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Promoter regulation and genetic engineering strategies for enhanced cellulase expression in Trichoderma reesei. Microbiol Res 2022; 259:127011. [DOI: 10.1016/j.micres.2022.127011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 03/15/2022] [Accepted: 03/16/2022] [Indexed: 01/18/2023]
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Sukumaran RK, Christopher M, Kooloth-Valappil P, Sreeja-Raju A, Mathew RM, Sankar M, Puthiyamadam A, Adarsh VP, Aswathi A, Rebinro V, Abraham A, Pandey A. Addressing challenges in production of cellulases for biomass hydrolysis: Targeted interventions into the genetics of cellulase producing fungi. BIORESOURCE TECHNOLOGY 2021; 329:124746. [PMID: 33610429 DOI: 10.1016/j.biortech.2021.124746] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 01/12/2021] [Accepted: 01/15/2021] [Indexed: 06/12/2023]
Abstract
Lignocellulosic materials are the favoured feedstock for biorefineries due to their abundant availability and non-completion with food. Biobased technologies for refining these materials are limited mainly by the cost of biomass hydrolyzing enzymes, typically sourced from filamentous fungi. Therefore, considerable efforts have been directed at improving the quantity and quality of secreted lignocellulose degrading enzymes from fungi in order to attain overall economic viability. Process improvements and media engineering probably have reached their thresholds and further production enhancements require modifying the fungal metabolism to improve production and secretion of these enzymes. This review focusses on the types and mechanisms of action of known fungal biomass degrading enzymes, our current understanding of the genetic control exerted on their expression, and possible routes for intervention, especially on modulating catabolite repression, transcriptional regulators, signal transduction, secretion pathways etc., in order to improve enzyme productivity, activity and stability.
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Affiliation(s)
- Rajeev K Sukumaran
- Centre for Biofuels, Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695019, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh 201002, India.
| | - Meera Christopher
- Centre for Biofuels, Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695019, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh 201002, India
| | - Prajeesh Kooloth-Valappil
- Centre for Biofuels, Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695019, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh 201002, India
| | - AthiraRaj Sreeja-Raju
- Centre for Biofuels, Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695019, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh 201002, India
| | - Reshma M Mathew
- Centre for Biofuels, Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695019, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh 201002, India
| | - Meena Sankar
- Centre for Biofuels, Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695019, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh 201002, India
| | - Anoop Puthiyamadam
- Centre for Biofuels, Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695019, India
| | - Velayudhanpillai-Prasannakumari Adarsh
- Centre for Biofuels, Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695019, India
| | - Aswathi Aswathi
- Centre for Biofuels, Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695019, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh 201002, India
| | - Valan Rebinro
- Centre for Biofuels, Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695019, India
| | - Amith Abraham
- Department of Chemical Engineering, Hanyang University, Seoul, Republic of Korea
| | - Ashok Pandey
- Centre for Innovation and Translational Research, CSIR-Indian Institute of Toxicology Research, Lucknow, India
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Abstract
The production of biofuels from plant biomass is dependent on the availability of enzymes that can hydrolyze the plant cell wall polysaccharides to their monosaccharides. These enzyme mixtures are formed by microorganisms but their native compositions and properties are often not ideal for application. Genetic engineering of these microorganisms is therefore necessary, in which introduction of DNA is an essential precondition. The filamentous fungus Trichoderma reesei-the main producer of plant-cell-wall-degrading enzymes for biofuels and other industries-has been subjected to intensive genetic engineering toward this goal and has become one of the iconic examples of the successful genetic improvement of fungi. However, the genetic manipulation of other enzyme-producing Trichoderma species is frequently less efficient and, therefore, rarely managed. In this chapter, we therefore describe the two potent methods of Trichoderma transformation mediated by either (a) polyethylene glycol (PEG) or (b) Agrobacterium. The methods are optimized for T. reesei but can also be applied for such transformation-resilient species as T. harzianum and T. guizhouense, which are putative upcoming alternatives for T. reesei in this field. The protocols are simple, do not require extensive training or special equipment, and can be further adjusted for T. reesei mutants with particular properties.
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Affiliation(s)
- Feng Cai
- Institute of Chemical, Environmental and Bioscience Engineering (ICEBE), TU Wien, Vienna, Austria.,FungiG, Fungal Genomics Laboratory, Nanjing Agricultural University, Nanjing, People's Republic of China
| | - Christian P Kubicek
- Institute of Chemical, Environmental and Bioscience Engineering (ICEBE), TU Wien, Vienna, Austria
| | - Irina S Druzhinina
- Institute of Chemical, Environmental and Bioscience Engineering (ICEBE), TU Wien, Vienna, Austria. .,FungiG, Fungal Genomics Laboratory, Nanjing Agricultural University, Nanjing, People's Republic of China.
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Abstract
Trichoderma reesei's potential as a rapid and efficient biomass degrader was first recognized in the 1950s when it was isolated from Army textiles during World War II. The microbe secreted cellulases that were degrading cotton-based tents and clothing of service members stationed on the Solomon Islands. In the 1970s, at the time of the first global oil crisis, research interest in T. reesei gained popularity as it was explored as part of the solution to the worlds growing dependence on fossil fuels. Much of this early work focused on classical mutagenesis and selection of hypercellulolytic strains. This early lineage was used as a starting point for both academic research with the goal of understanding secretion and regulation of expression of the complex mixture of enzymes required for cellulosic biomass decay as well as for its development as a host for industrial enzyme production. In 2001, at the onset of the second major oil crisis, the US Department of Energy supported research programs in microbial cellulases to produce ethanol from biomass which led to another surge in the study of T. reesei. This further accelerated the development of molecular biology and recombinant DNA tools in T. reesei. In addition to T. reesei's role in bio-ethanol production, it is used to produce industrial enzymes with a broad range of applications supporting the bio-based economy. To date there are around 243 commercially available enzyme products manufactured by fermentation of microorganisms; 30 of these are made using Trichoderma as a host, 21 of which are recombinant products sold for use in food, feed, and technical applications including textiles and pulp and paper.
