海洋放线菌F1发酵条件优化及抑菌物质性质的初步研究

Optimization of fermentation conditions of marine actinomycete strain F1 and the study of antimicrobial active substance

目的对筛选出的海洋放线菌F1的发酵培养基及条件进行优化,并对菌株F1分泌的有活性的次级代谢产物的特性进行了初步研究。方法采用单因素实验和正交试验的方法对发酵培养基及发酵条件进行优化,观察pH值、温度、光照、紫外线、储藏温度对抑菌物质稳定性的影响,了解抑菌物质的极性及疏水特性。结果优化的最佳培养基为：可溶性淀粉20.0g,NaCl 1.0g,胰蛋白胨0.5g,Yeast Extract 2.0g,K2HPO4·3H2O 0.5g,MgSO4·7H2O 0.5g,FeSO4·7H2O 0.01g,陈海水1000mL,pH 7.4~7.6,固体培养基加1.5%的琼脂粉。摇瓶装量30%,接种量10%,发酵时间168h时抑菌抑菌圈最大,抑菌物质有较好的热、光、紫外线及储藏温度稳定性,pH值在3~12有活性,在强酸环境中失活,耐碱不耐酸,活性物质溶于石油醚和乙酸乙酯,不溶于正丁醇。结论通过优化实验确定了菌株F1最优发酵培养基及发酵条件,抑菌物质有较好的稳定性,有较大极性和水溶性。

Objective To optimize the fermentation conditions of the marine actinomycete strain F1 which possessed strong antibacterial activity, and to study the characteristics of active substances secreted by strain F1. Methods Single-factor experiment and orthogonal tests were used to optimize the fermentation medium and conditions. The effect of pH, temperature, light, ultraviolet and storage temperature on the stability of active substances was investigated to study the polarity and the hydrophobic nature of the antibacterial substances. Results The optimum composition of the fermentation medium was as follow： soluble starch 2. 0 g, NaCl 0. 5 g, Tryptone 0. 5 g, Yeast Extract 2. 0 g, K2HPO4 · 3H2O 0. 5 g, MgSO4 · 7H2O 0. 5 g, FeSO4 ·7H2O 0. 01 g, seawater 1000 mL, pH 7.4~7.6, and 1.5% agar for solid medium. The optimal shaking flask filled by 30%, inoculum concentration 10%, fermentation time 168 h. The active substances exhibited stability against heat, light, ultraviolet and storage tem- perature, and possessed activity in alkali, but not under strong acid. The active substances were solu-ble in ethyl acetate and petroleum ether, and insoluble in n-butyl alcohol. Conclusion The optimal fer mentation medium and conditions were obtained, and active substances possess the great stability, po larity and water-solubility.