration of 0.001 to 100 g per litre, especially 0.005 to 75 g per litre, in particular 0.01 to 50 g per litre, such as 0.1 to 25 g per litre, for example 1 to 10 g per litre. The reaction may be carried out in various modes of operation such as batch mode, fed batch mode or continuous mode. The reaction is typically performed at a scale which can provide commercial quantities of product saponin. A batch reaction volume may be at least 10 ml, especially at least 100 ml, in particular at least 1 L. A batch reaction volume may be 500 ml to 2000 L, especially 1 L to 1000 L, in particular 10 L to 500 L, such as 25 L to 200 L. Completion and mass balance Enzymes are desirably adequately selective for the conversion of a starting saponin into a product saponin rather than other conversions of the starting saponin. As used herein, the term selectivity means at least 25% (mole basis) of converted starting saponin results in the intended product saponin, in particular at least 50%, especially at least 75%, such as at least 90% (e.g. at least 95%). The concept of selectivity may also be applied in the context of the conversion of a plurality of starting saponins into a plurality of product saponins such that at least 25% of converted starting saponins (mole basis) result in the intended product saponins, in particular at least 50%, especially at least 75%, such as at least 90% (e.g. at least 95%). Desirably conversion of a starting saponin into a product saponin is complete. However, rate of conversion, specificity of conversion (including rate of non-specific conversion(s)), product inhibition, starting saponin stability under reaction conditions, product saponin stability under reaction conditions and the like mean that conversions may not be complete or that it is desirable (e.g. for maximum yield or to obtain a balance between yield and process time) for a conversion to be stopped prior to completion. Removal of enzymes At the point the reaction has progressed to the desired extent it may be stopped by denaturing or otherwise removing the enzyme. For example, the pH of reaction mixture may be adjusted to about pH to 3.5 to 4, especially pH 3.5 to 4, in particular pH 3.8 and/or the addition of sufficient quantities of anti-solvents or denaturing solvents such as acetonitrile. Precipitated enzyme may be removed by filtration. Other definitions By the term ‘Preceding peak’, it is meant the peak immediately preceding the QS-21 main peak in the HPLC-UV methods described herein (see Fig.2). By the term ‘m/z’, it is meant the mass to charge ratio of the monoisotope peak. Unless otherwise specified, ‘m/z’ is determined by negative ion electrospray mass spectrometry. By the term ‘ion abundance’, it is meant the amount of a specified m/z measured in the sample, or in a given peak as required by the context. The mass chromatogram for the specified m/z may be extracted from the MS total ion chromatogram in the UPLC-UV/MS methods described herein. The mass chromatogram plots the signal intensity versus time. Ion abundance is measured as the area of the integrated peak. The area for a specified m/z / area for a relative reference m/z = relative abundance. By the term ‘UV absorbance at 214 nm’, it is meant the area of an integrated peak in the UV absorbance chromatogram. The (area for a specified peak)/(area of all integrated peaks in the chromatogram) x 100 = percentage area for the specified peak. By the term ‘UV absorbance at 214 nm and relative ion abundance’, it is meant an estimate for the percentage of a given m/z for co-eluting species. (Percentage area for given UV peak)x (relative ion abundance for m/z of interest in given peak)/(sum of all relative ion abundance for given peak) = percentage of m/z of interest in the given UV peak, assumes relative ion abundance included for all coeluting species. By the term ‘wherein the monoisotope of the most abundant species is 1988 m/z’, it is meant the monoisotope of the most abundant species, first peak in the isotopic group with highest response per m/z is m/z 1987.9. The most abundant species may be determined by creating a combined spectrum across the entire total ion chromatogram using the UPLC-UV/MS method (negative ion electrospray) as described herein. By the term ‘dried’, it is meant that substantially all solvent has been removed. A dried extract will typically contain less than 5% solvent w/w, especially less than 2.5% (such as less than 5% water w/w, especially less than 2.5%). Suitably the dried extract will contain 100 ppm or less acetonitrile (w/w). Further, there is provided a method for the manufacture of a saponin composition comprising the steps of: (i) treating a crude aqueous plant cell culture extract from from Quillaja saponaria by polyvinylpolypyrollidone (PVPP) adsorption; (ii) enzymatically modifying the treated extract with a glucosidase and/or a rhamnosidase; (iii) purifying the modified extract by reverse phase chromatography using a polystyrene resin; and (iv) purifying the modified extract by reverse phase chromatography using a phenyl resin to provide a saponin composition. There is also provided a method for the manufacture of a saponin composition comprising the steps of: (i) treating a crude aqueous plant cell culture extract from Quillaja saponaria by polyvinylpolypyrollidone adsorption; (ii) enzymatically modifying the treated extract with an engineered glucosidase polypeptide; (iii) purifying the modified extract by reverse phase chromatography using a polystyrene resin; and (iv) purifying the modified extract by reverse phase chromatography using a phenyl resin to provide a saponin composition. Additionally provided a method for the manufacture of a saponin composition comprising the steps of: (i) treating a crude aqueous plant cell culture extract from Quillaja saponaria by polyvinylpolypyrollidone adsorption; (ii) enzymatically modifying the treated extract with an engineered rhamnosidase polypeptide; (iii) purifying the modified extract by reverse phase chromatography using a polystyrene resin; and (iv) purifying the modified extract by reverse phase chromatography using a phenyl resin to provide a saponin composition. Also provided is a method for the manufacture of a saponin composition comprising the steps of: (i) treating a crude aqueous plant cell culture extract fromQuillaja saponaria by polyvinylpolypyrollidone adsorption; (ii) enzymatically modifying the treated extract with an engineered glucosidase and an engineered rhamnosidase; (iii) purifying the modified extract by reverse phase chromatography using a polystyrene resin; and (iv) purifying the modified extract by reverse phase chromatography using a phenyl resin to provide a saponin composition. Suitably the QS-21 main peak content in an aqueous solution of a crude aqueous plant cell culture extract from Quillaja saponaria is at least 1g/L, such as at least 2g/L, especially at least 2.5 g/L and in particular at least 2.8 g/L (e.g. as determined by UV absorbance relative to a control sample of known concentration). The step of purifying the extract by polyvinylpolypyrollidone adsorption involves treatment of the extract with polyvinylpolypyrollidone adsorbant e.g. resin. Typically, the extract is agitated with the polyvinylpolypyrollidone resin. The extract may subsequently be separated from the polyvinylpolypyrollidone resin with adsorbed impurities by filtration. This step of the process generally removes polyphenolic impurities such as tannins. The step of purifying the extract by reverse phase chromatography using a polystyrene resin typically uses acetonitrile and water as solvent, usually acidified with a suitable acid such as acetic acid. An example of a suitable resin is Amberchrom XT20. Chromatography may be undertaken using isocratic conditions, though is typically operated under a solvent gradient (continuous, such as linear, or stepped), such as those provided in the Examples. This step of the process generally removes non-saponin material and enriches the desired saponins. Each polystyrene chromatography run is typically at a scale of between 25-200g of QS-21, such as between 50-150g and in particular between 70-110g (amounts being based on QS-21 main peak content in the material by UV). Purifying the extract by reverse phase chromatography using a phenyl resin typically uses acetonitrile and water as solvent, usually acidified with a suitable acid such as acetic acid. Chromatography may be undertaken using a solvent gradient (continuous, such as linear, or stepped), though is typically operated under isocratic conditions. This step of the process provides the final purification of the desired saponins. Selected fractions may be pooled to maximise yield of material matching the required criteria. Each phenyl chromatography run is typically at a scale of between 4-40 g of QS-21, such as between 10-30 g and in particular between 13-21 g (amounts being based on QS-21 main peak content in the material by UV). The method may comprise the further step of removing solvent to provide a dried saponin extract. Consequently, the invention provides a method for the manufacture of a saponin composition comprising the steps of: (i) treating a crude aqueous plant cell culture extract from Quillaja saponaria by polyvinylpolypyrollidone adsorption; (ii) enzymatically modifying the treated extract with a glucosidase and/or a rhamnosidase; (iii) purifying the modified extract by reverse phase chromatography using a polystyrene resin; and (iv) purifying the modified extract by reverse phase chromatography using a phenyl resin; and (v) removing solvent to provide a dried saponin composition. The invention also provides a method for the manufacture of a saponin composition comprising the steps of: (i) treating a crude aqueous plant cell culture extract from Quillaja saponaria by polyvinylpolypyrollidone adsorption; (ii) enzymatically modifying the treated extract with an engineered glucosidase polypeptide; (iii) purifying the modified extract by reverse phase chromatography using a polystyrene resin; and (iv) purifying the modified extract by reverse phase chromatography using a phenyl resin; and (v) removing solvent to provide a dried saponin composition. Further provided is a method for the manufacture of a saponin composition comprising the steps of: (i) treating a crude aqueous plant cell culture extract from Quillaja saponaria by polyvinylpolypyrollidone adsorption; (ii) enzymatically modifying the treated extract with an engineered rhamnosidase polypeptide; (iii) purifying the modified extract by reverse phase chromatography using a polystyrene resin; and (iv) purifying the modified extract by reverse phase chromatography using a phenyl resin; and (v) removing solvent to provide a dried saponin composition. Additionally provided is a method for the manufacture of a saponin composition comprising the steps of: (i) treating a crude aqueous plant cell culture extract from Quillaja saponaria by polyvinylpolypyrollidone adsorption; (ii) enzymatically modifying the treated extract with an engineered glucosidase polypeptide and an engineered rhamnosidase polypeptide; (iii) purifying the modified extract by reverse phase chromatography using a polystyrene resin; and (iv) purifying the modified extract by reverse phase chromatography using a phenyl resin; and (v) removing solvent to provide a dried saponin composition. In order to improve drying efficiency, it may be desirable to undertake further steps of concentrating the extract, such as by capture and release using an appropriate technique, for example reverse phase chromatography (e.g. using a C8 resin), and/or exchanging the solvent in advance of the drying step. Also provided is a method for the manufacture of a saponin composition comprising the steps: (i) treating a crude aqueous plant cell culture extract from Quillaja saponaria by polyvinylpolypyrollidone adsorption; (ii) enzymatically modifying the treated extract with a glucosidase and/or a rhamnosidase; (iii) purifying the modified extract by reverse phase chromatography using a polystyrene resin; and (iv) purifying the modified extract by reverse phase chromatography using a phenyl resin; (v) optionally concentrating the modified extract; (vi) optionally exchanging the solvent; and (vii) removing the remaining solvent to provide a dried saponin composition; wherein steps (v) and (vi) may be optionally be in reverse order or undertaken concurrently, though are typically in the order shown. Further provided is a method for the manufacture of a saponin composition comprising the steps: (i) treating a crude aqueous plant cell culture extract from Quillaja saponaria by polyvinylpolypyrollidone adsorption; (ii) enzymatically modifying the treated extract with an engineered glucosidase polypeptide; (iii) purifying the modified extract by reverse phase chromatography using a polystyrene resin; and (iv) purifying the modified extract by reverse phase chromatography using a phenyl resin; (v) optionally concentrating the modified extract; (vi) optionally exchanging the solvent; and (vii) removing the remaining solvent to provide a dried saponin composition; wherein steps (v) and (vi) may be optionally be in reverse order or undertaken concurrently, though are typically in the order shown. Additionally provided is a method for the manufacture of a saponin composition comprising the steps: (i) treating a crude aqueous plant cell culture extract from Quillaja saponaria by polyvinylpolypyrollidone adsorption; (ii) enzymatically modifying the treated extract with an engineered rhamnosidase polypeptide; (iii) purifying the modified extract by reverse phase chromatography using a polystyrene resin; and (iv) purifying the modified extract by reverse phase chromatography using a phenyl resin; (v) optionally concentrating the modified extract; (vi) optionally exchanging the solvent; and (vii) removing the remaining solvent to provide a dried saponin composition; wherein steps (v) and (vi) may be optionally be in reverse order or undertaken concurrently, though are typically in the order shown. The invention provides a method for the manufacture of a saponin composition comprising the steps: (i) treating a crude aqueous plant cell culture extract from Quillaja saponaria by polyvinylpolypyrollidone adsorption; (ii) enzymatically modifying the treated extract with an engineered glucosidase polypeptide and an engineered rhamnosidase polypeptide; (iii) purifying the modified extract by reverse phase chromatography using a polystyrene resin; and (iv) purifying the modified extract by reverse phase chromatography using a phenyl resin; (v) optionally concentrating the modified extract; (vi) optionally exchanging the solvent; and (vii) removing the remaining solvent to provide a dried saponin composition; wherein steps (v) and (vi) may be optionally be in reverse order or undertaken concurrently, though are typically in the order shown. Also provided is a method for the manufacture of a saponin composition comprising the steps: (i) treating a crude aqueous plant cell culture extract from Quillaja saponaria by polyvinylpolypyrollidone adsorption; (ii) enzymatically modifying the treated extract with a glucosidase and/or a rhamnosidase; (iii) purifying the modified extract by diafiltration, ultrafiltration or dialysis; (iv) purifying the modified extract by reverse phase chromatography using a polystyrene resin; (v) purifying the modified extract by reverse phase chromatography using a phenyl resin; (vi) concentrating the modified extract by reverse phase chromatography using a C8 resin; (vii) exchanging the solvent; and (viii) removing the remaining solvent to provide a dried saponin composition. Further provided is a method for the manufacture of a saponin composition comprising the steps: (i) treating a crude aqueous plant cell culture extract from Quillaja saponaria by polyvinylpolypyrollidone adsorption; (ii) enzymatically modifying the treated extract with an engineered glucosidase polypeptide; (iii) purifying the modified extract by diafiltration, ultrafiltration or dialysis; (iv) purifying the modified extract by reverse phase chromatography using a polystyrene resin; (v) purifying the modified extract by reverse phase chromatography using a phenyl resin; (vi) concentrating the modified extract by reverse phase chromatography using a C8 resin; (vii) exchanging the solvent; and (viii) removing the remaining solvent to provide a dried saponin composition. Additionally provided is a method for the manufacture of a saponin composition comprising the steps: (i) treating a crude aqueous plant cell culture extract from Quillaja saponaria by polyvinylpolypyrollidone adsorption; (ii) enzymatically modifying the treated extract with an engineered rhamnosidase polypeptide; (iii) purifying the modified extract by diafiltration, ultrafiltration or dialysis; (iv) purifying the modified extract by reverse phase chromatography using a polystyrene resin; (v) purifying the modified extract by reverse phase chromatography using a phenyl resin; (vi) concentrating the modified extract by reverse phase chromatography using a C8 resin; (vii) exchanging the solvent; and (viii) removing the remaining solvent to provide a dried saponin composition. The invention provides a method for the manufacture of a saponin composition comprising the steps: (i) treating a crude aqueous plant cell culture extract from Quillaja saponaria by polyvinylpolypyrollidone adsorption; (ii) enzymatically modifying the treated extract with an engineered glucosidase polypeptide and an engineered rhamnosidase polypeptide; (iii) purifying the modified extract by diafiltration, ultrafiltration or dialysis; (iv) purifying the modified extract by reverse phase chromatography using a polystyrene resin; (v) purifying the modified extract by reverse phase chromatography using a phenyl resin; (vi) concentrating the modified extract by reverse phase chromatography using a C8 resin; (vii) exchanging the solvent; and (viii) removing the remaining solvent to provide a dried saponin composition. The step of purifying the extract by diafiltration, ultrafiltration or dialysis, is suitably purification by diafiltration. typically using tangential flow. An appropriate example of a membrane is a 30kDa cut-off. This step of the process generally removes salts, sugars and other low molecular weight materials. Concentration of the extract may be performed using any suitable technique. For example, concentration may be performed using a capture and release methodology, such as reverse phase chromatography, in particular using a C8 resin. The reverse phase chromatography typically uses acetonitrile and water as solvent, usually acidified with a suitable acid such as acetic acid. Chromatography is typically operated under a solvent gradient, with the saponin extract captured in low organic solvent and eluted in high organic solvent, in particular, a stepped solvent gradient. Exchanging the solvent may be performed using any suitable technique, in particular diafiltration, ultrafiltration or dialysis, especially diafiltration. Solvent exchange may be useful, for example, in reducing the acetonitrile content such as described in WO2014016374. A suitable membrane may be selected to allow solvent exchange while retaining the saponin extract, such as a 1kDa membrane. Drying, by removing the solvent, may be undertaken by any suitable means, in particular by lyophilisation. During drying, degradation of the saponin extract can occur, leading to the formation of lyo impurity. Consequently, it is desirable to dry under conditions which limit formation of lyo impurity, such as by limiting the drying temperature and/or drying time. Suitably removal of solvent is undertaken by a single lyophilisation process. The extent of drying required will depend on the nature of the solvent, for example non-pharmaceutically acceptable solvents will desirably be removed to a high degree, whereas some pharmaceutically acceptable solvents (such as water) may be removed to a lesser degree. Suitably the methods of the present invention are undertaken at a scale of between 25- 1000 g of QS-21, such as between 50-500 g and in particular between 100-500 g (amounts being based on QS-21 main peak content in the material by UV). Provided is a product saponin prepared according to the present invention. There