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Lv X, Zheng F, Li C, Zhang W, Chen G, Liu W. Characterization of a copper responsive promoter and its mediated overexpression of the xylanase regulator 1 results in an induction-independent production of cellulases in Trichoderma reesei. BIOTECHNOLOGY FOR BIOFUELS 2015; 8:67. [PMID: 25926888 PMCID: PMC4413991 DOI: 10.1186/s13068-015-0249-4] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 03/30/2015] [Indexed: 05/07/2023]
Abstract
BACKGROUND Trichoderma reesei represents an important workhorse for industrial production of cellulases as well as other proteins. The large-scale production is usually performed in a substrate-inducing manner achieved by a fine-tuned cooperation of a suite of transcription factors. Their production and subsequent analysis are, however, often either difficult to manipulate or complicated by the concomitant production of other inducible proteins. Alternatives to control gene expression independent of the nutritional state are thus preferred in some cases to facilitate not only biochemical studies of proteins but also genetic engineering of the producer. RESULTS We identified a copper transporter encoding gene tcu1 (jgi:Trire2:52315) in T. reesei, the transcription of which was highly responsive to copper availability. Whereas excess copper repressed the expression of tcu1 from T. reesei, eliminating copper addition in the medium resulted in a high-level transcription of tcu1. The usefulness of the system was further illustrated by the high-level expression of specific cellulases driven by the tcu1 promoter in T. reesei when cultivated on D-glucose or glycerol as the sole carbon source. A recombinant T. reesei strain, which overexpressed the main transcription activator of hydrolases (xylanase regulator 1) under the control of tcu1 promoter, was found to be relieved from the carbon catabolite repression and thus displayed a constitutive cellulase expression. Moreover, the amount and activities of cellulases produced by this strain on glycerol or glucose fully recapitulated those of the parental strain produced on Avicel. CONCLUSION Expression of T. reesei tcu1 gene was tightly controlled by copper availability, and a homologous protein expression system was developed based on this promoter. Deregulation of XYR1 (xylanase regulator 1) mediated by the tcu1 promoter not only overcame the carbon catabolite repression of cellulases but also resulted in their full expression even on the non-inducing carbon sources.
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Affiliation(s)
- Xinxing Lv
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, No.27 Shanda South Road, Jinan, 250100 Shandong People’s Republic of China
| | - Fanglin Zheng
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, No.27 Shanda South Road, Jinan, 250100 Shandong People’s Republic of China
| | - Chunyan Li
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, No.27 Shanda South Road, Jinan, 250100 Shandong People’s Republic of China
| | - Weixin Zhang
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, No.27 Shanda South Road, Jinan, 250100 Shandong People’s Republic of China
| | - Guanjun Chen
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, No.27 Shanda South Road, Jinan, 250100 Shandong People’s Republic of China
| | - Weifeng Liu
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, No.27 Shanda South Road, Jinan, 250100 Shandong People’s Republic of China
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Efficient production and evaluation of lignocellulolytic enzymes using a constitutive protein expression system in Penicillium oxalicum. J Ind Microbiol Biotechnol 2015; 42:877-87. [PMID: 25868624 DOI: 10.1007/s10295-015-1607-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 03/10/2015] [Indexed: 12/20/2022]
Abstract
Native lignocellulolytic enzyme systems secreted by filamentous fungi can be further optimized by protein engineering or supplementation of exogenous enzyme components. We developed a protein production and evaluation system in cellulase-producing fungus Penicillium oxalicum. First, by deleting the major amylase gene amy15A, a strain Δ15A producing few extracellular proteins on starch was constructed. Then, three lignocellulolytic enzymes (BGL4, Xyn10B, and Cel12A) with originally low expression levels were successfully expressed with selected constitutive promoters in strain Δ15A. BGL4 and Cel12A overexpression resulted in increased specific filter paper activity (FPA), while the overexpression of Xyn10B improved volumetric FPA but not specific FPA. By switching the culture medium, this platform is convenient to produce originally low-expressed lignocellulolytic enzymes in relatively high purities on starch and to evaluate the effect of their supplementation on the performance of a complex cellulase system on cellulose.
