Improvement of Saccharification and Delignification Efficiency of <i>Trichoderma reesei</i> Rut-C30 by Genetic Bioengineering

oleh: Raja Mohan Gopalakrishnan, Tamilvendan Manavalan, Janani Ramesh, Kalaichelvan Puthupalayam Thangavelu, Klaus Heese

Format: Article
Diterbitkan: MDPI AG 2020-01-01

Deskripsi

<i>Trichoderma reesei</i> produces various saccharification enzymes required for biomass degradation. However, the lack of an effective lignin-degrading enzyme system reduces the species&#8217; efficiency in producing fermentable sugars and increases the pre-treatment costs for biofuel production. In this study, we heterologously expressed the <i>Ganoderma lucidum</i> RMK1 versatile peroxidase gene (<i>vp1</i>) in the Rut-C30 strain of <i>T. reesei</i>. The expression of purified 6&#215;His-tag&#8722;containing recombinant <i>G. lucidum</i>-derived protein (rVP1) was confirmed through western blot, which exhibited a single band with a relative molecular weight of 39 kDa. In saccharification and delignification studies using rice straw, the transformant (tVP7, <i>T. reesei</i> Rut-C30 expressing <i>G. lucidum</i>-derived rVP1) showed significant improvement in the yield of total reducing sugar and delignification, compared with that of the parent <i>T. reesei</i> Rut-C30 strain. Scanning electron microscopy (SEM) of tVP7-treated paddy straw showed extensive degradation of several layers of its surface compared with the parent strain due to the presence of <i>G. lucidum</i>-derived rVP1. Our results suggest that the expression of ligninolytic enzymes in cellulase hyperproducing systems helps to integrate the pre-treatment and saccharification steps that may ultimately reduce the costs of bioethanol production.