响应面法优化热泉菌Bacillus sp.Lc50-1的发酵产卡拉胶酶条件

Optimization of Carrageenase Fermantation Conditions of Hot Spring Bacterium Bacillus sp.Lc50-1 by Response Surface Methodology

采用响应面法对1株高产卡拉胶酶的印度尼西亚热泉菌Bacillus sp.Lc50-1的发酵条件进行优化。分别以培养温度、pH值、C源、N源、金属离子及接种量作为唯一变量进行单因素实验,筛选出对酶活有显著影响的单因素取值范围;参考单因素实验结果,再利用Box-Behnken设计及响应面分析法进行回归分析以确定最佳发酵条件。结果表明,培养温度、卡拉胶浓度(C源)、蛋白胨浓度(N源)、KCl浓度(金属离子)与酶活存在着显著的相关性,通过求解回归方程得到Bacillus sp.Lc50-1的最佳发酵条件为:培养温度47.5℃、蛋白胨0.25%、卡拉胶0.3%、KCl 21.55mmol·L-1,优化后发酵上清液的酶活达到8.9U·mL-1,比优化前提高了1.5倍。

In this study, the response surface methodology was employed to optimize the fermentation conditions of carrageenase produced by thermophilic bacterium Bacillus sp. 50-1 from Indonesia. The ranges of single factors （temperature, pH, carbon sources, nitrogen sources, metal ions and substrate） were selected by single test firstly. Then variance analysis was conducted through Box-Behnken design and response surface analysis to further optimize fermentation conditions. The results showed that the carrageenase activity had an obvious correlation with the culture temperature and the concentrations of carrageen, trypton and KCL in the culture medium. The optimal fermentation conditions were as follows, incubation temperature was 47. 5℃, peptone 0.25%, carrageenan 0.3%, KCl 21.55 mmol·L^-1. The maximum yield of carrageenase after optimization was 8.82 U · mL^-1 , a1.5 times increase was achieved compared with that of before optimization.