Improving the efficiency of the bioconversion of plant raw materials with mutant cellulases of Penicillium verruculosum

Abstract

Plant biomass is the main type of organic material on Earth. The efficiency of biocatalytic conversion of plant raw materials determines the cost of their biotechnological processing to produce commercially valuable products such as organic alcohols and acids, carbohydrates, and hydrocarbons. New recombinant Penicillium canescens strains that produce not only their own enzyme complex but also heterologous cellulases (i.e., mutant and wild-type cellobiohydrolase I (CBH I) and endoglucanase II (EG II) of P. verruculosum) are constructed. Enzymatic agents (EAs) prepared on the basis of recombinant strains of P. canescens are found to be more active in the hydrolysis of crushed aspen wood. Yields of glucose and reducing sugars are observed 24–72 h after hydrolysis with EAs prepared in recombinant strains to be from 48 to 52 and 60 to 64%, respectively, higher than those for hydrolysis with EAs prepared in the initial recipient strain. The presence of N45A and N194A site-specific mutations introduced to reduce surface glycosilation thus results in a substantial increase in the yields of desired CBH I and EG II.