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Giwa AS, Ali N, Akhter MS. Cellulose Degradation Enzymes in Filamentous Fungi, A Bioprocessing Approach Towards Biorefinery. Mol Biotechnol 2023:10.1007/s12033-023-00900-1. [PMID: 37839042 DOI: 10.1007/s12033-023-00900-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 09/04/2023] [Indexed: 10/17/2023]
Abstract
The economic exploration of renewable energy resources has hot fundamentals among the countries besides dwindling energy resources and increasing public pressure. Cellulose accumulation is a major bio-natural resource from agricultural waste. Cellulases are the most potential enzymes that systematically degrade cellulosic biomass into monomers which could be further processed into several efficient value-added products via chemical and biological reactions including useful biomaterial for human benefits. This could lower the environmental risks problems followed by an energy crisis. Cellulases are mainly synthesized by special fungal genotypes. The strain Trichoderma orientalis could highly express cellulases and was regarded as an ideal strain for further research, as the genetic tools have found compatibility for cellulose breakdown by producing effective cellulose-degrading enzymes. This strain has found a cellulase production of about 35 g/L that needs further studies for advancement. The enzyme activity of strain Trichoderma orientalis needed to be further improved from a molecular level which is one of the important methods. Considering synthetic biological approaches to unveil the genetic tools will boost the knowledge about commercial cellulases bioproduction. Several genetic transformation methods were significantly cited in this study. The transformation approaches that are currently researchers are exploring is transcription regulatory factors that are deeply explained in this study, that are considered essential regulators of gene expression.
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Affiliation(s)
- Abdulmoseen Segun Giwa
- School of Environment and Civil Engineering, Nanchang Institute of Science and Technology, Nanchang, 330108, China
| | - Nasir Ali
- Institute of Biotechnology Genetic Engineering, The University of Agriculture, Peshawar, 25130, Khyber Pakhtunkhwa, Pakistan.
| | - Mohammed Salim Akhter
- Department of Chemistry, College of Science, University of Bahrain, Sakheer Campus Bahrain, Zallaq, Bahrain
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In Vitro Characterization of a Nuclear Receptor-like Domain of the Xylanase Regulator 1 from Trichoderma reesei. J Fungi (Basel) 2022; 8:jof8121254. [PMID: 36547587 PMCID: PMC9784857 DOI: 10.3390/jof8121254] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 11/22/2022] [Accepted: 11/23/2022] [Indexed: 11/29/2022] Open
Abstract
Engineering transcription factors is an interesting research target gaining increasing attention, such as in the case of industrially used organisms. With respect to sustainability, biomass-degrading saprophytic fungi, such as Trichoderma reesei, are promising industrial work horses because they exhibit a high secretory capacity of native and heterologously expressed enzymes and compounds. A single-point mutation in the main transactivator of xylanase and cellulase expressions in T. reesei Xyr1 led to a strongly deregulated and enhanced xylanase expression. Circular dichroism spectroscopy revealed a change in secondary structure caused by this mutation. According to electrophoretic mobility shift assays and determination of the equilibrium-binding constants, the DNA-binding affinity of the mutated Xyr1 was considerably reduced compared to the wild-type Xyr1. Both techniques were also used to investigate the allosteric response to carbohydrates (D-glucose-6-phosphate, D-xylose, and sophorose) signalling the repression or induction of Xyr1 target genes. The mutated Xyr1 no longer exhibited a conformational change in response to these carbohydrates, indicating that the observed deregulation is not a simple matter of a change in DNA-binding of the transactivator. Altogether, we postulate that the part of Xyr1 where the mutation is located functions as a nuclear receptor-like domain that mediates carbohydrate signals and modulates the Xyr1 transactivating activity.
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Mattam AJ, Chaudhari YB, Velankar HR. Factors regulating cellulolytic gene expression in filamentous fungi: an overview. Microb Cell Fact 2022; 21:44. [PMID: 35317826 PMCID: PMC8939176 DOI: 10.1186/s12934-022-01764-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 02/27/2022] [Indexed: 12/19/2022] Open
Abstract
The growing demand for biofuels such as bioethanol has led to the need for identifying alternative feedstock instead of conventional substrates like molasses, etc. Lignocellulosic biomass is a relatively inexpensive feedstock that is available in abundance, however, its conversion to bioethanol involves a multistep process with different unit operations such as size reduction, pretreatment, saccharification, fermentation, distillation, etc. The saccharification or enzymatic hydrolysis of cellulose to glucose involves a complex family of enzymes called cellulases that are usually fungal in origin. Cellulose hydrolysis requires the synergistic action of several classes of enzymes, and achieving the optimum secretion of these simultaneously remains a challenge. The expression of fungal cellulases is controlled by an intricate network of transcription factors and sugar transporters. Several genetic engineering efforts have been undertaken to modulate the expression of cellulolytic genes, as well as their regulators. This review, therefore, focuses on the molecular mechanism of action of these transcription factors and their effect on the expression of cellulases and hemicellulases.
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Affiliation(s)
- Anu Jose Mattam
- Hindustan Petroleum Green R and D Centre (HPGRDC), KIADB Industrial Area, Tarabanahalli, Devanagundi, Hoskote, Bangalore, 560067, India
| | - Yogesh Babasaheb Chaudhari
- Hindustan Petroleum Green R and D Centre (HPGRDC), KIADB Industrial Area, Tarabanahalli, Devanagundi, Hoskote, Bangalore, 560067, India
| | - Harshad Ravindra Velankar
- Hindustan Petroleum Green R and D Centre (HPGRDC), KIADB Industrial Area, Tarabanahalli, Devanagundi, Hoskote, Bangalore, 560067, India.
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4
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Xu W, Fang Y, Ding M, Ren Y, Meng X, Chen G, Zhang W, Liu W. Elimination of the Sugar Transporter GAT1 Increased Xylanase I Production in Trichoderma reesei. Front Microbiol 2022; 13:810066. [PMID: 35154055 PMCID: PMC8825865 DOI: 10.3389/fmicb.2022.810066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 01/04/2022] [Indexed: 11/17/2022] Open
Abstract
The filamentous fungus Trichoderma reesei secretes large quantities of cellulases and hemicellulases that have found wide applications in industry. Compared with extensive studies on the mechanism controlling cellulase gene expression, less is known about the regulatory mechanism behind xylanase gene expression. Herein, several putative sugar transporter encoding genes that showed significant upregulation on xylan were identified in T. reesei. Deletion of one such gene, gat1, resulted in increased xylanase production but hardly affected cellulase induction. Further analyses demonstrated that deletion of gat1 markedly increased XYNI production at the transcriptional level and only exerted a minor effect on XYNII synthesis. In contrast, overexpressing gat1 caused a continuous decrease in xyn1 expression. Deletion of gat1 also affected the expression of xyn1 and pectinase genes when T. reesei was cultivated with galacturonic acid as the sole carbon source. Transcriptome analyses of Δgat1 and its parental strain identified 255 differentially expressed genes that are enriched in categories of glycoside hydrolases, lipid metabolism, transporters, and transcriptional factors. The results thus implicate a repressive role of the sugar transporter GAT1 in xyn1 expression and reveal that distinct regulatory mechanisms may exist in controlling the expression of different xylanase genes in T. reesei.
