海洋来源链霉菌MY0504产纤溶酶的发酵条件优化

【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,NaCl5.0 g/L,K_2HPO_4·3H_2O3.0 g/L,MgSO_4·7H_2O 0.5 g/L,FeSO_4·7H_2O 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°C,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。

Optimization of fermentation for fibrinolytic enzyme production by Streptomyces MY0504 from ocean

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, NaCl 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 °C, 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.