两株真菌混合发酵产纤维素酶的条件及其优化

Cellulase production condition and optimization by two mixed fungi Fermentation

采用两株真菌X-13和X-6分别进行单菌和混合菌固态发酵产纤维素酶能力对比,结果表明两株菌混合固态发酵时,纤维素酶活比单独固态发酵分别提高了31.0%和40.7%。通过单因素实验选出了最适合混菌发酵产酶的秸秆和氮源分别为稻草秸秆和硫酸铵;最适装瓶量为250 mL装5 g;最适产酶温度为30℃;最佳产酶时间为4-6 d。用响应面分析法对X-13和X-6混合菌固态发酵条件进行优化,最后得到最优的发酵条件是稻草∶麸皮为1∶2、硫酸铵为3.65 g、接种量为0.75 mL、料水比为1∶2.5、X-13∶X-6为2∶3、培养基初始pH为5.8、吐温-80加入量为0.1%、培养温度为30℃、培养时间为6 d;在该条件下进行混合菌固体发酵,使纤维素酶活从12.181 U/g增长到25.928 U/g,提高了112.9%。

The solid-state fermentation（SSF） method was introduced into the cellulase-producing ability analysis.The individual and mixed fermentation of two fungi X-13,X-6 were compared.The results showed that cellulase activity in the mixed fermentation increased by 31.0% and 40.7% respectively,compared to the individual fermentation.Single-factor test showed that,the optimum straw and nitrogen source were rice straw and（NH4）2SO4 respectively.The media amount was 5 g.The optimum temperature was 30℃ and the optimum time was 4~6 days.Response Surface Methodology（RSM） was used to optimize the fermentation condition of cellulase production by the two fungi mixed.The optimum fermentation condition was rice straw：bran 1∶2,（NH4）2SO4 3.65 g/L,the inoculum size 0.75 mL,stuff：water 1∶2.5,X-13∶X-6 2∶3,initial pH 5.8,tween-80 0.1%,cultural temperature 30℃,incubation time 6 days.Under the optimum condition,the cellulase activity reached 25.928 U/g,which was increased by 112.9% compared with the initial cellulase activity 12.181 U/g.