Cellulose induced protein 1 (Cip1) from Trichoderma reesei enhances the enzymatic hydrolysis of pretreated lignocellulose

Abstract

Background Trichoderma reesei is currently the main strain for the commercial production of cellulase. Cellulose induced protein 1 (Cip1) is one of the most abundant proteins in extracellular proteins of T. reesei. Reported literatures about Cip1 mainly focused on the regulation of Cip1 and its possible enzyme activities, but the effect of Cip1 on the enzymatic hydrolysis of lignocellulose and possible mechanism have not still been reported. Results In this study, Cip1 from T. reesei was cloned, expressed and purified, and its effects on enzymatic hydrolysis of several different pretreated lignocellulose were investigated. It was found that Cip1 could promote the enzymatic hydrolysis of pretreated lignocellulose, and the promoting effect was significantly better than that of bovine serum albumin (BSA). And especially for the lignocellulosic substrate with high lignin content such as liquid hot water pretreated corn stover and corncob residue, the promoting effect of Cip1 was even better than that of the commercial cellulase when adding equal amount protein. It was also showed that the metal ions Zn2+ and Cu2+ influenced the promoting effect on enzymatic hydrolysis. The Cip1 protein had no lyase activity, but it could destroy the crystal structure of cellulose and reduce the non-productive adsorption of cellulase on lignin, which partly interpreted the promoting effect of Cip1 on enzymatic hydrolysis of lignocellulose. Conclusion The Cip1 from T. reesei could significantly promote the enzymatic hydrolysis of pretreated lignocellulose, and the promotion of Cip1 was even higher than that of commercial cellulase in the enzymatic hydrolysis of the substrates with high lignin content. This study will help us to better optimize cellulase to improve its ability to degrade lignocellulose, thereby reducing the cost of enzymes required for enzymatic hydrolysis.

Tailoring the expression of Xyr1 leads to efficient production of lignocellulolytic enzymes in Trichoderma reesei for improved saccharification of corncob residues

“…It is known that accessory proteins, such as glucuronoyl esterase (Cip1 and Cip2), swollenin (Swo1), and AA9 lytic polysaccharide monooxygenases (LPMOs), play important roles in enhancing lignocellulose degradation [ 34 ]. Especially, Cip1 can reduce the non-productive adsorption of lignin by cellulase and Cip2 acts in the cleavage of hemicellulose-lignin crosslinks [ 35 , 36 ]. Ma et al demonstrated by RNA sequencing in T. reesei that Xyr1 could stimulate the expression of those accessory protein-encoding genes [ 37 ].…”

Reformulating the Hydrolytic Enzyme Cocktail of Trichoderma reesei by Combining XYR1 Overexpression and Elimination of Four Major Cellulases to Improve Saccharification of Corn Fiber

“…49 Considering that cellulose is always embedded in the hemicellulose matrix mainly composed of xylan, increased xylanase and arabinofuranosidase activities would be anticipated to contribute to enhancing the overall efficiency of lignocellulose hydrolysis. On the other hand, the enhanced production of nonhydrolytic SWOI and CIPI that have been found to significantly promote the enzymatic hydrolysis of biomass materials 11,12 might also play important roles in contributing to the degradation of corn fiber.…”

“…Apart from (hemi)­cellulolytic enzymes, nonhydrolytic proteins, including swollenin (SWOI) and cellulose-induced proteins (CIPI and CIPII), have also been identified in T. reesei secretome. ,, These components have been shown to contribute to promoting lignocellulose hydrolysis. − …”

Induction of cellulase production in Trichoderma reesei by a glucose–sophorose mixture as an inducer prepared using stevioside

“…Moreover, during the fermentation induction process, a low level of basal cellulase from T. reesei is always required to hydrolyse solid inducers to produce small molecules, which can then enter cells to induce cellulase production; therefore, the induction efficiency of solid inducers is unsatisfactory, and the fermentation of T. reesei with solid inducers has no application prospects. [6][7][8] For soluble inducers, the heat transfer efficiency in the fermenter is high, and energy consumption is low. Moreover, a higher induction efficiency can be achieved with soluble inducers because cellulase production can be directly induced in cells without the need for a basal cellulase level to degrade the inducer into small molecules.…”

“…Moreover, during the fermentation induction process, a low level of basal cellulase from T. reesei is always required to hydrolyse solid inducers to produce small molecules, which can then enter cells to induce cellulase production; therefore, the induction efficiency of solid inducers is unsatisfactory, and the fermentation of T. reesei with solid inducers has no application prospects. 6–8…”