表面活性剂对加利利链霉菌AF1发酵的影响

Effects of surfactants on fermentation of Streptomyces galilaeus AF1

【目的】研究表面活性剂对加利利链霉菌Streptomyces galilaeus AF1菌株发酵的影响。【方法】利用单因素试验优化表面活性剂的添加种类、初步浓度及最佳添加时间,采用Box-Behnken试验和响应面分析对表面活性剂添加质量浓度进行组合优化。流式细胞仪测定细胞荧光强度,确定表面活性剂对AF1菌株细胞膜的影响。【结果】表面活性剂的最优添加质量浓度:吐温–80为8.95 g·L^(–1)、曲拉通X–100为2.09 g·L^(–1)、山梨醇为3.89 g·L^(–1),最优添加时间为接种后5 d;细胞膜透性测定结果表明,试验组的AF1菌株细胞荧光强度极显著高于对照组。【结论】试验得到的响应面模型对因变量的解释程度达94.89%,具有实际意义;添加最优表面活性剂组合后,加利利链霉菌AF1的细胞膜通透性极显著增大,间接导致胞内活性物质的外排量增加,提高了抗菌活性物质的生物合成量。

【Objective】To study the effects of surfactants on fermentation of Streptomyces galilaeus AF1strain.【Method】The single factor experiments were performed to optimize the surfactant type and the initial concentration and determine the best adding time.The Box-Behnken test design and response surface analysis were used to determine the most appropriate concentrations of surfactants.Flow cytometer instrument was used to measure the cell fluorescence intensity and investigate the effects of surfactant on cell membranes of AF1.【Result】The optimum concentrations of added surfactants were8.95g·L–1Tween-80,2.09g·L–1Triton X-100and3.89g·L–1sorbitol.The best adding time was five days after inoculation.The membrane permeability test results showed that the cell fluorescence intensity of AF1of the test group was significantly higher than that of the control group.【Conclusion】The response surface model explained94.89%of the variation in the dependent variables and therefore had practical significance.Membrane permeability of the AF1strain significantly increased after adding the optimal surfactants complex,which led to increased efflux of intracellular active substance and biosythesis of antibacterial substance.