Description NOVEL MICROORGANISM CAPABLE OF METABOLIZING ISOFLAVONE Technical Field [1] The present invention relates to a novel microorganism capable of metabolizing isoflavone. More particularly, the invention relates to a novel microorganism capable of metabolizing daidzein and genistein into dihydrodaidzein and dihydrogenistein re¬ spectively, under anaerobic conditions. Background Art [2] Isoflavones are non-steroid compounds with estrogen s effects produced by plants. The compounds mainly consisting of daidzein and genistein universally exist in leguminous plants, especially, soybeans at high concentration (Eldridge and Kwolek, J. Agric. Food Chem., 31:394-396, 1983; Wang and Murphy, J. Agric. Food Chem, 42:1666-1673, 1994), and have been known to have various physiological activities including anticancer (Adlercreutz, H. et al., Lancet 339:1233, 1992; Hirano, T. et al., Life ScL 55:1061-1069, 1994), antimutation (Hartman, P. E., and D. M. Shankel. Environ. MoI. Mutagen. 15:145-18, 1990), antioxidation (Jha, H. C. et al., Biochem. Pharmacol. 34:1367-1369, 1985) and antiproliferation of tumor cells (Hirano, T. et al., Res. Commun. Chem. Pathol. Pharmacol. 64:69-78, 1989). [3] Generally, isoflavones contained in foods exist in their glycoside forms where sugar is coupled and isoflavones ingested via diet are metabolized by intestinal mi¬ croorganisms before absorption. Researchers found that various metabolites are produced from isoflavones by reduction, O-demethylation, ring-cleavage or hydrolysis. It was reported that when human excretion was cultured with daidzein and genistein under anaerobic conditions, dihydrodaidzein, benzopyran-4,7-diol, 3-(4-hydroxyphenyl) and equol are produced from daidzein and dihydrogenistein is produced from genistein (Chang and Nair, J. Natr. Proc, 58:1892-1896, 1995). Further, the thus produced compounds were known to have more effective estrogen's effects (Xu et al., J. Nutr. 125:2307-2315, 1995). [4] As interests in isoflavone metabolites increase, studies about microorganisms me¬ tabolizing isoflavones are being actively conducted. It was disclosed that Eubacterium limosum metabolizes formononetin and biochenin A into daidzein and genistein re¬ spectively by O-demethylation (Hur H.G. et al., FEMS Microbiol. Lett., 192(l):21-25, 2000). Also, human intestinal bacteria, Clostridium sp. HGH6, which reduces daidzein and genistein to dihydrodaidzein and dihydrogenistein and cleaves A-ring structure into O-Dma, was isolated and identified (Hur et al., Arch. Microbiol., 174:422-428, 2000). The biotransformation rates of Clostridium sp. HGH6 of converting daidzein and genistein into dihydrodaidzein and dihydrogenistein re¬ spectively are as low as 18% and 33% respectively. Meanwhile, besides using mi¬ croorganisms, dihydrodaidzein can be chemically synthesized from daidzein by hy- drogenation. However, it is not easy to control the degree of hydrogenation reaction and it produces by-products. [5] Thus, the inventors have completed the invention by isolating a novel strain me¬ tabolizing daidzein and genistein with high activity from the stomach contents of cows as a result of screening novel microorganisms capable of metabolizing isoflavones with high activity, and optimizing its culture conditions. Disclosure of Invention Technical Problem [6] Therefore, it is an object of the present invention to provide a microorganism capable of metabolizing isoflavones. [7] Also, it is another object of the invention to provide a method of producing isoflavone metabolites using the microorganism. [8] Also, it is another object of the invention to provide a composition comprising the microorganism and isoflavones. Technical Solution [9] In order to achieve the aforementioned objects, the present invention provides a mi¬ croorganism capable of metabolizing isoflavones. [10] Also, the invention provides a method of producing isoflavone metabolites using the microorganism. [11] Also, the invention provides a composition comprising the microorganism and isoflavones. Advantageous Effects [12] The novel microorganism of the invention is capable of metabolizing isoflavone and it thus enables the production of isoflavone metabolites. Also, compositions comprising the microorganism and isoflavone can be used for prevention or treatment of climacteric diseases especially, osteoporosis, and they can be used as antioxidants, anticancer agents, antimutagens, etc. Brief Description of the Drawings [13] FlG. 1 shows metabolic pathway from daidzein into R- and S-dihydrodaidzein by the microorganism of the invention. [14] FlG. 2 shows phylogenetic tree between the microorganism according to the invention and known strains. [15] FlG. 3 shows HPLC analysis results of the culture media of the microorganism of the invention incubated in BHI media containing daidzein or genistein. D represents daidzein and G represents genistein. [16] FlG. 4 shows chiral stationary-phase HPLC analysis results of isomers of dihy- drodaidzein and dihydrogenistein produced by the microorganism of the invention (DHDl: R-DHD, DHD2: S-DHD, DHGl: R-DHG, DHG2: S-DHG). [17] FlG. 5 shows CD spectrum results of dihydrodaidzein and dihydrogenistein produced by the microorganism of the invention (DHDl: R-DHD demonstrated by solid lines, DHD2: S-DHD by dotted lines, DHGl: R-DHG by solid lines, DHG2: S- DHG by dotted lines). [18] FlG. 6 shows growth curves of the microorganism of the invention when incubated in media with daidzein added or without daidzein added and pH changes of the culture media obtained when incubated in media without daidzein added (Δ: When daidzein was added, A: When daidzein was not added, •: pH changes when daidzein was not added). [19] FlG. 7 shows yield of dihydrodaidzein according to initial pH of culture media when dihydrodaidzein is produced from daidzein by the microorganism of the invention. [20] FlG. 8 shows yield of dihydrodaidzein according to the concentration of daidzein when dihydrodaidzein is produced from daidzein by the microorganism of the invention. [21] FlG. 9 shows kinetics of the biotransformation of daidzein by the microorganism of the invention (D: dihydrodaidzein, ■ daidzein). Mode for the Invention [22] The invention is further described in detail. [23] The microorganism of the invention is a strain capable of metabolizing isoflavone, isolated from the stomach contents of cows. [24] The isolation and identification of the microorganism according to the invention were carried out by the following procedures. After the stomach contents of cows were diluted sequentially, they were incubated on agar plates and about 1000 colonies were thus obtained. In order to select colonies capable of metabolizing isoflavones from the above colonies, each colony was incubated anaerobically in media containing isoflavones and analyzed using HPLC. As a result, 15 strains producing products which presumptively seem to be the metabolites of isoflavones were isolated and among them, one strain showing the most excellent activity was isolated (see Example 1). [25] The microorganism isolated above was identified by the analysis of the nucleotide sequences of its 16S rDNA (ribosomal DNA). As a result, it showed high homology with OUT-46 strains isolated from gastrointestines of pigs which had been previously reported (Laser et al., Appl. Environ, Microbiol., 68:673-69, 2002). However, the mi¬ croorganism isolated in the invention produced isoflavone metabolites from isoflavones with much higher activity than OUT-46. Thus, the inventors named the mi¬ croorganism isolated in the invention SNU-NiuO16 and deposited it under deposition number KCCM- 10491 with Korean Culture Center of Microorganisms, which is an in¬ ternational depository under Budapest treaty. [26] Novel microorganism SNU-NiuO16 (KCCM- 10491) according to the invention is capable of metabolizing daidzein into dihydrodaidzein (DHD) and genistein into dihy- drogenistein (DHG). More particularly, the microorganism according to the invention is characterized by producing daidzein into S- and R- type DHD of equal amount and producing genistein into