Design, Construction And Characterisation Of Co-expression Vectors For The Cellulases Development

Filamentous fungus Trichoderma reesei is one of the most efficient cellulase producers and has a long history in producing cellulase. It has an excellent extracellular secretion capability for a large amount of proteins. Cellulases derived from T. reesei have their highest activity at acidic pH, thereby limiting the application of cellulases under neutral or alkaline conditions, especially in textile industry.In order to develop the cellulases for the textile industry,5cellulase genes were expressed in T. reesei Rut C30. The activities of the pWEF31-V3transformants reached38.3±6.8IU/mL at pH8.0, which retained about37.2%of the maximal activity at pH6.0. The enzymatic properties of pWEF31-V3transformants exhibited above80%residual relative activities at pH5-7. For the coexpression of proteins in T. reesei, a series of gene expression devices were standardized and modularized constructed. Taking alkaline cellulase as a report gene, the efficiency and characteristics of those devices were detailed studied. And two strongest gene expression devices were used in a proof-of-principle approach to achieve the co-expression of an alkaline endoglucanase and an alkaline exoglucanase. And higher activities of both cellulose degrading and biostoning were observed by the co-expression of alkaline endoglucanase and exoglucanase than the activities obtained by the expression of only endoglucanase or exoglucanase. This study will make the process of multiple engineering genes expression easier and more reliable in T. reesei.