Key Laboratory of Animal Epidemic Etiology & Immunological Prevention of Ministry of Agriculture, College of Animal Sciences, Zhejiang University, Hangzhou 310029, PR China.
Microbiol Res. 2010 Mar 31;165(3):190-8. doi: 10.1016/j.micres.2009.04.001. Epub 2009 Aug 4.
Cellulase-producing fungi Trichoderma viride were cultured and fermented on the solid-state wheat bran fermentation medium. The characteristics of its carboxymethyl cellulase (CMCase) in the condition of this solid-state fermentation were evaluated, and the optimum culture time, optimum pH and optimum temperature for CMCase activity of T. viride fermented in this solid state were 60h, 5.0 and 50 degrees C, respectively. Carboxymethyl cellulose sodium (CMC-Na) and Congo red were used to screen the strains that had stronger ability to produce enzymes. After the compound mutagenesis by microwave and ultraviolet, seven mutant strains (M-B1-M-B7) were selected and their CMCase activities were assayed. Five of them (M-B1, M-B2, M-B3, M-B5 and M-B7) had significantly stronger ability to produce enzymes than the normal wild type, and they were also very stable for a long period up to 9 generations to produce cellulase. Molecular studies showed that there were some base mutations in endoglucanase I (EG I) genes of mutants M-B1, M-B2, M-B3 and M-B5, but no change in M-B7, suggesting that some amino mutations in EG I proteins caused by base mutations could lead to enhanced cellulase production.
固态发酵麦麸培养产纤维素酶真菌绿色木霉，评估其在固态发酵条件下的羧甲基纤维素酶（CMCase）特性，得到绿色木霉固态发酵的最适培养时间、最适 pH 值和最适 CMCase 活性温度分别为 60h、5.0 和 50℃。采用羧甲基纤维素钠（CMC-Na）和刚果红筛选产酶能力较强的菌株。经微波和紫外线复合诱变后，筛选出 7 株突变株（M-B1-M-B7），并对其 CMCase 活性进行了测定。其中 5 株（M-B1、M-B2、M-B3、M-B5 和 M-B7）产生酶的能力明显强于正常野生型，而且在长达 9 代的时间内非常稳定，能够持续产生纤维素酶。分子研究表明，突变株 M-B1、M-B2、M-B3 和 M-B5 的内切葡聚糖酶 I（EG I）基因存在一些碱基突变，但 M-B7 没有变化，表明 EG I 蛋白中的一些氨基酸突变可能导致纤维素酶产量的增加。