S- and R-type DHG of equal amount under anaerobic conditions (see Example 5). This means that an enzyme produced by SNU-NiuO16 of the invention, which involves in metabolization of daidzein into DHD, does not have stereospecificity. Metabolic pathway from daidzein to racemic metabolite S-DHD or R-DHD is shown in FIG. 1. [27] The microorganism capable of metabolizing isoflavone according to the present invention can be used to produce isoflavone metabolites. Accordingly, the invention provides a method of producing isoflavone metabolites comprising inoculating mi¬ croorganism SNU-NiuO16 (KCCM- 10491) of the invention into media containing isoflavone and incubating it under anaerobic conditions. [28] In the above method, it is preferred that the isoflavone is daidzein or genistein. The isoflavone metabolite is preferably dihydrodaidzein or dihydrogenistein. [29] The media used above is not limited to specific ones and it refers to conventional culture media containing suitable carbon sources, nitrogen sources, amino acids and vitamins. For the carbon sources, there can be used glucose, molasses, lactose, sucrose, maltose, dextrin, starch, mannitol, sorbitol or glycerol. Preferably, glucose or molasses is used. For the nitrogen sources, there can be used inorganic nitrogen sources such as ammonia, ammonium chloride and ammonium sulfate, or organic nitrogen sources such as peptone, NZ-amine, beef extract, yeast extract, corn steep liquor, casein hy- drolysate, fish or its decomposition products and dehydrated soybean cake or its de¬ composition products. Preferably, yeast extract or corn steep liquor is used. For the inorganic compounds, there can be used kalium monohydrogen phosphate, kalium dihydrogen phosphate, magnesium sulfate, ferrous sulfate, manganese sulfate or calcium carbonate, and if necessary, vitamins or auxotrophic bases can be further added. As examples of commercially available, non-specific growth media, there can be mentioned BHI, TSB, Bacto Cooked Meat Medium, and Schaedler Anaerobe Broth. The BHI media was used in the Examples of the invention. [30] The microorganism according to the invention can be cultured under anaerobic conditions, preferably, 5 ~ 10 % CO , 5 ~ % H and 75 ~ 90 % N . [31] Besides, it is preferable that the incubation of the microorganism according to the invention is carried out in the media having an initial pH of 6.0 ~ 8.0 and preferably 6.0 ~ 7.0, with the final concentration of isoflavone of 400 ~ 800 μM for 2 - 5 days. [32] In an embodiment of the invention, the production rate of isoflavone metabolites according to the initial pH of media was quantitatively analyzed to establish optimum conditions for the production of isoflavone metabolites by the microorganism of the invention. As a result, when the initial pH of media was 6.0 ~ 7.0, reduction rate of daidzein into DHD was 90% and when the initial pH of media was 7.5 ~ 8.0, reduction rate of daidzein into DHD was 70%. Accordingly, it can be said that the optimal initial pH of media for the production of isoflavone metabolites from isoflavone by the mi¬ croorganism of the invention was 6.0 ~ 8.0, preferably 6.0 ~ 7.0 (see Example 5-2). [33] Further, in another embodiment of the invention, to establish the optimal conditions for the production of isoflavone metabolites by the microorganism according to the invention, the production rate of isoflavone metabolites according to the concentration of isoflavone was quantitatively analyzed. As a result, until daidzein was added at a concentration of 800 μM, daidzein was totally biotransformed into DHD but when the concentration of daidzein was 1000 μM, DHD exceeding 800 μM was not produced. Accordingly, it can be said that the optimal concentration of isoflavone to be added for the production of isoflavone metabolites from the isoflavone by the microorganism of the invention is up to 800 μM (see Example 5-3). [34] Furthermore, in another embodiment of the invention, kinetics of biotransformation of daidzein into DHD by the microorganism according to the invention