is provided the use of a product saponin prepared according to the present invention in the manufacture of a medicament. Additionally, provided is a product saponin prepared according to the present invention for use as a medicament, in particular as an adjuvant. Also provided is an adjuvant composition comprising a product saponin prepared according to the present invention. There is provided a crude plant cell culture extract (such as from Quillaja species, especially Quillaja saponaria), such as water and/or lower alcohol extract, especially aqueous extract which has been treated by a glucosidase. There is also provided a crude plant cell culture extract (such as from Quillaja species, especially Quillaja saponaria), such as water and/or lower alcohol extract, especially aqueous extract which has been treated by a rhamnosidase. Also provided is a crude plant cell culture extract (such as from Quillaja species, especially Quillaja saponaria), such as water and/or lower alcohol extract, especially aqueous plant cell culture extract which has been treated by a glucosidase and a rhamnosidase. There is provided a PVPP treated plant cell culture extract (such as from Quillaja species, especially Quillaja saponaria), such as water and/or lower alcohol extract, especially aqueous extract which has been treated by a glucosidase. There is also provided a PVPP treated plant cell culture extract (such as from Quillaja species, especially Quillaja saponaria), such as water and/or lower alcohol extract, especially aqueous extract which has been treated by a rhamnosidase. Also provided is a PVPP treated plant cell culture extract (such as from Quillaja species, especially Quillaja saponaria), such as water and/or lower alcohol extract, especially aqueous plant cell culture extract which has been treated by a glucosidase and a rhamnosidase. Also provided is a saponin composition containing at least 93% QS-21 main peak and <0.25% 2018 component by UV absorbance at 214 nm. Suitably wherein the monoisotope of the most abundant species is 1987.9 m/z. Desirably, the saponin composition contains at least 98% QS-21 group by UV absorbance at 214 nm. Desirably, the saponin composition extract contains 1% or less of lyo impurity by UV absorbance at 214 nm. Desirably, the saponin composition contains 1% or less of largest peak outside the QS-21 group by UV absorbance at 214 nm. Also provided is a saponin composition containing at least 98% QS-21 group, at least 93% QS-21 main peak, <0.25% 2018 component, 1% or less of largest peak outside the QS-21 group by UV absorbance at 214 nm and wherein the monoisotope of the most abundant species is 1987.9 m/z. Suitably the saponin composition contains <0.23% 2018 component, especially <0.21% 2018 component, in particular <0.21% 2018 component, such as 0.2% or less 2018 component. In some embodiments, the saponin composition does not contain 2018 component. The saponin composition desirably comprises at least 40%, such as at least 50%, suitably at least 60%, especially at least 70% and desirably at least 80%, for example at least 90% (as determined by UV absorbance at 214 nm and by relative ion abundance) QS-211988 A component, QS-211856 A component and/or QS-212002 A component. In certain embodiments, the saponin composition comprises at least 40%, such as at least 50%, in particular at least 60%, especially at least 65%, such as at least 70%, QS-211988 A component as determined by UV absorbance at 214 nm and by relative ion abundance. In certain embodiments the saponin composition contains 90% or less, such as 85% or less, or 80% or less, QS-211988 A component as determined by UV absorbance at 214 nm and by relative ion abundance. In certain embodiments, the saponin composition contains from 40% to 90% QS-211988 A component, such as 50% to 85% QS-211988 A component, especially 70% to 80% QS-211988 A component as determined by UV absorbance at 214 nm and by relative ion abundance. In certain embodiments, the saponin composition contains more than 90% QS-211988 A component, especially 95% to 99% QS-211988 A component as determined by UV absorbance at 214 nm and by relative ion abundance. In certain embodiments, the saponin composition contains 30% or less, such as 25% or less, QS-211856 A as determined by UV absorbance at 214 nm and by relative ion abundance. In certain embodiments, the saponin composition contains at least 5%, such as at least 10% QS-211856 A by UV absorbance at 214 nm and by relative ion abundance. In certain embodiments, the saponin composition contains from 5% to 30% QS-211856 A, such as 10% to 25% QS-211856 A as determined by UV absorbance at 214 nm and by relative ion abundance. In certain embodiments, the saponin composition contains 40% or less, such as 30% or less, in particular 20% or less, especially 10% or less QS-212002 A component by UV absorbance at 214 nm and by relative ion abundance. In certain embodiments, the saponin composition contains at least 0.5%, such as at least 1%, QS-212002 A component by UV absorbance at 214 nm and by relative ion abundance. In certain embodiments, the saponin composition contains from 0.5% to 40% QS-212002 A component, such as 1% to 10% QS-212002 A component as determined by UV absorbance at 214 nm and by relative ion abundance. In certain embodiments, the saponin composition contains from 0.1% to 0.5%, especially 0,4%, QS-21 2002 A component by UV absorbance at 214 nm and by relative ion abundance. In further embodiments, the saponin composition contains more than 90% QS-211988 A component as determined by UV absorbance at 214 nm and by relative ion abundance, between 1% to 10% QS-211856 A as determined by UV absorbance at 214 nm and by relative ion abundance, between 0.1% to 0.5% QS-212002 A component by UV absorbance at 214 nm and by relative ion abundance, and does not contain 2018 component as determined by UV absorbance at 214 nm and by relative ion abundance. Also provided is a plant cell culture extract containing at least 98% QS-21 group, at least 93% QS-21 main peak, <0.25% 2018 component, 1% or less of largest peak outside the QS-21 group by UV absorbance at 214 nm and wherein the monoisotope of the most abundant species is 1987.9 m/z. Suitably the plant cell culture extract contains <0.23% 2018 component, especially <0.21% 2018 component, in particular <0.21% 2018 component, such as 0.2% or less 2018 component. In some embodiments, the plant cell culture extract does not contain 2018 component. The plant cell culture extract desirably comprises at least 40%, such as at least 50%, suitably at least 60%, especially at least 70% and desirably at least 80%, for example at least 90% (as determined by UV absorbance at 214 nm and by relative ion abundance) QS-211988 A component, QS-211856 A component and/or QS-212002 A component. In certain embodiments, the plant cell culture extract comprises at least 40%, such as at least 50%, in particular at least 60%, especially at least 65%, such as at least 70%, QS-211988 A component as determined by UV absorbance at 214 nm and by relative ion abundance. In certain embodiments the plant cell culture extract contains 90% or less, such as 85% or less, or 80% or less, QS-211988 A component as determined by UV absorbance at 214 nm and by relative ion abundance. In certain embodiments, the plant cell culture extract contains from 40% to 90% QS-211988 A component, such as 50% to 85% QS-211988 A component, especially 70% to 80% QS-211988 A component as determined by UV absorbance at 214 nm and by relative ion abundance. In certain embodiments, the plant cell culture extract contains more than 90% QS-211988 A component, especially 95% to 99% QS-211988 A component as determined by UV absorbance at 214 nm and by relative ion abundance. In certain embodiments, the plant cell culture extract contains 30% or less, such as 25% or less, QS-21 1856 A as determined by UV absorbance at 214 nm and by relative ion abundance. In certain embodiments, the plant cell culture extract contains at least 5%, such as at least 10% QS-21 1856 A by UV absorbance at 214 nm and by relative ion abundance. In certain embodiments, the plant cell culture extract contains from 5% to 30% QS-211856 A, such as 10% to 25% QS- 211856 A as determined by UV absorbance at 214 nm and by relative ion abundance. In certain embodiments, the plant cell culture extract contains 40% or less, such as 30% or less, in particular 20% or less, especially 10% or less QS-212002 A component by UV absorbance at 214 nm and by relative ion abundance. In certain embodiments, the plant cell culture extract contains at least 0.5%, such as at least 1%, QS-212002 A component by UV absorbance at 214 nm and by relative ion abundance. In certain embodiments, the plant cell culture extract contains from 0.5% to 40% QS-212002 A component, such as 1% to 10% QS-212002 A component as determined by UV absorbance at 214 nm and by relative ion abundance. In certain embodiments, the plant cell culture extract contains from 0.1% to 0.5%, especially 0,4%, QS-212002 A component by UV absorbance at 214 nm and by relative ion abundance. In further embodiments, the plant cell culture extract contains more than 90% QS-21 1988 A component as determined by UV absorbance at 214 nm and by relative ion abundance, between 1% to 10% QS-211856 A as determined by UV absorbance at 214 nm and by relative ion abundance, between 0.1% to 0.5% QS-212002 A component by UV absorbance at 214 nm and by relative ion abundance, and does not contain 2018 component as determined by UV absorbance at 214 nm and by relative ion abundance. By the term ‘lyo impurity’, it is meant the triterpenoid glycosides identified as ‘Lyophilization Peak’ in Figure 6. Suitably the lyo impurity in the UPLC-UV/MS methods described herein has a retention time of approximately 4.7 min and the primary component of the peak having a monoisotopic molecular weight of 1855.9. The terms 2018 component, QS- 21 main peak, QS-21 group may be understood such as by reference to the examples herein. The saponin compositions of the present invention (i.e. a composition comprising a product saponin prepared according to the present invention) may be combined with further adjuvants, such as a TLR4 agonist, in particular lipopolysaccharide TLR4 agonists, such as lipid A derivatives, especially a monophosphoryl lipid A e.g.3-de-O-acylated monophosphoryl lipid A (3D-MPL). 3D-MPL is sold under the name ‘MPL’ by GlaxoSmithKline Biologicals N.A. and is referred throughout the document as 3D-MPL. See, for example, US Patent Nos.4,436,727; 4,877,611; 4,866,034 and 4,912,094. 3D-MPL can be produced according to the methods described in GB 2220211 A. Chemically it is a mixture of 3-deacylated monophosphoryl lipid A with 4, 5 or 6 acylated chains. Other TLR4 agonists which may be of use in the present invention include Glucopyranosyl Lipid Adjuvant (GLA) such as described in WO2008/153541 or WO2009/143457 or the literature articles Coler RN et al. (2011) Development and Characterization of Synthetic Glucopyranosyl Lipid Adjuvant System as a Vaccine Adjuvant. PLoS ONE 6(1): e16333. doi:10.1371/journal.pone.0016333 and Arias MA et al. (2012) Glucopyranosyl Lipid Adjuvant (GLA), a Synthetic TLR4 Agonist, Promotes Potent Systemic and Mucosal Responses to Intranasal Immunization with HIVgp140. PLoS ONE 7(7): e41144. doi:10.1371/journal.pone.0041144. WO2008/153541 or WO2009/143457 are incorporated herein by reference for the purpose of defining TLR4 agonists which may be of use in the present invention. A particular alkyl glucosaminide phosphate (AGP) of interest is set forth as follows: TLR4 agonists of interest include:
3-deacyl monophosphoryl hexa-acyl lipid A. Another TLR4 agonist of interest is: 3-deacyl monophosphoryl lipid A. A TLR4 agonist of interest is dLOS (as described in Han, 2014): . A typical adult human dose of adjuvant will comprise a saponin composition, such as a Q-21 composition, at amounts between 1 and 100 ug per human dose. The saponin extract may be used at a level of about 50 ug. Examples of suitable ranges are 40-60 ug, suitably 45- 55 ug or 49-51 ug, such as 50 ug. In a further embodiment, the human dose comprises saponin composition, such as a Q-21 composition, at a level of about 25 ug. Examples of lower ranges include 20-30 ug, suitably 22-28 ug or 24-26 ug, such as 25 ug. Human doses intended for children may be reduced compared to those intended for an adult (e.g. reduction by 50%). The TLR4 agonists, such as a lipopolysaccharide, such as 3D-MPL, can be used at amounts between 1 and 100 ug per human dose. 3D-MPL may be used at a level of about 50 ug. Examples of suitable ranges are 40-60 ug, suitably 45-55 ug or 49-51 ug, such as 50 ug. In a further embodiment, the human dose comprises 3D-MPL at a level of about 25 ug. Examples of lower ranges include 20-30 ug, suitably 22-28 ug or 24-26 ug, such as 25 ug. Human doses intended for children may be reduced compared to those intended for an adult (e.g. reduction by 50%). When both a TLR4 agonist and a saponin composition, such as a Q-21 composition, are present in the adjuvant, then the weight ratio of TLR4 agonist to saponin is suitably between 1:5 to 5:1, suitably 1:1. For example, where 3D-MPL is present at an amount of 50 ug or 25 ug, then suitably QS-21 may also be present at an amount of 50 ug or 25 ug per human dose. Adjuvants may also comprise a suitable carrier, such as an emulsion (e.g. an oil in water emulsion, such as a squalene-containing oil in water emulsion) or liposomes. The present invention provides an adjuvant composition comprising a plant cell culture extractaccording to the present invention. Suitably the adjuvant composition further comprises a TLR4 agonist. Liposomes The term ‘liposome’ is well known in the art and defines a general category of vesicles which comprise one or more lipid bilayers surrounding an aqueous space. Liposomes thus consist of one or more lipid and/or phospholipid bilayers and can contain other molecules, such as proteins or carbohydrates, in their structure. Because both lipid and aqueous phases are present, liposomes can encapsulate or entrap water-soluble material, lipid-soluble material, and/or amphiphilic compounds. Liposome size may vary from 30 nm to several um depending on the phospholipid composition and the method used for their preparation. The liposomes of use in the present invention suitably contain DOPC, or, consist essentially of DOPC and sterol (with saponin and optionally TLR4 agonist). In the present invention, the liposome size will be in the range of 50 nm to 200 nm, especially 60 nm to 180 nm, such as 70-165 nm. Optimally, the liposomes should be stable and have a diameter of ~100 nm to allow convenient sterilization by filtration. Structural integrity of the liposomes may be assessed by methods such as dynamic light scattering (DLS) measuring the size (Z-average diameter, Zav) and polydispersity of the liposomes, or, by electron microscopy for analysis of the structure of the liposomes. In one embodiment the average particle size is between 95 and 120 nm, and/or, the polydispersity (PdI) index is not more than 0.3 (such as not more than 0.2). Further excipients In a further embodiment, a buffer is added to an adjuvant composition. The pH of a liquid preparation is adjusted in view of the components of the composition and necessary suitability for administration to the subject. Suitably, the pH of a liquid mixture is at least 4, at least 5, at least 5.5, at least 5.8, at least 6. The pH of the liquid mixture may be less than 9, less than 8, less than 7.5 or less than 7. In other embodiments, pH of the liquid mixture is between 4 and 9, between 5 and 8, such as between 5.5 and 8. Consequently, the pH will suitably be between 6- 9, such as 6.5-8.5. In a particularly preferred embodiment the pH is between 5.8 and 6.4. An appropriate buffer may be selected from acetate, citrate, histidine, maleate, phosphate, succinate, tartrate and TRIS. In one embodiment, the buffer is a phosphate buffer such as Na/Na2PO4, Na/K2PO4 or K/K2PO4. The buffer can be present in the liquid mixture in an amount of at least 6mM, at least 10 mM or at least 40mM. The buffer can be present in the liquid mixture in an amount of less than 100 mM, less than 60 mM or less than 40 mM. It is well known that for parenteral administration solutions should have a pharmaceutically acceptable osmolality to avoid cell distortion or lysis. A pharmaceutically acceptable osmolality will generally mean that solutions will have an osmolality which is approximately isotonic or mildly hypertonic. Suitably the compositions (when reconstituted, if presented in dried form) will have an osmolality in the range of 250 to 750 mOsm/kg, for example, the osmolality may be in the range of 250 to 550 mOsm/kg, such as in the range of 280 to 500 mOsm/kg. In a particularly preferred embodiment, the osmolality may be in the range of 280 to 310 mOsm/kg. Osmolality may be measured according to techniques known in the art, such as by the use of a commercially available osmometer, for example the Advanced® Model 2020 available from Advanced Instruments Inc. (USA). An ‘isotonicity agent’ is a compound that is physiologically tolerated and imparts a suitable tonicity to a formulation to prevent the net flow of water across cell membranes that are in contact with the formulation. In some embodiments, the isotonicity agent used for the composition is a salt (or mixtures of salts), conveniently the salt is sodium chloride, suitably at a concentration of approximately 150 nM. In other embodiments, however, the composition comprises a non-ionic isotonicity agent and the concentration of sodium chloride in the composition is less than 100 mM, such as less than 80 mM, e.g. less than 50 mM, such as less 40 mM, less than 30 mM and especially less than 20 mM. The ionic strength in the composition may be less than 100 mM, such as less than 80 mM, e.g. less than 50 mM, such as less 40 mM or less than 30 mM. In a particular embodiment, the non-ionic isotonicity agent is a polyol, such as sucrose and/or sorbitol. The concentration of sorbitol may e.g. between about 3% and about 15% (w/v), such as between about 4% and about 10% (w/v). Adjuvants comprising an immunologically active saponin fraction and a TLR4 agonist wherein the isotonicity agent is salt or a polyol have been described in WO2012/080369. Suitably, a human dose volume of between 0.05 ml and 1 ml, such as between 0.1 and 0.5 ml, in particular a dose volume of about 0.5 ml, or 0.7 ml. The volumes of the compositions used may depend on the delivery route and location, with smaller doses being given by the intradermal route. A unit dose container may contain an overage to allow for proper manipulation of materials during administration of the unit dose. The ratio of saponin:DOPC will typically be in the order of 1:50 to 1:10 (w/w), suitably between 1:25 to 1:15 (w/w), and preferably 1:22 to 1:18 (w/w), such as 1:20 (w/w). Suitably the saponin is presented in a less reactogenic composition where it is quenched with an exogenous sterol, such as cholesterol. Cholesterol is disclosed in the Merck Index, 13th Edn., page 381, as a naturally occurring sterol found in animal fat. Cholesterol has the formula (C27H46O) and is also known as (3β)-cholest-5-en-3-ol. The ratio of saponin:sterol will typically be in the order of 1:100 to 1:1 (w/w), suitably between 1:10 to 1:1 (w/w), and preferably 1:5 to 1:1 (w/w). Suitably excess sterol is present, the ratio of saponin:sterol being at least 1:2 (w/w). In one embodiment, the ratio of saponin:sterol is 1:5 (w/w). In one embodiment, the sterol is cholesterol. The amount of liposome (weight of lipid and sterol) will typically be in the range of 0.1 mg to 10 mg per human dose of a composition, in particular 0.5 mg to 2 mg per human dose of a composition. In a particularly suitable embodiment, liposomes used in the invention comprise DOPC and a sterol, in particular cholesterol. Thus, in a particular embodiment, a composition used in the invention comprises saponin extract in the form of a liposome, wherein said liposome comprises DOPC and a sterol, in particular cholesterol. A particular adjuvant of interest features liposomes comprising DOPC and cholesterol, with TLR4 agonist and a saponin prepared according to the present invention, especially 3D- MPL and a saponin prepared according