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Pirayre A, Duval L, Blugeon C, Firmo C, Perrin S, Jourdier E, Margeot A, Bidard F. Glucose-lactose mixture feeds in industry-like conditions: a gene regulatory network analysis on the hyperproducing Trichoderma reesei strain Rut-C30. BMC Genomics 2020; 21:885. [PMID: 33302864 PMCID: PMC7731781 DOI: 10.1186/s12864-020-07281-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 11/25/2020] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND The degradation of cellulose and hemicellulose molecules into simpler sugars such as glucose is part of the second generation biofuel production process. Hydrolysis of lignocellulosic substrates is usually performed by enzymes produced and secreted by the fungus Trichoderma reesei. Studies identifying transcription factors involved in the regulation of cellulase production have been conducted but no overview of the whole regulation network is available. A transcriptomic approach with mixtures of glucose and lactose, used as a substrate for cellulase induction, was used to help us decipher missing parts in the network of T. reesei Rut-C30. RESULTS Experimental results on the Rut-C30 hyperproducing strain confirmed the impact of sugar mixtures on the enzymatic cocktail composition. The transcriptomic study shows a temporal regulation of the main transcription factors and a lactose concentration impact on the transcriptional profile. A gene regulatory network built using BRANE Cut software reveals three sub-networks related to i) a positive correlation between lactose concentration and cellulase production, ii) a particular dependence of the lactose onto the β-glucosidase regulation and iii) a negative regulation of the development process and growth. CONCLUSIONS This work is the first investigating a transcriptomic study regarding the effects of pure and mixed carbon sources in a fed-batch mode. Our study expose a co-orchestration of xyr1, clr2 and ace3 for cellulase and hemicellulase induction and production, a fine regulation of the β-glucosidase and a decrease of growth in favor of cellulase production. These conclusions provide us with potential targets for further genetic engineering leading to better cellulase-producing strains in industry-like conditions.
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Affiliation(s)
- Aurélie Pirayre
- IFP Energies nouvelles, 1 et 4 avenue de Bois-Préau, Rueil-Malmaison, 92852, France.
| | - Laurent Duval
- IFP Energies nouvelles, 1 et 4 avenue de Bois-Préau, Rueil-Malmaison, 92852, France
- Laboratoire d'Informatique Gaspard-Monge (LIGM), ESIEE Paris, Université-Gustave Eiffel, Marne-la-Vallée, F-77454, France
| | - Corinne Blugeon
- Genomic facility, Institut de Biologie de l'ENS (IBENS), Département de biologie, École normale supérieure, CNRS, INSERM, Université PSL, Paris, 75005, France
| | - Cyril Firmo
- Genomic facility, Institut de Biologie de l'ENS (IBENS), Département de biologie, École normale supérieure, CNRS, INSERM, Université PSL, Paris, 75005, France
| | - Sandrine Perrin
- Genomic facility, Institut de Biologie de l'ENS (IBENS), Département de biologie, École normale supérieure, CNRS, INSERM, Université PSL, Paris, 75005, France
| | - Etienne Jourdier
- IFP Energies nouvelles, 1 et 4 avenue de Bois-Préau, Rueil-Malmaison, 92852, France
| | - Antoine Margeot
- IFP Energies nouvelles, 1 et 4 avenue de Bois-Préau, Rueil-Malmaison, 92852, France
| | - Frédérique Bidard
- IFP Energies nouvelles, 1 et 4 avenue de Bois-Préau, Rueil-Malmaison, 92852, France
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Ionic liquid-tolerant cellulase system of Stachybotrys microspora exploited in the in situ saccharification of lignocellulosic biomass. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.113167] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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Liu P, Lin A, Zhang G, Zhang J, Chen Y, Shen T, Zhao J, Wei D, Wang W. Enhancement of cellulase production in Trichoderma reesei RUT-C30 by comparative genomic screening. Microb Cell Fact 2019; 18:81. [PMID: 31077201 PMCID: PMC6509817 DOI: 10.1186/s12934-019-1131-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 05/02/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Cellulolytic enzymes produced by the filamentous fungus Trichoderma reesei are commonly used in biomass conversion. The high cost of cellulase is still a significant challenge to commercial biofuel production. Improving cellulase production in T. reesei for application in the cellulosic biorefinery setting is an urgent priority. RESULTS Trichoderma reesei hyper-cellulolytic mutant SS-II derived from the T. reesei NG14 strain exhibited faster growth rate and more efficient lignocellulosic biomass degradation than those of RUT-C30, another hyper-cellulolytic strain derived from NG14. To identify any genetic changes that occurred in SS-II, we sequenced its genome using Illumina MiSeq. In total, 184 single nucleotide polymorphisms and 40 insertions and deletions were identified. SS-II sequencing revealed 107 novel mutations and a full-length wild-type carbon catabolite repressor 1 gene (cre1). To combine the mutations of RUT-C30 and SS-II, the sequence of one confirmed beneficial mutation in RUT-C30, cre196, was introduced in SS-II to replace full-length cre1, forming the mutant SS-II-cre196. The total cellulase production of SS-II-cre196 was decreased owing to the limited growth of SS-II-cre196. In contrast, 57 genes mutated only in SS-II were selected and knocked out in RUT-C30. Of these, 31 were involved in T. reesei growth or cellulase production. Cellulase activity was significantly increased in five deletion strains compared with that in two starter strains, RUT-C30 and SS-II. Cellulase production of T. reesei Δ108642 and Δ56839 was significantly increased by 83.7% and 70.1%, respectively, compared with that of RUT-C30. The amount of glucose released from pretreated corn stover hydrolyzed by the crude enzyme from Δ108642 increased by 11.9%. CONCLUSIONS The positive attribute confirmed in one cellulase hyper-producing strain does not always work efficiently in another cellulase hyper-producing strain, owing to the differences in genetic background. Genome re-sequencing revealed novel mutations that might affect cellulase production and other pathways indirectly related to cellulase formation. Our strategy of combining the mutations of two strains successfully identified a number of interesting phenotypes associated with cellulase production. These findings will contribute to the creation of a gene library that can be used to investigate the involvement of various genes in the regulation of cellulase production.
