Cloning and Heterologous Expression of the Gene Encoding a Family 7 Glycosyl Hydrolase from Penicilliumfuniculosum

摘要

The gene encoding for a family 7 glycosyl hydrolase, designated cel7a, from the filamentous fungus Penicillium funiculosum was cloned from genomic DNA and expressed in Aspergillus awamori under the control of the A. niger glucoamylase promoter using the E. coli/Aspergillus shuttle vector pFE2. Characteristics of the recombinant enzyme were compared to those of the native enzyme and to the Cel7A enzyme from Trichoderma reesei. Unexpectedly, the glycosyl hydrolase isolated from the filamentous fungus Penicillium funiculosum broth demonstrated performance superior to that of Trichoderma reesei Cel7A when tested as part of a two-cellulase mixture with Acidothermus cellulolyticus El endoglucanase in the saccharification of pretreated corn stover. The mature enzyme consists of a 504 residue glycoprotein with a molecular weight of 52,436 Daltons. In pursuit of the goal of increasing the heterologous production of this enzyme, the endogenous signal peptide was replaced genetically with the signal peptides from T. reesei Cel7A, P. funiculosum Cel7A and A. niger GA.