一株海绵附生菌Bacillus firmus的培养条件优化及α-GI活性成分初步分析

Optimization on culture conditions for a sponge-associated bacterium Bacillus firmus and preliminary analysis on its products with inhibiting activity against α-glucosidase

为寻找新型α-葡萄糖苷酶抑制(α-glucosidase inhibition,α-GI)活性化合物来源,针对前期研究发现的具有α-GI活性的海绵附生微生物坚强芽孢杆菌(Bacillus firmus),对其发酵培养条件进行优化,并对其活性组分中主要成分进行初步分析.以α-GI活性为主要检测对象,选出蛋白胨、酵母膏、Na Cl和p H值共4个因素进行正交优化试验.结合菌株生长情况和代谢产物产量指标,发现在MB培养基的基础上,蛋白胨质量浓度3 g/dm3、酵母膏质量浓度3 g/dm3、Na Cl质量浓度19.5 g/dm3、p H值为7.5的组合为最优培养条件.在优化后的培养条件下,规模化发酵该菌株,提取其代谢产物粗提物,经活性追踪下的二次色谱柱分离,获得一个高抑制活性组分,抑制率达82.4%.该组分经GC-MS分析后发现,活性组分中主要成分为环二肽类及哌啶酮类物质.本研究结果为寻找新型α-GI活性化合物提供了一个新的、可扩大生产的来源.

In order to find new and active α-glucosidase inhibitors,the medium composition of a sponge-associated bacterium Bacillus firmus,which had been found possessing α-glucosidase inhibition （α-GI）activity in the previ-ous studies,was optimized through the orthogonal test.The active components in crude extracts of this strain were also isolated and analyzed.For an effective α-glucosidase inhibition,rapid cell growth （in terms of cell wet weight） and high crude extract production of the metabolites,an orthogonal test was conducted and it indicates that the com-bination of peptone 3 g/dm3 ,yeast extract 3 g/dm3 ,NaCl 19.5 g/dm3 and pH =7.5 is the optimal conditions based on the MB medium.The strain was fermented in large scale under the optimized conditions and the metabo-lites crude extract was extracted.After twice separation guided by α-GI activities on silicagel column,a sub-frac-tion with high activity of 82.4% against α-glucosidase was then obtained.The GC-MS analysis indicates that cyclic dipeptides and piperidones contributed major components in this active sub-fraction.Present study provided a new and applicable resource for the promising α-glucosidase inhibitors.