加利利链霉菌AF1产孢条件的优化

Optimization of sporulation conditions for Streptommyces galilaeus AF1

【目的】筛选加利利链霉菌(Streptommyces galilaeus)AF1菌株孢子的最佳培养条件。【方法】利用固体发酵法,首先采用单因素试验对培养加利利链霉菌(Streptommyces galilaeus)AF1菌株的固体产孢基质大米、玉米粉、木薯渣、黄豆粉、麸皮、麦片进行筛选,然后研究培养时间、温度、料液比、接种量、外加碳源、外加氮源对加利利链霉菌AF1产孢量的影响。在单因素试验的基础上,采用正交试验对AF1菌株的产孢条件进行优化。【结果】筛选的最佳固体产孢基质为大米。优化得到的最佳培养条件为培养温度28℃,培养时间6d,接种量10%(每20g大米接种2mL孢子悬液),初始料(g)液(mL)比为1∶1,葡萄糖添加量1.5%(质量分数),蛋白胨添加量1.5%(质量分数)。在最佳培养条件下,加利利链霉菌AF1产孢数可达3.87×109 g-1,比优化前提高了29%。【结论】在优化培养条件下得到的加利利链霉菌AF1产孢水平高,能适应大规模培养接种体的要求。

【Objective】This study explored the optimal sporulation conditions for Streptommyces galilaeus AF1.【Method】The solid fermentation conditions of spores production of S.galilaeus AF1 were studied.Single factor experiments were firstly conducted to screen the solid sporulation substrates(rice,corn flour,cassava residue,soybean flour,bran and oatmeal).Then,the effects of incubation time,temperature,liquid to solid ratio,inoculation amount,carbon source and nitrogen source on sporulation yield of S.galilaeus AF1 were tested.The conditions affecting the sporulation yield were optimized by orthogonal test based on single factor experiments.【Result】The best substrate was rice and the best fermentation conditions were incubation temperature 28℃,incubation time 6 d,inoculation amount 10%(2 mL spore suspension inoculated in 20 g rice),liquid(mL)to solid(g)ratio 1∶1,1.5%(m/m)glucose as carbon source,and 1.5%(m/m)peptone as nitrogen source.Under above conditions,the conidia amount reached 3.87×10^9 g^-1,which was 29%higher than original medium.【Conclusion】The obtained S.galilaeus AF1 had high sporulation level and met the requirement of large scale inoculum.