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Affiliation(s)
- Wenqiang Xu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Yu Fang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Mingyang Ding
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Yajing Ren
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Xiangfeng Meng
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Guanjun Chen
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Weixin Zhang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Weifeng Liu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
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Tomico-Cuenca I, Mach RL, Mach-Aigner AR, Derntl C. An overview on current molecular tools for heterologous gene expression in Trichoderma. Fungal Biol Biotechnol 2021; 8:11. [PMID: 34702369 PMCID: PMC8549263 DOI: 10.1186/s40694-021-00119-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 10/16/2021] [Indexed: 11/10/2022] Open
Abstract
Fungi of the genus Trichoderma are routinely used as biocontrol agents and for the production of industrial enzymes. Trichoderma spp. are interesting hosts for heterologous gene expression because their saprotrophic and mycoparasitic lifestyles enable them to thrive on a large number of nutrient sources and some members of this genus are generally recognized as safe (GRAS status). In this review, we summarize and discuss several aspects involved in heterologous gene expression in Trichoderma, including transformation methods, genome editing strategies, native and synthetic expression systems and implications of protein secretion. This review focuses on the industrial workhorse Trichoderma reesei because this fungus is the best-studied member of this genus for protein expression and secretion. However, the discussed strategies and tools can be expected to be transferable to other Trichoderma species.
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Affiliation(s)
- Irene Tomico-Cuenca
- Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Gumpendorfer Strasse 1a, 1060, Wien, Austria
| | - Robert L Mach
- Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Gumpendorfer Strasse 1a, 1060, Wien, Austria
| | - Astrid R Mach-Aigner
- Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Gumpendorfer Strasse 1a, 1060, Wien, Austria
| | - Christian Derntl
- Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Gumpendorfer Strasse 1a, 1060, Wien, Austria.
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Zhang S, Zhao S, Shang W, Yan Z, Wu X, Li Y, Chen G, Liu X, Wang L. Synergistic mechanism of GH11 xylanases with different action modes from Aspergillus niger An76. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:118. [PMID: 33971954 PMCID: PMC8112042 DOI: 10.1186/s13068-021-01967-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 05/03/2021] [Indexed: 05/28/2023]
Abstract
BACKGROUND Xylan is the most abundant hemicellulose polysaccharide in nature, which can be converted into high value-added products. However, its recalcitrance to breakdown requires the synergistic action of multiple enzymes. Aspergillus niger, possessing numerous xylan degrading isozyme-encoding genes, are highly effective xylan degraders in xylan-rich habitats. Therefore, it is necessary to explore gene transcription, the mode of action and cooperation mechanism of different xylanase isozymes to further understand the efficient xylan-degradation by A. niger. RESULTS Aspergillus niger An76 encoded a comprehensive set of xylan-degrading enzymes, including five endo-xylanases (one GH10 and four GH11). Quantitative transcriptional analysis showed that three xylanase genes (xynA, xynB and xynC) were up-regulated by xylan substrates, and the order and amount of enzyme secretion differed. Specifically, GH11 xylanases XynA and XynB were initially secreted successively, followed by GH10 xylanase XynC. Biochemical analyses displayed that three GH11 xylanases (XynA, XynB and XynD) showed differences in catalytic performance and product profiles, possibly because of intricate hydrogen bonding between substrates and functional residues in the active site architectures impacted their binding capacity. Among these, XynB had the best performance in the degradation of xylan and XynE had no catalytic activity. Furthermore, XynA and XynB showed synergistic effects during xylan degradation. CONCLUSIONS The sequential secretion and different action modes of GH11 xylanases were essential for the efficient xylan degradation by A. niger An76. The elucidation of the degradation mechanisms of these xylanase isozymes further improved our understanding of GH-encoding genes amplification in filamentous fungi and may guide the design of the optimal enzyme cocktails in industrial applications.
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Affiliation(s)
- Shu Zhang
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237 Shandong China
| | - Sha Zhao
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237 Shandong China
- School of Life Sciences, Shandong University, Qingdao, 266237 Shandong China
| | - Weihao Shang
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237 Shandong China
| | - Zijuan Yan
- School of Life Sciences, Shandong University, Qingdao, 266237 Shandong China
| | - Xiuyun Wu
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237 Shandong China
- State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan, 250353 Shandong China
| | - Yingjie Li
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237 Shandong China
| | - Guanjun Chen
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237 Shandong China
| | - Xinli Liu
- State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan, 250353 Shandong China
| | - Lushan Wang
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, 266237 Shandong China
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7
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Derntl C, Mach R, Mach-Aigner A. Application of the human estrogen receptor within a synthetic transcription factor in Trichoderma reesei. Fungal Biol Biotechnol 2020; 7:12. [PMID: 32765896 PMCID: PMC7396459 DOI: 10.1186/s40694-020-00102-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 07/17/2020] [Indexed: 12/28/2022] Open
Abstract
Background Synthetic gene expression systems offer a possibility for controllable and targeted induction of the expression of genes of interest, which is a fundamental technique necessary for basic research and industrial applications. The human estrogen receptor α contains a ligand binding domain that enforces dimerization and nuclear import upon binding of the inducer 17β-estradiol. In this study, we tested the potential of this ligand binding domain to be used in filamentous fungi as an auto-regulatory domain in a synthetic transcription factor. Results We constructed the synthetic transcription factor SynX by fusing the DNA-binding domain of Xyr1 (Xylanase Regulator 1), the transactivation domain of Ypr1 (Yellow Pigment Regulator 1), and the ligand binding domain of the human estrogen receptor α. SynX is able to strongly induce the gene expression of xylanases and an aldose reductase by addition of 17β-estradiol, but SynX does not induce gene expression of cellulases. Importantly, the induction of xylanase activities is mostly carbon source independent and can be fine-tuned by controlling the concentration of 17β-estradiol. Conclusion The ability of SynX to induce gene expression of xylanase encoding genes by addition of 17β-estradiol demonstrates that the ligand binding domain of the human estrogen receptor α works in filamentous fungi, and that it can be combined with a transactivation domain other than the commonly used transactivation domain of herpes simplex virion protein VP16.
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Affiliation(s)
- Christian Derntl
- Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Gumpendorfer Strasse 1a, 1060 Vienna, Austria
| | - Robert Mach
- Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Gumpendorfer Strasse 1a, 1060 Vienna, Austria
| | - Astrid Mach-Aigner
- Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Gumpendorfer Strasse 1a, 1060 Vienna, Austria
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Tini F, Beccari G, Benfield AH, Gardiner DM, Covarelli L. Role of the XylA gene, encoding a cell wall degrading enzyme, during common wheat, durum wheat and barley colonization by Fusarium graminearum. Fungal Genet Biol 2019; 136:103318. [PMID: 31841669 DOI: 10.1016/j.fgb.2019.103318] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 11/04/2019] [Accepted: 12/06/2019] [Indexed: 12/15/2022]
Abstract
Fusarium graminearum is the main causal agent of fusarium head blight (FHB) of wheat and barley. This filamentous fungus is able to produce hydrolytic enzymes, such as xylanases, that cause cell wall degradation, permitting host colonization. This study investigated the role of the F. graminearum XylA (FGSG_10999) gene during infection, using a knockout mutant in strain CS3005. Assays were carried out on common wheat, durum wheat and barley to compare virulence of a XylA knockout to that of wild type strain. These assays were conducted on wheat and barley seedling roots, seedling stem bases and heads. Furthermore, additional in vitro experiments were conducted to investigate the role of XylA gene in the utilisation of D-xylose, the main component of cereals cell wall. In planta assays showed the importance of XylA gene for F. graminearum virulence towards its main hosts. A positive correlation between symptom incidence and fungal biomass development was also observed for both the wild type and the knockout strains. Finally, gene expression studies performed in a liquid medium enriched with D-xylose, a known xylanase inducer in other fungi, showed that the absence of the gene in the FGSG_10999 locus was not compensated by two other F. graminearum xylanase encoding genes analysed (loci FGSG_06445 and FGSG_11478).
