关键词: 响应面; α -半乳糖苷酶; 固体发酵; 里氏木霉

Abstract:

The culture conditions of Trichoderma reesei solid-state fermentation to produce α-galactosidase were optimized by response surface method. First of all, according to the single factors,the experiments were designed as Plackett-Burman and three main factorswere selected out:The ratio of corn cob and bagasse carbon source, the ratio of beef extract and ammonium nitrogen source and the fermentation initial pH. On the basis of using the method of the steepest uphill path approximation maximum response area, the response surface method was used to determine the main factors of the interaction between the main factors and the optimal culture conditions. The results showed that the optimized culture conditions in Trichoderma reesei solid-state fermentation producing α-galactosidase were:the ratio of carbon source (namely corn cobsand to bagasse ratio) was 3.86, the ratio of nitrogen source (beef paste to ammonium sulfate) was 1.17, and the initial pH was 9.12. After optimization, the α-galactosidase activity produced in Trichoderma reesei solid-state fermentation could be up to 342.98 U/g and were close to 353.43 U/g, the model prediction. It was increased by 113.91% than before optimization. In conclusion,the most important factors in Trichoderma reesei solid-state fermentation were carbon source, nitrogen source and pH value,which interacted each other.The activity of α- galactosidase was maximum when the ratio of carbon source was up to 3.86, the ratio of nitrogen source was up to 1.17 and pH value reach to 9.12.

Key words: response surface; α-galactosidase; solid-state fermentation; Trichoderma reesei