to the present invention. Another adjuvant of interest features liposomes comprising DOTAP and DMPC, with TLR4 agonist and a saponin prepared according to the present invention, especially dLOS and a saponin prepared according to the present invention. Antigens The adjuvants prepared according to the present invention may be utilised in conjunction with an immunogen or antigen. In some embodiments a polynucleotide encoding the immunogen or antigen is provided. The adjuvant may be administered to a subject separately from an immunogen or antigen, or the adjuvant may be combined, either during manufacturing or extemporaneously, with an immunogen or antigen to provide an immunogenic composition for combined administration. As used herein, a subject is a mammalian animal, such as a rodent, non-human primate, or human. Consequently, there is provided a method for the preparation of an immunogenic composition comprising an immunogen or antigen, or a polynucleotide encoding the immunogen or antigen, said method comprising the steps of: (i) preparing an adjuvant composition comprising a saponin prepared according to the present invention; (ii) mixing the adjuvant with an immunogen or antigen, or a polynucleotide encoding the immunogen or antigen. There is also provided the use of an adjuvant comprising a saponin prepared according to the present invention in the manufacture of a medicament. Suitably the medicament comprises an immunogen or antigen, or a polynucleotide encoding the immunogen or antigen. Further provided is an adjuvant comprising a saponin prepared according to the present invention for use as a medicament. Suitably the medicament comprises an immunogen or antigen, or a polynucleotide encoding the immunogen or antigen. By the term ‘immunogen’, it is meant a polypeptide which is capable of eliciting an immune response. Suitably the immunogen is an antigen which comprises at least one B or T cell epitope. The elicited immune response may be an antigen specific B cell response, which produces neutralizing antibodies. The elicited immune response may be an antigen specific T cell response, which may be a systemic and/or a local response. The antigen specific T cell response may comprise a CD4+ T cell response, such as a response involving CD4+ T cells expressing a plurality of cytokines, e.g. IFNgamma, TNFalpha and/or IL2. Alternatively, or additionally, the antigen specific T cell response comprises a CD8+ T cell response, such as a response involving CD8+ T cells expressing a plurality of cytokines, e.g. IFNgamma, TNFalpha and/or IL2. The antigen may be derived (such as obtained from) from a human or non-human pathogen including, e.g., bacteria, fungi, parasitic microorganisms or multicellular parasites which infect human and non-human vertebrates, or from a cancer cell or tumor cell. In one embodiment, the antigen is a recombinant protein, such as a recombinant prokaryotic protein. A plurality of antigens may be provided. For example, a plurality of antigens may be provided to strengthen the elicited immune response (e.g. to ensure strong protection), a plurality of antigens may be provided to broaden the immune response (e.g. to ensure protection against a range of pathogen strains or in a large proportion of a subject population) or a plurality of antigens may be provided to currently elicit immune responses in respect of a number of disorders (thereby simplifying administration protocols). Where a plurality of antigens are provided, these may be as distinct proteins or may be in the form of one or more fusion proteins. Antigen may be provided in an amount of 0.1 to 100 ug per human dose. The present invention may be applied for use in the treatment or prophylaxis of a disease or disorder associated with one or more antigens described above. In one embodiment the disease or disorder is selected from malaria, tuberculosis, COPD, HIV and herpes. The adjuvant may be administered separately from an immunogen or antigen, or may be combined, either during manufacturing or extemporaneously), with an immunogen or antigen to provide an immunogenic composition for combined administration. Sterilisation For parenteral administration in particular, compositions should be sterile. Sterilisation can be performed by various methods although is conveniently undertaken by filtration through a sterile grade filter. Sterilisation may be performed a number of times during preparation of an adjuvant or immunogenic composition, but is typically performed at least at the end of manufacture. By ‘sterile grade filter’, it is meant a filter that produces a sterile effluent after being challenged by microorganisms at a challenge level of greater than or equal to 1x10 7 /cm 2 of effective filtration area. Sterile grade filters are well known to the person skilled in the art of the invention for the purpose of the present invention, sterile grade filters have a pore size between 0.15 and 0.25 um, suitably 0.18-0.22um, such as 0.2 or 0.22 um. The membranes of the sterile grade filter can be made from any suitable material known to the skilled person, for example, but not limited to cellulose acetate, polyethersulfone (PES), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE). In a particular embodiment of the invention, one or more or all of the filter membranes of the present invention comprise polyethersulfone (PES), in particular hydrophilic polyethersulfone. In a particular embodiment of the invention, the filters used in the processes described herein are a double layer filter, in particular a sterile filter with built-in prefilter having larger pore size than the pore size of the end filter. In one embodiment the sterilizing filter is a double layer filter wherein the pre-filter membrane layer has a pore size between 0.3 and 0.5 nm, such as 0.35 or 0.45 nm. According to further embodiments, filters comprise asymmetric filter membrane(s), such as asymmetric hydrophilic PES filter membrane(s). Alternatively, the sterilizing filter layer may be made of PVDF, e.g. in combination with an asymmetric hydrophilic PES pre-filter membrane layer. In light of the intended medical uses, materials should be of pharmaceutical grade (such as parenteral grade). Clauses of the invention The invention is illustrated by the following clauses: Clause 1. A method for making a product saponin, said method comprising the steps of: (i) providing a plant cell culture extract comprising saponins; and (ii) enzymatically converting a starting saponin from the plant cell culture extract to a product saponin. Clause 2. A method for making a product saponin, said method comprising the steps of: (i) culturing plant cells capable of synthesizing saponins under conditions leading to the synthesis of saponins; (ii) recovering saponins from the plant cell culture; and (iii) enzymatically converting a starting saponin from the recovered saponins to the product saponin. Clause 3. A method for making a product saponin, said method comprising the steps of: (i) culturing plant cells capable of synthesizing saponins under conditions leading to the synthesis of saponins; (ii) enzymatically converting a starting saponin from the synthesized saponins to the product saponin; and (iii) recovering saponins from the plant cell culture. Clause 4. A method for increasing the amount of a product saponin obtainable from a plant cell culture, said method comprising the steps of: (i) culturing plant cells capable of synthesizing saponins under conditions leading to the synthesis of saponins; (ii) recovering saponins from the plant cell culture; and (iii) enzymatically converting a starting saponin from the recovered saponins to the product saponin. Clause 5. A method for increasing the amount of a product saponin obtainable from a plant cell culture, said method comprising the steps of: (i) culturing plant cells capable of synthesizing saponins under conditions leading to the synthesis of saponins; (ii) enzymatically converting a starting saponin from the synthesized saponins to the product saponin; and (iii) recovering saponins from the plant cell culture. Clause 6. A method for reducing the amount of a starting saponin obtainable from a plant cell culture, said method comprising the following steps of: (i) culturing plant cells capable of synthesizing saponins under conditions leading to the synthesis of saponins; (ii) recovering saponins from the plant cell culture; and (iii) enzymatically converting the starting saponin from the recovered saponins to a product saponin. Clause 7. A method for reducing the amount of a starting saponin obtainable from a plant cell culture, said method comprising the following steps of: (i) culturing plant cells capable of synthesizing saponins under conditions leading to the synthesis of saponins; (ii) enzymatically converting a starting saponin from the synthesized saponins to the product saponin; and (iii) recovering saponins from the plant cell culture. Clause 8. A method for producing saponins by plant cell culture, said method comprising the steps of: (i) culturing plant cells capable of synthesizing saponins under conditions leading to the synthesis of saponins; and (ii) recovering saponins from the plant cell culture, wherein the yield of a product saponin is increased by enzymatically converting a starting saponin from recovered saponins to the product saponin. Clause 9. The method according to any clause 3, 5 or 7, wherein the enzymatic conversion of step (ii) is carried out by adding glycosidase(s) into the culture medium used in step (i). Clause 10. The method according to any one of clauses 1 to 9, wherein the plant cells are grown in suspension. Clause 11. The method according to any one of clauses 2 to 10, wherein during step (i), cells are elicited with at least one elicitor. Clause 12. The method according to clause 11, wherein the at least one elicitor is methyl jasmonate (MeJa). Clause 13. The method according to clause 12, wherein MeJa is used at a concentration ranging from 0.5 to 10 µM/PCV %. Clause 14. The method according to any one of clauses 2 to 10, wherein during step (i), the plant cells are depleted from any nitrogen source. Clause 15. The method according to clause 14, wherein nitrogen depletion is performed by removing the culture medium used in step (i) and replacing it with a medium containing no source of nitrogen. Clause 16. The method according to clause 15, wherein nitrogen depletion duration ranges from 1 to 9 days. Clause 17. The method according to any one of clauses 11 to 13, wherein before elicitation, cells are depleted from any nitrogen source, as described in clause 14, 15 or 16. Clause 18. The method according to any one of clauses 1 to 17, wherein the saponins are naturally occurring saponins. Clause 19. The method according to any one of clauses 1 to 17, wherein the saponins are artificial saponins. Clause 20. The method according to any one of clauses 1 to 19, wherein the saponins are steroid glycosides. Clause 21. The method according to any one of clauses 1 to 19, wherein the saponins are terpenoid glycosides. Clause 22. The method according to clause 21, wherein the saponins are triterpenoid glycosides. Clause 23. The method according to clause 22, wherein the saponins are quillaic acid glycosides. Clause 24. The method according to any one of clauses 1 to 23, wherein the plant cell culture extract or the plant cells are from genera Gypsophilia, Saponaria or Quillaja. Clause 25. The method according to clause 24, wherein the plant cell culture extract or the plant cells are from Quillaja species. Clause 26. The method according to clause 25, wherein the plant cell culture extract or the plant cells are from Quillaja brasiliensis. Clause 27. The method according to clause 25, wherein the plant cell culture extract or the plant cells are from Quillaja saponaria. Clause 28. The method according to any one of clause 25 to 27, wherein the starting saponin is a QS-18 family component. Clause 29. The method according to clause 28, wherein the starting saponin is a QS-18 2150 A component. Clause 30. The method according to clause 29, wherein the starting saponin is QS-18 2150 A V1. Clause 31. The method according to clause 29, wherein the starting saponin is QS-18 2150 A V2. Clause 32. The method according to clause 28, wherein the starting saponin is QS-18 2018 A component. Clause 33. The method according to clause 28, wherein the starting saponin is a QS-18 2164 A component. Clause 34. The method according to clause 33, wherein the starting saponin is QS-18 2164 A V1. Clause 35. The method according to clause 33, wherein the starting saponin is QS-18 2164 A V2. Clause 36. The method according to clause 28, wherein the starting saponin is a QS-18 2150 B component. Clause 37. The method according to clause 36, wherein the starting saponin is QS-18 2150 B V1. Clause 38. The method according to clause 36, wherein the starting saponin is QS-18 2150 B V2. Clause 39. The method according to clause 28, wherein the starting saponin is QS-18 2018 B component. Clause 40. The method according to clause 28, wherein the starting saponin is a QS-18 2164 B component. Clause 41. The method according to clause 40, wherein the starting saponin is QS-18 2164 B V1. Clause 42. The method according to clause 40, wherein the starting saponin is QS-18 2164 B V2. Clause 43. The method according to any one of clause 25 to 27, wherein the starting saponin is a desglucosyl-QS-17 family component. Clause 44. The method according to clause 43, wherein the starting saponin is a desglucosyl-QS-172134 A component. Clause 45. The method according to clause 44, wherein the starting saponin is desglucosyl-QS-172134 A V1. Clause 46. The method according to clause 44, wherein the starting saponin is desglucosyl-QS-172134 A V2. Clause 47. The method according to clause 43, wherein the starting saponin is desglucosyl-QS-172002 A component. Clause 48. The method according to clause 43, wherein the starting saponin is a desglucosyl-QS-172148 A component. Clause 49. The method according to clause 48, wherein the starting saponin is desglucosyl-QS-172148 A V1. Clause 50. The method according to clause 48, wherein the starting saponin is desglucosyl-QS-172148 A V2. Clause 51. The method according to clause 43, wherein the starting saponin is a desglucosyl-QS-172134 B component. Clause 52. The method according to clause 51, wherein the starting saponin is desglucosyl-QS-172134 B V1. Clause 53. The method according to clause 51, wherein the starting saponin is desglucosyl-QS-172134 B V2. Clause 54. The method according to clause 43, wherein the starting saponin is desglucosyl-QS-172002 B component. Clause 55. The method according to clause 43, wherein the starting saponin is a desglucosyl-QS-172148 B component. Clause 56. The method according to clause 55, wherein the starting saponin is desglucosyl-QS-172148 B V1. Clause 57. The method according to clause 55, wherein the starting saponin is desglucosyl-QS-172148 B V2. Clause 58. The method according to any one of clause 25 to 27, wherein the starting saponin is a QS-17 family component. Clause 59. The method according to clause 58, wherein the starting saponin is a QS-17 2296 A component. Clause 60. The method according to clause 59, wherein the starting saponin is QS-17 2296 A V1. Clause 61. The method according to clause 59, wherein the starting saponin is QS-17 2296 A V2. Clause 62. The method according to clause 58, wherein the starting saponin is QS-17 2164 A component. Clause 63. The method according to clause 58, wherein the starting saponin is a QS-17 2310 A component. Clause 64. The method according to clause 63, wherein the starting saponin is QS-17 2310 A V1. Clause 65. The method according to clause 63, wherein the starting saponin is QS-17 2310 A V2. Clause 66. The method according to clause 58, wherein the starting saponin is a QS-17 2296 B component. Clause 67. The method according to clause 66, wherein the starting saponin is QS-17 2296 B V1. Clause 68. The method according to clause 66, wherein the starting saponin is QS-17 2296 B V2. Clause 69. The method according to clause 58, wherein the starting saponin is QS-17 2164 B component. Clause 70. The method according to clause 58, wherein the starting saponin is a QS-17 2310 B component. Clause 71. The method according to clause 70, wherein the starting saponin is QS-17 2310 B V1. Clause 72. The method according to clause 70, wherein the starting saponin is QS-17 2310 B V2. Clause 73. The method according to any one of clause 25 to 27, wherein the starting saponin is a desarabinofuranosyl-QS-18 family component. Clause 74. The method according to clause 73, wherein the starting saponin is a desarabinofuranosyl-QS-182018 A component. Clause 75. The method according to clause 74, wherein the starting saponin is desarabinofuranosyl-QS-182018 A V1. Clause 76. The method according to clause 74, wherein the starting saponin is desarabinofuranosyl-QS-182018 A V2. Clause 77. The method according to clause 73, wherein the starting saponin is desarabinofuranosyl-QS-181886 A component. Clause 78. The method according to clause 73, wherein the starting saponin is a desarabinofuranosyl-QS-182032 A component. Clause 79. The method according to clause 78, wherein the starting saponin is desarabinofuranosyl-QS-182032 A V1. Clause 80. The method according to clause 78, wherein the starting saponin is desarabinofuranosyl-QS-182032 A V2. Clause 81. The method according to clause 73, wherein the starting saponin is a desarabinofuranosyl-QS-182018 B component. Clause 82. The method according to clause 81, wherein the starting saponin is desarabinofuranosyl-QS-182018 B V1. Clause 83. The method according to clause 81, wherein the starting saponin is desarabinofuranosyl-QS-182018 B V2. Clause 84. The method according to clause 73, wherein the starting saponin is desarabinofuranosyl-QS-181886 B component. Clause 85. The method according to clause 73, wherein the starting saponin is a desarabinofuranosyl-QS-182032 B component. Clause 86. The method according to clause 85, wherein the starting saponin is desarabinofuranosyl-QS-182032 B V1. Clause 87. The method according to clause 85, wherein the starting saponin is desarabinofuranosyl-QS-182032 B V2. Clause 88. The method according to any one of clause 25 to 27, wherein the starting saponin is an acetylated desglucosyl-QS-17 family component. Clause 89. The method according to clause 88, wherein the starting saponin is an acetylated desglucosyl-QS-172176 A component. Clause 90. The method according to clause 89, wherein the starting saponin is acetylated desglucosyl-QS-172176 A V1. Clause 91. The method according to clause 89, wherein the starting saponin is acetylated desglucosyl-QS-172176 A V2. Clause 92. The method according to clause 88, wherein the starting saponin is acetylated desglucosyl-QS-172044 A component. Clause 93. The method according to clause 88, wherein the starting saponin is an acetylated desglucosyl-QS-172190 A component. Clause 94. The method according to clause 93, wherein the starting saponin is acetylated desglucosyl-QS-172190 A V1. Clause 95. The method according to clause 93, wherein the starting saponin is acetylated desglucosyl-QS-172190 A V2. Clause 96. The method according to either clause 28 or 43, wherein the product saponin is a QS-21 family component. Clause 97. The method according to any one of clauses 29, 44 or 96, wherein the product saponin is a QS-211988 A component. Clause 98. The method according to any one of clauses 30, 45 or 97, wherein the product saponin is QS-211988 A V1. Clause 99. The method according to any one of clauses 31, 46 or 97, wherein the product saponin is QS-211988 A V2. Clause 100. The method according to any one of clauses 32, 47 or 96, wherein the product saponin is QS-211856 A component. Clause 101. The method according to any one of clauses 33, 48 or 96, wherein the product saponin is a QS-212002 A component. Clause 102. The method according to any one of clauses 34, 49 or 101, wherein the product saponin is QS-212002 A V1. Clause 103. The method according to any one of clauses 35, 50 or 101, wherein the product saponin is QS-212002 A V2. Clause 104. The method according to any one of clauses 36, 51 or 96, wherein the product saponin is a QS-211988 B component. Clause 105. The method according to any one of clauses 37, 52 or 