Alleviating product inhibition of Trichoderma reesei cellulase complex with a product-activated mushroom endoglucanase

Gen Zou; Dapeng Bao; Ying Wang; Sichi Zhou; Meili Xiao; Zhanshan Yang; Yinmei Wang; Zhihua Zhou

doi:10.1016/j.biortech.2020.124119

Alleviating product inhibition of Trichoderma reesei cellulase complex with a product-activated mushroom endoglucanase

Bioresour Technol. 2021 Jan:319:124119. doi: 10.1016/j.biortech.2020.124119. Epub 2020 Sep 15.

Authors

Gen Zou¹, Dapeng Bao², Ying Wang³, Sichi Zhou³, Meili Xiao⁴, Zhanshan Yang³, Yinmei Wang⁵, Zhihua Zhou⁶

Affiliations

¹ Shanghai Key Laboratory of Agricultural Genetics and Breeding; Institute of Edible Fungi, Shanghai Academy of Agriculture Science, 1000 Jinqi Rd, Fengxian 201403, Shanghai, China; CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Science, Fenglin Rd 300, Shanghai 200032, China. Electronic address: zougen@sibs.ac.cn.
² Shanghai Key Laboratory of Agricultural Genetics and Breeding; Institute of Edible Fungi, Shanghai Academy of Agriculture Science, 1000 Jinqi Rd, Fengxian 201403, Shanghai, China. Electronic address: baodapeng@saas.sh.cn.
³ Shanghai Key Laboratory of Agricultural Genetics and Breeding; Institute of Edible Fungi, Shanghai Academy of Agriculture Science, 1000 Jinqi Rd, Fengxian 201403, Shanghai, China.
⁴ CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Science, Fenglin Rd 300, Shanghai 200032, China. Electronic address: xiaomeili@sippe.ac.cn.
⁵ CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Science, Fenglin Rd 300, Shanghai 200032, China. Electronic address: wangyinmei@cemps.ac.cn.
⁶ CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Science, Fenglin Rd 300, Shanghai 200032, China. Electronic address: zhouzhihua@sippe.ac.cn.

PMID: 32957048
DOI: 10.1016/j.biortech.2020.124119

Abstract

Product inhibition of cellulase is a challenging issue in industrial processes. Here, we introduced a product-activated mushroom cellulase, PaCel3A from Polyporus arcularius, into Trichoderma reesei. The filter paper activity, carboxymethyl cellulase activity, and saccharification efficiency (substrate: pretreated rice straw, PRS) of transformants increased significantly with this enzyme (by 18.4-26.8%, 13.8-22.8%, and 17.0%, respectively). A mutant of PaCel3A, PaCel3AM, obtained based on B-factor analysis, saturated mutagenesis, and residual activity assay, showed improved thermostability. The PRS saccharification efficiency using the cellulase complex from T. reesei transformants overexpressing pacel3am increased by 56.4%-63.0%. In addition, the T. reesei cellulase complex obtained by adding the purified recombinant PaCel3AM from T. reesei (rCel3aM-tr) to hydrolyze PRS resulted in increased reducing sugar yields at all sampling points, outperforming the cellulase complexes without rCel3aM-tr. These results suggest that introducing product-activated cellulase genes is a simple and feasible method to alleviate the product inhibition of cellulase.

Keywords: Cellulase; Lignocellulose; Product inhibition; Trichoderma reesei.

MeSH terms

Agaricales*
Cellulase* / genetics
Mutagenesis
Trichoderma*

Substances

Cellulase