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Affiliation(s)
- F Tini
- Department of Agricultural, Food and Environmental Sciences, University of Perugia, Borgo XX Giugno, 74, 06121 Perugia, Italy
| | - G Beccari
- Department of Agricultural, Food and Environmental Sciences, University of Perugia, Borgo XX Giugno, 74, 06121 Perugia, Italy
| | - A H Benfield
- CSIRO Agriculture and Food, Queensland Bioscience Precinct, Brisbane 4067, QLD, Australia
| | - D M Gardiner
- CSIRO Agriculture and Food, Queensland Bioscience Precinct, Brisbane 4067, QLD, Australia
| | - L Covarelli
- Department of Agricultural, Food and Environmental Sciences, University of Perugia, Borgo XX Giugno, 74, 06121 Perugia, Italy.
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Llanos A, Déjean S, Neugnot-Roux V, François JM, Parrou JL. Carbon sources and XlnR-dependent transcriptional landscape of CAZymes in the industrial fungus Talaromyces versatilis: when exception seems to be the rule. Microb Cell Fact 2019; 18:14. [PMID: 30691469 PMCID: PMC6348686 DOI: 10.1186/s12934-019-1062-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 01/13/2019] [Indexed: 11/19/2022] Open
Abstract
Background Research on filamentous fungi emphasized the remarkable redundancy in genes encoding hydrolytic enzymes, the similarities but also the large differences in their expression, especially through the role of the XlnR/XYR1 transcriptional activator. The purpose of this study was to evaluate the specificities of the industrial fungus Talaromyces versatilis, getting clues into the role of XlnR and the importance of glucose repression at the transcriptional level, to provide further levers for cocktail production. Results By studying a set of 62 redundant genes representative of several categories of enzymes, our results underlined the huge plasticity of transcriptional responses when changing nutritional status. As a general trend, the more heterogeneous the substrate, the more efficient to trigger activation. Genetic modifications of xlnR led to significant reorganisation of transcriptional patterns. Just a minimal set of genes actually fitted in a simplistic model of regulation by a transcriptional activator, and this under specific substrates. On the contrary, the diversity of xlnR+ versus ΔxlnR responses illustrated the existence of complex and unpredicted patterns of co-regulated genes that were highly dependent on the culture condition, even between genes that encode members of a functional category of enzymes. They notably revealed a dual, substrate-dependant repressor-activator role of XlnR, with counter-intuitive transcripts regulations that targeted specific genes. About glucose, it appeared as a formal repressive sugar as we observed a massive repression of most genes upon glucose addition to the mycelium grown on wheat straw. However, we also noticed a positive role of this sugar on the basal expression of a few genes, (notably those encoding cellulases), showing again the strong dependence of these regulatory mechanisms upon promoter and nutritional contexts. Conclusions The diversity of transcriptional patterns appeared to be the rule, while common and stable behaviour, both within gene families and with fungal literature, the exception. The setup of a new biotechnological process to reach optimized, if not customized expression patterns of enzymes, hence appeared tricky just relying on published data that can lead, in the best scenario, to approximate trends. We instead encourage preliminary experimental assays, carried out in the context of interest to reassess gene responses, as a mandatory step before thinking in (genetic) strategies for the improvement of enzyme production in fungi.![]() Electronic supplementary material The online version of this article (10.1186/s12934-019-1062-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Agustina Llanos
- LISBP, Université de Toulouse, INSA, INRA, CNRS, Toulouse, France.,Adisseo France S.A.S, 135 Avenue de Rangueil, 31077, Toulouse, France
| | - Sébastien Déjean
- Institut de Mathématiques de Toulouse, UMR5219-Université de Toulouse; CNRS-UPS, 31062, Toulouse Cedex 9, France
| | | | - Jean M François
- LISBP, Université de Toulouse, INSA, INRA, CNRS, Toulouse, France
| | - Jean-Luc Parrou
- LISBP, Université de Toulouse, INSA, INRA, CNRS, Toulouse, France.
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Cruz-Magalhães V, Nieto-Jacobo MF, van Zijll de Jong E, Rostás M, Padilla-Arizmendi F, Kandula D, Kandula J, Hampton J, Herrera-Estrella A, Steyaert JM, Stewart A, Loguercio LL, Mendoza-Mendoza A. The NADPH Oxidases Nox1 and Nox2 Differentially Regulate Volatile Organic Compounds, Fungistatic Activity, Plant Growth Promotion and Nutrient Assimilation in Trichoderma atroviride. Front Microbiol 2019; 9:3271. [PMID: 30728815 PMCID: PMC6351448 DOI: 10.3389/fmicb.2018.03271] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2018] [Accepted: 12/17/2018] [Indexed: 12/04/2022] Open
Abstract
In eukaryotic systems, membrane-bound NADPH oxidases (Nox) generate reactive oxygen species (ROS) as a part of normal physiological functions. In the soil-borne mycoparasitic and plant facultative symbiont Trichoderma atroviride, Nox1 and the regulator NoxR are involved in differentiation induced by mechanical damage, while the role of Nox2 has not been determined. The knock-out strains Δnox1, ΔnoxR and Δnox2 were compared to the parental strain (WT) in their ability to grow and conidiate under a series of stress conditions (osmotic, oxidative, membrane, and cell-wall stresses). All three genes were differentially involved in the stress-response phenotypes. In addition, several interactive experiments with biotic factors (plant seedlings and other fungi) were performed comparing the mutant phenotypes with the WT, which was used as the reference strain. Δnox1 and ΔnoxR significantly reduced the antagonistic activity of T. atroviride against Rhizoctonia solani and Sclerotinia sclerotiorum in direct confrontation assays, but Δnox2 showed similar activity to the WT. The Δnox1, ΔnoxR, and Δnox2 mutants showed quantitative differences in the emission of several volatile organic compounds (VOCs). The effects of a blend of these volatiles on plant-growth promotion of Arabidopsis thaliana seedlings were determined in closed-chamber experiments. The increase in root and shoot biomass induced by T. atroviride VOCs was significantly lowered by ΔnoxR and Δnox1, but not by Δnox2. In terms of fungistatic activity at a distance, Δnox2 had a significant reduction in this trait against R. solani and S. sclerotiorum, while fungistasis was highly increased by ΔnoxR and Δnox1. Identification and quantification of individual VOCs in the blends emitted by the strains was performed by GC-MS and the patterns of variation observed for individual volatiles, such as 6-Pentyl-2H-pyran-2-one (6PP-1) and (E)-6-Pent-1-enylpyran-2-one (6PP-2) were consistent with their negative effects in plant-growth promotion and positive effects in fungistasis at a distance. Nox1 and NoxR appear to have a ubiquitous regulatory role of in a variety of developmental and interactive processes in T. atroviride either as positive or negative modulators. Nox2 may also have a role in regulating production of VOCs with fungistatic activity.