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Affiliation(s)
- Pei Liu
- State Key Lab of Bioreactor Engineering, East China University of Science and Technology, P.O.B. 311, 130 Meilong Road, Shanghai, 200237 China
| | - Aibo Lin
- State Key Lab of Bioreactor Engineering, East China University of Science and Technology, P.O.B. 311, 130 Meilong Road, Shanghai, 200237 China
| | - Guoxiu Zhang
- State Key Lab of Bioreactor Engineering, East China University of Science and Technology, P.O.B. 311, 130 Meilong Road, Shanghai, 200237 China
| | - Jiajia Zhang
- State Key Lab of Bioreactor Engineering, East China University of Science and Technology, P.O.B. 311, 130 Meilong Road, Shanghai, 200237 China
| | - Yumeng Chen
- State Key Lab of Bioreactor Engineering, East China University of Science and Technology, P.O.B. 311, 130 Meilong Road, Shanghai, 200237 China
| | - Tao Shen
- Sunson Industry Group Co, Ltd, Beijing, China
| | - Jian Zhao
- State Key Lab of Bioreactor Engineering, East China University of Science and Technology, P.O.B. 311, 130 Meilong Road, Shanghai, 200237 China
| | - Dongzhi Wei
- State Key Lab of Bioreactor Engineering, East China University of Science and Technology, P.O.B. 311, 130 Meilong Road, Shanghai, 200237 China
| | - Wei Wang
- State Key Lab of Bioreactor Engineering, East China University of Science and Technology, P.O.B. 311, 130 Meilong Road, Shanghai, 200237 China
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Druzhinina IS, Kubicek CP. Genetic engineering of Trichoderma reesei cellulases and their production. Microb Biotechnol 2017; 10:1485-1499. [PMID: 28557371 PMCID: PMC5658622 DOI: 10.1111/1751-7915.12726] [Citation(s) in RCA: 133] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 04/11/2017] [Accepted: 04/11/2017] [Indexed: 11/26/2022] Open
Abstract
Lignocellulosic biomass, which mainly consists of cellulose, hemicellulose and lignin, is the most abundant renewable source for production of biofuel and biorefinery products. The industrial use of plant biomass involves mechanical milling or chipping, followed by chemical or physicochemical pretreatment steps to make the material more susceptible to enzymatic hydrolysis. Thereby the cost of enzyme production still presents the major bottleneck, mostly because some of the produced enzymes have low catalytic activity under industrial conditions and/or because the rate of hydrolysis of some enzymes in the secreted enzyme mixture is limiting. Almost all of the lignocellulolytic enzyme cocktails needed for the hydrolysis step are produced by fermentation of the ascomycete Trichoderma reesei (Hypocreales). For this reason, the structure and mechanism of the enzymes involved, the regulation of their expression and the pathways of their formation and secretion have been investigated in T. reesei in considerable details. Several of the findings thereby obtained have been used to improve the formation of the T. reesei cellulases and their properties. In this article, we will review the achievements that have already been made and also show promising fields for further progress.
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Affiliation(s)
- Irina S. Druzhinina
- Microbiology GroupResearch Area Biochemical TechnologyInstitute of Chemical, Environmental and Biological EngineeringTU WienViennaAustria
| | - Christian P. Kubicek
- Microbiology GroupResearch Area Biochemical TechnologyInstitute of Chemical, Environmental and Biological EngineeringTU WienViennaAustria
- Present address:
Steinschötelgasse 7Wien1100Austria
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Aloulou-Abdelkefi M, Trigui-Lahiani H, Gargouri A. Autoclaved mycelium induces efficiently the production of hydrolytic enzymes for protoplast preparation of autologous fungus. APPL BIOCHEM MICRO+ 2017. [DOI: 10.1134/s000368381702003x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Ivanova C, Ramoni J, Aouam T, Frischmann A, Seiboth B, Baker SE, Le Crom S, Lemoine S, Margeot A, Bidard F. Genome sequencing and transcriptome analysis of Trichoderma reesei QM9978 strain reveals a distal chromosome translocation to be responsible for loss of vib1 expression and loss of cellulase induction. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:209. [PMID: 28912831 PMCID: PMC5588705 DOI: 10.1186/s13068-017-0897-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 08/29/2017] [Indexed: 05/05/2023]
Abstract
BACKGROUND The hydrolysis of biomass to simple sugars used for the production of biofuels in biorefineries requires the action of cellulolytic enzyme mixtures. During the last 50 years, the ascomycete Trichoderma reesei, the main source of industrial cellulase and hemicellulase cocktails, has been subjected to several rounds of classical mutagenesis with the aim to obtain higher production levels. During these random genetic events, strains unable to produce cellulases were generated. Here, whole genome sequencing and transcriptomic analyses of the cellulase-negative strain QM9978 were used for the identification of mutations underlying this cellulase-negative phenotype. RESULTS Sequence comparison of the cellulase-negative strain QM9978 to the reference strain QM6a identified a total of 43 mutations, of which 33 were located either close to or in coding regions. From those, we identified 23 single-nucleotide variants, nine InDels, and one translocation. The translocation occurred between chromosomes V and VII, is located upstream of the putative transcription factor vib1, and abolishes its expression in QM9978 as detected during the transcriptomic analyses. Ectopic expression of vib1 under the control of its native promoter as well as overexpression of vib1 under the control of a strong constitutive promoter restored cellulase expression in QM9978, thus confirming that the translocation event is the reason for the cellulase-negative phenotype. Gene deletion of vib1 in the moderate producer strain QM9414 and in the high producer strain Rut-C30 reduced cellulase expression in both cases. Overexpression of vib1 in QM9414 and Rut-C30 had no effect on cellulase production, most likely because vib1 is already expressed at an optimal level under normal conditions. CONCLUSION We were able to establish a link between a chromosomal translocation in QM9978 and the cellulase-negative phenotype of the strain. We identified the transcription factor vib1 as a key regulator of cellulases in T. reesei whose expression is absent in QM9978. We propose that in T. reesei, as in Neurospora crassa, vib1 is involved in cellulase induction, although the exact mechanism remains to be elucidated. The data presented here show an example of a combined genome sequencing and transcriptomic approach to explain a specific trait, in this case the QM9978 cellulase-negative phenotype, and how it helps to better understand the mechanisms during cellulase gene regulation. When focusing on mutations on the single base-pair level, changes on the chromosome level can be easily overlooked and through this work we provide an example that stresses the importance of the big picture of the genomic landscape during analysis of sequencing data.