104, wherein the product saponin is QS-211988 B V1. Clause 106. The method according to any one of clauses 38, 53 or 104, wherein the product saponin is QS-211988 B V2. Clause 107. The method according to any one of clauses 39, 54 or 96, wherein the product saponin is QS-211856 B component. Clause 108. The method according to any one of clauses 40, 55 or 96, wherein the product saponin is a QS-212002 B component. Clause 109. The method according to any one of clauses 41, 56 or 108, wherein the product saponin is QS-212002 B V1. Clause 110. The method according to any one of clauses 42, 57 or 108, wherein the product saponin is QS-212002 B V2. Clause 111. The method according to clause 58, wherein the product saponin is a QS-18 family component. Clause 112. The method according to either clause 59 or 111, wherein the product saponin is a QS-182150 A component. Clause 113. The method according to either clause 60 or 112, wherein the product saponin is QS-182150 A V1. Clause 114. The method according to either clause 61 or 112, wherein the product saponin is QS-182150 A V2. Clause 115. The method according to either clause 62 or 111, wherein the product saponin is QS-182018 A component. Clause 116. The method according to either clause 63 or 111, wherein the product saponin is a QS-182164 A component. Clause 117. The method according to either clause 64 or 116, wherein the product saponin is QS-182164 A V1. Clause 118. The method according to either clause 65 or 116, wherein the product saponin is QS-182164 A V2. Clause 119. The method according to either clause 66 or 111, wherein the product saponin is a QS-182150 B component. Clause 120. The method according to either clause 67 or 119, wherein the product saponin is QS-182150 B V1. Clause 121. The method according to either clause 68 or 119, wherein the product saponin is QS-182150 B V2. Clause 122. The method according to either clause 69 or 111, wherein the product saponin is QS-182018 B component. Clause 123. The method according to either clause 70 or 111, wherein the product saponin is a QS-182164 B component. Clause 124. The method according to either clause 71 or 123, wherein the product saponin is QS-182164 B V1. Clause 125. The method according to either clause 72 or 123, wherein the product saponin is QS-182164 B V2. Clause 126. The method according to clause 58, wherein the product saponin is a desglucosyl-QS-17 family component. Clause 127. The method according to either clause 59 or 126, wherein the product saponin is a desglucosyl-QS-172134 A component. Clause 128. The method according to either clause 60 or 127, wherein the product saponin is desglucosyl-QS-172134 A V1. Clause 129. The method according to either clause 61 or 127, wherein the product saponin is desglucosyl-QS-172134 A V2. Clause 130. The method according to either clause 62 or 126, wherein the product saponin is desglucosyl-QS-172002 A component. Clause 131. The method according to either clause 63 or 126, wherein the product saponin is a desglucosyl-QS-172148 A component. Clause 132. The method according to either clause 64 or 131, wherein the product saponin is desglucosyl-QS-172148 A V1. Clause 133. The method according to either clause 65 or 131, wherein the product saponin is desglucosyl-QS-172148 A V2. Clause 134. The method according to either clause 66 or 126, wherein the product saponin is a desglucosyl-QS-172134 B component. Clause 135. The method according to either clause 67 or 134, wherein the product saponin is desglucosyl-QS-172134B V1. Clause 136. The method according to either clause 68 or 134, wherein the product saponin is desglucosyl-QS-172134 B V2. Clause 137. The method according to either clause 69 or 126, wherein the product saponin is desglucosyl-QS-172002 B component. Clause 138. The method according to either clause 70 or 126, wherein the product saponin is a desglucosyl-QS-172148 B component. Clause 139. The method according to either clause 71 or 138, wherein the product saponin is desglucosyl-QS-172148 B V1. Clause 140. The method according to either clause 72 or 138, wherein the product saponin is desglucosyl-QS-172148 B V2. Clause 141. The method according to clause 73, wherein the product saponin is a desarabinofuranosyl-QS-21 family component. Clause 142. The method according to either clause 74 or 141, wherein the product saponin is a desarabinofuranosyl-QS-211856 A component. Clause 143. The method according to either clause 75 or 142, wherein the product saponin is desarabinofuranosyl-QS-211856 A V1. Clause 144. The method according to either clause 76 or 142, wherein the product saponin is desarabinofuranosyl-QS-211856 A V2. Clause 145. The method according to either clause 77 or 141, wherein the product saponin is desarabinofuranosyl-QS-211712 A component. Clause 146. The method according to either clause 78 or 141, wherein the product saponin is a desarabinofuranosyl-QS-211870 A component. Clause 147. The method according to either clause 79 or 146, wherein the product saponin is desarabinofuranosyl-QS-211870 A V1. Clause 148. The method according to either clause 80 or 146, wherein the product saponin is desarabinofuranosyl-QS-211870 A V2. Clause 149. The method according to either clause 81 or 141, wherein the product saponin is a desarabinofuranosyl-QS-211856 B component. Clause 150. The method according to either clause 82 or 149, wherein the product saponin is desarabinofuranosyl-QS-211856 B V1. Clause 151. The method according to either clause 83 or 149, wherein the product saponin is desarabinofuranosyl-QS-211856 B V2. Clause 152. The method according to either clause 84 or 141, wherein the product saponin is desarabinofuranosyl-QS-211712 B component. Clause 153. The method according to either clause 85 or 141, wherein the product saponin is a desarabinofuranosyl-QS-211870 B component. Clause 154. The method according to either clause 86 or 153, wherein the product saponin is desarabinofuranosyl-QS-211870 B V1. Clause 155. The method according to either clause 87 or 153, wherein the product saponin is desarabinofuranosyl-QS-211870 B V2. Clause 156. The method according to clause 88, wherein the product saponin is an acetylated QS-21 family component. Clause 157. The method according to either clause 89 or 156, wherein the product saponin is an acetylated QS-212030 A component. Clause 158. The method according to either clause 90 or 157, wherein the product saponin is acetylated QS-212030 A V1. Clause 159. The method according to either clause 91 or 157, wherein the product saponin is acetylated QS-212030 A V2. Clause 160. The method according to either clause 92 or 156, wherein the product saponin is acetylated QS-211898 A component. Clause 161. The method according to either clause 93 or 156, wherein the product saponin is an acetylated QS-212044 A component. Clause 162. The method according to either clause 94 or 161, wherein the product saponin is acetylated QS-212044 A V1. Clause 163. The method according to either clause 95 or 161, wherein the product saponin is acetylated QS-212044 A V2. Clause 164. The method according to any one of clauses 1 to 163, wherein a single starting saponin is converted to a single product saponin. Clause 165. The method according to any one of clauses 1 to 163, wherein a plurality of starting saponins are converted to a plurality of product saponins. Clause 166. The method according to clause 165, wherein the plurality of starting saponins comprises QS-18 family components, such as described in any one of clauses 29 to 42. Clause 167. The method according to either clause 165 or 166, wherein the plurality of starting saponins comprises desglucosyl-QS-17 family components, such as described in any one of clauses 44 to 57. Clause 168. The method according to any one of clauses 165 to 167, wherein the plurality of starting saponins comprises QS-17 family components, such as described in any one of clauses 59 to 72. Clause 169. The method according to any one of clauses 165 to 168, wherein the plurality of starting saponins comprises desarabinofuranosyl-QS-18 family components, such as described in any one of clause 74 to 87. Clause 170. The method according to any one of clauses 165 to 169, wherein the plurality of starting saponins comprises acetylated desglucosyl-QS-17 family components, such as described in any one of clause 89 to 95. Clause 171. The method according to any one of clauses 1 to 170, wherein the starting saponin is a minor component in a saponin-containing composition, such as a minor component in a plant cell culture extract or in saponins synthesized by a plant cell culture. Clause 172. The method according to any one of clauses 1 to 170, wherein the starting saponin is a major component in a saponin-containing composition, such as a major component in a plant cell culture extract or in saponins synthesized by a plant cell culture. Clause 173. The method according to any one of clauses 1 to 172, wherein the starting saponin is partially purified. Clause 174. The method according to any one of clauses 1 to 172, wherein the starting saponin is substantially purified. Clause 175. The method according to any one of clauses 1 to 174, wherein the enzymatic conversion involves the removal of a single sugar residue. Clause 176. The method according to clause 175, wherein the enzymatic conversion involves the removal of a glucose residue. Clause 177. The method according to clause 176, wherein the enzymatic conversion involves the removal of a beta-glucose residue. Clause 178. The method according to clause 177, wherein the enzymatic conversion involves the removal of the beta-glucose residue: Clause 179. The method according to clause 175, wherein the enzymatic conversion involves the removal of a rhamnose residue. Clause 180. The method according to clause 179, wherein the enzymatic conversion involves the removal of an alpha-rhamnose residue. Clause 181. The method according to clause 180, wherein the enzymatic conversion involves the removal of the alpha-rhamnose residue: Clause 182. The method according to any one of clauses 1 to 174, wherein the enzymatic conversion involves the removal of a plurality of sugar residues. Clause 183. The method according to any one of clauses 1 to 182, wherein the method involves multiple enzymatic conversions. Clause 184. The method according to clause 183, wherein the multiple enzymatic conversions are undertaken in series. Clause 185. The method according to clause 183, wherein the multiple enzymatic conversions are undertaken in parallel. Clause 186. The method according to any one of clauses 183 to 185, wherein the multiple enzymatic conversions comprise, such as consist of, the removal of glucose and rhamnose. Clause 187. The method according to clause 186, wherein the multiple enzymatic conversions comprise, such as consist of, the removal of a beta-glucose residue and an alpha-rhamnose residue. Clause 188. The method according to clause 187, wherein the multiple enzymatic conversions comprise, such as consist of, the removal of: Clause 189. The method according to any one of clauses 1 to 42, 58 to 87, 96 to 110, 126 to 155 or 164 to 174, wherein the enzymatic conversion is carried out by an enzyme demonstrating beta exo glucosidase activity. Clause 190. The method according to any one of clauses 1 to 27, 43 to 57, 88 to 125 or 156 to 174, wherein the enzymatic conversion is carried out by an enzyme demonstrating alpha exo rhamnosidase activity. Clause 191. The method according to any one of clauses 1 to 190, wherein the glycosidase is of external origin. Clause 192. The method according to any one of clauses 1 to 191, wherein the enzymatic conversion occurs in an extra cellular environment. Clause 193. The method according to any one of clauses 1 to 192, wherein the glycosidase is recombinantly produced. Clause 194. The method according to any one of clauses 1 to 193, wherein the glycosidase is provided in the form of a lysate, such as a clarified lysate and in particular an E. coli lysate or clarified lysate. Clause 195. The method according to any one of clauses 1 to 194, wherein the enzymatic conversion is undertaken at pH 4 to 9, especially pH 5 to 8, and in particular pH 5.5 to 7.5 such as pH 5.5 to 6.5. Clause 196. The method according to any one of clauses 1 to 195, wherein the enzymatic conversion is undertaken at 10 degC to 60 degC, especially 15 degC to 50 degC, in particular 15 degC to 45 degC, such as 20 degC to 42 degC. Clause 197. The method according to any one of clauses 1 to 196, wherein the enzymatic conversion occurs over a period of up to 2 days, especially up to 1 day, in particular up to 18 hrs, such as 12 hrs, for example up to 6 hrs. Clause 198. The method according to any one of clauses 1 to 197, wherein the enzymatic conversion occurs in water or an aqueous solution with water miscible co- solvent(s). Clause 199. The method according to any one of clauses 1 to 198, wherein the starting saponins are present at a concentration of 0.001 to 100 g per litre, especially 0.005 to 75 g per litre, in particular 0.01 to 50 g per litre, such as 0.1 to 25 g per litre, for example 1 to 10 g per litre. Clause 200. The method according to any one of clauses 1 to 199, wherein the enzymatic conversion occurs in a batch reaction volume of 500 ml to 2000 L, especially 1 L to 1000 L, in particular 10 L to 500 L, such as 25 L to 200 L. Clause 201. The method according to any one of clauses 1 to 200, wherein the weight of each glycosidase present is in the range of 0.0001 mg to 25 mg per ml, especially 0.0001 mg to 5 mg per ml, in particular 0.0001 mg to 1 mg per ml, such as 0.001 mg to 0.5 mg per ml. Clause 202. The method according to any one of clauses 1 to 201, wherein the weight of each glycosidase present is in the range of 0.01 mg to 100 mg of dried clarified lysate per ml, especially 0.01 mg to 30 mg per ml, in particular 0.01 mg to 5 mg per ml, such as 0.01 mg to 1 mg per ml. Clause 203. Use of a glycosidase for enzymatically converting a starting saponin to the product saponin, such as in a method of any one of clauses 1 to 202. Clause 204. The method or use according to any one of clauses 189 or 191 to 203, wherein the glucosidase comprises, such as consists of, an amino acid sequence according to SEQ ID No.262, 208, 63, 229, 250, 5, 101, 207, 169, 247, 302, 324, 319, 9, 240, 325, 338, 850, 879, 868, 826, 804, 888, 881, 891, 816, 827, 857, 853, 842, 814, 886, 885, 838, 829, 808, 828, 870, 873, 844, 882, 874, 825, 824, 823, 810, 894, 849, 803, 890, 841, 832, 830, 845, 871, 837, 883 or 809 or functional variants thereof. Clause 205. The use or method according to clause 204, wherein the enzyme comprises, such as consists of, an amino acid sequence according to SEQ ID No.262, 208, 63, 229, 250, 5, 101, 207, 169, 247, 302, 324, 319, 9, 240, 325 or 338, or functional variants thereof. Clause 206. The use or method according to clause 205, wherein the enzyme comprises, such as consists of, an amino acid sequence according to SEQ ID No.262, 208, 63, 229, 250, 5, 101, 207, 169, 247, 302, 324 or 319, or functional variants thereof. Clause 207. The use or method according to clause 206, wherein the enzyme comprises, such as consists of, an amino acid sequence according to SEQ ID No.262, 208, 63, 229, 250, 5, 101 or 207, or functional variants thereof. Clause 208. The use or method according to clause 207, wherein the enzyme comprises, such as consists of, an amino acid sequence according to SEQ ID No.262, or functional variants thereof. Clause 209. The use or method according to clause 208, wherein the enzyme is an engineered glucosidase polypeptide according to any one of clauses 225 to 341. Clause 210. The method or use according to any one of clauses 190 to 209, wherein the rhamnosidase comprises, such as consists of, an amino acid sequence according to SEQ ID No.992, 1003, 1052, 1073, 1017, 1055, 1075, 1001, 1007, 1061, 1079, 1027, 1039, 1041, 989, 1053, 1018, 1066, 1082, 1076, 993, 1077, 1046, 1015, 1063, 1054, 1074, 1067 or 1033, or functional variants thereof. Clause 211. The use or method according to clause 210, wherein the enzyme comprises, such as consists of, an amino acid sequence according to SEQ ID No.992, 1003, 1052, 1073, 1017, 1055, 1075, 1001, 1007, 1061, 1079, 1027, 1039, 1041, 989, 1053, 1018, 1066, 1082, 1076, 993 or 1077, or functional variants thereof. Clause 212. The use or method according to clause 211, wherein the enzyme comprises, such as consists of, an amino acid sequence according to SEQ ID No.992, 1003, 1052, 1073, 1017, 1055, 1075, 1001, 1007, 1061, 1079, 1027, 1039, 1041 or 989, or functional variants thereof. Clause 213. The use or method according to clause 212, wherein the enzyme comprises, such as consists of, an amino acid sequence according to SEQ ID No.1017, or functional variants thereof. Clause 214. The use or method according to clause 213, wherein the enzyme is an engineered rhamnosidase polypeptide according to any one of clauses 342 to 429. Clause 215. A saponin prepared by the method of any one of clauses 1 to 202 and 204 to 214. Clause 216. A saponin-containing composition comprising a product saponin prepared by the method of any one of clauses 1 to 202 and 204 to 214. Clause 217. The saponin-containing composition according to clause 216, comprising QS- 21 family components. Clause 218. An adjuvant composition comprising a saponin or saponin-containing composition according to any one of clauses 215 to 217. Clause 219. An adjuvant composition prepared using a saponin or saponin-containing composition according to any one of clauses 215 to 217. Clause 220. Use of a saponin or saponin-containing composition according to any one of clauses 215 to 217 in the manufacture of an adjuvant composition. Clause 221. An immunogenic composition comprising a saponin or saponin-containing composition according to any one of clauses 215 to 217 and an antigen. Clause 222. An immunogenic composition comprising a saponin or saponin-containing composition according to any one of clauses 215 to 217 and a polynucleotide encoding an antigen. Clause 223. A kit of parts comprising: (i) a saponin or saponin-containing composition according to any one of clauses 215 to 217; and (ii) an antigen. Clause 224. A kit of parts comprising: (i) a saponin or saponin-containing composition according to any one of clauses 215 to 217; and (ii) a polynucleotide encoding an antigen. Clause 225. An engineered glucosidase polypeptide comprising an amino acid sequence that is at least 80% identical to the amino acid sequence of SEQ ID No.262, or a functional fragment thereof, wherein the engineered glucosidase polypeptide includes at least one residue substitution from: F44Y; V60L; G117A; F170N; V263G or V263L; N351H or N351Q; A355H, A355I, A355L, A355M, A355R, A355T or A355W; A356P; R357A, R357C, R357K, R357M or R357Q; G362C; T365A, T365N or T365S; L367C; V394R; V395Y; Q396E, Q396G, Q396N, Q396P, Q396R, Q396S or Q396Y; F430W; R435F; V438T; V440F; F442M or F442Q; G444T; A473F or A473R; L474C, L474I or L474V; I475F; L492C, L492G, L492H, L492I, L492N, L492Q, L492V, L492W or L492Y; Q493F or Q493H; P494H or P494I; S495I, S495K or S495Q; G496P or G496W; D498A, D498E, D498F, D498I, D498K, D498L, D498N, D498P, D498R, D498S, D498T or D498V; A502R; M504G or M504R; L507A or L507R; T508M; L529M; F535P; A536D or A536E; A537R; F541A, F541I, F541L, F541M or F541V; L542I; Q543G or Q543L; E547L; and Y585W, for use in the method of any clause 1 to 214. Clause 226. The polypeptide according to clause 225, having one of the substitutions. Clause 227. The polypeptide according to clause 225, having two of the substitutions. Clause 228. The polypeptide according to clause 225, having three of the substitutions. Clause 229. The polypeptide according to clause 225, having four of the substitutions. Clause 230. The polypeptide according to clause 225, having five of the substitutions. Clause 231. The polypeptide according to clause 225, having six of the substitutions. Clause 232. The polypeptide according to clause 225, having seven of the substitutions. Clause 233. The polypeptide according to clause 225, having eight of the substitutions. Clause 234. The polypeptide according to clause 225, having nine of the substitutions. Clause 235. The polypeptide according to clause 225, having ten of the substitutions. Clause 236. The polypeptide according to clause 