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Affiliation(s)
- Valter Cruz-Magalhães
- Bio-Protection Research Centre, Lincoln University, Lincoln, New Zealand.,Department of Biological Sciences (DCB), State University of Santa Cruz (UESC), Ilhéus, Brazil
| | | | | | - Michael Rostás
- Bio-Protection Research Centre, Lincoln University, Lincoln, New Zealand
| | | | - Diwakar Kandula
- Bio-Protection Research Centre, Lincoln University, Lincoln, New Zealand
| | - Janaki Kandula
- Bio-Protection Research Centre, Lincoln University, Lincoln, New Zealand
| | - John Hampton
- Bio-Protection Research Centre, Lincoln University, Lincoln, New Zealand
| | | | | | - Alison Stewart
- The Foundation for Arable Research (FAR), Christchurch, New Zealand
| | - Leandro Lopes Loguercio
- Department of Biological Sciences (DCB), State University of Santa Cruz (UESC), Ilhéus, Brazil
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Benocci T, Aguilar-Pontes MV, Kun RS, Lubbers RJM, Lail K, Wang M, Lipzen A, Ng V, Grigoriev IV, Seiboth B, Daly P, de Vries RP. Deletion of either the regulatory gene ara1 or metabolic gene xki1 in Trichoderma reesei leads to increased CAZyme gene expression on crude plant biomass. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:81. [PMID: 31007715 PMCID: PMC6454604 DOI: 10.1186/s13068-019-1422-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 04/03/2019] [Indexed: 05/17/2023]
Abstract
BACKGROUND Trichoderma reesei is one of the major producers of enzymes for the conversion of plant biomass to sustainable fuels and chemicals. Crude plant biomass can induce the production of CAZymes in T. reesei, but there is limited understanding of how the transcriptional response to crude plant biomass is regulated. In addition, it is unknown whether induction on untreated recalcitrant crude plant biomass (with a large diversity of inducers) can be sustained for longer. We investigated the transcriptomic response of T. reesei to the two industrial feedstocks, corn stover (CS) and soybean hulls (SBH), over time (4 h, 24 h and 48 h), and its regulatory basis using transcription factor deletion mutants (Δxyr1 and Δara1). We also investigated whether deletion of a xylulokinase gene (Δxki1) from the pentose catabolic pathway that converts potential inducers could lead to increased CAZyme gene expression. RESULTS By analyzing the transcriptomic responses using clustering as well as differential and cumulative expression of plant biomass degrading CAZymes, we found that corn stover induced a broader range and higher expression of CAZymes in T. reesei, while SBH induced more pectinolytic and mannanolytic transcripts. XYR1 was the major TF regulating CS utilization, likely due to the significant amount of d-xylose in this substrate. In contrast, ARA1 had a stronger effect on SBH utilization, which correlates with a higher abundance of l-arabinose in SBH that activates ARA1. Blocking pentose catabolism by deletion of xki1 led to higher expression of CAZyme encoding genes on both substrates at later time points. Surprisingly, this was also observed for Δara1 at later time points. Many of these genes were XYR1 regulated, suggesting that inducers for this regulator accumulated over time on both substrates. CONCLUSION Our data demonstrates the complexity of the regulatory system related to plant biomass degradation in T. reesei and the effect the feedstock composition has on this. Furthermore, this dataset provides leads to improve the efficiency of a T. reesei enzyme cocktail, such as by the choice of substrate or by deleting xki1 to obtain higher production of plant biomass degrading CAZymes.
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Affiliation(s)
- Tiziano Benocci
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Maria Victoria Aguilar-Pontes
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Roland Sándor Kun
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Ronnie J. M. Lubbers
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Kathleen Lail
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
| | - Mei Wang
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
| | - Anna Lipzen
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
| | - Vivian Ng
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
| | - Igor V. Grigoriev
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
- Department of Plant and Microbial Biology, University of California Berkeley, Berkeley, CA 94598 USA
| | - Bernhard Seiboth
- Research Area Biochemical Technology, Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, 1060 Vienna, Austria
| | - Paul Daly
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Ronald P. de Vries
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
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Ike M, Tokuyasu K. Cellulase Production of Trichoderma reesei ( Hypocrea jecorina) by Continuously Fed Cultivation Using Sucrose as Primary Carbon Source. J Appl Glycosci (1999) 2018; 65:51-56. [PMID: 34354513 PMCID: PMC8056898 DOI: 10.5458/jag.jag.jag-2018_0005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 09/29/2018] [Indexed: 10/31/2022] Open
Abstract
To expand the range of soluble carbon sources for our enzyme production system, we investigated the properties of sucrose utilization and its effect on cellulase production by Trichoderma reesei M2-1. We performed batch cultivation of T. reesei M2-1 on sucrose and related sugars along with cellobiose, which was used as a cellulase inducer. The results clearly revealed that the hydrolysis products of sucrose, i.e. glucose and fructose, but not sucrose, can be used as a carbon source for enzyme production. In a 10-day continuous feeding experiment using invertase-treated sucrose/cellobiose, the fungal strain produced cellulases with a filter paper-degrading activity of 20.3 U/mL and production efficiency of 254 U/g-carbon sources. These values were comparable with those of glucose/cellobiose feeding (21.2 U/mL and 265 U/g-carbon sources, respectively). Furthermore, the comparison of the specific activities clearly indicated that the compositions of both produced enzymes were similar. Therefore, enzymatically hydrolyzed sucrose can be utilized as an alternative carbon source to glucose in our enzyme production system with T. reesei M2-1.