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Affiliation(s)
- Christa Ivanova
- IFP Energies Nouvelles, 1-4 Avenue de Bois-Préau, 92852 Rueil-Malmaison, France
- Present Address: Genetics of Biofilms Unit, Department of Microbiology, Institut Pasteur, 25-28 Rue du Dr Roux, 75015 Paris, France
| | - Jonas Ramoni
- Molecular Biotechnology, Research Division Biochemical Technology, Institute of Chemical Engineering, TU-Wien, 1060 Vienna, Austria
| | - Thiziri Aouam
- IFP Energies Nouvelles, 1-4 Avenue de Bois-Préau, 92852 Rueil-Malmaison, France
| | - Alexa Frischmann
- Molecular Biotechnology, Research Division Biochemical Technology, Institute of Chemical Engineering, TU-Wien, 1060 Vienna, Austria
| | - Bernhard Seiboth
- Molecular Biotechnology, Research Division Biochemical Technology, Institute of Chemical Engineering, TU-Wien, 1060 Vienna, Austria
| | - Scott E. Baker
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA 99354 USA
| | - Stéphane Le Crom
- Evolution Paris Seine-Institut de Biologie Paris Seine (EPS-IBPS), Sorbonne Universités, UPMC Univ Paris 06, Univ Antilles, Univ Nice Sophia Antipolis, CNRS, 75005 Paris, France
| | - Sophie Lemoine
- École normale supérieure, PSL Research University, CNRS, Inserm, Institut de Biologie de l’École normale supérieure (IBENS), Plateforme Génomique, 75005 Paris, France
| | - Antoine Margeot
- IFP Energies Nouvelles, 1-4 Avenue de Bois-Préau, 92852 Rueil-Malmaison, France
| | - Frédérique Bidard
- IFP Energies Nouvelles, 1-4 Avenue de Bois-Préau, 92852 Rueil-Malmaison, France
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Min BE, Hwang HG, Lim HG, Jung GY. Optimization of industrial microorganisms: recent advances in synthetic dynamic regulators. ACTA ACUST UNITED AC 2017; 44:89-98. [DOI: 10.1007/s10295-016-1867-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 11/04/2016] [Indexed: 12/27/2022]
Abstract
Abstract
Production of biochemicals by industrial fermentation using microorganisms requires maintaining cellular production capacity, because maximal productivity is economically important. High-productivity microbial strains can be developed using static engineering, but these may not maintain maximal productivity throughout the culture period as culture conditions and cell states change dynamically. Additionally, economic reasons limit heterologous protein expression using inducible promoters to prevent metabolic burden for commodity chemical and biofuel production. Recently, synthetic and systems biology has been used to design genetic circuits, precisely controlling gene expression or influencing genetic behavior toward a desired phenotype. Development of dynamic regulators can maintain cellular phenotype in a maximum production state in response to factors including cell concentration, oxygen, temperature, pH, and metabolites. Herein, we introduce dynamic regulators of industrial microorganism optimization and discuss metabolic flux fine control by dynamic regulators in response to metabolites or extracellular stimuli, robust production systems, and auto-induction systems using quorum sensing.
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Affiliation(s)
- Byung Eun Min
- grid.49100.3c 0000000107424007 Department of Chemical Engineering Pohang University of Science and Technology 77 Cheongam-ro, Nam-gu 37673 Pohang Gyeongbuk Korea
| | - Hyun Gyu Hwang
- grid.49100.3c 0000000107424007 School of Interdisciplinary Bioscience and Bioengineering Pohang University of Science and Technology 77 Cheongam-ro, Nam-gu 37673 Pohang Gyeongbuk Korea
| | - Hyun Gyu Lim
- grid.49100.3c 0000000107424007 Department of Chemical Engineering Pohang University of Science and Technology 77 Cheongam-ro, Nam-gu 37673 Pohang Gyeongbuk Korea
| | - Gyoo Yeol Jung
- grid.49100.3c 0000000107424007 Department of Chemical Engineering Pohang University of Science and Technology 77 Cheongam-ro, Nam-gu 37673 Pohang Gyeongbuk Korea
- grid.49100.3c 0000000107424007 School of Interdisciplinary Bioscience and Bioengineering Pohang University of Science and Technology 77 Cheongam-ro, Nam-gu 37673 Pohang Gyeongbuk Korea
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Bischof RH, Ramoni J, Seiboth B. Cellulases and beyond: the first 70 years of the enzyme producer Trichoderma reesei. Microb Cell Fact 2016; 15:106. [PMID: 27287427 PMCID: PMC4902900 DOI: 10.1186/s12934-016-0507-6] [Citation(s) in RCA: 280] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 06/01/2016] [Indexed: 11/10/2022] Open
Abstract
More than 70 years ago, the filamentous ascomycete Trichoderma reesei was isolated on the Solomon Islands due to its ability to degrade and thrive on cellulose containing fabrics. This trait that relies on its secreted cellulases is nowadays exploited by several industries. Most prominently in biorefineries which use T. reesei enzymes to saccharify lignocellulose from renewable plant biomass in order to produce biobased fuels and chemicals. In this review we summarize important milestones of the development of T. reesei as the leading production host for biorefinery enzymes, and discuss emerging trends in strain engineering. Trichoderma reesei has very recently also been proposed as a consolidated bioprocessing organism capable of direct conversion of biopolymeric substrates to desired products. We therefore cover this topic by reviewing novel approaches in metabolic engineering of T. reesei.
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Affiliation(s)
- Robert H Bischof
- Austrian Centre of Industrial Biotechnology (ACIB) GmbH c/o Institute of Chemical Engineering, TU Wien, Gumpendorferstraße 1a, 1060, Vienna, Austria
| | - Jonas Ramoni
- Molecular Biotechnology, Research Area Biochemical Technology, Institute of Chemical Engineering, TU Wien, Gumpendorferstraße 1a, 1060, Vienna, Austria
| | - Bernhard Seiboth
- Austrian Centre of Industrial Biotechnology (ACIB) GmbH c/o Institute of Chemical Engineering, TU Wien, Gumpendorferstraße 1a, 1060, Vienna, Austria. .,Molecular Biotechnology, Research Area Biochemical Technology, Institute of Chemical Engineering, TU Wien, Gumpendorferstraße 1a, 1060, Vienna, Austria.
