Development of a powerful synthetic hybrid promoter to improve the cellulase system of Trichoderma reesei for efficient saccharification of corncob residues

• DOI: 10.1186/s12934-021-01727-8
• Publication Date: 2022-01-04T08:03:26Z
• Authors: Yifan Wang; Ruiyan Liu; Hong Liu; Xihai Li; Linjing Shen; Weican Zhang; Xin Song; Weifeng Liu; Xiangmei Liu; Yaohua Zhong
• Keywords: Corncob; Aspergillus oryzae

The filamentous fungus Trichoderma reesei is a widely used workhorse for cellulase production in industry due to its prominent secretion capacity of extracellular cellulolytic enzymes. However, some key components are not always sufficient this cocktail, making the conversion cellulose-based biomass costly on industrial scale. Development strong and efficient promoters would enable cocktail be optimized bioconversion biomass.In study, synthetic hybrid promoter was constructed applied optimize system T. saccharification towards corncob residues. Firstly, series 5' truncated different lengths were established based constitutive Pcdna1. strongest amongst them Pcdna1-3 (- 640 - 1 bp upstream translation initiation codon ATG), exhibiting 1.4-fold higher activity than that native cdna1 promoter. Meanwhile, activation region 821 622 ATG devoid Cre1-binding sites) inducible Pcbh1 cloned identified an amplifier initiating gene expression. Finally, fused Pcdna1-3, generating novel Pcc. This engineered Pcc drove expression by displaying 1.6- 1.8-fold stronger fluorescence intensity Pcdna1 under condition using egfp as reporter gene, respectively. Furthermore, overexpress Aspergillus niger β-glucosidase BGLA coding bglA endoglucanase EG2 eg2, achieving 43.5-fold BGL 1.2-fold EG increase, Ultimately, overcome defects reesei, eg2 co-overexpressed control bglA-eg2 double strain QPEB70 exhibited 178% increase total activity, whose displayed 2.3- 2.4-fold efficiency acid-pretreated delignified residues parental strain, respectively.The generated employed improve expressing specific components. Therefore, construction allow particular genes expressed at desired levels, which viable strategy enzyme bioconversion.