【摘要】 利用米曲霉直接转化盾叶薯蓣制备了薯蓣皂苷元,转化中最重要的影响因素是pH、接种量和培养温度.在pH6.0的66.7mmol/LNa2HPO4-KH2PO4缓冲液中,8%接种量、37℃培养84h后提温至50℃继续转化8h的条件下,薯蓣皂苷元得率可达17.06mg/g,是粗酶液转化的6.77倍.转化过程中甾体的总摩尔数分别是微波辅助提取和酸水解的1.73和1.47倍.转化产物经质谱和核磁共振鉴定与薯蓣皂苷元同质.直接微生物转化法优于酶解法.更多还原

【Abstract】 The pH, biomass inoculation, and culture temperature were proved to be the main factors in direct biotransformation of steroidal saponins in Dioscorea zingiberensis C.H. Wright by Aspergillus oryzae to produce diosgenin. Under the transformation conditions of 66.7 mmol/L Na2HPO4-KH2PO4 buffer with pH 6.0, 8% biomass inoculation, culturing at 37℃ for 84 h, then 50℃ for 8 h, the highest yield of diosgenin was 17.06 mg/g, which was 6.77 times to that of crude enzyme transformation. Biotransformation of D. zingiberensis by A. oryzae could raise total moles of steroidal constituent 1.73 times to that of extract of D. zingiberensis and 1.47 times to that of acid hydrolysis, respectively. The biotransformation product was identified as diosgenin by MS and NMR. Direct biotransformation of Dioscorea zingiberensis raw herb by Aspergillus oryzae was demonstrated to be superior to enzymolysis method.更多还原