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14
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van den Brink J, Maitan-Alfenas GP, Zou G, Wang C, Zhou Z, Guimarães VM, de Vries RP. Synergistic effect ofAspergillus nigerandTrichoderma reeseienzyme sets on the saccharification of wheat straw and sugarcane bagasse. Biotechnol J 2014; 9:1329-38. [DOI: 10.1002/biot.201400317] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Revised: 07/09/2014] [Accepted: 08/12/2014] [Indexed: 01/06/2023]
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15
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Xiong Y, Sun J, Glass NL. VIB1, a link between glucose signaling and carbon catabolite repression, is essential for plant cell wall degradation by Neurospora crassa. PLoS Genet 2014; 10:e1004500. [PMID: 25144221 PMCID: PMC4140635 DOI: 10.1371/journal.pgen.1004500] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2013] [Accepted: 05/27/2014] [Indexed: 11/18/2022] Open
Abstract
Filamentous fungi that thrive on plant biomass are the major producers of hydrolytic enzymes used to decompose lignocellulose for biofuel production. Although induction of cellulases is regulated at the transcriptional level, how filamentous fungi sense and signal carbon-limited conditions to coordinate cell metabolism and regulate cellulolytic enzyme production is not well characterized. By screening a transcription factor deletion set in the filamentous fungus Neurospora crassa for mutants unable to grow on cellulosic materials, we identified a role for the transcription factor, VIB1, as essential for cellulose utilization. VIB1 does not directly regulate hydrolytic enzyme gene expression or function in cellulosic inducer signaling/processing, but affects the expression level of an essential regulator of hydrolytic enzyme genes, CLR2. Transcriptional profiling of a Δvib-1 mutant suggests that it has an improper expression of genes functioning in metabolism and energy and a deregulation of carbon catabolite repression (CCR). By characterizing new genes, we demonstrate that the transcription factor, COL26, is critical for intracellular glucose sensing/metabolism and plays a role in CCR by negatively regulating cre-1 expression. Deletion of the major player in CCR, cre-1, or a deletion of col-26, did not rescue the growth of Δvib-1 on cellulose. However, the synergistic effect of the Δcre-1; Δcol-26 mutations circumvented the requirement of VIB1 for cellulase gene expression, enzyme secretion and cellulose deconstruction. Our findings support a function of VIB1 in repressing both glucose signaling and CCR under carbon-limited conditions, thus enabling a proper cellular response for plant biomass deconstruction and utilization.
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Affiliation(s)
- Yi Xiong
- Plant and Microbial Biology Department and The Energy Biosciences Institute, The University of California, Berkeley, Berkeley, California, United States of America
| | - Jianping Sun
- Plant and Microbial Biology Department and The Energy Biosciences Institute, The University of California, Berkeley, Berkeley, California, United States of America
| | - N. Louise Glass
- Plant and Microbial Biology Department and The Energy Biosciences Institute, The University of California, Berkeley, Berkeley, California, United States of America
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16
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Malavazi I, Goldman GH, Brown NA. The importance of connections between the cell wall integrity pathway and the unfolded protein response in filamentous fungi. Brief Funct Genomics 2014; 13:456-70. [PMID: 25060881 DOI: 10.1093/bfgp/elu027] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In the external environment, or within a host organism, filamentous fungi experience sudden changes in nutrient availability, osmolality, pH, temperature and the exposure to toxic compounds. The fungal cell wall represents the first line of defense, while also performing essential roles in morphology, development and virulence. A polarized secretion system is paramount for cell wall biosynthesis, filamentous growth, nutrient acquisition and interactions with the environment. The unique ability of filamentous fungi to secrete has resulted in their industrial adoption as fungal cell factories. Protein maturation and secretion commences in the endoplasmic reticulum (ER). The unfolded protein response (UPR) maintains ER functionality during exposure to secretion and cell wall stress. UPR, therefore, influences secretion and cell wall homeostasis, which in turn impacts upon numerous fungal traits important to pathogenesis and biotechnology. Subsequently, this review describes the relevance of the cell wall and UPR systems to filamentous fungal pathogens or industrial microbes and then highlights interconnections between the two systems. Ultimately, the possible biotechnological applications of an enhanced understanding of such regulatory systems in combating fungal disease, or the removal of natural bottlenecks in protein secretion in an industrial setting, are discussed.
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17
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Amore A, Giacobbe S, Faraco V. Regulation of cellulase and hemicellulase gene expression in fungi. Curr Genomics 2013; 14:230-49. [PMID: 24294104 PMCID: PMC3731814 DOI: 10.2174/1389202911314040002] [Citation(s) in RCA: 136] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Revised: 04/22/2013] [Accepted: 04/23/2013] [Indexed: 11/22/2022] Open
Abstract
Research on regulation of cellulases and hemicellulases gene expression may be very useful for increasing the production of these enzymes in their native producers. Mechanisms of gene regulation of cellulase and hemicellulase expression in filamentous fungi have been studied, mainly in Aspergillus and Trichoderma. The production of these extracellular enzymes is an energy-consuming process, so the enzymes are produced only under conditions in which the fungus needs to use plant polymers as an energy and carbon source. Moreover, production of many of these enzymes is coordinately regulated, and induced in the presence of the substrate polymers. In addition to induction by mono- and oligo-saccharides, genes encoding hydrolytic enzymes involved in plant cell wall deconstruction in filamentous fungi can be repressed during growth in the presence of easily metabolizable carbon sources, such as glucose. Carbon catabolite repression is an important mechanism to repress the production of plant cell wall degrading enzymes during growth on preferred carbon sources. This manuscript reviews the recent advancements in elucidation of molecular mechanisms responsible for regulation of expression of cellulase and hemicellulase genes in fungi.