was examined. As a result, when the microorganism of the invention was incubated for 40 hours under anaerobic conditions, daidzein was totally reduced to DHD. Accordingly, it can be said that the incubation time of the microorganism according to the invention for the production of DHD from daidzein is approximately 40 hours or so (see Example 5-4). [35] After the incubation is complete, the isoflavone metabolites can be isolated from the culture media and purified by methods known in the pertinent art. For example, membrane filtration, fractional precifitation, crystallization or column chromatography can be used. The isolated and purified isoflavone metabolites can be further processed into dietary or medicinal forms. [36] Further, the invention provides a pharmaceutical or dietary composition comprising the microorganism of the invention and isoflavone. The microorganism can be added thereto in the form of its lyophilized strain, or this lyophilized strain can be added after treatment with a suitable coating agent. The isoflavone can be its glycosides or various materials containing isoflavone as well as the isoflavone itself. For example, the various materials containing isoflavone are not limited to but include natural plants such as soybeans or arrowroots and their processed products. As an example of the processed soybean products, there can be mentioned tofu, soymilk, soy sauces and soy pastes. [37] The composition of the invention can further comprise elements accelerating maintenance or proliferation of microorganisms. For example, it can further comprise galactosylsucrose, soybean-oligosaccharide, lactulose, lactitol or fructo- oligosaccharide. [38] The composition of the invention can be formulated and administered by various dosage forms and methods. This can be prepared by mixing an effective amount of the microorganism of the invention and DHD with carriers which are conventionally employed in pharmaceutical or dietary fields. For the carriers, for example, there are binders, lubricants, disintegrants, excipients, solubilizers, dispersants, stabilizers, suspension agents, pigments or flavors. The composition of the invention can be formulated into various dosage forms according to conventional methods. Dose can be suitably adjusted according to absorption rate, deactivation rate and excretion rate of an active component in body, age, gender and conditions of patients, and seriousness of diseases to be cured. [39] The composition of the invention can be provided as a pharmaceutical composition in the form of solutions, emulsions, granules, powders, capsules, or tablets. [40] When the composition of the invention is manufactured in the form of foods, it can be formulated in the form of drinks, dairy products, fermented milks, bars, granules, powders, capsules or tablets. In processing the composition of the invention, it would be preferable to avoid heating or pressurization because it contains microorganism. [41] The composition of the invention, if necessary, can further comprise various kinds of additives exhibiting nutrition supply effects. For example, there can be vitamins, zinc or selenium. [42] The composition of the invention can be used for prevention or treatment of climacteric diseases especially, osteoporosis and it can be also used as antioxidants, anticancer agents, antimutagens, etc. [43] The invention is further described by way of Examples in detail. It should be understood, however, that the following examples are intended to illustrate the invention more fully without limiting the scope of the invention. [44] [45] EXAMPLE 1 [46] Isolation of Microorganism Capable of Metabolizing Isoflavone [47] After fistula was surgically formed in abdominal walls of a healthy bull (raised in Department of Animal Science, Seoul National University), 50 D of gastrointestinal contents of the cow was collected. This specimen was put in a 50 D-tube and 5 D of sterilized mineral oil was added thereto. The specimen was kept in the freezer of -70 °C and used for experiment. The specimens, the gastrointestinal contents of cow obtained in the above, were diluted sequentially from 10"1 to 10"8 with BHI (brain heart infusion) liquid media (Difco Co., Detroit, MI). 