Efficient production of skimmin and 6'-succinylskimmin from umbelliferone by organic solvent-tolerant Bacillus licheniformis ZSP01 using nitrogen sources regulation strategy

An organic solvent-tolerant Bacillus licheniformis ZSP01 was newly isolated and utilized as a whole-cell biocatalyst for efficient production of skimmin and 6'-succinylskimmin from umbelliferone. Strikingly, the production of skimmin and 6'-succinylskimmin was significantly increased in the reaction media added with 10% dimethylsulfoxide (DMSO), and was separately regulated by adjusting the nitrogen sources in the fermentation medium. Efficient production of skimmin with a molar yield of 81% by resting cells of strain ZSP01 was achieved by using tryptone as nitrogen source for fermentation. Furthermore, efficient production of the novel compound, 6'-succinylskimmin, with a molar yield of 90% was obtained by using tryptone and yeast extract as a composite nitrogen source for fermentation. The glucosylation catalyzed by strain ZSP01 demonstrated an exquisite regioselectivity for a hydroxyl group at C-7 of the coumarin sheleton without neighboring substituents.