225, having eleven of the substitutions. Clause 237. The polypeptide according to clause 225, having twelve of the substitutions. Clause 238. The polypeptide according to clause 225, having thirteen of the substitutions. Clause 239. The polypeptide according to clause 225, having fourteen of the substitutions. Clause 240. The polypeptide according to clause 225, having fifteen of the substitutions. Clause 241. The polypeptide according to clause 225, having sixteen of the substitutions. Clause 242. The polypeptide according to clause 225, having seventeen of the substitutions. Clause 243. The polypeptide according to clause 225, having eighteen of the substitutions. Clause 244. The polypeptide according to clause 225, having nineteen of the substitutions. Clause 245. The polypeptide according to clause 225, having twenty of the substitutions. Clause 246. The polypeptide according to clause 225, having twenty-one of the substitutions. Clause 247. The polypeptide according to clause 225, having twenty-two of the substitutions. Clause 248. The polypeptide according to clause 225, having twenty-three of the substitutions. Clause 249. The polypeptide according to clause 225, having twenty-four of the substitutions. Clause 250. The polypeptide according to clause 260, having twenty-five of the substitutions. Clause 251. The polypeptide according to clause 225, having twenty-six to thirty of the substitutions. Clause 252. The polypeptide according to clause 225, having thirty-one to forty-three substitutions of the substitutions. Clause 253. The polypeptide according to any one of clauses 225 to 252, comprising F44Y. Clause 254. The polypeptide according to any one of clauses 225 to 253, comprising V60L. Clause 255. The polypeptide according to any one of clauses 225 to 254, comprising G117A. Clause 256. The polypeptide according to any one of clauses 225 to 255, comprising F170N. Clause 257. The polypeptide according to any one of clauses 225 to 256, comprising V263G or V263L. Clause 258. The polypeptide according to clause 257, comprising V263L. Clause 259. The polypeptide according to any one of clauses 225 to 258, comprising N351H or N351Q. Clause 260. The polypeptide according to clause 259, comprising N351H. Clause 261. The polypeptide according to any one of clauses 225 to 260, comprising A355H, A355I, A355L, A355M, A355R, A355T or A355W. Clause 262. The polypeptide according to clause 261, comprising A355H. Clause 263. The polypeptide according to clause 261, comprising A355I. Clause 264. The polypeptide according to clause 261, comprising A355L. Clause 265. The polypeptide according to clause 261, comprising A355M. Clause 266. The polypeptide according to clause 261, comprising A355R. Clause 267. The polypeptide according to clause 261, comprising A355T. Clause 268. The polypeptide according to clause 261, comprising A355W. Clause 269. The polypeptide according to any one of clauses 225 to 268, comprising A356P. Clause 270. The polypeptide according to any one of clauses 225 to 269, comprising R357A, R357C, R357K, R357M or R357Q. Clause 271. The polypeptide according to clause 270, comprising R357M. Clause 272. The polypeptide according to any one of clauses 225 to 271, comprising G362C. Clause 273. The polypeptide according to any one of clauses 225 to 272, comprising T365A, T365N or T365S. Clause 274. The polypeptide according to clause 273, comprising T365N. Clause 275. The polypeptide according to any one of clauses 225 to 274, comprising L367C. Clause 276. The polypeptide according to any one of clauses 225 to 275, comprising V394R. Clause 277. The polypeptide according to any one of clauses 225 to 276, comprising V395Y. Clause 278. The polypeptide according to any one of clauses 225 to 277, comprising Q396E, Q396G, Q396N, Q396P, Q396R, Q396S or Q396Y. Clause 279. The polypeptide according to clause 278, comprising Q396R. Clause 280. The polypeptide according to any one of clauses 225 to 279, comprising F430W Clause 281. The polypeptide according to any one of clauses 225 to 280, comprising R435F. Clause 282. The polypeptide according to any one of clauses 225 to 281, comprising V438T. Clause 283. The polypeptide according to any one of clauses 225 to 282, comprising V440F. Clause 284. The polypeptide according to any one of clauses 225 to 283, comprising F442M or F442Q. Clause 285. The polypeptide according to clause 284, comprising F442Q. Clause 286. The polypeptide according to any one of clauses 225 to 285, comprising G444T. Clause 287. The polypeptide according to any one of clauses 225 to 286, comprising A473F or A473R. Clause 288. The polypeptide according to clause 287, comprising A473F. Clause 289. The polypeptide according to any one of clauses 225 to 288, comprising L474C, L474I or L474V. Clause 290. The polypeptide according to clause 289, comprising L474C. Clause 291. The polypeptide according to any one of clauses 225 to 290, comprising I475F. Clause 292. The polypeptide according to any one of clauses 225 to 291, comprising L492C, L492G, L492H, L492I, L492N, L492Q, L492V, L492W or L492Y. Clause 293. The polypeptide according to clause 292, comprising L492H. Clause 294. The polypeptide according to clause 292, comprising L492N. Clause 295. The polypeptide according to clause 292, comprising L492V. Clause 296. The polypeptide according to any one of clauses 225 to 295, comprising Q493F or Q493H. Clause 297. The polypeptide according to any one of clauses 225 to 296, comprising P494I. Clause 298. The polypeptide according to any one of clauses 225 to 297, comprising S495I, S495K or S495Q. Clause 299. The polypeptide according to any one of clauses 225 to 298, comprising G496P or G496W. Clause 300. The polypeptide according to any one of clauses 225 to 299, comprising G496P. Clause 301. The polypeptide according to any one of clauses 225 to 300, comprising D498A, D498E, D498F, D498I, D498K, D498L, D498N, D498P, D498R, D498S, D498T or D498V. Clause 302. The polypeptide according to clause 301, comprising D498P. Clause 303. The polypeptide according to any one of clauses 225 to 302, comprising A502R; Clause 304. The polypeptide according to any one of clauses 225 to 303, comprising M504G or M504R. Clause 305. The polypeptide according to any one of clauses 225 to 304, comprising M504R. Clause 306. The polypeptide according to any one of clauses 225 to 305, comprising L507A or L507R. Clause 307. The polypeptide according to clause 306, comprising L507R. Clause 308. The polypeptide according to any one of clauses 225 to 307, comprising T508M. Clause 309. The polypeptide according to any one of clauses 225 to 308, comprising L529M. Clause 310. The polypeptide according to any one of clauses 225 to 309, comprising F535P. Clause 311. The polypeptide according to any one of clauses 225 to 310, comprising A536D or A536E. Clause 312. The polypeptide according to any one of clauses 225 to 311, comprising A537R. Clause 313. The polypeptide according to any one of clauses 225 to 312, comprising F541A, F541I, F541L, F541M or F541V. Clause 314. The polypeptide according to clause 313, comprising F541I. Clause 315. The polypeptide according to any one of clauses 225 to 314, comprising L542I. Clause 316. The polypeptide according to any one of clauses 225 to 315, comprising Q543G or Q543L. Clause 317. The polypeptide according to any one of clauses 225 to 316, comprising E547L. Clause 318. The polypeptide according to any one of clauses 225 to 317, comprising Y585W. Clause 319. The polypeptide according to clause 225, comprising one mutation which is T365N. Clause 320. The polypeptide according to clause 225, comprising R357M, T365N, A473F, L474C and I475F. Clause 321. The polypeptide according to clause 225, comprising F44Y, R357M, T365N, F442Q, A473F, L474C and I475F. Clause 322. The polypeptide according to clause 225, comprising F44Y, V263L, R357M, T365N, F442Q, A473F, L474C, I475F and F541I. Clause 323. The polypeptide according to clause 225, comprising at least one residue substitution from F44Y, V263L, A355W, R357M, T365N, L367C, Q396R, F442Q, L474C, I475F and F541I, Clause 324. The polypeptide according to clause 323, comprising F44Y, V263L, A355W, R357M, T365N, L367C, Q396R, F442Q, L474C, I475F and F541I, Clause 325. The polypeptide according to any one of clauses 225 to 324, comprising an amino acid sequence that is at least 80% identical to the amino acid sequence of SEQ ID No.262, or a functional fragment thereof, wherein the engineered glucosidase polypeptide includes at least one residue substitution from: F44Y; V263L; N351H; A355H, A355M or A355W; R357M; T365N; L367C; Q396R; V438T; F442Q; L474C; I475F; L492V, L492N or L492H, M504R; L507R; and F541I. Clause 326. The polypeptide according to any one of clauses 225 to 324 comprising an amino acid sequence that is at least 85% identical to the amino acid sequence of SEQ ID No.262. Clause 327. The polypeptide according to any one of clauses 225 to 324 comprising an amino acid sequence that is at least 90% identical to the amino acid sequence of SEQ ID No.262. Clause 328. The polypeptide according to any one of clauses 225 to 324 comprising an amino acid sequence that is at least 95% identical to the amino acid sequence of SEQ ID No.262. Clause 329. The polypeptide according to any one of clauses 225 to 324 comprising an amino acid sequence that is at least 98% identical to the amino acid sequence of SEQ ID No.262. Clause 330. The polypeptide according to any one of clauses 225 to 324, wherein the functional variant comprises a sequence having a fragment of at least 100, especially at least 200, particularly at least 300, such as at least 400, for example at least 500 contiguous amino acids of SEQ ID No.262. Clause 331. The polypeptide according to clause 225, comprising the amino acid sequence of SEQ ID No.1179. Clause 332. The polypeptide according to clause 225, comprising the amino acid sequence of SEQ ID No.1180. Clause 333. The polypeptide according to clause 225, comprising the amino acid sequence of SEQ ID No.1181. Clause 334. The polypeptide according to clause 225, comprising the amino acid sequence of SEQ ID No.1182. Clause 335. The polypeptide according to clause 225, comprising the amino acid sequence of SEQ ID No.1183. Clause 336. The polypeptide according to any one of clauses 225 to 324, further comprising an affinity tag. Clause 337. The polypeptide according to clause 336, wherein the affinity tag is a poly-his tag, such as a hexa-his tag. Clause 338. The polypeptide according to either clause 336 or 337, wherein the affinity tag is N-terminally located. Clause 339. The polypeptide according to clause 338, comprising an amino acid sequence of SEQ ID No.1177. Clause 340. The polypeptide according to either clause 336 or 337, wherein the affinity tag is C-terminally located. Clause 341. The polypeptide according to clause 340, comprising an amino acid sequence of SEQ ID No.1178. Clause 342. An engineered rhamnosidase polypeptide comprising an amino acid sequence that is at least 80% identical to the amino acid sequence of SEQ ID No.1017, or a functional fragment thereof, wherein the engineered rhamnosidase polypeptide includes at least one residue substitution from: (i) A56C (ii) A143P (iii) Q181H, Q181R or Q181S (iv) L214M (v) G215S (vi) F216M (vii) G218D or G218N (viii) K219G (ix) A238M (x) T252Y (xi) T311W (xii) V326C (xiii) G357C (xiv) S369C, S369I, S369K or S369M (xv) I487M, I487Q or I487V (xvi) K492N (xvii) V499T (xviii) G508S (xix) R543C (xx) L557Y (xxi) G634A (xxii) S635N (xxiii) A690C and (xxiv) Q921H, for use in the method of any clause 1 to 214. Clause 343. A polypeptide comprising an amino acid sequence of sequence of SEQ ID No. 1017 with one to twenty-four mutations selected from the list consisting of: (i) A56C (ii) A143P (iii) Q181H, Q181R or Q181S (iv) L214M (v) G215S (vi) F216M (vii) G218D or G218N (viii) K219G (ix) A238M (x) T252Y (xi) T311W (xii) V326C (xiii) G357C (xiv) S369C, S369I, S369K or S369M (xv) I487M, I487Q or I487V (xvi) K492N (xvii) V499T (xviii) G508S (xix) R543C (xx) L557Y (xxi) G634A (xxii) S635N (xxiii) A690C and (xxiv) Q921H. Clause 344. The polypeptide according to either clause 342 or 343, having one of the substitutions. Clause 345. The polypeptide according to either clause 342 or 343, having two of the substitutions. Clause 346. The polypeptide according to either clause 342 or 343, having three of the substitutions. Clause 347. The polypeptide according to either clause 342 or 343, having four of the substitutions. Clause 348. The polypeptide according to either clause 342 or 343, having five of the substitutions. Clause 349. The polypeptide according to either clause 342 or 343, having six of the substitutions. Clause 350. The polypeptide according to either clause 342 or 343, having seven of the substitutions. Clause 351. The polypeptide according to either clause 342 or 343, having eight of the substitutions. Clause 352. The polypeptide according to either clause 342 or 343, having nine of the substitutions. Clause 353. The polypeptide according to either clause 342 or 343, having ten of the substitutions. Clause 354. The polypeptide according to either clause 342 or 343, having eleven of the substitutions. Clause 355. The polypeptide according to either clause 342 or 343, having twelve of the substitutions. Clause 356. The polypeptide according to either clause 342 or 343, having thirteen of the substitutions. Clause 357. The polypeptide according to either clause 342 or 343, having fourteen of the substitutions. Clause 358. The polypeptide according to either clause 342 or 343, having fifteen of the substitutions. Clause 359. The polypeptide according to either clause 342 or 343, having sixteen of the substitutions. Clause 360. The polypeptide according to either clause 342 or 343, having seventeen of the substitutions. Clause 361. The polypeptide according to either clause 342 or 343, having eighteen of the substitutions. Clause 362. The polypeptide according to either clause 342 or 343, having nineteen of the substitutions. Clause 363. The polypeptide according to either clause 342 or 343, having twenty of the substitutions. Clause 364. The polypeptide according to either clause 342 or 343, having twenty-one of the substitutions. Clause 365. The polypeptide according to either clause 342 or 343, having twenty-two of the substitutions. Clause 366. The polypeptide according to either clause 342 or 343, having twenty-three of the substitutions. Clause 367. The polypeptide according to either clause 342 or 343, having twenty-four of the substitutions. Clause 368. The polypeptide according to any one of clauses 342 to 367, comprising A56C. Clause 369. The polypeptide according to any one of clauses 342 to 368, comprising A143P. Clause 370. The polypeptide according to any one of clauses 342 to 369, comprising Q181H, Q181R or Q181S. Clause 371. The polypeptide according to clause 370, comprising Q181H. Clause 372. The polypeptide according to clause 370, comprising Q181R. Clause 373. The polypeptide according to clause 370, comprising Q181S. Clause 374. The polypeptide according to any one of clauses 342 to 373, comprising L214M. Clause 375. The polypeptide according to any one of clauses 342 to 374, comprising G215S. Clause 376. The polypeptide according to any one of clauses 342 to 375, comprising F216M. Clause 377. The polypeptide according to any one of clauses 342 to 376, comprising G218D or G218N. Clause 378. The polypeptide according to clause 377, comprising G218D. Clause 379. The polypeptide according to clause 377, comprising G218N. Clause 380. The polypeptide according to any one of clauses 342 to 379, comprising K219G. Clause 381. The polypeptide according to any one of clauses 342 to 380, comprising A238M. Clause 382. The polypeptide according to any one of clauses 342 to 381, comprising T252Y. Clause 383. The polypeptide according to any one of clauses 342 to 382, comprising T311W. Clause 384. The polypeptide according to any one of clauses 342 to 383, comprising V326C. Clause 385. The polypeptide according to any one of clauses 342 to 384, comprising G357C. Clause 386. The polypeptide according to any one of clauses 342 to 385, comprising S369C, S369I, S369K or S369M. Clause 387. The polypeptide according to clause 386, comprising S369C. Clause 388. The polypeptide according to clause 386, comprising S369I. Clause 389. The polypeptide according to clause 386, comprising S369K. Clause 390. The polypeptide according to clause 386, comprising S369M. Clause 391. The polypeptide according to any one of clauses 342 to 390, comprising I487M, I487Q or I487V. Clause 392. The polypeptide according to clause 391, comprising I487M. Clause 393. The polypeptide according to clause 391, comprising I487Q. Clause 394. The polypeptide according to clause 391, comprising I487V. Clause 395. The polypeptide according to any one of clauses 342 to 394, comprising K492N. Clause 396. The polypeptide according to any one of clauses 342 to 395, comprising V499T. Clause 397. The polypeptide according to any one of clauses 342 to 396, comprising G508S. Clause 398. The polypeptide according to any one of clauses 342 to 397, comprising R543C. Clause 399. The polypeptide according to any one of clauses 342 to 398, comprising L557Y. Clause 400. The polypeptide according to any one of clauses 342 to 399, comprising G634A. Clause 401. The polypeptide according to any one of clauses 342 to 400, comprising S635N. Clause 402. The polypeptide according to any one of clauses 342 to 401, comprising A690C. Clause 403. The polypeptide according to any one of clauses 342 to 402, comprising Q921H. Clause 404. The polypeptide according to either clause 342 or 343, comprising one mutation which is K219G. Clause 405. The polypeptide according to clause 342 or 343, comprising A143P, L214M, K219G and Q921H. Clause 406. The polypeptide according to clause 342 or 343, comprising A143P, L214M, K219G, G357C and Q921H. Clause 407. The polypeptide according to clause 406, comprising A143P, L214M, G215S, G218N, K219G, G357C, G508S, G634A and Q921H. Clause 408. The polypeptide according to clause 342 or 343, comprising A143P, L214M, G215S, K219G, G357C, G508S, G634A and Q921H and one to sixteen mutations selected from the list consisting of: (i) A56C (ii) Q181H, Q181R or Q181S (iii) F216M (iv) G218D or G218N (v) A238M (vi) T252Y (vii) T311W (viii) V326C (ix) S369C, S369I, S369K or S369M (x) I487M, I487Q or I487V (xi) K492N (xii) V499T (xiii) R543C (xiv) L557Y (xv) S635N and (xvi) A690C. Clause 409. The polypeptide according to clause 408, comprising G218D or G218N. Clause 410. The polypeptide according to any one of clauses 342 to 409, comprising an amino acid sequence that is at least 85% identical to the amino acid sequence of SEQ ID No.1017. Clause 411. The polypeptide according to any one of clauses 342 to 409, comprising an amino acid sequence that is at least 90% identical to the amino acid sequence of SEQ ID No.1017. Clause 412. The polypeptide according to any one of clauses 342 to 409, comprising an amino acid sequence that is at least 95% identical to the amino acid sequence of SEQ ID No.1017. Clause 413. The polypeptide according to any one of clauses 342 to 409, comprising an amino acid sequence that is at least 98% identical to the amino acid sequence of SEQ ID No.1017. Clause 414. The polypeptide according to any one of clauses 342 to 409, wherein the functional variant comprises a sequence having a fragment of at least 100, especially at least 200, particularly at least 300, such as at least 400, for example at least 500 contiguous amino acids of SEQ ID No.1017. Clause 415. The polypeptide according to clause 342, comprising the amino acid sequence of SEQ ID No.1189. Clause 416. The polypeptide according to clause 342, comprising the amino acid sequence of SEQ ID No.1190. Clause 417. The polypeptide according to clause 342, comprising the amino acid sequence of SEQ ID No.1191. Clause 418. The polypeptide according to clause 342, comprising the amino acid sequence of SEQ ID No.1192. Clause 419. The polypeptide according to clause 342, comprising the amino acid sequence of SEQ ID No.1193. Clause 420. The polypeptide according to any one of clauses 342 to 419, further comprising an affinity tag. Clause 421. The polypeptide according to clause 420, wherein the affinity tag is a poly-his tag, such as a hexa-his