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Affiliation(s)
- Antonella Amore
- Department of Chemical Sciences, University of Naples “Federico II”, Complesso Universitario Monte S. Angelo, via Cintia, 4 80126 Naples, Italy
| | - Simona Giacobbe
- Department of Chemical Sciences, University of Naples “Federico II”, Complesso Universitario Monte S. Angelo, via Cintia, 4 80126 Naples, Italy
| | - Vincenza Faraco
- Department of Chemical Sciences, University of Naples “Federico II”, Complesso Universitario Monte S. Angelo, via Cintia, 4 80126 Naples, Italy
- School of Biotechnological Sciences, University of Naples “Federico II” Italy
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18
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Kubicek CP. Systems biological approaches towards understanding cellulase production by Trichoderma reesei. J Biotechnol 2013; 163:133-42. [PMID: 22750088 PMCID: PMC3568919 DOI: 10.1016/j.jbiotec.2012.05.020] [Citation(s) in RCA: 119] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Revised: 04/27/2012] [Accepted: 05/02/2012] [Indexed: 01/07/2023]
Abstract
Recent progress and improvement in "-omics" technologies has made it possible to study the physiology of organisms by integrated and genome-wide approaches. This bears the advantage that the global response, rather than isolated pathways and circuits within an organism, can be investigated ("systems biology"). The sequencing of the genome of Trichoderma reesei (teleomorph Hypocrea jecorina), a fungus that serves as a major producer of biomass-degrading enzymes for the use of renewable lignocellulosic material towards production of biofuels and biorefineries, has offered the possibility to study this organism and its enzyme production on a genome wide scale. In this review, I will highlight the use of genomics, transcriptomics, proteomics and metabolomics towards an improved and novel understanding of the biochemical processes that involve in the massive overproduction of secreted proteins.
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19
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The intracellular galactoglycome in Trichoderma reesei during growth on lactose. Appl Microbiol Biotechnol 2013; 97:5447-56. [PMID: 23299458 DOI: 10.1007/s00253-012-4667-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Revised: 12/15/2012] [Accepted: 12/17/2012] [Indexed: 10/27/2022]
Abstract
Lactose (1,4-0-β-D-galactopyranosyl-D-glucose) is used as a soluble carbon source for the production of cellulases and hemicellulases for-among other purposes-use in biofuel and biorefinery industries. The mechanism how lactose induces cellulase formation in T. reesei is enigmatic, however. Previous results from our laboratory raised the hypothesis that intermediates from the two galactose catabolic pathway may give rise to the accumulation of intracellular oligogalactosides that could act as inducer. Here we have therefore used high-performance anion-exchange chromatography-mass spectrometry to study the intracellular galactoglycome of T. reesei during growth on lactose, in T. reesei mutants impaired in galactose catabolism, and in strains with different cellulase productivities. Lactose, allo-lactose, and lactulose were detected in the highest amounts in all strains, and two trisaccharides (Gal-β-1,6-Gal-β-1,4-Glc/Fru and Gal-β-1,4-Gal-β-1,4-Glc/Fru) also accumulated to significant levels. Glucose and galactose, as well as four further oligosaccharides (Gal-β-1,3/1,4/1,6-Gal; Gal-β-1,2-Glc) were only detected in minor amounts. In addition, one unknown disaccharide (Hex-β-1,1-Hex) and four trisaccharides were also detected. The accumulation of the unknown hexose disaccharide was shown to correlate with cellulase formation in the improved mutant strains as well as the galactose pathway mutants, and Gal-β-1,4-Gal-β-1,4-Glc/Fru and two other unknown hexose trisaccharides correlated with cellulase production only in the pathway mutants, suggesting that these compounds could be involved in cellulase induction by lactose. The nature of these oligosaccharides, however, suggests their formation by transglycosylation rather than by glycosyltransferases. Based on our results, the obligate nature of both galactose catabolic pathways for this induction must have another biochemical basis than providing substrates for inducer formation.
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20
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21
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Quantitative proteomic analysis of secretome of microbial consortium during saw dust utilization. J Proteomics 2012; 75:5590-603. [DOI: 10.1016/j.jprot.2012.08.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2012] [Revised: 07/28/2012] [Accepted: 08/13/2012] [Indexed: 11/23/2022]
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22
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Adav SS, Chao LT, Sze SK. Quantitative secretomic analysis of Trichoderma reesei strains reveals enzymatic composition for lignocellulosic biomass degradation. Mol Cell Proteomics 2012; 11:M111.012419. [PMID: 22355001 DOI: 10.1074/mcp.m111.012419] [Citation(s) in RCA: 111] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Trichoderma reesei is a mesophilic, filamentous fungus, and it is a major industrial source of cellulases, but its lignocellulolytic protein expressions on lignocellulosic biomass are poorly explored at present. The extracellular proteins secreted by T. reesei QM6a wild-type and hypercellulolytic mutant Rut C30 grown on natural lignocellulosic biomasses were explored using a quantitative proteomic approach with 8-plex high throughput isobaric tags for relative and absolute quantification (iTRAQ) and analyzed by liquid chromatography tandem mass spectrometry. We quantified 230 extracellular proteins, including cellulases, hemicellulases, lignin-degrading enzymes, proteases, protein-translocating transporter, and hypothetical proteins. Quantitative iTRAQ results suggested that the expressions and regulations of these lignocellulolytic proteins in the secretome of T. reesei wild-type and mutant Rut C30 were dependent on both nature and complexity of different lignocellulosic carbon sources. Therefore, we discuss here the essential lignocellulolytic proteins for designing an enzyme mixture for optimal lignocellulosic biomass hydrolysis.
