PURPOSE: To obtain the titled novel substance having antitumor activity and low toxicity, useful as a remedy for tumor, etc., and having β-1,3-glucopyranose units in the main chain and the side chains, by separating from the culturing liquid obtained by culturing β-1,3-glucan-producing bacteria.
CONSTITUTION: Strain of Pestalotia No.815 (FERM-P No.5147), etc. is cultured in a medium containing a carbon source such as glucose, etc., a nitrogen source such as peptone, etc. and minerals under aerobic conditions. After culturing, mycelia are removed from the culturing mixture by e.g. filtration, and the liquid phase thus obtained is mixed with a precipitant such as methanol to precipitate crude glucan, which is purified to obtain the objective polysaccharide having a main chain composed of β-1,3-glucopyranose units of formula I (GlC is glucopyranose residue) as recurring units, and side chains of formula II (n is 0W1). The number of the side chains is about 55W75 per 100 units of glucose, and the number of the side chains wherein n=1, is about 2W8.
NAKAYAMA MINEO
MIYAJI HIDENORI
NAGAE HIDEO
