Abstract
BackgroundThe filamentous fungus Trichoderma reesei is a major workhorse employed to produce cellulase, which hydrolyzes lignocellulosic biomass for the production of cellulosic ethanol and bio-based products. However, the economic efficiency of biorefineries is still low.ResultsIn this study, the truncation of cellulase activator ACE3 was identified and characterized in T. reesei classical mutant NG14 and its direct descendants for the first time. We demonstrated that the truncated ACE3 is the crucial cause of cellulase hyper-production in T. reesei NG14 branch. Replacing the native ACE3 with truncated ACE3 in other T. reesei strains remarkably improves cellulase production. By truncating ACE3, we engineered a T. reesei mutant, PC-3-7-A723, capable of producing more cellulase than other strains. In a 30-L fermenter, fed-batch fermentation with PC-3-7-A723 drastically increased the maximum cellulase titer (FPase) to 102.63 IU/mL at 240 h, which constitutes a 20–30% improvement to that of the parental strain PC-3-7.ConclusionsThis work characterized the function of truncated ACE3 and demonstrated that analysis of classical mutants allows rational engineering of mutant strains with improved cellulase production necessary to process lignocellulosic biomass. Our rational engineering strategy might be useful for enhancing the production of other bio-based products.
Highlights
The filamentous fungus Trichoderma reesei is a major workhorse employed to produce cellulase, which hydrolyzes lignocellulosic biomass for the production of cellulosic ethanol and bio-based products
There are many mutagenic events occurring in transcription factors (TFs) that contribute to the improvement of cellulases in different T. reesei classical hyper-producing mutants
We scanned the never-studied mutations located in TFs for cellulase production from the genome data of classical mutagenic strains to determine whether such mutations can contribute to the improvements of cellulase or not
Summary
The filamentous fungus Trichoderma reesei is a major workhorse employed to produce cellulase, which hydrolyzes lignocellulosic biomass for the production of cellulosic ethanol and bio-based products. Further mutagenesis using NTG (N-nitroguanidine) led to the isolation of the hyper-producer strain NG14 that exhibited two- to fivefold increased cellulase activity compared to the QM6a parental strain [8]. T. reesei strain PC-3-7 [10], derived from QM9414 through several rounds of mutagenesis, is a cellulase hyper-producing mutant that exhibits twice as much cellulase activity as QM9414 [11]. This has led to the identification of a large number of mutagenic events that contribute to the improvements of cellulase in the QM9414 and NG14 branch [5, 12,13,14]. The genomes of some strains have been sequenced [8, 15], making the organism open to targeted improvement by genetic engineering
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