tag. Clause 422. The polypeptide according to either clause 420 or 421, wherein the affinity tag is N-terminally located. Clause 423. The polypeptide according to clause 422, comprising an amino acid sequence of SEQ ID No.1177. Clause 424. The polypeptide according to either clause 420 or 421, wherein the affinity tag is C-terminally located. Clause 425. The polypeptide according to clause 424, comprising an amino acid sequence of SEQ ID No.1178. Clause 426. The polypeptide according to any one of clauses 342 to 425, comprising 1100 residues or fewer, especially 1050 residues or fewer, in particular 1000 residues or fewer, such as 950 residues or fewer. Clause 427. The polypeptide according to any one of clauses 342 to 426, consisting of an amino acid sequence of SEQ ID No.1 with one to twenty-four mutations selected from the list consisting of: (i) A56C (ii) A143P (iii) Q181H, Q181R or Q181S (iv) L214M (v) G215S (vi) F216M (vii) G218D or G218N (viii) K219G (ix) A238M (x) T252Y (xi) T311W (xii) V326C (xiii) G357C (xiv) S369C, S369I, S369K or S369M (xv) I487M, I487Q or I487V (xvi) K492N (xvii) V499T (xviii) G508S (xix) R543C (xx) L557Y (xxi) G634A (xxii) S635N (xxiii) A690C and (xxiv) Q921H. Clause 428. A method for preparing an adjuvant comprising the steps of preparing a saponin according to the method of any one of the clauses 1 to 214, and formulating the saponin into an adjuvant. Clause 429. The method according to clause 428, wherein the saponin comprises QS-21 family components. Clause 430. A method for preparing an immunogenic composition comprising the steps of preparing an adjuvant according to the method of any one of clauses 1 to 214, and formulating the adjuvant into a composition comprising an antigen or a polynucleotide encoding an antigen. Clause 431. A method for preparing an immunogenic composition comprising the steps of preparing an adjuvant according to the method of any one of clauses 1 to 214, and formulating the adjuvant into a composition comprising an antigen or a polynucleotide encoding an antigen. Clause 432. The method according to clauses 430 and 431 wherein the saponin comprises QS-21 family components. Clause 433. A method for producing saponins by plant cell culture, said method comprising the steps of: (i) culturing plant cells capable of synthesizing quillaic acid triterpene glycosides saponins, such as plant cells from Quillaja saponaria, in a culture medium, (ii) depleting the culture medium from any nitrogen source, as described in any one of clauses 15 to 17, (iii) eliciting the cells with an elicitor, as described in clause 12 or 13, (iv) preparing a crude plant cell culture extract, (v) enzymatically converting starting saponins, as described in any one of clauses 28 to 95, from the crude plant cell culture extract to product saponins, as described in any one of clauses 96 to 163 and (vi) optionally purifying the product saponins, wherein the enzymatic conversion is as described in any one of clauses 175 to 202 and 204 to 214. The teaching of all references in the present application, including patent applications and granted patents, are herein fully incorporated by reference to the fullest extent possible. A composition or method or process defined as “comprising” certain elements is understood to encompass a composition, method or process (respectively) consisting of those elements. As used herein, ‘consisting essentially of’ means additional components may be present provided they do not alter the overall properties or function. In respect of numerical values, the terms 'approximately', ‘around’ or ‘about’ will typically mean a value within plus or minus 10 percent of the stated value, especially within plus or minus 5 percent of the stated value and in particular the stated value. Throughout the specification, including the claims, where the context permits, the term ‘comprising’ and variants thereof such as ‘comprises’ are to be interpreted as including the stated element (e.g. integer) or elements (e.g. integers) without necessarily excluding any other elements (e.g. integers). Thus a composition ‘comprising’ X may consist exclusively of X or may include something additional e.g. X + Y. The word ‘substantially’ does not exclude ‘completely’ e.g. a composition which is ‘substantially free’ from Y may be completely free from Y. Where necessary, the word ‘substantially’ may be omitted from the definition of the invention. As used herein, the singular forms ‘a’, ‘an’ and ‘the’ include plural references unless the content clearly dictates otherwise. As used herein, ng refers to nanograms, ug or µg refers to micrograms, mg refers to milligrams, mL or ml refers to milliliter, and mM refers to millimolar. Similar terms, such as um, are to be construed accordingly. Unless specifically stated, a process comprising a step of mixing two or more components does not require any specific order of mixing. Thus components can be mixed in any order. Where there are three components then two components can be combined with each other, and then the combination may be combined with the third component, etc. The invention will be further described by reference to the following, non-limiting, examples: EXAMPLES Crude bark extract was separated by reverse phase HPLC using a C4 column and gradient elution: mobile phase A - water/acetonitrile, 7/3 v/v with 0.15% trifluoroacetic acid; mobile phase B - acetonitrile with 0.15% trifluoroacetic acid. UV detection was at 214 nm. Crude bark extract samples are diluted as necessary with purified water. Polyvinylpolypyrrolidone (PVPP; 60 mg/mL) was added, the mixture stirred for approximately 30 minutes, and then centrifuged to separate the PVPP resin from the supernatant. The supernatant was then analysed to provide an HPLC UV chromatogram. Fig.1 provides a representative example of an HPLC UV chromatogram. The peak corresponding to the QS-21 fraction is indicated. Example 2 – Analytical Methods HPLC-UV Equipment Waters Alliance 2690/2695 separations module Waters 2487 UV Detector or 2996 PDA Detector Vydac Protein C44.6 x 250mm 5um column Mobile Phase A (MPA) - 0.15% trifluoroacetic acid in water/acetonitrile (70:30 v/v) Mobile Phase B (MPB) - 0.15% trifluoroacetic acid in acetonitrile Table 1 - HPLC-UV Linear gradient conditions 40ul of sample is injected. UV detection is set at 214nM. Using a blank injection for reference, integration of peaks in the chromatogram provides a total absorbance. Peak of interest (e.g. QS-21 main peak) is compared to total absorbance to determine peak content as a percentage. The HPLC-UV method is also conveniently used to determine QS-21 main peak content and Preceding peak to QS-21 main peak ratio. UPLC-UV Equipment Waters Acquity UPLC Waters Acquity Tunable UV Detector Waters Acquity BEH C182.1x100mm 1.7um column Mobile Phase A (MPA) - 0.025% acetic acid in water/acetonitrile (70:30 v/v) Mobile Phase B (MPB) - 0.025% trifluoroacetic acid in water/acetonitrile (30:70 v/v) Table 2 - UPLC-UV Linear gradient conditions Column temperature 28 degrees C. 10ul of sample is injected. UV detection is set at 214nM. Using a blank injection for reference, integration of peaks in the chromatogram provides a total absorbance. Peak of interest (e.g. QS-21 main peak) is compared to total absorbance to determine peak content as a percentage. The UPLC-UV method is also conveniently used to determine 2018/QS-21 Ratio. UPLC-UV/MS Equipment Waters Acquity UPLC Waters Acquity Tunable UV Detector Waters Single-Quadrupole Mass Detector SQD1 (scanning range 1400 to 2040 M/Z) Waters Acquity BEH C182.1x100mm 1.7um column Mobile Phase A (MPA) - 0.025% trifluoroacetic acid in water/acetonitrile/isopropyl alcohol (75:20:5 v/v) Mobile Phase B (MPB) - 0.025% trifluoroacetic acid in water/acetonitrile/isopropyl alcohol (10:72:18 v/v) Table 3 - UPLC-UV/MS Linear gradient conditions Test sample is prepared in 0.2% acetic acid in water/acetonitrile (70:30 v/v). Column temperature 55 degrees C. 10ul of sample is injected. UV detection is set at 214nM. By the term ‘QS-21 group’, it is meant the triterpenoid glycosides identified from the B- isomer to the peak preceding the lyo impurity in the UPLC-UV/MS methods described herein. Although retention times vary slightly between runs, the QS-21 group is located at approximately 3.8 min (QS-21 B-isomer) to approximately 4.5 minutes (prior to lyo impurity peak, containing desarabinofuranosyl-QS-211856 A component). Using a blank injection for reference, integration of peaks in the chromatogram that elute after the solvent front between 0.5 and around 5.50 minutes and do not appear in the blank is undertaken. The monoisotope of the most abundant species is identified by combining TIC over the entire chromatogram to create a combined spectrum. Ratio of QS-212002 A component to QS-211988 A component is calculated by comparing the ion current associated with the QS-212002 A component with the ion current associated with the QS-211988 A component within the QS-21 main peak. Fig.5 provides a chromatogram of an exemplary saponin extract. Fig.6 shows expanded detail of the region including the QS-21 group and impurity peak. Fig.7A and 7B provide extracted mass chromatograms for QS-211988 A (Fig.7A) and QS-212002 A (Fig.7B) molecular weight ions of an exemplary purified Quillaja saponaria saponin extract. Example 3 – Purification of a crude aqueous extract of Quillaja saponaria Crude aqueous extract of Quillaja saponaria material having a 2018 component to QS- 21 main peak ratio of 0.064 or lower and a Preceding peak to QS-21 main peak ratio of 0.4 or lower, was treated with PVPP (1kg PVPP per litre of crude aqueous extract). After adsorption the mixture was filtered to separate the PVPP and bound impurities from the liquor. Fig.2 provides an example HPLC-UV chromatogram for crude aqueous extract of Quillaja saponaria (used for Preceding peak to QS-21 main peak ratio determination and QS-21 main peak content). Fig.3 provides an example UPLC-UV chromatogram for crude aqueous extract of Quillaja saponaria (used for 2018 component to QS-21 main peak ratio determination). Filtered liquor was concentrated and further purified by ultrafiltration/diafiltration using water and a 30kD Hellicon membrane. Resulting permeate was purified by reverse phase chromatography using a polystyrene resin (Amberchrom XT20). Table 4 - Reverse phase chromatography polystyrene resin gradient conditions Eluent B: 90% Acetonitrile and 0.25% acetic acid Column: 30 cm ID, approximately 17.7 to 20.5 L volume Loading: 50-110g per injection Fractions were pooled to provide polystyrene purified saponin extract with a composition: % QS-21 main peak ≥ 18% (by HPLC) and 2018 component/QS-21 main peak ratio ≤ 0.054 (by UPLC-UV). Fig.4 provides an example UPLC-UV chromatogram for a polystyrene purified saponin extract pool. The combined polystyrene purified fraction pool was further purified by reverse phase chromatography using a phenyl resin (EPDM). Table 5 - Reverse phase chromatography phenyl resin gradient conditions Eluent B: 90% Acetonitrile and 0.25% acetic acid Eluent C: 35.2% acetonitrile and 0.25% acetic acid Column: 45 cm ID, approximately 39.8 to 42.9 L volume Loading: 13-21g per injection QS-21-containing fractions were pooled to provide phenyl purified saponin extract with a composition: %QS-21 group ≥ 98.5 %QS-21 main peak ≥ 94.5 %2018 component ≤ 2.7% Main peak outside of the QS-21 group ≤ 1% (by UPLC-UV/MS). The combined phenyl purified saponin extract was concentrated by capture and release with reverse phase chromatography using a C8 resin (Lichroprep RP8) and the following conditions: Loaded to column conditioned at 24% acetonitrile and 0.20% acetic acid. Eluted with 60% acetonitrile and 0.20% acetic acid. 11 cm column, approximately 0.87 to 0.97 L volume Load: 50-142 g per injection The C8 concentrated saponin extract was subjected to solvent exchange using ultrafiltration/diafiltration and a Pellicon 1kDa membrane to reduce acetonitrile content below 21%. The resulting solvent exchanged saponin extract was then lyophilised in a single step to provide a final purified saponin extract product. The use of the process as described in Example 3 can consistently provide a purified saponin extract of Quillaja saponaria having a defined content in terms of QS-21 main peak and 2018 component, presenting a chromatographic profile comparable to the chromatograms shown in Fig.5 to 9. Example 4 – Screening of glucosidases for deglucosylation of QS-18 to QS-21 Method Enzyme selection The enzyme family of hydrolases (E.C.3.2.1.-) that act on glycosidic bonds (‘glycoside hydrolases’ (GH) or ‘glycosidases’), contains at present approximately one million members having wide ranging activities across molecules containing glycans and polysaccharides. A typical QS-18 family molecule contains a number of such glycosidic bonds, with the presence of the 1-3 bond between the alpha-L-rhamnose on the linear tetrasaccharide and the branched terminal beta-D-glucose differentiating the QS-18 family from the QS-21 family. The specific hydrolysis of this bond by a beta-glucosidase, i.e. an enzyme with exo-beta-1,3-glucosidase activity (E.C.3.2.1.21 and E.C.3.2.1.58) will therefore convert QS-18 family components to QS- 21 family components. Specific members of the glycoside hydrolase family having exo-beta-1,3- glucosidase activity were initially identified using the CAZy (Carbohydrate Active enZyme) database (www.cazy.com), with GH families 1, 3 and 5 purported to have enzyme members with the desired exo-beta-1,3 activity. All sequences annotated by CAZy from GH families 1,3 and 5 were obtained, and separate curated hidden Markov model profiles constructed for each which were then used to identify additional familial enzymes by searching the 209 million protein member Uniprot (www.uniprot.org) knowledgebase with the software HMMER (Eddy, 1998). In total, 22,594 sequences: 12,049, 9,278 and 1,267 representatives from GH families 1,3 and 5, respectively, were identified using this method. MMSeqs2 (Hauser, 2016) was then used to cluster each group of enzyme sequences using the default clustering workflow and parameters with a minimum sequence identity and coverage of 30% and 80%, respectively. In cases where the initial clustering yielded clusters with more than 1000 members, a second sub-clustering was performed at a higher 50% or 70% identity to ensure diverse exemplars from these larger clusters were represented more prominently. All clusters were then examined, and exemplars selected from each with preferences for annotation quality, known experimental activity, existing three dimensional structures from the Protein Data Bank (www.wwpdb.org) or known extremophile organisms as annotated by Uniprot. A final set of 400 diverse candidate enzymes was selected. Polynucleotide sequences encoding each selected enzyme linked to an N- terminal 6xHis tag and Tev-cleavage site were prepared (amino acid sequence for His-tag linker, inserted N-terminally of normal start methionine, is provided in SEQ ID No.1177) using a proprietary genetic-algorithm based codon optimization code. Details of the candidate enzyme and polynucleotide sequences are summarised below in Table 6. Table 6 – Glucosidase candidate sequences Experiment 4-1 - Screening of glucosidases for deglucosylation with purified QS-18 (0.04 mg/ml) at pH 7.5 and room temperature Nucleotide sequences were sub-cloned into pET24b+ for expression. 10 uL of E. coli cells (One Shot® BL21(DE3) chemically competent E. coli) were transferred to each well of a 96 well PCR plate (prechilled on ice). 10 uL autoclaved water was added to the DNA, resuspended by pipetting, and 1 uL of plasmid DNA (15-30 ng) was transferred to the competent cells. Immediately after addition, the resulting mixture was mixed by pipetting. Cells were heat shocked by placing the plate in a thermal cycler at 42˚C for 30 seconds then transferred directly to an ice bath for 2 min. 100 uL sterile Lysogeny Broth (LB) medium was added to each well containing transformed cells. The content of each plate was transferred into a 96-deep well plate pre-aliquoted with 400 uL LB and the plate was incubated at 37˚C with shaking and 85% humidity for 1 hour. After outgrowth, 500 uL of sterile LB containing 100 ug/mL kanamycin was added to the plates containing cells and plates incubated at 37 ˚C with shaking overnight (18 hours) with humidity control (85%). 1000 mLs of Overnight Express Media was supplemented with 1 mL kanamycin 50 mg/mL and 20 mL of 50% v/v glycerol added (50 ug/mL kanamycin final and 1% glycerol). 96- Well Assay Block 2mL plates were aliquoted with 380 uL of media per well. Pre-inoculum (20 uL) from transformation plates was added. The plates were sealed appropriately and incubated at 37 ˚C at 300 with shaking for 2 h. After 2 h the temperature was lowered to 20˚C and incubation continued for 20 h. The liquid cultures were centrifuged for 10 minutes at 4˚C. The supernatant was discarded, plates blotted on an absorbent material to remove residue and the plates frozen at - 80˚C. Lysis buffer was prepared according to the following protocol: 1. Polymyxin B sulphate (0.5 mg/mL) was suspended in 100 mM potassium phosphate pH 7.5 2. The mixture was sonicated until polymyxin B sulphate had dissolved 3. Lysozyme (1 mg/mL) and benzonase (0.1 uL/mL lysis buffer) were added 2 copies of each cell pellet plate were removed from -80 degC freezer and allowed to thaw. 200 uL of lysis buffer was added to each well of one copy of the cell pellet plates. Plates were shaken at room temperature for 10 mins.190 uL of cell pellet/lysis buffer was transferred to a corresponding fresh cell pellet plate. These plates were incubated at room temperature with shaking for 2 hours. Lysate was clarified by centrifugation (10 min, 4 degC). QS-18 was obtained by analogous methods to Example 3, collecting a QS-18-containing phenyl fraction following phenyl treatment (presence of m/z corresponding to key components was confirmed by MS and the phenyl fraction then used without further treatment). QS-18 solution was prepared by diluting aqueous QS-18 (ca 1 mg/mL) with 100 mM potassium phosphate pH 7.5 to 0.2 mg/ml.40 uL clarified lysate was transferred into fresh 96 well PCR plates. 10 uL QS-18 solution added to each well of lysate to a final concentration of 0.04 mg/ml. Incubated at room temperature with shaking for 20 h. Quenched with 50 uL MeCN and shaken at room temperature for 10 mins. Samples were analysed by LC-MS/MS using a Waters Acquity H class coupled to a Waters Xevo Tandem Quadrupole (TQD) Mass Spectrometer. LCMS/MS 3 min method Enzyme activity was calculated as: % conversion = 100 x QS-21 peak area (QS-21 peak area + QS-18 peak area) The negative control reactions, which utilised a plasmid expressing an unrelated protein, had an average % conversion of 0.42% with a standard deviation (S.D.) of 0.10%. Candidate enzymes with % conversion > 0.72%, i.e. > 3 S.D. above negative control, were considered to be positive hits and are listed below in Table 7. Sample results are shown in Fig.10 for a QS- 21 standard, Fig.11 for negative control and Fig.12 for treatment with the glucosidase of SEQ ID No.262. Experiment 4-2 - Screening of glucosidases for deglucosylation with purified QS-18 (1 mg/ml) at pH 6 and 30 deg C Lysates were prepared in an identical manner to Experiment 4-1 above, except the lysis buffer was prepared in 100 mM potassium phosphate buffer pH 6. QS-18 solution was prepared by dissolving QS-18 in 100 mM potassium phosphate buffer pH 6 (2 mg/mL). 12 uL clarified lysate was transferred into fresh 96 well PCR plates.12 uL QS-18 solution was added (1 mg/ml final concentration), plates sealed and incubated overnight (30°C) for 18 hrs. After quenching with 25 uL MeCN and shaking for 10 mins (RT), samples were analysed using the LC-MS/MS protocol described in Experiment 4-1 and enzyme activity determined in an analogous manner. The negative control reactions had an average % conversion of 0.38% with a standard deviation (S.D.) of 0.06%. Sequences with % conversion > 0.56% i.e. > 3 S.D. above negative control are listed in Table 7. Experiment 4-3 - Screening of glucosidases for deglucosylation with QS-18 in Crude Bark Extract (1 in 2000 dilution) at pH 7 and 30 deg C Lysates were prepared according to the following procedure. 