100 D of diluents were smeared on BHI agar plates and then incubated in an anaerobic chamber (5 % CO , 10 % H , 85 % N ) at 37 °C for 24 hours. After incubation, 500 colonies having different morphology from one another were isolated and randomly divided into 50 groups so that each group contained 10 colonies. They were each inoculated in 10 D of BHI liquid media containing 100 μM of daidzein (Indofine, Somerville, NJ) and incubated under the same anaerobic conditions as above at 37 °C for one week. After incubation, in order to investigate ability of metabolizing daidzein, each culture media was withdrawn and analyzed using HPLC. 200 D of the above culture media was extracted with 1 D of ethyl acetate and concentrated using a concentrator (Automated EnvironmentalSpeed Vac AES 1010, ThermoSavant, New York, N. Y.). The concentrates were re-dissolved in 200 D of acetonitrile and 10 D of the thus obtained solution was poured into HPLC. [48] For HPLC analysis, Varian ProStar HPLC (Varian, Walnut Creek, CA.) equipped with Waters ODS C18 columns (particle size 5 D, 4.6 x 250 mm, Fullerton, CA.) and PDA (photo diode array) detector was used. For mobile phase, there were used 10% acetonitrile solution (A) and 90% acetonitrile solution (B) buffered with 0.1% acetic acid. In elution programs, A and B in the ratio of 70:30 (v/v) were eluted for 15 min. and increased in a straight line to 50:50 (v/v), which were then eluted for 10 min. and increased in a straight line to 70:30 (v/v), which were then eluted for 5 min. Row rate was 10 D/min. Every specimen was monitored at 270 nm. UV spectrums of peaks were recorded at 200 to 400 nm. [49] As a result of HPLC analysis, peaks which presumptively seemed to be the metabolites of daidzein were detected in 15 strains and they were isolated. Among them, a strain which showed the largest peak area regarded as being the metabolite of daidzein and thus was expected to most effectively metabolize daidzein was isolated and named SNU-NiuO16. [50] [51] EXAMPLE 2 [52] Identification of Isolated Microorganism [53] [54] In order to identify the strain isolated in above Example 1, SNU-NiuO16, the nucleotide sequences of its 16S rDNA were analyzed. First, chromosomal DNA was extracted from the strain of Example 1 using 0.05 N NaOH. 1 D of SNU-NiuO16 culture media of above Example 1 was withdrawn and subject to centrifugation (Eppendorf Centrifuge 5415D, Hamburg, Germany) at 15,700 g for 5 min. After the supernatants were removed therefrom, 30 D of 0.05 N NaOH was then added. Then, the tube was placed in boiling water for 15 min. to extract genomic DNA. 16S rDNA gene was amplified using the genomic DNA extracted above as a template and two primers p27F(5'-AGA GTT TGA TCM TGG CTC AG-31, SEQ. ID. NO. 1) and pl492R(5'-GGY TAC CTT GTT ACG ACT T-3', SEQ. ID. NO. 2) (Lane D.J., In Nucleic Acid Techniques in Bacterial Systematics 16S/23S rRNA sequencing, 115-175, Jonh Wiley and Sons, New York, 1991). In the primer sequences, M refers to A or C and Y refers to TAJ or C. The PCR program for amplification was conducted as follows. The denaturation was carried out at 94 °C for 5 min., the cycle of 94 °C for 1 min., 55 °C for 30 sec. and 72 °C for 1 min and 30 sec. was repeated 29 times and then, the final elongation was carried out at 72 °C for 10 min. The PCR products were purified from the agarose gel using Accu Prep gel purification kit (Accu. Chem. Sci. Corp. Westbury, N. Y.) and then, the 16S rDNA PCR products were ligated and transformed using ToPo-cloning kit (Invitrogen, Carlsbad, C.A.). [55] The 16S rDNA gene sequences amplified in the above were analyzed using ABI 377 Xl Upgrade DNA Sequencer (Perkin Elmer, Boston, M.A.) and program supplied by the manufacturers. For homology analysis, the sequences (1459 bp) of 16S rDNA of the microorganism according to the invention were compared with the sequences registered with GenBank Database using BLAST program. Also, the rate of nucleotide substitution was calculated and phylogenetic tree was prepared using a neighbor- joining method. As an out-group, E.coli ATCC 11775T was used. [56] As a result, the gene sequences of 16S rDNA of SNU-NiuO16 of Example 1 exhibited low homology with those of known strains. The strain of the invention showed high homology (98.1 %) with OUT-46 isolated from gastrointestines of pigs (Laser et al., Appl. Environ. Micrbiol. 