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Affiliation(s)
- Masakazu Ike
- 1 Food Biotechnology Division, Food Research Institute, National Agriculture and Food Research Organization (NARO)
| | - Ken Tokuyasu
- 1 Food Biotechnology Division, Food Research Institute, National Agriculture and Food Research Organization (NARO)
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Borin GP, Carazzolle MF, Dos Santos RAC, Riaño-Pachón DM, Oliveira JVDC. Gene Co-expression Network Reveals Potential New Genes Related to Sugarcane Bagasse Degradation in Trichoderma reesei RUT-30. Front Bioeng Biotechnol 2018; 6:151. [PMID: 30406095 PMCID: PMC6204389 DOI: 10.3389/fbioe.2018.00151] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 10/03/2018] [Indexed: 12/11/2022] Open
Abstract
The biomass-degrading fungus Trichoderma reesei has been considered a model for cellulose degradation, and it is the primary source of the industrial enzymatic cocktails used in second-generation (2G) ethanol production. However, although various studies and advances have been conducted to understand the cellulolytic system and the transcriptional regulation of T. reesei, the whole set of genes related to lignocellulose degradation has not been completely elucidated. In this study, we inferred a weighted gene co-expression network analysis based on the transcriptome dataset of the T. reesei RUT-C30 strain aiming to identify new target genes involved in sugarcane bagasse breakdown. In total, ~70% of all the differentially expressed genes were found in 28 highly connected gene modules. Several cellulases, sugar transporters, and hypothetical proteins coding genes upregulated in bagasse were grouped into the same modules. Among them, a single module contained the most representative core of cellulolytic enzymes (cellobiohydrolase, endoglucanase, β-glucosidase, and lytic polysaccharide monooxygenase). In addition, functional analysis using Gene Ontology (GO) revealed various classes of hydrolytic activity, cellulase activity, carbohydrate binding and cation:sugar symporter activity enriched in these modules. Several modules also showed GO enrichment for transcription factor activity, indicating the presence of transcriptional regulators along with the genes involved in cellulose breakdown and sugar transport as well as other genes encoding proteins with unknown functions. Highly connected genes (hubs) were also identified within each module, such as predicted transcription factors and genes encoding hypothetical proteins. In addition, various hubs contained at least one DNA binding site for the master activator Xyr1 according to our in silico analysis. The prediction of Xyr1 binding sites and the co-expression with genes encoding carbohydrate active enzymes and sugar transporters suggest a putative role of these hubs in bagasse cell wall deconstruction. Our results demonstrate a vast range of new promising targets that merit additional studies to improve the cellulolytic potential of T. reesei strains and to decrease the production costs of 2G ethanol.
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Affiliation(s)
- Gustavo Pagotto Borin
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Campinas, Brazil.,Programa de Pós-Graduação em Genética e Biologia Molecular, Instituto de Biologia, Universidade de Campinas (UNICAMP), Campinas, Brazil
| | - Marcelo Falsarella Carazzolle
- Laboratório de Genômica e Expressão (LGE), Departamento de Genética, Evolução, Microbiologia e Imunologia, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), Campinas, Brazil
| | | | | | - Juliana Velasco de Castro Oliveira
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Campinas, Brazil.,Programa de Pós-Graduação em Genética e Biologia Molecular, Instituto de Biologia, Universidade de Campinas (UNICAMP), Campinas, Brazil
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14
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Fitz E, Wanka F, Seiboth B. The Promoter Toolbox for Recombinant Gene Expression in Trichoderma reesei. Front Bioeng Biotechnol 2018; 6:135. [PMID: 30364340 PMCID: PMC6193071 DOI: 10.3389/fbioe.2018.00135] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 09/12/2018] [Indexed: 01/05/2023] Open
Abstract
The ascomycete Trichoderma reesei is one of the main fungal producers of cellulases and xylanases based on its high production capacity. Its enzymes are applied in food, feed, and textile industry or in lignocellulose hydrolysis in biofuel and biorefinery industry. Over the last years, the demand to expand the molecular toolbox for T. reesei to facilitate genetic engineering and improve the production of heterologous proteins grew. An important instrument to modify the expression of key genes are promoters to initiate and control their transcription. To date, the most commonly used promoter for T. reesei is the strong inducible promoter of the main cellobiohydrolase cel7a. Beside this one, there is a number of alternative inducible promoters derived from other cellulase- and xylanase encoding genes and a few constitutive promoters. With the advances in genomics and transcriptomics the identification of new constitutive and tunable promoters with different expression strength was simplified. In this review, we will discuss new developments in the field of promoters and compare their advantages and disadvantages. Synthetic expression systems constitute a new option to control gene expression and build up complex gene circuits. Therefore, we will address common structural features of promoters and describe options for promoter engineering and synthetic design of promoters. The availability of well-characterized gene expression control tools is essential for the analysis of gene function, detection of bottlenecks in gene networks and yield increase for biotechnology applications.
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Affiliation(s)
- Elisabeth Fitz
- Research Division Biochemical Technology, Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Vienna, Austria.,Austrian Centre of Industrial Biotechnology (ACIB) GmbH, Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Vienna, Austria
| | - Franziska Wanka
- Austrian Centre of Industrial Biotechnology (ACIB) GmbH, Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Vienna, Austria
| | - Bernhard Seiboth
- Research Division Biochemical Technology, Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Vienna, Austria.,Austrian Centre of Industrial Biotechnology (ACIB) GmbH, Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Vienna, Austria
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15
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Rassinger A, Gacek-Matthews A, Strauss J, Mach RL, Mach-Aigner AR. Truncation of the transcriptional repressor protein Cre1 in Trichoderma reesei Rut-C30 turns it into an activator. Fungal Biol Biotechnol 2018; 5:15. [PMID: 30151221 PMCID: PMC6100732 DOI: 10.1186/s40694-018-0059-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Accepted: 08/02/2018] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND The filamentous fungus Trichoderma reesei (T. reesei) is a natural producer of cellulolytic and xylanolytic enzymes and is therefore industrially used. Many industries require high amounts of enzymes, in particular cellulases. Strain improvement strategies by random mutagenesis yielded the industrial ancestor strain Rut-C30. A key property of Rut-C30 is the partial release from carbon catabolite repression caused by a truncation of the repressor Cre1 (Cre1-96). In the T. reesei wild-type strain a full cre1 deletion leads to pleiotropic effects and strong growth impairment, while the truncated cre1-96 enhances cellulolytic activity without the effect of growth deficiencies. However, it is still unclear which function Cre1-96 has in Rut-C30. RESULTS In this study, we deleted and constitutively expressed cre1-96 in Rut-C30. We found that the presence of Cre1-96 in Rut-C30 is crucial for its cellulolytic and xylanolytic performance under inducing conditions. In the case of the constitutively expressed Cre1-96, the cellulase activity could further be improved approximately twofold. The deletion of cre1-96 led to growth deficiencies and morphological abnormalities. An in silico domain prediction revealed that Cre1-96 has all necessary properties that a classic transactivator needs. Consequently, we investigated the cellular localization of Cre1-96 by fluorescence microscopy using an eYFP-tag. Cre1-96 is localized in the fungal nuclei under both, inducing and repressing conditions. Furthermore, chromatin immunoprecipitation revealed an enrichment of Cre1-96 in the upstream regulatory region of the main transactivator of cellulases and xylanases, Xyr1. Interestingly, transcript levels of cre1-96 show the same patterns as the ones of xyr1 under inducing conditions. CONCLUSIONS The findings suggest that the truncation turns Cre1 into an activating regulator, which primarily exerts its role by approaching the upstream regulatory region of xyr1. The conversion of repressor proteins to potential activators in other biotechnologically used filamentous fungi can be applied to increase their enzyme production capacities.
