海洋来源链霉菌MY0504产纤溶酶的发酵条件优化

摘要

[目的]以发酵液纤溶酶活力为指标,优化海洋来源的链霉菌菌株MY0504的发酵条件.[方法]在菌株生长曲线及单因素试验基础上,采用Plackett-Burman设计筛选影响纤溶酶活性的主要因素,进一步用最陡爬坡试验及Box-Behnken中心组合设计法优化发酵条件.[结果]纤溶酶活性最高的发酵条件为:葡萄糖21.68 g/L,酵母粉25.31 g/L,NaC1 5.0 g/L,K2HPO4·3H2O3.0 g/L,MgSO4·7H2O 0.5 g/L,FeSO4·7H2O 0.02 g/L,装液量50 mL (250 mL摇瓶),接种量10％(体积比),初始pH 7.5,温度24℃,转速200 r/min,培养时间4.5 d.发酵液纤溶酶活性可达2 190.6 U/mL.[结论]确定了MY0504菌株产纤溶酶的最优发酵条件,为该酶的进一步分离纯化及性质研究奠定基础.%[Objective] To optimize the fermentation conditions of Streptomyces strain MY0504 from marine environment and improve the fibrinolytic activity in fermentation broth.[Methods] Based on the growth curve of MY0504 and single factor test,the main factors affecting enzyme activity were found through the Plackett-Burman design,and the fermentation conditions were further optimized using steepest ascent experiment and Box-Behnken central composite design.[Results] The optimal fermentation conditions were as follows:glucose 21.68 g/L,yeast powder 25.31 g/L,NaC1 5.0 g/L,K2HPO4·3H2O 3.0 g/L,MgSO4·7H2O 0.5 g/L,FeSO4·7H2O 0.02 g/L,medium volume 50 mL (250 mL flask),inoculum size 10％ (V/V),initial pH 7.5,fermentation temperature 24 ℃,shaking speed 200 r/min,fermentation time 4.5 d.The enzyme activity reached 2 190.6 U/mL in fermentation broth.[Conclusion] The optimal fermentation conditions of strain MY0504 producing fibrinolytic enzyme were obtained,which lay a foundation for further purification and characterization of the fibrinolytic enzyme.