50 uL of 50% v/v glycerol was transferred to each well of a flat bottom 96 well plate.50 uL from each well of the overnight culture plate (in LB) from Experiment 4-1 was transferred and mixed by pipette aspiration. The plate was then covered with a foil seal and frozen at -80˚C as a glycerol stock of the transformants. Glycerol stock plates were removed from -80°C freezer and allowed to thaw. Overnight cultures were prepared by pipetting 5 mL LB into 50 mL tubes with Kanamycin as a selection marker at a final concentration of 50 μg / mL. Cultures were inoculated with 10 μL of glycerol stock and incubated overnight at 37 °C with shaking. Flask cultures were prepared by pipetting 25 mL Terrific Broth (TB) into 250 mL conical flasks with Kanamycin as selection marker at a final concentration of 50 μg / mL. Overnight cultures OD 600 was measured using a spectrophotometer and initial inoculum volume calculated for a starting OD ~ 0.1. Cultures were inoculated and incubated at 37 °C with shaking up to OD ~ 0.6. Cultures were induced with 1 mM IPTG and temperature was reduced to 20 °C with shaking. Cultures were then incubated overnight. Cultures were harvested in individual 1 mL aliquots (in 2 mL tubes). 1 mL aliquots were centrifuged at 13000 g for 3 min and supernatant discarded. Pellets were frozen at -20 °C. Lysis buffer was prepared according to the following protocol: - Polymyxin B sulphate (0.5 mg/mL) and Lysozyme (1 mg/mL) were suspended in 50 mM phosphate buffer, 0.3 M NaCl, pH 8. - Benzonase (20 U / mL) and 0.05 % Tween-20 were added. 1 mL of Lysis buffer was added to a pellet from 1 mL culture aliquot. Lysed samples were incubated at room temperature with shaking for 2 hours. Lysate was clarified by centrifugation at 13000 g, 5 min, 4 °C. Crude bark extract (CBE) obtained by aqueous extraction of Quillaja saponaria and containing at least 2.80 mg/ml QS-21 (by HPLC-UV) was diluted 1 in 400 in 50 mM potassium phosphate buffer at pH 7.100 ul diluted CBE was added to 400 ul of each lysate to give a final dilution of 1 in 2000. As diluted CBE was added to the lysate, the solution was vortexed for ~5 seconds and then a 80 ul sample taken and quenched with 160 ul methanol (MeOH). This was used as a time 0 sample. The reaction solutions and controls were then left to shake at 30 o C. Samples were taken after 1 h in the same way as the time 0 sample. Samples were analysed by LCMS/MS using the protocol described in Experiment 4-1 and enzyme activity determined in an analogous manner. Enzyme activity is calculated as the % conversion of the QS-18 present in the crude bark extract: % conversion = 100 x (%QS-18t=0 - %QS-18t=1hr) %QS-18t=0 where %QS-18 = 100 x QS-18 peak area (QS-21 peak area + QS-18 peak area) Experiment 4-4 - Screening of glucosidases for deglucosylation of QS-18 in Crude Bark Extract (1 in 20 dilution) to QS-21 Lysates were prepared as in Experiment 4-2. Crude bark extract (CBE) was adjusted to pH 6 by dropwise addition of 2M NaOH with stirring.25 uL of clarified lysate was transferred to a reaction plate, 22.5 ul of 100 mM potassium phosphate buffer pH 6 was added, 2.5 ul CBE at pH 6 was added. Reaction plates were sealed, incubated at 25 degC with shaking for 18 hours, then quenched by addition of 50 uL acetonitrile (MeCN). Quenched reaction plates were re-sealed and incubated at 20 degC with shaking for 10 min. The reaction plates were centrifuged (10 min, 4 degC) and analysed by UV HPLC with the method below: UV Method EM2020N435545v1_2 Three key peaks of interest are apparent using this chromatography: Left Peak (retention time approximately 2.30-2.35 min) comprising mainly QS-17 family components; Middle Peak (retention time approximately 2.37-2.42 min) comprising mainly QS-18 family components and desglucosyl-QS-17 family components; and Right Peak (retention time approximately 2.44-2.50 min) comprising mainly QS-21 family components. Peak identity was supported by MS/MS. Enzyme activity is calculated as the % conversion of the Middle Peak present in the crude bark extract: % conversion = 100 x (%Middle Peakt=0 - %Middle Peakt=1hr) %Middle Peakt=0 where %Middle = 100 x Middle Peak area (Right Peak area + Middle Peak area) Fig.13 provides exemplary chromatograms following glucosidase SEQ ID No.262 treatment and for the negative control. Results Table 7 N.T. indicates not tested Based on detection of QS-182150 and QS-211988 components by LCMS/MS (Examples 4-1, 4-2 and 4-3) or UV HPLC quantification of Middle Peak (mainly QS-18 family and desglucosyl-QS-17 family) and Right Peak (mainly QS-21 family) (Example 4-4), Example 4 shows that a number of suitable glucosidases could be identified by screening a set of candidate enzymes (38 from 400, 9.5%). Glucosidases were capable of converting QS-18 family components to QS-21 family components at a range of pHs, concentrations of starting materials and purity of starting materials. Although certain candidate enzymes did not demonstrate notable conversion under the conditions tested, this may be due to issues with enzyme expression, suitability of conditions (i.e. enzymes may function under other conditions) or a fundamental lack of required enzyme activity. Example 5 – Screening of additional glucosidases for deglucosylation of QS-18 to QS-21 Method Enzyme selection Additional candidate glucosidases were selected based on amino acid similarity to an active site model based on positive hits from Example 4. A final set of 94 additional candidate enzymes was selected. Codon optimized polynucleotide sequences encoding each selected enzyme linked to an N-terminal 6xHis tag were prepared. Details of the additional candidate enzyme and polynucleotide sequences are summarised below in Table 8. Table 8 – Additional glucosidase candidate sequences Experiment 5-1 - Screening of additional glucosidases for deglucosylation with purified QS-18 (0.04 mg/ml) at pH 7.5 and 30 deg C The 94 additional genes, together with positive control (DNA encoding SEQ ID No.262) and negative control, were transformed, expressed, lysed and reacted in the same manner as described above for Experiment 4-1, except the reaction was incubated at 30 degrees C for 18 hours. Samples were analysed by LCMS/MS according to the procedure in Experiment 4-1. The results for all enzymes demonstrating a % conversion of at least 3 are shown in Table 9. Experiment 5-2 - Screening of additional glucosidases for deglucosylation with QS-18 in Crude Bark Extract (80%) at pH 6 and 35 deg C A plate was lysed at pH 6 as described in Experiment 4-2.40 uL of clarified lysate was transferred to a reaction plate The pH of CBE was adjusted to pH 6 by dropwise addition of 2M NaOH with stirring. 160 uL of pH 6 CBE was added to each well of the reaction plate. The reaction plate was sealed and incubated at 35 deg C with shaking for 18 hours. The reaction plate was quenched by adding 200 uL of MeCN (2% acetic acid (AcOH), 1mg/mL hexanophenone) to each well of the plates. The quenched reaction plate was re- sealed and incubated at 20 deg C with shaking for 10 min. The reaction plate was then centrifuged (10 min, 4 degC). 200 uL was transferred from each well of the quenched plate to the corresponding wells of a fresh 96 well plate and sealed. The plate was analysed by UV HPLC with the method of Experiment 4-4. Experiment 5-3 - Screening of additional glucosidases for deglucosylation with QS-18 in Treated Bark Extract (80%) at pH 6 and 35 deg C Experiment 5-1 was repeated, replacing CBE with Treated Bark Extract (TBE) at pH 6. TBE was prepared from CBE by PVPP treatment and concentration, to provide TBE with a QS- 21 concentration of approximately 4 g/L. TBE was adjusted to pH 6 by dropwise addition of 2M NaOH with stirring. Table 9 Based on detection of QS-182150 and QS-211988 components by LCMS/MS (Example 5-1) or UV HPLC quantification of Middle Peak (mainly QS-18 family and desglucosyl- QS-17 family) and Right Peak (mainly QS-21 family) (Examples 5-2 and 5-3), Example 5 shows that a number of suitable glucosidases could be identified by screening a set of candidate enzymes, and also that candidate enzymes demonstrating similarity to previously identified suitable glucosidases were more likely to also be suitable glucosides (51 from 94, 54%). Glucosidases were capable of converting QS-18 family components to QS-21 family components at a range of pHs, concentrations of starting materials and purity of starting materials. Again, although certain candidate enzymes did not demonstrate notable conversion under the conditions tested, this may be due to issues with enzyme expression, suitability of conditions (i.e. enzymes may function under other conditions) or a fundamental lack of required enzyme activity. Example 6 – Screening of rhamnosidases for derhamnosylation of QS-17 to QS-18 Method Enzyme selection Conversion of QS-17 family components to QS-18 family components involves hydrolysis of the 1,2 glycosidic bond between the alpha-L-arabinofuranose and alpha-L- rhamnose found at the terminus of the acyl chain portion of the molecules. Glycoside hydrolases from families 78 and 106 exhibit the exo-alpha-1,2 rhamnosidase activity (E.C. 3.2.1.40) necessary to cleave this bond as annotated by the CAZy (Carbohydrate Active enZyme) database (www.cazy.com). All sequences annotated by CAZy from GH families 78 and 106 were obtained, and separate curated hidden Markov model profiles constructed for each which were then used to identify additional familial enzymes by searching the 209 million protein member Uniprot (www.uniprot.org) knowledgebase with the software HMMER (Eddy, 1998). In total, 11,749 sequences were identified: 10,653, and 1096 representatives from GH families 78 and 106, respectively. MMSeqs2 (Hauser, 2016) was then used to cluster each group of enzyme sequences using the default clustering workflow and parameters with a minimum sequence identity and coverage of 30% and 80%, respectively. In cases where the initial clustering yielded clusters with more than 1000 members, a second sub-clustering was performed at a higher 50% or 70% identity to ensure diverse exemplars from these larger clusters were represented more prominently. All clusters were then examined, and exemplars selected from each with preferences for annotation quality, known experimental activity, existing three dimensional structures from the Protein Data Bank (www.wwpdb.org) or known extremophile organisms as annotated by Uniprot. A final set of 94 diverse candidate enzymes was selected. Polynucleotide sequences encoding each selected enzyme linked to a C-terminal 6xHis tag and Tev-cleavage site (amino acid sequence for linker His-tag, inserted N-terminally of stop codon, is provided in SEQ ID No.1178) were prepared using a proprietary genetic- algorithm based codon optimization code. Details of the candidate enzyme and polynucleotide sequences are summarised below in Table 10. Table 10 – Rhamnosidase candidate sequences Experiment 6-1 - Screening of rhamnosidases for derhamnosylation of saponins in Treated Bark Extract (2%) Synthetic nucleotide sequences corresponding to SEQ ID 989 to 1082 were subcloned, transformed, expressed and lysed in an identical manner to Experiment 4-1 with the exception that a single cell pellet plate was lysed with 200 ul lysis buffer. Treated bark extract (TBE) solution was prepared by diluting 1 volume with 9 volumes of 100 mM potassium phosphate pH 7.5.40 uL clarified lysate was transferred into fresh 96 well PCR plates. 10 uL 10 x diluted TBE solution added to each well of lysate to a final concentration of 2% (1/50). Plates were incubated at 30 degC with shaking for 18 h. Quenched with 50 uL MeCN + 2% AcOH and shaken at room temperature for 10 mins mins prior to centrifugation (10 min, 4degC) to remove particulates. Samples were analysed by LCMS/MS using method of Experiment 4-1. The following MS-MS transitions were monitored to observe loss of rhamnose from starting saponins to product derhamnosylated saponins. Fig.14 to 19 provide exemplary chromatograms following negative control treatment and rhamnosidase SEQ ID No.1017 treatment. Data is expressed as TIC peak area ratio percent (PAR%) for rhamnosylated starting saponin to derhamnosylated product: PAR% = 100 x rhamnosylated starting saponin (rhamnosylated starting saponin + derhamnosylated product saponin) Activity was measured for the removal of the alpha-O-rhamnosylation at the C2 position of the arabinofuranose moiety of QS-172296 component to produce QS-182150 component; desglucosyl-QS-172134 to produce QS-211988 component and QS-172310 component to produce QS-182164. No activity was detected for the removal of the C3 saccharide rhamnose as demonstrated by no effect on QS-182164 component (QS-182164/QS-211988 ratio is unchanged). Additionally no endo cleavage of the C28 saccharide rhamnose attached to the C2 position of the fucose was observed. Table 11 Experiment 6-2 Screening of rhamnosidases for derhamnosylation of saponins in Treated Bark Extract (25%) A subset of rhamnosidases were expressed and lysed as in the method of experiment 6- 1. Treated bark extract (TBE) solution was adjusted to pH 7.4 by addition of NaOH (2M). 75 uL clarified lysate was transferred into fresh 96 well PCR plates. 25 uL TBE solution (pH 7.4) was added to each well of lysate to a final concentration of 25%. Plates were incubated at 30 degC with shaking for 19.5 h. Quenched with 100 uL MeCN + 2% AcOH and shaken at room temperature for 10 mins prior to centrifugation (10 min, 4degC) to remove particulates. Samples were analysed by UV HPLC using method of Experiment 4-4. Three key peaks of interest are apparent using this chromatography: Left Peak (retention time approximately 2.30-2.35 min) comprising mainly QS- 17 family components; Middle Peak (retention time approximately 2.37-2.42 min) comprising mainly QS-18 family components and desglucosyl-QS-17 family components; and Right Peak (retention time approximately 2.44-2.50 min) comprising mainly QS-21 family components. Peak identity was supported by MS/MS. Enzyme mediated hydrolysis of the alpha-O-rhamnosylation at the C2 position of the arabinofuranose moiety of QS-17 family components leads to a decrease in Left Peak and an increase in Middle Peak due to formation of QS-18 family components. Enzyme mediated hydrolysis of the alpha-O-rhamnosylation at the C2 position of the arabinofuranose moiety of desglucosyl-QS-17 family components leads to a decrease in Middle Peak and an increase in Right Peak due to formation of QS-21 family components. The relative percentage of each peak was determined. A decrease in Left Peak and a concomitant increase in Middle Peak and Right Peak is observed for enzymes active under these conditions. Results for the tested subset of rhamnosidases are provided below in Table 12. Table 12 Example UV HPLC chromatograms are shown in Fig.20 for SEQ ID No.1017 treatment and negative control. Experiment 6-3 Screening of rhamnosidases for derhamnosylation of saponins in Crude Bark Extract (80%) Selected variants were expressed and lysed as in the method of experiment 6-1. Crude bark extract (CBE) solution was adjusted to pH 7.4 by addition of NaOH (2M).20 uL clarified lysate was transferred into fresh 96 well PCR plates. 80 uL CBE solution (pH 7.4) was added to each well of lysate to a final concentration of 80%. Plates were incubated at 30 degC with shaking for 19.5 h. Quenched with 100 uL MeCN + 2% AcOH and shaken at room temperature for 10 mins prior to centrifugation (10 min, 4degC) to remove particulates. Samples were analysed by UV HPLC using method of Experiment 4-4. Three key peaks of interest are apparent using this chromatography: Left Peak (retention time approximately 2.30-2.35 min) comprising mainly QS-17 family components; Middle Peak (retention time approximately 2.37-2.42 min) comprising mainly QS-18 family components and desglucosyl-QS-17 family components; and Right Peak (retention time approximately 2.44-2.50 min) comprising mainly QS-21 family components. Peak identity was supported by MS/MS. Enzyme mediated hydrolysis of the alpha-O-rhamnosylation at the C2 position of the arabinofuranose moiety of QS-17 family components leads to a decrease in Left Peak and an increase in Middle Peak due to formation of QS-18 family components. Enzyme mediated hydrolysis of the alpha-O-rhamnosylation at the C2 position of the arabinofuranose moiety of desglucosyl-QS-17 family components leads to a decrease in Middle Peak and an increase in Right Peak due to formation of QS-21 family components. The relative percentage of each peak was determined. A decrease in Left Peak and a concomitant increase in Middle Peak and Right Peak is observed for enzymes active under these conditions. Results for the tested subset of rhamnosidases are provided below in Table 13: Table 13 Example UV HPLC chromatograms are shown in Fig.21 for SEQ ID No.1017 treatment and negative control. Based on detection of QS-172296, QS-172310, QS-182150, QS-182164, desglucosyl-QS-172134 and QS-211988 components by LCMS/MS (Example 6-1) or UV HPLC quantification of QS-17, QS-18 and QS-21 peaks (Examples 6-2 and 6-3), Example 6 shows that a number of rhamnosidases could be identified by screening a set of candidate enzymes (29 from 94, 31% achieving a QS-17 PAR% of 4.5 or less in Example 6-1). Rhamosidases were capable of converting QS-17 family components to QS-18 family components and desglucosyl-QS-17 family components to QS-21 family components at a range of concentrations of starting materials and purity of starting materials. Again, although certain candidate enzymes did not demonstrate notable conversion under the conditions tested, this may be due to issues with enzyme expression, suitability of conditions (i.e. enzymes may function under other conditions) or a fundamental lack of required enzyme activity. EXAMPLE 7 – Deglucosylation and derhamnosylation of saponins in Crude Bark Extract (50%) Method E. coli cells expressing glucosidase SEQ ID No.262 (as His-tagged enzyme, DNA SEQ ID No. 662) and separately rhamnosidase SEQ_ID No.1017 (as His-tagged form, DNA SEQ ID No. 1111) were grown in a fermenter, isolated, lysed, clarified and the resulting lysate lyophilised to yield powder containing each of the expressed enzymes. 500 uL CBE was mixed with 500 uL volume sodium acetate buffer (50 mM, pH 6) containing 30 g/L lyophilised powder containing the glucosidase, and 3 g/L lyophilised powder containing the rhamnosidase, and incubated at 37 degC for 24 hours. The reaction was quenched by the addition of an equal volume of MeOH and analysed by LC- MS/MS using the method of Experiment 4-1 monitoring the transitions in the table below Table 14 Results Fig.22 provides exemplary LCMS/MS chromatograms for QS-211988 component content at T0 (Panel A) and at 24 hrs (Panel B). Results for all components monitored are summarised below:
Table 15 Components possessing alpha-O-rhamnosylation at the C2 position of the arabinofuranose moiety are reduced below the detection limit while components possessing a glucose moiety show >78% reduction after treatment for 24 h. The corresponding products of selective rhamnose and glucose hydrolysis show substantial increases. EXAMPLE 8 – Screening of glucosidase variants for deglucosylation of saponins in crude bark extract Method Libraries of genetic variants encoding mutations in the wild type Modestobacter marinus glucosidase (SEQ ID No.262) were prepared using molecular biology techniques, enzymes were prepared linked to an N-terminally located His-tag. Single monoclonal colonies were grown in 400 ul of expression medium and protein expressed. Cell pellets were lysed in 200 ul of the relevant buffer (Table 16) Lysate was diluted appropriately in the relevant buffer to allow a lysate loading of the indicated % loading (1% loading corresponds to use of 2 ul original lysate in a 200 ul reaction). In some experiments a rhamnosidase was also present during the screening reaction (and also in controls, negating any impact on results). Crude bark extract (CBE) obtained by aqueous extraction of Quillaja saponaria and containing at least 2.80 mg/ml QS-21 (by HPLC-UV). The pH of CBE was adjusted to pH 6 by dropwise addition of 2M NaOH with stirring. The relevant concentration of the relevant glucosidase was added. The appropriate relative volume of pH 6 CBE (160ul (for 80%) or 150 ul (for 75%)) was added to each well of the reaction plate. The reaction plate was sealed and incubated at the relevant temperature with shaking overnight for between 18 and 22 hours. The reaction plate was quenched by adding 200 uL of MeCN (2% AcOH, 1mg/mL hexanophenone) to each well of the plates. The quenched reaction plate was re-sealed and incubated at 20 deg C with shaking for 10 min. The reaction plate was then centrifuged (10 min, 4 degC). 200 uL was transferred from each well of the quenched plate to the corresponding wells of a fresh 96 well plate and sealed. The plate was analysed by UV HPLC with the method below: UV Method EM2020N435545v2_2 A negative control (a lysate not expressing test enzymes) and a positive control (expressing the parent comparator – wild type or previous variant as appropriate). Fold improvement over parent (FIOP) for the glucosidase (shorter method) is calculated as follows: % right peak = 100* right peak area/(right peak area + left peak area) Average % right peak area is calculated for negative controls (per plate) and subtracted from all wells to give the increase in % right peak for each well above average negative control Average increase in % right peak is calculated for positive controls per plate FIOP = observed increase in % right peak divided by average positive control increase Results Fig.23 provides illustrative chromatograms following treatment of CBE with enzymes and for a negative control. Table 16 TBD - to be determined FIOP - fold improvement over parent (i.e. preceding enzyme), Cumulative FIOP is the product of preceding rounds and is nominally the fold improvement over the original wild-type (WT) starting point (however, since conditions change between rounds and WT isn’t used as a control Cumulative FIOP is not a direct measure but an estimate). The following mutations were associated with enzymes demonstrating improved activity in at least one instance: F44Y; V60L; G117A; F170N; V263G or V263L; N351H or N351Q; A355H, A355I, A355L, A355M, A355R, A355T or A355W; A356P; R357A, R357C, R357K, R357M or R357Q; G362C; T365A, T365N or T365S; L367C; V394R; V395Y; Q396E, Q396G, Q396N, Q396P, Q396R, Q396S or Q396Y; F430W; R435F; V438T; V440F; F442M or F442Q; G444T; A473F or A473R; L474C, L474I or L474V; I475F; L492C, L492G, L492H, L492I, L492N, L492Q, L492V, L492W or L492Y; Q493F or Q493H; P494H or P494I; S495I, S495K or S495Q; G496P or G496W; D498A, D498E, D498F, D498I, D498K, D498L, D498N, D498P, D498R, D498S, D498T or D498V; A502R; M504G or M504R; L507A or L507R; T508M; L529M; F535P; A536D or A536E; A537R; F541A, F541I, F541L, F541M or F541V; L542I; Q543G or Q543L; E547L; and Y585W. EXAMPLE 9 – Screening of rhamnosidase variants for derhamnosylation of saponins in crude bark extract Method Libraries of genetic variants encoding mutations in the wild type Kribbella flavida rhamnosidase (SEQ ID No.1017) were prepared using molecular biology techniques, enzymes were prepared linked to a C-terminally located His-tag. Single monoclonal colonies were grown in 400 ul of expression medium and protein expressed. Cell pellets were lysed in 200 ul of the relevant buffer (Table 17). Lysate was diluted appropriately in the relevant buffer to allow a lysate loading of the indicated % loading (1% loading corresponds to use of 2 ul original lysate in a 200 ul reaction). Crude bark extract (CBE) obtained by aqueous extraction of Quillaja saponaria and containing at least 2.80 mg/ml QS-21 (by HPLC-UV) was adjusted to pH 6 by dropwise addition of 2M NaOH with stirring. The relevant concentration of the relevant glucosidase was added. The appropriate relative volume of pH 6 CBE (160ul (for 80%) or 150 ul (for 75%)) was added to each well of the reaction plate. The reaction plate was sealed and incubated at the relevant temperature and time. The reaction plate was quenched by adding 200 uL of MeCN (2% AcOH, 1mg/mL hexanophenone) to each well of the plates. The quenched reaction plate was re-sealed and incubated at 20 deg C with shaking for 10 min. The reaction plate was then centrifuged (10 min, 4 degC). 200 uL was transferred from each well of the quenched plate to the corresponding wells of a fresh 96 well plate and sealed. The plate was analysed by UV HPLC with the method described in Example 4. Three key peaks of interest are apparent using this chromatography: Left Peak (retention time approximately 2.30-2.35 min) comprising mainly QS-17 family components; Middle Peak (retention time approximately 2.37-2.42 min) comprising mainly QS-18 family components and desglucosyl-QS-17 family components; and Right Peak (retention time approximately 2.44-2.50 min) comprising mainly QS-21 family components. Peak identity was supported by MS/MS. Enzyme activity is calculated as the % conversion of the Left Peak present in the crude bark extract: % conversion = 100 x (%Right Peak ) (%Left Peak + %Right Peak) where %Right = 100 x Right Peak area (Right Peak area + Left Peak area + Middle Peak area) Fig.24 provides illustrative chromatograms following enzyme treatment of CBE and for a negative control. Table 17 R2 (SEQ ID No.1190) - A143P, L214M, K219G, Q921H; R3 (SEQ ID No.1191) - A143P, L214M, K219G, G357C, Q921H R4 (SEQ ID No.1192) - A143P, L214M, G215S, G218N, K219G, G357C, G508S, G634A, Q921H R5 (SEQ ID No.1193) - A143P, L214M, G215S, G218D, K219G, G357C, G508S, G634A, A690C, Q921H Results Table 18 FIOP - fold improvement over parent (i.e. preceding enzyme), Cumulative FIOP is the product of preceding rounds and is nominally the fold improvement over the original WT starting point (however, since conditions change between rounds and WT isn’t used as a control Cumulative FIOP is not a direct measure but an estimate). The following mutations were associated with enzymes demonstrating improved activity in at least one instance: (i) A56C (ii) A143P (iii) Q181H, Q181R or Q181S (iv) L214M (v) G215S (vi) F216M (vii) G218D or G218N (viii) K219G (ix) A238M (x) T252Y (xi) T311W (xii) V326C (xiii) G357C (xiv) S369C, S369I, S369K or S369M (xv) I487M, I487Q or I487V (xvi) K492N (xvii) V499T (xviii) G508S (xix) R543C (xx) L557Y (xxi) G634A (xxii) S635N (xxiii) A690C and (xxiv) Q921H. EXAMPLE 10 – Deglucosylation and derhamnosylation of saponins in Crude Bark Extract (50%) using engineered enzymes Method Lyophilised powders from clarified cell lysate expressing glucosidases (from Example 8 WT glucosidase and engineered glucosidase polypeptides G1 to G5) and rhamnosidases (from Example 9 WT rhamnosidase and engineered rhamnosidase polypeptides R1 to R5) were dissolved in 200 mM sodium acetate aqueous solution at pH 5.8 to prepare the enzyme solutions at 4 fold the final reaction concentration as shown in Tables 19 and 20. Each glucosidase solution was combined with an equal volume of 200 mM sodium acetate aqueous solution at pH 5.8 and separately with an equal volume of 200 mM sodium acetate aqueous solution at pH 5.8 containing 2 mg/ml rhamnosidase R5. This is a sufficient loading of rhamnosidase to effect complete hydrolysis of the relevant rhamnose moiety within 4 hours. Each rhamnosidase solution was combined with an equal volume of 200 mM sodium acetate aqueous solution at pH 5.8 and separately with an equal volume of 200 mM sodium acetate aqueous solution at pH 5.8 containing 2 mg/ml glucosidase G5. This is a sufficient loading of glucosidase to effect complete hydrolysis of the relevant glucose moiety within 4 hours. CBE was adjusted to pH of 6.0 to 6.2 with 2M sodium hydroxide and an equal volume added to the enzyme solution to prepare the reaction mix (i.e.50% CBE concentration in reaction mix) and the concentration of glucosidase and/or rhamnosidase is shown in Tables 19 and 20. The reaction mix was heated to 35 degC for the time indicated in Tables 19 and 20, after which the reaction was quenched by addition of an equal volume of MeCN containing 2% acetic acid and shaken at room temperature for 10 mins prior to centrifugation (10 min, 4degC) to remove particulates. Samples were analysed by UV HPLC using method of Experiment 4-4. Results The change in composition of the Left, Middle and Right peaks is shown in in Tables 19 and 20. The composition changes by the action of the enzymes depending on the presence or absence of the partner enzyme. The extent of reaction is proportional to the enzyme concentration and the reaction time under these conditions. The tables show data for enzyme concentrations and the reaction times providing for equivalent extents of reaction. The improvement resulting from the mutations introduced for each variant is equal to the fold change in enzyme concentration x time (i.e. fold improvement = (enzyme concentration x time) for preceding variant ÷ (enzyme concentration x time) for later variant). A cumulative fold improvement over the original enzyme variant is calculated by the product of the individual fold improvements. The glucosidase G5 shows approximately 800 fold improvement over WT glucosidase. The rhamnosidase R5 shows approximately 30 fold improvement over WT rhamnosidase. Variants G5 and R5 were found to demonstrate activity across a range of reaction conditions from 25degC to 40 degC, from pH 5 to 7 (maintaining >80% relative activity for pH 5.4 to 6.2, and >50% for pH 5.2 to 7), and with a range of CBE loadings to at least 150% (achieved by redissolving lyophilised CBE in a smaller volume).
Table 19
Table 20
EXAMPLE 11 – Deglucosylation and derhamnosylation of saponins in Crude Bark Extract (50%) using engineered enzymes Method Lyophilised powders from clarified cell lysate expressing engineered glucosidase polypeptide G3 from Example 8 and engineered rhamnosidase polypeptide R2 were dissolved in 200 mM sodium acetate aqueous solution at pH 5.8 to a concentration of 3 g/L (glucosidase) and 2 g/L (rhamnosidase). For a 1L reaction, sodium acetate buffer 200mM (700mL) was charged to a stirred reactor. Under constant agitation, glucosidase enzyme powder (2.1g) and rhamnosidase enzyme powder (1.4g) were added and agitated for 30 mins until all the enzyme powder was suspended. The resulting enzyme solution (700mL) was depth filtered (nom.3- 9µm) and then sterile filtered (0.2µm). CBE (700mL) containing 4.1 g/L QS-21, with a Preceding Peak ratio of 0.25 and a 2018/QS-21 ratio of 0.054 to 0.057 was depth filtered and then sterile filtered (0.2µm). Filtered CBE (500mL) was charged to a stirred reactor, heated to 37 degC and the pH adjusted to pH of 6.0 to 6.2 with 2M sodium hydroxide. Enzyme solution (500mL) was then charged to the reactor and the solution stirred at 37 degC for 5 hours. After 5 hours glacial acetic acid was charged into the reaction mixture gradually under moderate agitation to adjust the pH to ~pH3.8 (target range pH3.5 to 4.0). The enzyme treated CBE was then purified analogously to the processes provided in Example 3. Results The purified saponin extract was determined to contain at least 98% QS-21 group, at least 93% QS-21 main peak, 0.2 % 2018 component, 1% or less of largest peak outside the QS-21 group by UV absorbance at 214 nm and wherein the monoisotope of the most abundant species was 1987.9 m/z. The increase of QS-21 by mass, based on the QS-21 concentration and the sample volumes, shows a 2.6-3.0x increase in the enzyme treated CBE. The increase of % QS-21 (as % of saponins) showed a 3.0-3.1x increase. Due to the improved saponin profile of the enzyme treated material a greater recovery yield is obtained while remaining within desired specifications (notably during polystyrene and phenyl resin chromatography where a greater proportion of QS-21 can be recovered). Overall dual enzyme treatment was found to result in approx.5.2- to 5.3-fold increase in yield compared to a conventional (non-enzyme treated) process. Figure 25 provides an example HPLC-UV chromatogram of untreated and enzyme treated CBE. Figure 26 (full acquisition) and Figure 27 (zoom) provide example UPLC-UV chromatograms of purified material obtained from untreated and enzyme treated CBE. EXAMPLE 12 – Deglucosylation and derhamnosylation of saponins in a Crude Cell Extract (CCE) obtained from a plant cell culture using engineered enzymes Preparation of plant cell culture Calli were established from the cambial meristematic cells of selected Quillaja saponaria plants. A young shoot from a growing plant was cut into small pieces. The outer layer was stripped away by surface sterilization in order to expose the cambial layer. Said cambial layer was then laid on agar plates containing Murashige and Skoog (MS) medium supplemented with the plant hormones 1-Naphthaleneacetic acid (NAA) and 6- Benzylaminopurine (BA) at 0.5 mg/L each. The plates were then incubated at 25 decC in the dark for 4 weeks, after which time it was sub-cultured to fresh solid MS medium (plus the above plant hormones) and incubated at 25 degC in the dark. After 8 weeks, the growing cambial cells were separated from the hard callus and transferred to fresh MS medium (plus the above plant hormones). The resulting callus is continually sub-cultured as above, every 4 weeks, to maintain viability. Suspension plant cell cultures were initiated by inoculating liquid medium with callus material in shake flasks. A 10% inoculum was used, e.g.3 g of callus material was inoculated into 30 ml liquid MS medium containing the NAA and 2,4-dichlorophenoxyacetic acid (2,4-D), at 0.5 mg/L each. Liquid volume as a percentage of the total flask volume was fixed at no more than 20%. The liquid suspension flasks were incubated, at a temperature of 25 degC on a shaker set at 200 rpm, for 14 days before being sub-cultured again into liquid medium. Subculture was achieved by allowing the large aggregates in the cell suspension to settle, before drawing off the liquid containing the fine cells in suspension into a centrifuge tube. This suspension was centrifuged, the supernatant was poured off, and the remaining cell pellet (packed cell volume ─ PCV) was re-suspended in fresh MS medium (plus NAA and 2,4-D). The volume of fresh medium added was such that the final cell concentration is 10% (as PCV) of the final volume. Sub-cultured suspension flasks were incubated at a temperature of 25 degC on a shaker set at 200 rpm for 14 days before being sub-cultured once again, as described above. Suspension plant cell cultures are maintained by further sub-culturing every 9 to 14 days. 3 suspension cell lines prepared and obtained as described above (18A/B-1, 5B-1 and 35A7) were grown in a plant cell culture medium including a nitrogen source. At Day 0 (D0), the culture medium was replaced with a medium which is devoid of any nitrogen source.5 days later (Day 5), 3.3 µM/PCV% MeJa was added directly to the culture medium. Enzymatic treatment 5 days after the MeJa was added (Day 10), the cells were centrifuged. The supernatant was discarded, while the cell pellet was frozen at -70 degC for 24h to cause lysis of the cells. The defrosted cell pellet was resuspended in 1 or 4 volumes (Total extr. vol. (mL) referred to in Table 21) of 35 mM Sodium Acetate buffer (at pH 6) containing 1 mg/ml each of glucosidase (SEQ ID No.1183) and rhamnosidase (SEQ ID No.1193) enzymes or in a buffer without enzymes (control negative treatment). Enzymatic reaction took place for 1 hour at 20 degC. The reaction was quenched by the addition of 2 volumes of MeOH and the saponin content within the reaction mixture was analysed. Negative control samples were similarly treated with MeOH. After quenching of the reaction, the reaction mixture was vortexed for 30 seconds prior to centrifugation. The supernatant was recovered and diluted.1 µL of the diluted sample was then used for analysing the content of saponins according to the LC-MS/MS method of Experiment 4-1 wherein the following transitions in the table below were monitored. Results Corresponding peak areas were measured, reflecting the amount of each respective saponin component and the proportion thereof in each crude plant cell culture extract. The comparison of the peak area between the control negative treatment samples and the enzymatically-treated samples reflect the effectiveness of the enzymes in their ability to hydrolyse the relevant rhamnosidase moiety and relevant glucosidase moiety, respectively. Taking into account the PCV % measured before the cells were centrifuged (and the cell pellet was frozen) and the extraction volume, the amount of each saponin component in each crude cell extract was retrospectively converted into saponin volumetric productivity expressed in ug/ml relative to the corresponding plant cell culture, which results being presented as graphs in Fig.28 and the data in Table 21. Fig.28 and Table 21 show that the content of saponin components possessing alpha-O- rhamnosylation at the C2 position of the arabinofuranose (e.g. QS-172310 A, desglucosyl-QS- 172134 A and QS-172296) and saponin components possessing a glucose moiety (e.g. QS-18 2150 A, QS-182164 and desarabinofuranosyl QS-182018 A) was significantly reduced after enzymatic treatment, while the content of saponin components having no such alpha-O- rhamnosylation and no such glucose moiety correspondingly increased after enzymatic treatment. Table 21 – Saponin volumetric productivity (ug/mL) (see grey-highlighted rows) 1 Dilution of the extracted sample (prior injection) 2’ ND’ is for non-detectable Calculations are as follows: As the only standard available at the time of the experiments was the QS-21 standard, the QS-21 standard was used for the purpose of determining the content of the samples in other saponins (QS-182150, QS-172296, QS-212002, QS-182164, QS-172310, Desglucosyl-QS- 17 2134, Desarabinofuranosyl-QS-18 2018, Desarabinofuranosyl-QS-21 1856). These other saponins are considered to have the same LCMS response factor as that of QS-211988. EXAMPLE 13 – Deglucosylation and derhamnosylation of saponins in a purified plant cell culture extract obtained from a plant cell culture using engineered enzymes The suspension cell line 35A7 prepared and cultivated as described in Example 12 was used (“pre-enzymation”). The enzymatic treatment was performed as described in Example 12. The enzymatic reaction was quenched by the addition of 2 volumes of MeOH. MeOH was then evaporated by vacuum distillation. Diafiltration (3kDa) was performed with 5 volumes of DI water to remove MeOH providing an aqueous crude cell extract (“post-enzymation”). pH of the extract was adjusted to 3.8 by adding glacial acetic acid. The adjusted extract was treated with 110 mg/ml PVPP for at least 1 hour. After adsorption, the mixture was filtered to separate the PVPP and bound impurities from the liquor. The filtered liquor was concentrated by 3kDa UF spin filter to < 5 ml. Diafiltration was performed with 5 volumes of water (“UF/DF concentration”). The Resulting permeate was purified by reverse phase chromatography using a polystyrene resin (Amberchrom XT20), as described in Example 3 (see Table 4). Fractions were pooled to provide polystyrene purified saponin plant cell culture extract with the following composition: % QS-21 main peak ≥ 18% (by HPLC). The combined polystyrene purified fraction pool was further purified by reverse phase chromatography using a phenyl resin (EPDM) (“phenyl chromatography”), as described in Example 3 (see Table 5). QS-21-containing fractions were pooled to provide phenyl purified saponin extract with the following composition: %QS-21 group ≥ 98.5 and %QS-21 main peak ≥ 94.5 (by UPLC-UV/MS). The same saponin components were analysed as described in Example 12, the concentration (ug/mL) and proportion (%) of each was calculated, in samples collected at the following steps (results are presented as graphs in Fig.29 and the data in Table 22): − Pre-enzymation − Post-enzymation − Post-UF/DF concentration − Post-phenyl chromatography Results Fig.29 and Table 22 confirm that the enzymatic treatment significantly increases the proportion of QS-211988 in a crude plant cell culture extract, while the proportion of undesired saponin components is decreased, the remaining undesired components being eliminated by further purification. Table 22 – Saponin proportion in a plant cell culture extract (%) pre-enzymation, post- enzymation, post-UF/DF concentration, and post-phenyl chromatography (see grey-highlighted rows) Dilution of the extracted sample (prior injection)’ND’ is for non-detectable Calculations are as follows: Bibliography Altschul S. et al. 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