High production of succinyl isoflavone glycosides by Bacillus licheniformis ZSP01 resting cells in aqueous miscible organic medium

To achieve efficient production of succinyldaidzin and succinylgenistin, resting cells of a solvent-stable strain Bacillus licheniformis ZSP01 were used to react with pure isoflavones or soybean flour extract in a reaction medium with 10% dimethyl sulfoxide. Strikingly, 0.8 mM daidzein, 0.8 mM genistein, 2.0 mM daidzin, and 2.0 mM genistin were transformed to succinyl isoflavone glycosides in 27 H (yield >90%). The soybean flour extract (6.1%, w/v) contained 0.32 mM daidzein, 0.84 mM daidzin, 0.38 mM genistein, and 1.04 mM genistin. Over 95% of total isoflavones (daidzein, daidzin, genistein, and genistin) in the soybean flour extract were converted to succinyl isoflavone glycosides after 27 H. Strain ZSP01 shows both high glycosylation and succinylation activities. These results suggest that B. licheniformis ZSP01 could be useful for the efficient production of succinyl soybean isoflavone glycosides.