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Affiliation(s)
- Alice Rassinger
- Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Gumpendorfer Str. 1a, 1060 Vienna, Austria
| | - Agnieszka Gacek-Matthews
- Fungal Genetics and Genomics Lab, Department of Applied Genetics and Cell Biology, BOKU-University of Natural Resources and Life Sciences, Konrad Lorenz Str. 24, 3430 Tulln/Donau, Austria
- Institute of Microbiology, University of Veterinary Medicine Vienna, Veterinärplatz 1, 1210 Vienna, Austria
| | - Joseph Strauss
- Fungal Genetics and Genomics Lab, Department of Applied Genetics and Cell Biology, BOKU-University of Natural Resources and Life Sciences, Konrad Lorenz Str. 24, 3430 Tulln/Donau, Austria
| | - Robert L. Mach
- Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Gumpendorfer Str. 1a, 1060 Vienna, Austria
| | - Astrid R. Mach-Aigner
- Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Gumpendorfer Str. 1a, 1060 Vienna, Austria
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Schneider WDH, Gonçalves TA, Uchima CA, Reis LD, Fontana RC, Squina FM, Dillon AJP, Camassola M. Comparison of the production of enzymes to cell wall hydrolysis using different carbon sources by Penicillium echinulatum strains and its hydrolysis potential for lignocelullosic biomass. Process Biochem 2018. [DOI: 10.1016/j.procbio.2017.11.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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17
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Lin C, Shen Z, Zhu T, Qin W. Bacterial Xylanase in Pseudomonas boreopolis LUQ1 is Highly Induced by Xylose. CANADIAN JOURNAL OF BIOTECHNOLOGY 2017. [DOI: 10.24870/cjb.2017-000112] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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18
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A Chrysoporthe cubensis enzyme cocktail produced from a low-cost carbon source with high biomass hydrolysis efficiency. Sci Rep 2017. [PMID: 28634326 PMCID: PMC5478631 DOI: 10.1038/s41598-017-04262-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Low cost and high efficiency cellulolytic cocktails can consolidate lignocellulosic ethanol technologies. Sugarcane bagasse (SCB) is a low cost agro-industrial residue, and its use as a carbon source can reduce the costs of fungi cultivation for enzyme production. Chrysoporthe cubensis grown under solid state fermentation (SSF) with wheat bran has potential to produce efficient enzymatic extracts for SCB saccharification. This fungus was grown under submersed fermentation (SmF) and SSF with in natura SCB, pretreated with acid or alkali and with others carbon sources. In natura SCB induced the highest carboxymethylcellulase (CMCase), xylanase, β-xylosidase, α-galactosidase and mannanase activities by C. cubensis under SSF. In natura and washed SCB, inducers of enzyme production under SSF, did not induce high cellulases and hemicellulases production by C. cubensis in SmF. The C. cubensis enzymatic extract produced under SSF with in natura SCB as a carbon source was more efficient for lignocelulolic biomass hydrolysis than extracts produced under SSF with wheat bran and commercial cellulolytic extract. Chrysoporthe cubensis showed high potential for cellulases and hemicellulases production, especially when grown under SSF with in natura SCB as carbon source.
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da Silva Delabona P, Rodrigues GN, Zubieta MP, Ramoni J, Codima CA, Lima DJ, Farinas CS, da Cruz Pradella JG, Seiboth B. The relation between xyr1 overexpression in Trichoderma harzianum and sugarcane bagasse saccharification performance. J Biotechnol 2017; 246:24-32. [DOI: 10.1016/j.jbiotec.2017.02.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 01/09/2017] [Accepted: 02/02/2017] [Indexed: 01/16/2023]
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20
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Benocci T, Aguilar-Pontes MV, Zhou M, Seiboth B, de Vries RP. Regulators of plant biomass degradation in ascomycetous fungi. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:152. [PMID: 28616076 PMCID: PMC5468973 DOI: 10.1186/s13068-017-0841-x] [Citation(s) in RCA: 125] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 06/06/2017] [Indexed: 05/05/2023]
Abstract
Fungi play a major role in the global carbon cycle because of their ability to utilize plant biomass (polysaccharides, proteins, and lignin) as carbon source. Due to the complexity and heterogenic composition of plant biomass, fungi need to produce a broad range of degrading enzymes, matching the composition of (part of) the prevalent substrate. This process is dependent on a network of regulators that not only control the extracellular enzymes that degrade the biomass, but also the metabolic pathways needed to metabolize the resulting monomers. This review will summarize the current knowledge on regulation of plant biomass utilization in fungi and compare the differences between fungal species, focusing in particular on the presence or absence of the regulators involved in this process.
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Affiliation(s)
- Tiziano Benocci
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Maria Victoria Aguilar-Pontes
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Miaomiao Zhou
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Bernhard Seiboth
- Research Area Biochemical Technology, Institute of Chemical and Biological Engineering, TU Wien, 1060 Vienna, Austria
| | - Ronald P. de Vries
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
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21
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Xiong L, Kameshwar AKS, Chen X, Guo Z, Mao C, Chen S, Qin W. The ACEII recombinant Trichoderma reesei QM9414 strains with enhanced xylanase production and its applications in production of xylitol from tree barks. Microb Cell Fact 2016; 15:215. [PMID: 28031033 PMCID: PMC5192574 DOI: 10.1186/s12934-016-0614-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2016] [Accepted: 12/06/2016] [Indexed: 01/08/2023] Open
Abstract
Background ACEII transcription factor plays a significant role in regulating the expression of cellulase and hemicellulase encoding genes. Apart from ACEII, transcription factors such as XYR1, CRE1, HAP2/3/5 complex and ACEI function in a coordinated pattern for regulating the gene expression of cellulases and hemicellulases. Studies have demonstrated that ACEII gene deletion results in decreased total cellulase and xylanase activities with reduced transcript levels of lignocellulolytic enzymes. Results In this study, we have successfully transformed the ACEII transcription factor encoding gene in Trichoderma reesei to significantly improve its degrading abilities. Transformation experiments on parental strain T. reesei QM9414 has resulted in five genetically engineered strains T/Ace2-2, T/Ace2-5, T/Ace2-8, T/Ace5-4 and T/Ace10-1. Among which, T/Ace2-2 has exhibited significant increase in enzyme activity by twofolds, when compared to parental strain. The T/Ace2-2 was cultured on growth substrates containing 2% bark supplemented with (a) sugar free + MA medium (b) glucose + MA medium and (c) xylose + MA medium. The bark degradation efficiency of genetically modified T/Ace2-2 strain was assessed by analyzing the xylitol production yield using HPAEC. By 6th day, about 10.52 g/l of xylitol was produced through enzymatic conversion of bark (2% bark + MA + xylose) by the T/Ace2-2 strain and by 7th day the conversion rate was found to be 0.21 g/g. Obtained results confirmed that bark growth medium supplemented with d-xylose has profoundly increased the conversion rate of bark by T/Ace2-2 strain when compared to sugar free and glucose supplemented growth media. Results obtained from scanning electron microscopy has endorsed our current results. Bark samples inoculated with T/Ace2-2 strain has showed large number of degraded cells with clearly visible cavities and fractures, by exposing the microfibrillar interwoven complex. Conclusion We propose a cost effective and ecofriendly method for the degradation of lignocellulosic biomass such as bark to produce xylitol by using genetically modified T. reesei. Efficient conversion rate and production yield obtained in our current study provides a great scope for the xylitol industries, as our method bypasses the pretreatment of bark achieving clean and low-cost xylitol production.