68:673-69, 2002) (HG. 2). The inventors registered the entire 16S rDNA gene sequences (1459 bp) of strain SNU-NiuO16 of the invention with NCBI GenBank (Registration Number AY263505, SEQ. ID. NO. 3), and deposited the same under deposition number KCCM- 10491 with Korean Culture Center of Microorganisms (KCCM) on April 24, 2003. [57] [58] EXAMPLE 3 [59] Isolation and Identification of Isoflavone Metabolites Produced by the Mi- croorganism of the Invention [60] In order to biosynthesize isoflavone metabolites in large quantity, SNU-NiuO16, the strain isolated in Example 1, was incubated overnight in a 500 D-flask containing 200 D of BHI liquid media under the same anaerobic conditions as above Example 1. Daidzein and genistein (40 mM stock solution dissolved in N,N-dimethyl formamide) were added to the media until their final concentrations became 800 μM. After the culture media was incubated in an aerobic chamber for 5 days, it was extracted three times with an equal volume of ethyl acetate and concentrated using a rotary vacuum evaporator (Eyela New Rotary Vacuum Evaporator NE, Rikakikai Co., Tokyo, Japan). The concentrated metabolites were dissolved in 6 D of methanol and purified using LC- 918 Recycling Preparative HPLC system. The purified metabolites were analyzed with HPLC according to the same methods as used in above Example 1 and identified using EI-MS and NMR spectrometers. EI-MS was analyzed using JMS-AX50510A Mass Spectrometer (JEOL, Co. Ltd. Japan) at positive mode (EI+). Source temperature was 250 °C and ionization voltage was 70 eV. Electron multiplier of 1.2 Kv was used. 1H and C NMR spectrums at acetone-d were analyzed at 400 MHz using Jnm-La NMR Spectrometer (JEOL, Co. Ltd. Japan) at temperature of 296 K. For H NMR analysis, 16 transients were measured along with 3 seconds relaxation delay using 32 K data point. 45 °C Pulse was 5.6 seconds and had an area of 400 MHz. 13C NMR was measured over an area of 100 MHz while collecting 64K data point. 45 °C Pulse was 5 seconds. Every calculation was conducted on silicon graphic INDY R4400 work station using MSI software (San Diego, LA). [61] As a result of HPLC analysis, when the strain of the invention was incubated in media containing daidzein, a peak presumptively regarded as being the metabolite of daidzein was detected at 7.9 min. Also, when the strain of the invention was incubated in media containing genistein, a peak presumptively regarded as being the metabolite of genistein was detected at 12.1 min. (FIG. 3). The UV spectrums of the two metabolites were the same as those of DHD and DHG which had been previously reported (Hur et al., Arch. Microbiol, 174:422-428, 2000). [62] Further, EI-MS spectrums of the daidzein and genistein metabolites were m/z 256(22.27)[M+H]+ and m/z 272(27.07) [M+H]+ corresponding to molecular formula of DHD(C H O ) and DHG(C H O ) respectively. Other spectrum ion peaks of the isolated metabolites showed the characteristics of DHD and DHG as follows: DHD MS/mz(rel. int.): 137(100), 120(47), 91(24), 65(11). DHG MS m/z(rel. int.): 153(100), 120(41), 91(18), 65(9). [63] 1H and 13C NMR of the daidzein and genistein metabolites are shown in Table 1 below and they are the same as those of the chemically synthesized DHD and DHG (Wahala C. et al., Proc. Soc. Exp. Biol. Med. 217:293-299, 1998). Accordingly, it was verified that the metabolites of daidzein and genistein produced by SNU-NiuO16 of the invention were DHD and DHG respectively. [64] Table 1 1H and 13C NMR of the daidzein and genistein metabolites produced by SNU-NiuO16 of the invention