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Chokhawala HA, Roche CM, Kim TW, Atreya ME, Vegesna N, Dana CM, Blanch HW, Clark DS. Mutagenesis of Trichoderma reesei endoglucanase I: impact of expression host on activity and stability at elevated temperatures. BMC Biotechnol 2015; 15:11. [PMID: 25879765 PMCID: PMC4347658 DOI: 10.1186/s12896-015-0118-z] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 01/28/2015] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Trichoderma reesei is a key cellulase source for economically saccharifying cellulosic biomass for the production of biofuels. Lignocellulose hydrolysis at temperatures above the optimum temperature of T. reesei cellulases (~50°C) could provide many significant advantages, including reduced viscosity at high-solids loadings, lower risk of microbial contamination during saccharification, greater compatibility with high-temperature biomass pretreatment, and faster rates of hydrolysis. These potential advantages motivate efforts to engineer T. reesei cellulases that can hydrolyze lignocellulose at temperatures ranging from 60-70°C. RESULTS A B-factor guided approach for improving thermostability was used to engineer variants of endoglucanase I (Cel7B) from T. reesei (TrEGI) that are able to hydrolyze cellulosic substrates more rapidly than the recombinant wild-type TrEGI at temperatures ranging from 50-70°C. When expressed in T. reesei, TrEGI variant G230A/D113S/D115T (G230A/D113S/D115T Tr_TrEGI) had a higher apparent melting temperature (3°C increase in Tm) and improved half-life at 60°C (t1/2 = 161 hr) than the recombinant (T. reesei host) wild-type TrEGI (t1/2 = 74 hr at 60°C, Tr_TrEGI). Furthermore, G230A/D113S/D115T Tr_TrEGI showed 2-fold improved activity compared to Tr_TrEGI at 65°C on solid cellulosic substrates, and was as efficient in hydrolyzing cellulose at 60°C as Tr_TrEGI was at 50°C. The activities and stabilities of the recombinant TrEGI enzymes followed similar trends but differed significantly in magnitude depending on the expression host (Escherichia coli cell-free, Saccharomyces cerevisiae, Neurospora crassa, or T. reesei). Compared to N.crassa-expressed TrEGI, S. cerevisiae-expressed TrEGI showed inferior activity and stability, which was attributed to the lack of cyclization of the N-terminal glutamine in Sc_TrEGI and not to differences in glycosylation. N-terminal pyroglutamate formation in TrEGI expressed in S. cerevisiae was found to be essential in elevating its activity and stability to levels similar to the T. reesei or N. crassa-expressed enzyme, highlighting the importance of this ubiquitous modification in GH7 enzymes. CONCLUSION Structure-guided evolution of T. reesei EGI was used to engineer enzymes with increased thermal stability and activity on solid cellulosic substrates. Production of TrEGI enzymes in four hosts highlighted the impact of the expression host and the role of N-terminal pyroglutamate formation on the activity and stability of TrEGI enzymes.
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Affiliation(s)
- Harshal A Chokhawala
- Energy Biosciences Institute, University of California, Berkeley, CA, 94720, USA.
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA, 94720, USA.
| | - Christine M Roche
- Energy Biosciences Institute, University of California, Berkeley, CA, 94720, USA.
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA, 94720, USA.
| | - Tae-Wan Kim
- Energy Biosciences Institute, University of California, Berkeley, CA, 94720, USA.
| | - Meera E Atreya
- Energy Biosciences Institute, University of California, Berkeley, CA, 94720, USA.
- Department of Chemistry, University of California, Berkeley, CA, 94720, USA.
| | - Neeraja Vegesna
- Department of Biotechnology, Indian Institute of Technology, Kharagpur, West Bengal, 721301, India.
| | - Craig M Dana
- Energy Biosciences Institute, University of California, Berkeley, CA, 94720, USA.
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA, 94720, USA.
| | - Harvey W Blanch
- Energy Biosciences Institute, University of California, Berkeley, CA, 94720, USA.
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA, 94720, USA.
| | - Douglas S Clark
- Energy Biosciences Institute, University of California, Berkeley, CA, 94720, USA.
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA, 94720, USA.
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Heterologous protein expression in Hypocrea jecorina: a historical perspective and new developments. Biotechnol Adv 2014; 33:142-154. [PMID: 25479282 DOI: 10.1016/j.biotechadv.2014.11.009] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 11/18/2014] [Accepted: 11/23/2014] [Indexed: 10/24/2022]
Abstract
Hypocrea jecorina, the sexual teleomorph of Trichoderma reesei, has long been favored as an industrial cellulase producer, first utilizing its native cellulase system and later augmented by the introduction of heterologous enzymatic activities or improved variants of native enzymes. Expression of heterologous proteins in H. jecorina was once considered difficult when the target was an improved variant of a native cellulase. Developments over the past nearly 30 years have produced strains, vectors, and selection mechanisms that have continued to simplify and streamline heterologous protein expression in this fungus. More recent developments in fungal molecular biology have pointed the way toward a fundamental transformation in the ease and efficiency of heterologous protein expression in this important industrial host. Here, 1) we provide a historical perspective on advances in H. jecorina molecular biology, 2) outline host strain engineering, transformation, selection, and expression strategies, 3) detail potential pitfalls when working with this organism, and 4) provide consolidated examples of successful cellulase expression outcomes from our laboratory.