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Affiliation(s)
- Lili Xiong
- School of Life Science and Engineering, Southwest Jiaotong University, Chengdu City, 610031, Sichuan Province, China.,Department of Biology, Lakehead University, Thunder Bay, ON, P7B 5E1, Canada
| | | | - Xi Chen
- State Key Laboratory for Agrobiotechnology and College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Zhiyun Guo
- School of Life Science and Engineering, Southwest Jiaotong University, Chengdu City, 610031, Sichuan Province, China
| | - Canquan Mao
- School of Life Science and Engineering, Southwest Jiaotong University, Chengdu City, 610031, Sichuan Province, China
| | - Sanfeng Chen
- State Key Laboratory for Agrobiotechnology and College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Wensheng Qin
- Department of Biology, Lakehead University, Thunder Bay, ON, P7B 5E1, Canada.
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RNA Sequencing Reveals Xyr1 as a Transcription Factor Regulating Gene Expression beyond Carbohydrate Metabolism. BIOMED RESEARCH INTERNATIONAL 2016; 2016:4841756. [PMID: 28116297 PMCID: PMC5223008 DOI: 10.1155/2016/4841756] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 11/06/2016] [Indexed: 12/04/2022]
Abstract
Xyr1 has been demonstrated to be the main transcription activator of (hemi)cellulases in the well-known cellulase producer Trichoderma reesei. This study comprehensively investigates the genes regulated by Xyr1 through RNA sequencing to produce the transcription profiles of T. reesei Rut-C30 and its xyr1 deletion mutant (Δxyr1), cultured on lignocellulose or glucose. xyr1 deletion resulted in 467 differentially expressed genes on inducing medium. Almost all functional genes involved in (hemi)cellulose degradation and many transporters belonging to the sugar porter family in the major facilitator superfamily (MFS) were downregulated in Δxyr1. By contrast, all differentially expressed protease, lipase, chitinase, some ATP-binding cassette transporters, and heat shock protein-encoding genes were upregulated in Δxyr1. When cultured on glucose, a total of 281 genes were expressed differentially in Δxyr1, most of which were involved in energy, solute transport, lipid, amino acid, and monosaccharide as well as secondary metabolism. Electrophoretic mobility shift assays confirmed that the intracellular β-glucosidase bgl2, the putative nonenzymatic cellulose-attacking gene cip1, the MFS lactose transporter lp, the nmrA-like gene, endo T, the acid protease pepA, and the small heat shock protein hsp23 were probable Xyr1-targets. These results might help elucidate the regulation system for synthesis and secretion of (hemi)cellulases in T. reesei Rut-C30.
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The Post-genomic Era of Trichoderma reesei: What's Next? Trends Biotechnol 2016; 34:970-982. [PMID: 27394390 DOI: 10.1016/j.tibtech.2016.06.003] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 06/09/2016] [Accepted: 06/13/2016] [Indexed: 11/21/2022]
Abstract
The ascomycete Trichoderma reesei is one of the most well studied cellulolytic microorganisms. This fungus is widely used in the biotechnology industry, mainly in the production of biofuels. Due to its importance, its genome was sequenced in 2008, opening new avenues to study this microorganism. In this 'post-genomic' era, a transcriptomic and proteomic era has emerged. Here, we present an overview of new findings in the gene expression regulation network of T. reesei. We also discuss new rational strategies to obtain mutants that produce hydrolytic enzymes with a higher yield, using metabolic engineering. Finally, we present how synthetic biology strategies can be used to create engineered promoters to efficiently synthesize enzymes for biomass degradation to produce bioethanol.
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Druzhinina IS, Kubicek CP. Familiar Stranger: Ecological Genomics of the Model Saprotroph and Industrial Enzyme Producer Trichoderma reesei Breaks the Stereotypes. ADVANCES IN APPLIED MICROBIOLOGY 2016; 95:69-147. [PMID: 27261782 DOI: 10.1016/bs.aambs.2016.02.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The filamentous fungus Trichoderma reesei (Hypocreales, Ascomycota) has properties of an efficient cell factory for protein production that is exploited by the enzyme industry, particularly with respect to cellulase and hemicellulase formation. Under conditions of industrial fermentations it yields more than 100g secreted protein L(-1). Consequently, T. reesei has been intensively studied in the 20th century. Most of these investigations focused on the biochemical characteristics of its cellulases and hemicellulases, on the improvement of their properties by protein engineering, and on enhanced enzyme production by recombinant strategies. However, as the fungus is rare in nature, its ecology remained unknown. The breakthrough in the understanding of the fundamental biology of T. reesei only happened during 2000s-2010s. In this review, we compile the current knowledge on T. reesei ecology, physiology, and genomics to present a holistic view on the natural behavior of the organism. This is not only critical for science-driven further improvement of the biotechnological applications of this fungus, but also renders T. reesei as an attractive model of filamentous fungi with superior saprotrophic abilities.
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Affiliation(s)
- I S Druzhinina
- Institute of Chemical Engineering, TU Wien, Vienna, Austria
| | - C P Kubicek
- Institute of Chemical Engineering, TU Wien, Vienna, Austria
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25
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The Renaissance of Neurospora crassa: How a Classical Model System is Used for Applied Research. Fungal Biol 2016. [DOI: 10.1007/978-3-319-27951-0_3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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26
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Nakazawa H, Kawai T, Ida N, Shida Y, Shioya K, Kobayashi Y, Okada H, Tani S, Sumitani JI, Kawaguchi T, Morikawa Y, Ogasawara W. A high performance Trichoderma reesei strain that reveals the importance of xylanase III in cellulosic biomass conversion. Enzyme Microb Technol 2015; 82:89-95. [PMID: 26672453 DOI: 10.1016/j.enzmictec.2015.08.019] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 08/31/2015] [Accepted: 08/31/2015] [Indexed: 11/19/2022]
Abstract
The ability of the Trichoderma reesei X3AB1strain enzyme preparations to convert cellulosic biomass into fermentable sugars is enhanced by the replacement of xyn3 by Aspergillus aculeatus β-glucosidase 1 gene (aabg1), as shown in our previous study. However, subsequent experiments using T. reesei extracts supplemented with the glycoside hydrolase (GH) family 10 xylanase III (XYN III) and GH Family 11 XYN II showed increased conversion of alkaline treated cellulosic biomass, which is rich in xylan, underscoring the importance of XYN III. To attain optimal saccharifying potential in T. reesei, we constructed two new strains, C1AB1 and E1AB1, in which aabg1 was expressed heterologously by means of the cbh1 or egl1 promoters, respectively, so that the endogenous XYN III synthesis remained intact. Due to the presence of wild-type xyn3 in T. reesei E1AB1, enzymes prepared from this strain were 20-30% more effective in the saccharification of alkaline-pretreated rice straw than enzyme extracts from X3AB1, and also outperformed recent commercial cellulase preparations. Our results demonstrate the importance of XYN III in the conversion of alkaline-pretreated cellulosic biomass by T. reesei.
