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Production of the versatile cellulase for cellulose bioconversion and cellulase inducer synthesis by genetic improvement of Trichoderma reesei.
Biotechnol Biofuels. 2017; 10:272.BB

Abstract

Background

The enzymes for efficient hydrolysis of lignocellulosic biomass are a major factor in the development of an economically feasible cellulose bioconversion process. Up to now, low hydrolysis efficiency and high production cost of cellulases remain the significant hurdles in this process. The aim of the present study was to develop a versatile cellulase system with the enhanced hydrolytic efficiency and the ability to synthesize powerful inducers by genetically engineering Trichoderma reesei.

Results

In our study, we employed a systematic genetic strategy to construct the carbon catabolite-derepressed strain T. reesei SCB18 to produce the cellulase complex that exhibited a strong cellulolytic capacity for biomass saccharification and an extraordinary high β-glucosidase (BGL) activity for cellulase-inducing disaccharides synthesis. We first identified the hypercellulolytic and uracil auxotrophic strain T. reesei SP4 as carbon catabolite repressed, and then deleted the carbon catabolite repressor gene cre1 in the genome. We found that the deletion of cre1 with the selectable marker pyrG led to a 72.6% increase in total cellulase activity, but a slight reduction in saccharification efficiency. To facilitate the following genetic modification, the marker pyrG was successfully removed by homologous recombination based on resistance to 5-FOA. Furthermore, the Aspergillus niger BGLA-encoding gene bglA was overexpressed, and the generated strain T. reesei SCB18 exhibited a 29.8% increase in total cellulase activity and a 51.3-fold enhancement in BGL activity (up to 103.9 IU/mL). We observed that the cellulase system of SCB18 showed significantly higher saccharification efficiency toward differently pretreated corncob residues than the control strains SDC11 and SP4. Moreover, the crude enzyme preparation from SCB18 with high BGL activity possessed strong transglycosylation ability to synthesize β-disaccharides from glucose. The transglycosylation product was finally utilized as the inducer for cellulase production, which provided a 63.0% increase in total cellulase activity compared to the frequently used soluble inducer, lactose.

Conclusions

In summary, we constructed a versatile cellulase system in T. reesei for efficient biomass saccharification and powerful cellulase inducer synthesis by combinational genetic manipulation of three distinct types of genes to achieve the customized cellulase production, thus providing a viable strategy for further strain improvement to reduce the cost of biomass-based biofuel production.

Authors+Show Affiliations

State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University, Jinan, 250100 People's Republic of China.State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University, Jinan, 250100 People's Republic of China.State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University, Jinan, 250100 People's Republic of China.State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University, Jinan, 250100 People's Republic of China.State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University, Jinan, 250100 People's Republic of China.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

29167702

Citation

Gao, Jia, et al. "Production of the Versatile Cellulase for Cellulose Bioconversion and Cellulase Inducer Synthesis By Genetic Improvement of Trichoderma Reesei." Biotechnology for Biofuels, vol. 10, 2017, p. 272.
Gao J, Qian Y, Wang Y, et al. Production of the versatile cellulase for cellulose bioconversion and cellulase inducer synthesis by genetic improvement of Trichoderma reesei. Biotechnol Biofuels. 2017;10:272.
Gao, J., Qian, Y., Wang, Y., Qu, Y., & Zhong, Y. (2017). Production of the versatile cellulase for cellulose bioconversion and cellulase inducer synthesis by genetic improvement of Trichoderma reesei. Biotechnology for Biofuels, 10, 272. https://doi.org/10.1186/s13068-017-0963-1
Gao J, et al. Production of the Versatile Cellulase for Cellulose Bioconversion and Cellulase Inducer Synthesis By Genetic Improvement of Trichoderma Reesei. Biotechnol Biofuels. 2017;10:272. PubMed PMID: 29167702.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Production of the versatile cellulase for cellulose bioconversion and cellulase inducer synthesis by genetic improvement of Trichoderma reesei. AU - Gao,Jia, AU - Qian,Yuanchao, AU - Wang,Yifan, AU - Qu,Yinbo, AU - Zhong,Yaohua, Y1 - 2017/11/15/ PY - 2017/06/13/received PY - 2017/11/07/accepted PY - 2017/11/24/entrez PY - 2017/11/24/pubmed PY - 2017/11/24/medline KW - Cellulase KW - Transglycosylation KW - Trichoderma reesei KW - cre1 KW - β-Disaccharides KW - β-Glucosidase SP - 272 EP - 272 JF - Biotechnology for biofuels JO - Biotechnol Biofuels VL - 10 N2 - Background: The enzymes for efficient hydrolysis of lignocellulosic biomass are a major factor in the development of an economically feasible cellulose bioconversion process. Up to now, low hydrolysis efficiency and high production cost of cellulases remain the significant hurdles in this process. The aim of the present study was to develop a versatile cellulase system with the enhanced hydrolytic efficiency and the ability to synthesize powerful inducers by genetically engineering Trichoderma reesei. Results: In our study, we employed a systematic genetic strategy to construct the carbon catabolite-derepressed strain T. reesei SCB18 to produce the cellulase complex that exhibited a strong cellulolytic capacity for biomass saccharification and an extraordinary high β-glucosidase (BGL) activity for cellulase-inducing disaccharides synthesis. We first identified the hypercellulolytic and uracil auxotrophic strain T. reesei SP4 as carbon catabolite repressed, and then deleted the carbon catabolite repressor gene cre1 in the genome. We found that the deletion of cre1 with the selectable marker pyrG led to a 72.6% increase in total cellulase activity, but a slight reduction in saccharification efficiency. To facilitate the following genetic modification, the marker pyrG was successfully removed by homologous recombination based on resistance to 5-FOA. Furthermore, the Aspergillus niger BGLA-encoding gene bglA was overexpressed, and the generated strain T. reesei SCB18 exhibited a 29.8% increase in total cellulase activity and a 51.3-fold enhancement in BGL activity (up to 103.9 IU/mL). We observed that the cellulase system of SCB18 showed significantly higher saccharification efficiency toward differently pretreated corncob residues than the control strains SDC11 and SP4. Moreover, the crude enzyme preparation from SCB18 with high BGL activity possessed strong transglycosylation ability to synthesize β-disaccharides from glucose. The transglycosylation product was finally utilized as the inducer for cellulase production, which provided a 63.0% increase in total cellulase activity compared to the frequently used soluble inducer, lactose. Conclusions: In summary, we constructed a versatile cellulase system in T. reesei for efficient biomass saccharification and powerful cellulase inducer synthesis by combinational genetic manipulation of three distinct types of genes to achieve the customized cellulase production, thus providing a viable strategy for further strain improvement to reduce the cost of biomass-based biofuel production. SN - 1754-6834 UR - https://www.unboundmedicine.com/medline/citation/29167702/Production_of_the_versatile_cellulase_for_cellulose_bioconversion_and_cellulase_inducer_synthesis_by_genetic_improvement_of_Trichoderma_reesei_ L2 - https://biotechnologyforbiofuels.biomedcentral.com/articles/10.1186/s13068-017-0963-1 DB - PRIME DP - Unbound Medicine ER -
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