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Giese H, Kruithof P, Meier K, Sieben M, Antonov E, Hommes RW, Büchs J. Improvement and scale-down of a Trichoderma reesei shake flask protocol to microtiter plates enables high-throughput screening. J Biosci Bioeng 2014; 118:702-9. [DOI: 10.1016/j.jbiosc.2014.05.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 05/20/2014] [Accepted: 05/21/2014] [Indexed: 10/25/2022]
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Karimi Aghcheh R, Németh Z, Atanasova L, Fekete E, Paholcsek M, Sándor E, Aquino B, Druzhinina IS, Karaffa L, Kubicek CP. The VELVET A orthologue VEL1 of Trichoderma reesei regulates fungal development and is essential for cellulase gene expression. PLoS One 2014; 9:e112799. [PMID: 25386652 PMCID: PMC4227869 DOI: 10.1371/journal.pone.0112799] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 10/15/2014] [Indexed: 11/25/2022] Open
Abstract
Trichoderma reesei is the industrial producer of cellulases and hemicellulases for biorefinery processes. Their expression is obligatorily dependent on the function of the protein methyltransferase LAE1. The Aspergillus nidulans orthologue of LAE1 - LaeA - is part of the VELVET protein complex consisting of LaeA, VeA and VelB that regulates secondary metabolism and sexual as well as asexual reproduction. Here we have therefore investigated the function of VEL1, the T. reesei orthologue of A. nidulans VeA. Deletion of the T. reesei vel1 locus causes a complete and light-independent loss of conidiation, and impairs formation of perithecia. Deletion of vel1 also alters hyphal morphology towards hyperbranching and formation of thicker filaments, and with consequently reduced growth rates. Growth on lactose as a sole carbon source, however, is even more strongly reduced and growth on cellulose as a sole carbon source eliminated. Consistent with these findings, deletion of vel1 completely impaired the expression of cellulases, xylanases and the cellulase regulator XYR1 on lactose as a cellulase inducing carbon source, but also in resting mycelia with sophorose as inducer. Our data show that in T. reesei VEL1 controls sexual and asexual development, and this effect is independent of light. VEL1 is also essential for cellulase gene expression, which is consistent with the assumption that their regulation by LAE1 occurs by the VELVET complex.
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Affiliation(s)
- Razieh Karimi Aghcheh
- Institute of Chemical Engineering, Research Division Biotechnology and Microbiology, Microbiology Group, Vienna University of Technology, 1060 Vienna, Austria
| | - Zoltán Németh
- Department of Biochemical Engineering, Faculty of Sciences and Technology, University of Debrecen, H-4032 Debrecen, Hungary
| | - Lea Atanasova
- Institute of Chemical Engineering, Research Division Biotechnology and Microbiology, Microbiology Group, Vienna University of Technology, 1060 Vienna, Austria
| | - Erzsébet Fekete
- Department of Biochemical Engineering, Faculty of Sciences and Technology, University of Debrecen, H-4032 Debrecen, Hungary
| | - Melinda Paholcsek
- Department of Human Genetics, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary
| | - Erzsébet Sándor
- Faculty of Agricultural and Food Science and Environmental Management, Institute of Food Science, H-4032 Debrecen, Hungary
| | - Benigno Aquino
- Institute of Chemical Engineering, Research Division Biotechnology and Microbiology, Microbiology Group, Vienna University of Technology, 1060 Vienna, Austria
| | - Irina S. Druzhinina
- Institute of Chemical Engineering, Research Division Biotechnology and Microbiology, Microbiology Group, Vienna University of Technology, 1060 Vienna, Austria
- Austrian Center of Industrial Biotechnology, c/o Institute of Chemical Engineering, Vienna University of Technology, 1060 Vienna, Austria
| | - Levente Karaffa
- Department of Biochemical Engineering, Faculty of Sciences and Technology, University of Debrecen, H-4032 Debrecen, Hungary
| | - Christian P. Kubicek
- Institute of Chemical Engineering, Research Division Biotechnology and Microbiology, Microbiology Group, Vienna University of Technology, 1060 Vienna, Austria
- Austrian Center of Industrial Biotechnology, 8010 Graz, Austria
- * E-mail:
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Zhang L, Fan Y, Zheng H, Du F, Zhang KQ, Huang X, Wang L, Zhang M, Niu Q. Isolation and characterization of a novel endoglucanase from a Bursaphelenchus xylophilus metagenomic library. PLoS One 2013; 8:e82437. [PMID: 24386096 PMCID: PMC3873927 DOI: 10.1371/journal.pone.0082437] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Accepted: 10/22/2013] [Indexed: 11/24/2022] Open
Abstract
A novel gene (designated as cen219) encoding endoglucanase was isolated from a Bursaphelenchus xylophilus metagenomic library by functional screening. Sequence analysis revealed that cen219 encoded a protein of 367 amino acids. SDS-PAGE analysis of purified endoglucanase suggested that Cen219 was a monomeric enzyme with a molecular mass of 40 kDa. The optimum temperature and pH for endoglucanase activity of Cen219 was separately 50°C and 6.0. It was stable from 30 to 50°C, and from pH 4.0 to 7.0. The activity was significantly enhanced by Mn2+ and dramatically reduced by detergent SDS and metals Fe3+, Cu2+ or Hg2+. The enzyme hydrolyzed a wide range of β-1, 3-, and β-1, 4-linked polysaccharides, with varying activities. Activities towards microcrystalline cellulose and filter paper were relatively high, while the highest activity was towards oat gum. The Km and Vmax of Cen219 towards CMC was 17.37 mg/ml and 333.33 U/mg, respectively. The findings have an insight into understanding the molecular basis of host–parasite interactions in B. xylophilus species. The properties also make Cen219 an interesting enzyme for biotechnological application.
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Affiliation(s)
- Lin Zhang
- Department of Life Science and Biotechnology, Nanyang Normal University, Nanyang, China
| | - Yongxin Fan
- Department of Life Science and Biotechnology, Nanyang Normal University, Nanyang, China
| | - Haoying Zheng
- Department of Life Science and Biotechnology, Nanyang Normal University, Nanyang, China
| | - Fengguang Du
- State Key Laboratory of Motor Bio-fuel technology, Henan Tianguan Group Co. Ltd., Nanyang, China
| | - Ke-qin Zhang
- Laboratory for Conservation and Utilization of Bio-Resources, and Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, China
| | - Xiaowei Huang
- Laboratory for Conservation and Utilization of Bio-Resources, and Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, China
| | - Linfeng Wang
- State Key Laboratory of Motor Bio-fuel technology, Henan Tianguan Group Co. Ltd., Nanyang, China
| | - Man Zhang
- State Key Laboratory of Motor Bio-fuel technology, Henan Tianguan Group Co. Ltd., Nanyang, China
| | - Qiuhong Niu
- Department of Life Science and Biotechnology, Nanyang Normal University, Nanyang, China
- * E-mail:
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Liu G, Qin Y, Li Z, Qu Y. Development of highly efficient, low-cost lignocellulolytic enzyme systems in the post-genomic era. Biotechnol Adv 2013; 31:962-75. [PMID: 23507038 DOI: 10.1016/j.biotechadv.2013.03.001] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Revised: 03/09/2013] [Accepted: 03/10/2013] [Indexed: 11/19/2022]
Abstract
The current high cost of lignocellulolytic enzymes is a major bottleneck in the economic bioconversion of lignocellulosic biomass to fuels and chemicals. Fungal lignocellulolytic enzyme systems are secreted at high levels, making them the most promising starting points for further development of highly efficient lignocellulolytic enzyme systems. In this paper, recent advances in improvement of fungal lignocellulolytic enzyme systems are reviewed, with an emphasis on the achievements made using genomic approaches. A general strategy for lignocellulolytic enzyme system development is proposed, including the improvement of the hydrolysis efficiencies and productivities of current enzyme systems. The applications of genomic, transcriptomic and proteomic analysis methods in examining the composition of native enzyme systems, discovery of novel enzymes and synergistic proteins from natural sources, and understanding of regulatory mechanisms for lignocellulolytic enzyme biosynthesis are summarized. By combining systems biology and synthetic biology tools, engineered fungal strains are expected to produce high levels of optimized lignocellulolytic enzyme systems.
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Affiliation(s)
- Guodong Liu
- State Key Laboratory of Microbial Technology, Shandong University, Jinan 250100, China
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