[65] [66] [67] the Invention [68] To analyze the isomers of DHD and DHG produced by the strain of the invention in Example 3, each metabolite was subject to chiral stationary-phase HPLC and specific rotation ([α] ) and CD (Circular Dichroism) were measured. For chiral stationar y- phase HPLC, Sumi Chiral OA-7000 (particle size 5 D, 4.6 x 250 nm, Sumika Chem. Osaka, Japan) was used and for mobile phase, 40% acetonitrile solvent dissolved in 20 mM potassium phosphate buffer (pH 3.0) was used. Isocratic elution program using the mobile phase was carried out for 35 min. Row rate was 1 D/min, and UV spectrums of peaks were recorded within ranges of 200 to 400 nm. Specific rotation was measured using Polarimeter Autopol (Rudolph, N. J.) after DHD and DHG produced in Example 3 were each dissolved in ethanol. CD was measured using Jasco J-715 Spectrometer (Jasco, Corp. Tokyo, Japan). [69] As a result of chiral stationary-phase HPLC analysis, racemic mixtures of DHD and DHG were eluted at 13 min. and 25 min., and 6.4 min and 12.5 min. respectively (FIG. 4). Also, the peaks of (R) and (S)-DHD, which are the metabolites of daidzein, showed the same area and the peaks of (R) and (S)-DHG, which are the metabolites of genistein, also showed the same area. Specific rotation of DHD and DHG was DHDl:[α]D24= -19.857°, DHD2:[α]D24= +19.085°, DHGl:[α]D24= -26.2°, DHG2:[α] D = +25.7° respectively. In this regard, it was known that R-DHD isolated from heartwoods of Pericopsis mooniana has a negative value ([α]D= -20.7° at chloroform) (Maurice, J. Chem. Soc. Perkin Trans.11:186-191, 1976) (Buckingham, J., Dictionary of Natural Products, 1st ed. Chapman and Hall, London, 1994). Accordingly, above DHD 1 is R-DHD. [70] Meanwhile, the CD spectrum of R-type DHD dissolved in ethanol exhibited positive and negative cotton effects in information regions of 250-360 nm (FlG. 5). R- type DHD exhibited high negative cotton effects at 320 nm and exhibited positive cotton effects at 282 nm. The CD spectrum of S-type DHD showed mirror image of the CD spectrum of R-type DHD. Also, the CD spectrums of R-type DHG and S-type DHG exhibited positive and negative cotton effects in information regions of 250-380 nm similarly with the CD spectrums of DHD (FlG. 5). R-type DHG exhibited high negative and positive cotton effects at 305 nm and 308 nm respectively. The CD spectrum of S-type DHG was mirror image of the CD spectrum of R-type DHG. R- type DHD and S-type DHD had the same melting point (R-type: 247.77 °C,; S-type: 247.11 0C). In case of DHG, R-type DHG had a melting point of 193.97 °C and S-type DHG had 194.30 °C. This is the first report about the melting points of the enantiomers of DHD and DHG. Meanwhile, strain SNU-NiuO16 of the invention did not reduce DHD and DHG into tetrahydrodaidzein and tetrahydrogenistein. [71] [72] EXAMPLE 5 [73] Establishment of Optimal Conditions for the Production of Isoflavone Metabolites by the Microorganism according to the Invention [74] For the production of DHD from daidzein by SNU-NiuO16 of the invention, the initial pH of media and substrate concentration were optimized. [75] [76] 5-1) Analysis of Growth of Microorganism of the Invention According to pH Change [77] SNU-NiuO16 of the invention was incubated overnight in a 14 D-plastic tube contai ning 5 D of BHI liquid media. The culture media was diluted using new BHI liquid media until O.D 600nm became 1.0. 30 D of the culture media was distributed in six 45 D-tubes for centrifugation containing 30 D of BHI liquid media. Among them, to three tubes daidzein (10 nM stock solution dissolved in N,N-dimethyl formamide) was added so that its final concentration became 100 μM and to the other three tubes, nothing was added. The culture media was withdrawn from the tubes every two hours and was analyzed using spectrometer at 600 nm to measure the growth of mi- croorganism. In the meantime, 1 D of culture media was withdrawn from the three tubes containing no daidzein every three hours and their pH was measured. [78] As a result, the growth of