长柄链格孢菌对熊果酸的生物转化工艺优化

目的:以熊果酸为底物,用长柄链格孢菌AS3.2875对熊果酸进行生物转化,并对培养基和转化条件进行优化。方法:以熊果酸的消耗率和28-O-β-D-吡喃葡萄糖熊果酸酯苷的生成率为指标,考察不同起始pH,磷酸盐,不同种类金属离子,孢子浓度,底物加入量,温度,转速,培养时间对熊果酸在长柄链格孢菌培养液中转化的影响,得到长柄链格孢菌对熊果酸的最佳转化条件。结果:优化后的培养条件为初始pH 5.0,0.25 g.L-1MgSO4,1.0 g.L-1K2HPO4,0.083 g.L-1FeSO4,孢子浓度为4%,底物加入量0.3 g.L-1,转速140 r.min-1,28℃,培养3 d。结论:长柄链格孢菌转化熊果酸生成28-O-β-D-吡喃葡萄糖熊果酸酯苷的生成率稳定在5%左右。

Optimization of biotransformation of ursolic acid by alternaria longipes

Objective: To conduct the biotransformation of ursolic acid by alternaria longipes AS3.2875,and optimize the culture medium and biotransformation conditions.Method: With the consumption rate of ursolic acid and the generation rate of 28-O-β-D-glucopyranose ursolic acid as indicators,the impact of different biotransformation conditions such as pH,phosphate,different kinds of metal ions,spore concentration,substrate quantity,temperature,shaking speed and cultivation time on the transformation of ursolic acid in alternaria longipes culture solution were detected to obtain the optimal biotransformation conditions of ursolic acid by alternaria longipes.Result: The optimized biotransformation conditions were as follows: initial pH value was 5.0,MgSO4 was 0.25 g·L-1,K2HPO4 was 1.0 g·L-1,FeSO4 was 0.083 g·L-1,spore concentration was 4%,substrate quantity was 0.3 g·L-1,shaking speed was 140 r·min-1,cultivation temperature was at 28 ℃ and cultivating time was 3 days.Conclusion: The generation rate of 28-O-β-D-glucopyranose ursolic acid by alternaria longipes stabilizes at around 5%.