羟丙基-β-环糊精对植物甾醇侧链生物转化反应的影响

Effect of Hydroxypropyl-β-cyclodextrin on the Side-Chain Bioconversion of Phytosterols by Mycobacterium sp.NRRL B-3683

研究了转化介质对分枝杆菌(Mycobacterium sp.NRRLB-3683)降解植物甾醇生物转化反应的影响。结果表明添加羟丙基-β-环糊精构建成一种新的超分子介质体系可以提高转化反应的反应速率和摩尔转化率,当植物甾醇质量浓度为5g·L-1,转化168h时植物甾醇摩尔转化率达到89.9%,较对照试验提高了3.1倍。在含有羟丙基-β-环糊精的转化体系中,研究了羟丙基-β-环糊精添加量、添加时间和底物质量浓度对植物甾醇生物转化反应的影响。研究表明,植物甾醇质量浓度为5～10g·L-1,转化0h时添加与植物甾醇摩尔比为2:1的羟丙基-β-环糊精,转化72h,底物摩尔转化率达到85%以上。本研究为环糊精超分子主体化合物在甾体生物转化反应中的应用提供了理论依据和基础数据。

Effect of various conversion mediums on phytosterols （PS） degradation by Mycobacterium sp. NRRL B-3683 was investigated. By adding hydroxypropyl-β-cyclodextrin （HP-β-CD） to the fermentation liquid, a new supramolecular conversion system with significant upgrades of reaction rate and its molar conversion was developed. When the PS concentration is 5 g.L-1, after 168 h conversion, the molar conversion ratio can reach 89.9%, which is 3.1 times the conversion ratio of the control experiment. The influences of the HP-β-CD to PS molar ratio in HP-β-CD conversion system, the HP-β-CD adding time and the PS concentration on the biotransformation were studied. The results show that the molar conversion ratio of PS can exceed 85% after 72 h conversion under following optimized conditions： the optimum HP-β-CD to PS molar ratio of 2：1, the HP-β-CD adding at 0 h and the PS concentration of 5-10 g.L-1. This study provides a theoretical foundation and basic data for the application of the cyclodcxtrin in the steroid biotransformation.