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Affiliation(s)
- Sunil S Adav
- School of Biological Sciences, Nanyang Technological University, Singapore
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23
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Differential regulation of the cellulase transcription factors XYR1, ACE2, and ACE1 in Trichoderma reesei strains producing high and low levels of cellulase. EUKARYOTIC CELL 2010; 10:262-71. [PMID: 21169417 DOI: 10.1128/ec.00208-10] [Citation(s) in RCA: 119] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Due to its capacity to produce large amounts of cellulases, Trichoderma reesei is increasingly being investigated for second-generation biofuel production from lignocellulosic biomass. The induction mechanisms of T. reesei cellulases have been described recently, but the regulation of the genes involved in their transcription has not been studied thoroughly. Here we report the regulation of expression of the two activator genes xyr1 and ace2, and the corepressor gene ace1, during the induction of cellulase biosynthesis by the inducer lactose in T. reesei QM 9414, a strain producing low levels of cellulase (low producer). We show that all three genes are induced by lactose. xyr1 was also induced by d-galactose, but this induction was independent of d-galactose metabolism. Moreover, ace1 was carbon catabolite repressed, whereas full induction of xyr1 and ace2 in fact required CRE1. Significant differences in these regulatory patterns were observed in the high-producer strain RUT C30 and the hyperproducer strain T. reesei CL847. These observations suggest that a strongly elevated basal transcription level of xyr1 and reduced upregulation of ace1 by lactose may have been important for generating the hyperproducer strain and that thus, these genes are major control elements of cellulase production.
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24
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Peterson R, Grinyer J, Joss J, Khan A, Nevalainen H. Fungal proteins with mannanase activity identified directly from a Congo Red stained zymogram by mass spectrometry. J Microbiol Methods 2009; 79:374-7. [PMID: 19854225 DOI: 10.1016/j.mimet.2009.10.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2009] [Revised: 10/14/2009] [Accepted: 10/14/2009] [Indexed: 10/20/2022]
Abstract
Secreted fungal proteins with mannanase activity were identified by mass spectrometry of bands excised from a Congo Red stained zymogram containing locust bean gum as substrate. This technique circumvents the need to locate corresponding bands on a parallel gel without substrate and provides good accuracy in targeting proteins for identification.
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Affiliation(s)
- Robyn Peterson
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, NSW 2109, Australia.
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25
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Tracking the roots of cellulase hyperproduction by the fungus Trichoderma reesei using massively parallel DNA sequencing. Proc Natl Acad Sci U S A 2009; 106:16151-6. [PMID: 19805272 DOI: 10.1073/pnas.0905848106] [Citation(s) in RCA: 157] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Trichoderma reesei (teleomorph Hypocrea jecorina) is the main industrial source of cellulases and hemicellulases harnessed for the hydrolysis of biomass to simple sugars, which can then be converted to biofuels such as ethanol and other chemicals. The highly productive strains in use today were generated by classical mutagenesis. To learn how cellulase production was improved by these techniques, we performed massively parallel sequencing to identify mutations in the genomes of two hyperproducing strains (NG14, and its direct improved descendant, RUT C30). We detected a surprisingly high number of mutagenic events: 223 single nucleotides variants, 15 small deletions or insertions, and 18 larger deletions, leading to the loss of more than 100 kb of genomic DNA. From these events, we report previously undocumented non-synonymous mutations in 43 genes that are mainly involved in nuclear transport, mRNA stability, transcription, secretion/vacuolar targeting, and metabolism. This homogeneity of functional categories suggests that multiple changes are necessary to improve cellulase production and not simply a few clear-cut mutagenic events. Phenotype microarrays show that some of these mutations result in strong changes in the carbon assimilation pattern of the two mutants with respect to the wild-type strain QM6a. Our analysis provides genome-wide insights into the changes induced by classical mutagenesis in a filamentous fungus and suggests areas for the generation of enhanced T. reesei strains for industrial applications such as biofuel production.
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26
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Margaritis A, Merchant RFJ, Yaguchi M. Thermostable Cellulases from Thermophilic Microorganisms. Crit Rev Biotechnol 2008. [DOI: 10.3109/07388558609150799] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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27
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Grinyer J, Kautto L, Traini M, Willows RD, Te'o J, Bergquist P, Nevalainen H. Proteome mapping of the Trichoderma reesei 20S proteasome. Curr Genet 2006; 51:79-88. [PMID: 17119969 DOI: 10.1007/s00294-006-0108-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2006] [Revised: 10/28/2006] [Accepted: 10/31/2006] [Indexed: 10/23/2022]
Abstract
The 26S proteasome, a multicatalytic protease comprising the catalytic 20S core particle and the 19S regulatory particle has a crucial role in cellular protein quality control. We have used a chromatography-based approach to purify and map the protein content of the 20S core particle from the industrially-exploited filamentous fungus Trichoderma reesei. There are no previous reports on the isolation or proteomic mapping of the proteasome from any filamentous fungus. From the reference map, 13 of the 14 20S proteasome subunits and many related proteins that co-purified with the 20S proteasome have been identified. These include 78 kDa glucose-regulated protein (BIP) and several chaperones including heat shock proteins involved in the unfolded protein response (UPR). Some proteasome interacting proteins (PIPs) were also identified on the proteome map and included 14-3-3-like protein, glyceraldehyde-3-phosphate dehydrogenase, transaldolase, actin, translation elongation factor, enolase, ATPase in the ER (CDC48), and eukaryotic initiation factor. We present here a master map for the 20S catalytic core to pave the way for future differential display studies addressing intracellular degradation of endogenous and foreign proteins in filamentous fungi.
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Affiliation(s)
- Jasmine Grinyer
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, NSW, 2109, Australia
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28
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29
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30
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Lekha PK, Lonsane BK. Production and application of tannin acyl hydrolase: state of the art. ADVANCES IN APPLIED MICROBIOLOGY 1997; 44:215-60. [PMID: 9311108 DOI: 10.1016/s0065-2164(08)70463-5] [Citation(s) in RCA: 257] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- P K Lekha
- Fermentation Technology and Bioengineering Department, Central Food Technological Research Institute, Mysore, India
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31
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Chauthaiwale J, Rao M. Production and Purification of Extracellular D-Xylose Isomerase from an Alkaliphilic, Thermophilic
Bacillus
sp. Appl Environ Microbiol 1994; 60:4495-9. [PMID: 16349464 PMCID: PMC202010 DOI: 10.1128/aem.60.12.4495-4499.1994] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
An alkaliphilic, thermophilic
Bacillus
sp. (NCIM 59) produced extracellular xylose isomerase at pH 10 and 50°C by using xylose or wheat bran as the carbon source. The distribution of xylose isomerase as a function of growth in comparison with distributions of extra- and intracellular marker enzymes such as xylanase and β-galactosidase revealed that xylose isomerase was truly secreted as an extracellular enzyme and was not released because of sporulation or lysis. The enzyme was purified to homogeneity by ammonium sulfate precipitation followed by gel filtration, preparative polyacrylamide gel electrophoresis, and ion-exchange chromatography. The molecular weight of xylose isomerase was estimated to be 160,000 by gel filtration and 50,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, indicating the presence of three subunits. The enzyme is most active at pH 8.0 and with incubation at 85°C for 20 min. Divalent metal ions Mg
2+
, Co
2+
, and Mn
2+
were required for maximum activity of the enzyme. The
K
m
values for D-xylose and D-glucose at 80°C and pH 7.5 were 6.66 and 142 mM, respectively, while
K
cat
values were 2.3 × 10
2
s
-1
and 0.5 × 10
2
s
-1
, respectively.
