Development of the cellulolytic fungus Trichoderma reesei strain with enhanced beta-glucosidase and filter paper activity using strong artificial cellobiohydrolase 1 promoter.
To improve the beta-glucosidase yield and total cellulase activity of Trichoderma reesei, extracellular beta-glucosidase (BGLI) was overexpressed under the control of the modified four-copy cbh1 promoter. Three transformants B2, B12 and B15 with successful integration of the bgl1 gene expression cassette were obtained, which exhibited 3.7-, 2.0- and 1.8-fold increase in beta-glucosidase activity than the parental strain RUT C30, respectively. The filter paper activities of the productive transformants B12 and B15 were improved by up to 130% and 55%, respectively. Saccharification of corncob residue with the crude enzyme dosages showed that the reducing sugar yields of B12 (5.59 mg/ml) and B15 (4.80 mg/ml) were 29% and 11% higher than that of RUT C30 (4.34 mg/ml), respectively. The present results proved that the modified four-copy cbh1 promoter was a useful tool for improving the cellulase activity of T. reesei, and the engineering strains developed in this study could be potentially used as promising cell factories for beta-glucosidase or cellulase production.
Zhang
Jiwei
J
State Key Laboratory of Microbial Technology, Shandong University, Jinan 250100, China.
Zhong
Yaohua
Y
Zhao
Xuena
X
Wang
Tianhong
T
D018533:Biomass; D050260:Carbohydrate Metabolism / Q000235:genetics; D002482:Cellulose / Q000378:metabolism*; D043366:Cellulose 1,4-beta-Cellobiosidase / Q000235:genetics*; D005374:Filtration; D011401:Promoter Regions, Genetic; D014170:Transformation, Genetic; D014242:Trichoderma / Q000201:enzymology*; D003313:Zea mays / Q000378:metabolism; D001617:beta-Glucosidase / Q000378:metabolism*
D002482:Cellulose; D001617:beta-Glucosidase; D043366:Cellulose 1,4-beta-Cellobiosidase