SNU-NiuO16 of the invention incubated in media containing no daidzein was sustained for 34 hours through lag phase (0-24 hours), log phase (24-30 hours) and stationary phase (30-32 hours). In case of adding daidzein, on the other hand, the growth of SNU-NiuO16 was delayed. When daidzein was not added, the pH of the culture media was almost stable for the initial 24 hours (pH 7.0 ~ 7.1), was abruptly decreased during 24 to 33 hours (pH 7.0 ~ 5.7), and became stable again (pH 5.7) (FlG. 6). When daidzein was added, the pH of the culture media showed abrupt decrease after incubation of 30 hours (not shown). From the results, it was verified that SNU-NiuO16 of the invention secretes acid as it grows. [79] [80] 5-2) Optimization of Initial pH of Media [81] 50 Dof the culture media of SNU-NiuO 16 (O.D 600nm = 1.0) was added to 10 ml-tubes containing 5 ml of BHI media and the pHs of the media were adjusted to pH 8.0, 7.5, 7.0, 6.0 and 4.5 respectively. To the media daidzein was added so that the final con¬ centration became 100 μM. After incubation for 3 days under anaerobic conditions, 200 D of the culture media was withdrawn and analyzed with HPLC according to the same methods as used in Example 1 to investigate effects of the initial pH of media on metabolic activity of daidzein by the microorganism of the invention. [82] As a result, when the initial pH of media was 6.0 ~ 7.0, about 90 % of daidzein was reduced to DHD and when pH was 7.5 ~ 8.0, about 70 % of daidzein was reduced to DHD. On the other hand, when the initial pH of media was 4.5, DHD was not produced from daidzein (FlG. 7). Accordingly, optimal pH range for the reduction of daidzein into DHD was 6.0 ~ 8.0. More preferably, it was 6.0 ~ 7.0. [83] [84] 5-3) Optimal Concentration of Daidzein [85] Daidzein (10 mM stock solution dissolved in N-N-dimethyl formamide) was added at different concentrations (final concentration 400, 600, 800, 1000 and 1200 μM re¬ spectively) to 10 ml of SNU-NiuO 16 culture media (O.D 600nm = 1.0), which were then incubated for 3 days under anaerobic conditions. The culture media was withdrawn and analyzed with HPLC according to the same methods as used in Example 1. [86] As a result, until the concentration of daidzein became 800 μM, daidzein was completely biotransformed into DHD. On the other hand, when the concentration of daidzein was increased to 1000 μM, DHD exceeding 800 μM was not produced (FlG. 8). In case of human intestinal bacteria Clostridium sp. HGH6, it was previously reported that when it was incubated for 7 days, 37.2 μM of dihydrodaidzein was produced from 400 μM of daidzein (Hur et al., Arch. Microbiol. 174:422-428, 2000). Accordingly, it was verified that SNU-NiuO16 of the invention has sig¬ nificantly higher activity than Clostridium sp. HGH6. In addition, it was verified that the optimal concentration of daidzein to be added is 800 μM. [87] [88] 5-4) Measurement of Biotransformation Kinetics of Daidzein by the Microorganism According to the Invention [89] Daidzein was added to 10 ml of the culture media of SNU-NiuO16 according to the invention in its log phase, which was then incubated for one week under anaerobic conditions. For the initial 48 hours of incubation, 200 D of the culture media was withdrawn from each tube every two hours and thereafter, specimen was withdrawn at intervals of 12 hours for one week and analyzed with HPLC according to the same methods as used in Example 1. [90] As a result, when incubation was carried out for 40 hours under anaerobic conditions, daidzein was totally quantitatively reduced to DHD (FIG. 9). Industrial Applicability [91] The novel microorganism of the invention is capable of metabolizing isoflavone and it thus enables the production of isoflavone metabolites. Also, compositions comprising the microorganism and isoflavone can be used for prevention or treatment of climacteric diseases especially, osteoporosis, and they can be used as antioxidants, anticancer agents, antimutagens, etc. Sequence Listing [92] Related sequence list was added as appendix file