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Affiliation(s)
- J Chauthaiwale
- Division of Biochemical Sciences, National Chemical Laboratory, Pune 411008, India
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32
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Taj-Aldeen SJ. Effect of starch on the induction of β-glucosidase in Trichoderma reesei. ACTA ACUST UNITED AC 1993. [DOI: 10.1016/s0953-7562(09)81128-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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33
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Taj-Aldeen SJ, Jaffar WN. Cellulase activity of a thermotolerant Aspergillus niveus isolated from desert soil. ACTA ACUST UNITED AC 1992. [DOI: 10.1016/s0953-7562(09)80990-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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34
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Yin XS, Li YX, Stark JR. Amylase, β-Glucanase and Protease Activities from a Mutant of Bacillus subtilis. STARCH-STARKE 1991. [DOI: 10.1002/star.19910431008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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35
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Stutzenberger F. Production and activity of Thermomonospora curvata cellulases on protein-extracted lucerne fibers. Appl Microbiol Biotechnol 1988. [DOI: 10.1007/bf00268201] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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36
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Durrands PK, Cooper RM. Development and analysis of pectic screening media for use in the detection of pectinase mutants. Appl Microbiol Biotechnol 1988. [DOI: 10.1007/bf00268215] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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37
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Stability of exo-inulase production on lactose in batch and continuous culture of a Kluyveromyces fragilis hyperproducing mutant. Enzyme Microb Technol 1988. [DOI: 10.1016/0141-0229(88)90131-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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38
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Bezbaruah RL, Pillai KR, Gogoi BK, Singh HD, Baruah JN. Effect of growth temperature on the externalization and localization of α-amylase inBacillus stearothermophilus. J Basic Microbiol 1987. [DOI: 10.1002/jobm.3620270905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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39
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Choline stimulates synthesis of extracellular proteins in Trichoderma reesei QM 9414. Arch Microbiol 1986. [DOI: 10.1007/bf00454954] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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40
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Wilhelm M, Sahm H. Purification and Characterization of two Extracellular ?-Glucosidases from Trichoderma viride ITCC 1433. ACTA ACUST UNITED AC 1986. [DOI: 10.1002/abio.370060203] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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41
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Glenn M, Ghosh A, Ghosh BK. Subcellular fractionation of a hypercellulolytic mutant, Trichoderma reesei Rut-C30: localization of endoglucanase in microsomal fraction. Appl Environ Microbiol 1985; 50:1137-43. [PMID: 4091550 PMCID: PMC238713 DOI: 10.1128/aem.50.5.1137-1143.1985] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The growing mycelia of Trichoderma reesei Rut-C30 are richly endowed with endoplasmic reticula and a variety of pleomorphic subcellular bodies. Mycelia of the culture growing in presence of avicel pH101 was fractionated in sucrose density gradients, and several morphologically and biochemically distinct fractions were isolated. Mycelia were homogenized in a Bead Beater, and the homogenate was freed of nucleus and wall fragments by low-speed centrifugation before fractionation. Organelle-free cytosol, which did not penetrate the gradient, contained (of the total) 72% of the vanadate-sensitive ATPase, 26% of carboxymethyl cellulase (CMCase), 2% of cytochrome c reductase, and 13% of the protein. Significant fractions separated on a gradient were light vesicles containing heavily stained material inside and ribosomes attached to the outside surface, intact vesicles resembling condensing vacuoles, large vesicles derived from the plasma membrane, and heavy vesicles containing crystalline material. The light-vesicle fraction contained a large portion of the cell-bound CMCase activity. The particle-bound ATPase and cytochrome c reductase activities were concentrated in heavy fractions. The fractionation in the presence of MgCl2 improved the preservation of subcellular bodies derived from the endoplasmic reticula. Although the CMCase activity of the light-vesicle fraction was 4 times higher than the activity in the heavy-vesicle fraction, the CMCase antibody-binding capacities of both fractions were about the same. This discrepancy between the catalytic activity and the antibody-binding capacity suggests that the heavy vesicles might have contained considerable amount of inactive CMCase compared with that present in the light vesicles.
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42
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Cellulase secretion from a hyper-cellulolytic mutant of Trichoderma reesei Rut-C30. Arch Microbiol 1984. [DOI: 10.1007/bf00454914] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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43
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Fein JE, Zawadzki BC, Lawford HG, Lawford GR. Controlling Morphological Instability of
Zymomonas mobilis
Strains in Continuous Culture. Appl Environ Microbiol 1983; 45:1899-904. [PMID: 16346320 PMCID: PMC242556 DOI: 10.1128/aem.45.6.1899-1904.1983] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Growth of
Zymomonas mobilis
ATCC 29191 and CP4 in a continuous stirred tank fermentor resulted in the selection of stable flocculating variants. Factors responsible for enhancing the system pressures selective for the morphological variants were identified. By incorporating some modifications into the design of the fermentor, it was possible to achieve steady-state operation of the chemostat with both wild-type and flocculating strains. Biochemical and microscopic studies were performed to elucidate the mechanism of flocculation in
Z. mobilis
.
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Affiliation(s)
- J E Fein
- Weston Research Centre, Toronto, Canada M4W 2L3, and Department of Biochemistry, University of Toronto, Toronto, Canada M5S 1A8
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