产纤维素酶真菌RX-3的筛选鉴定及产酶条件优化

Screening,Identification and Optimization of Enzyme Production Conditions of Cellulase-Producing Fungus RX-3

筛选获得一株高产纤维素酶的真菌并进行产酶优化及酶学性质探究,可为纤维素酶在废纸造纸中的应用提供参考。利用刚果红鉴定法筛选若干株产纤维素酶的菌株,以DNS显色法测定菌株CMCase酶活。选取产酶能力最强即酶活最高的菌株对其进行产酶条件优化。最后,收集菌株产生的粗酶液探究其酶学特性。实验结果表明:真菌RX-3的产酶能力最强,经鉴定为曲霉属中的黑曲霉;真菌RX-3的最佳产酶条件是,麦麸和蛋白胨分别为RX-3的碳源和氮源、接种量为2%、最适pH环境为4。真菌RX-3所产纤维素酶的酶学特性是,最适反应时间为25 min,最适反应温度为50℃,底物与酶液最适比为3:1,Fe^(2+)和Mn^(2+)对酶活性起促进作用,Zn^(2+)、Mg^(2+)和Cu^(2+)对酶活性起抑制作用。

A fungus with high yield of cellulase was screened for enzyme production optimization and enzymatic property exploration to provide a reference for the application of cellulase in regenerated papermaking.Several strains producing cellulase were screened by Congo red identification method,and the CMCase activity of the strains was determined by DNS colorimetric method.The strain with the strongest enzyme production ability and the highest enzyme activity was selected to optimize the enzyme production conditions.Finally,the crude enzyme produced by the strain was collected to explore its enzymatic properties.The results showed that the enzyme production ability of fungus RX-3 was the strongest,and it was identified as Aspergillus sp..The optimum enzyme production conditions of fungus RX-3 were as follows:wheat bran and peptone were the carbon source and nitrogen source of RX-3,respectively,the inoculation amount was 2%,and the optimum pH environment was 4.The enzymatic properties of cellulase produced by fungus RX-3 were as follows:the optimum reaction time was 25 min,the optimum reaction temperature was 50℃,the optimum ratio of substrate to enzyme solution was 3:1,Fe^(2+)and Mn^(2+)promoted the enzyme activity,and Zn^(2+),Mg^(2+)and Cu^(2+)inhibited the enzyme activity.