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Affiliation(s)
- Hikaru Nakazawa
- Department of Bioengineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka 940-2188, Japan
| | - Tetsushi Kawai
- Japan Bioindustry Association, AIST Tsukuba Central 6, 1-1-1Higashi, Tsukuba, Ibaraki 305-8566, Japan
| | - Noriko Ida
- Japan Bioindustry Association, AIST Tsukuba Central 6, 1-1-1Higashi, Tsukuba, Ibaraki 305-8566, Japan
| | - Yosuke Shida
- Department of Bioengineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka 940-2188, Japan
| | - Kouki Shioya
- Department of Bioengineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka 940-2188, Japan
| | - Yoshinori Kobayashi
- Japan Bioindustry Association, AIST Tsukuba Central 6, 1-1-1Higashi, Tsukuba, Ibaraki 305-8566, Japan
| | - Hirofumi Okada
- Department of Bioengineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka 940-2188, Japan
| | - Shuji Tani
- Graduate School of Agriculture and Biological Sciences and Research Institute for Advanced Science and Technology, Osaka Prefecture University, 1-1 Gakuen-cho, Sakai, Osaka 599-8531, Japan
| | - Jun-Ichi Sumitani
- Graduate School of Agriculture and Biological Sciences and Research Institute for Advanced Science and Technology, Osaka Prefecture University, 1-1 Gakuen-cho, Sakai, Osaka 599-8531, Japan
| | - Takashi Kawaguchi
- Graduate School of Agriculture and Biological Sciences and Research Institute for Advanced Science and Technology, Osaka Prefecture University, 1-1 Gakuen-cho, Sakai, Osaka 599-8531, Japan
| | - Yasushi Morikawa
- Japan Bioindustry Association, AIST Tsukuba Central 6, 1-1-1Higashi, Tsukuba, Ibaraki 305-8566, Japan
| | - Wataru Ogasawara
- Department of Bioengineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka 940-2188, Japan.
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Miao Y, Liu D, Li G, Li P, Xu Y, Shen Q, Zhang R. Genome-wide transcriptomic analysis of a superior biomass-degrading strain of A. fumigatus revealed active lignocellulose-degrading genes. BMC Genomics 2015; 16:459. [PMID: 26076650 PMCID: PMC4469458 DOI: 10.1186/s12864-015-1658-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Accepted: 05/28/2015] [Indexed: 12/14/2022] Open
Abstract
Background Various saprotrophic microorganisms, especially filamentous fungi, can efficiently degrade lignocellulose that is one of the most abundant natural materials on earth. It consists of complex carbohydrates and aromatic polymers found in the plant cell wall and thus in plant debris. Aspergillus fumigatus Z5 was isolated from compost heaps and showed highly efficient plant biomass-degradation capability. Results The 29-million base-pair genome of Z5 was sequenced and 9540 protein-coding genes were predicted and annotated. Genome analysis revealed an impressive array of genes encoding cellulases, hemicellulases and pectinases involved in lignocellulosic biomass degradation. Transcriptional responses of A. fumigatus Z5 induced by sucrose, oat spelt xylan, Avicel PH-101 and rice straw were compared. There were 444, 1711 and 1386 significantly differently expressed genes in xylan, cellulose and rice straw, respectively, when compared to sucrose as a control condition. Conclusions Combined analysis of the genomic and transcriptomic data provides a comprehensive understanding of the responding mechanisms to the most abundant natural polysaccharides in A. fumigatus. This study provides a basis for further analysis of genes shown to be highly induced in the presence of polysaccharide substrates and also the information which could prove useful for biomass degradation and heterologous protein expression. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1658-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Youzhi Miao
- Jiangsu Key Lab and Engineering Center for Solid Organic Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Nanjing Agricultural University, Nanjing, 210095, P.R. China.
| | - Dongyang Liu
- Jiangsu Key Lab and Engineering Center for Solid Organic Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Nanjing Agricultural University, Nanjing, 210095, P.R. China.
| | - Guangqi Li
- Jiangsu Key Lab and Engineering Center for Solid Organic Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Nanjing Agricultural University, Nanjing, 210095, P.R. China.
| | - Pan Li
- Jiangsu Key Lab and Engineering Center for Solid Organic Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Nanjing Agricultural University, Nanjing, 210095, P.R. China.
| | - Yangchun Xu
- Jiangsu Key Lab and Engineering Center for Solid Organic Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Nanjing Agricultural University, Nanjing, 210095, P.R. China.
| | - Qirong Shen
- Jiangsu Key Lab and Engineering Center for Solid Organic Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Nanjing Agricultural University, Nanjing, 210095, P.R. China.
| | - Ruifu Zhang
- Jiangsu Key Lab and Engineering Center for Solid Organic Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Nanjing Agricultural University, Nanjing, 210095, P.R. China. .,Key Laboratory of Microbial Resources Collection and Preservation, Ministry of Agriculture, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, 100081, P.R. China.
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Huang ZB, Chen XZ, Qin LN, Wu HQ, Su XY, Dong ZY. A novel major facilitator transporter TrSTR1 is essential for pentose utilization and involved in xylanase induction in Trichoderma reesei. Biochem Biophys Res Commun 2015; 460:663-9. [PMID: 25817789 DOI: 10.1016/j.bbrc.2015.03.087] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 03/06/2015] [Indexed: 01/15/2023]
Abstract
Trichoderma reesei (teleomorph Hypocrea jecorina) is an industrially important filamentous fungus for glycoside hydrolases production, with its xylanolytic enzymes widely applied in many areas. However, the molecular mechanisms underlying xylanase expression are still insufficiently understood. In particular, the effect of sugar transporter on the induction of xylanase expression is unclear. In this work, we identified a novel major facilitator transporter TrSTR1 that is capable of transporting xylose by using a xylose utilization system in Saccharomyces cerevisiae. In T. reesei, TrSTR1 is essential for the utilization of d-xylose, l-arabinose, and even their downstream metabolites D-xylitol and L-arabitol. TrSTR1 is also involved in the induction of xylanase expression since both the xylanase activity and extracellular protein concentration in the Tu6△str1 strain were decreased, which further confirmed by a qRT-PCR analysis of the transcript levels of the key transcriptional regulators. Our observations provide new insights into connections between pentose utilization and xylanase production in T. reesei.
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Affiliation(s)
- Zhen-Bang Huang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Xiu-Zhen Chen
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.
| | - Li-Na Qin
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.
| | - Hong-Qing Wu
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.
| | - Xiao-Yun Su
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
| | - Zhi-Yang Dong
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.
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KURRATAA'YUN, YOPI, MERYANDINI ANJA. Characterization of Xylanase activity produced by Paenibacillus sp. XJ18 from TNBD Jambi, Indonesia. HAYATI JOURNAL OF BIOSCIENCES 2015. [DOI: 10.4308/hjb.22.1.20] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Derntl C, Rassinger A, Srebotnik E, Mach RL, Mach-Aigner AR. Xpp1 regulates the expression of xylanases, but not of cellulases in Trichoderma reesei. BIOTECHNOLOGY FOR BIOFUELS 2015; 8:112. [PMID: 26246855 PMCID: PMC4526299 DOI: 10.1186/s13068-015-0298-8] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 07/24/2015] [Indexed: 05/22/2023]
Abstract
BACKGROUND The ascomycete Trichoderma reesei is industrially used for the production of cellulases. During the production process xylanases are co-secreted, which uses energy and nutrients. Cellulases and xylanases share the same main regulators, which makes a knowledge-based strain design difficult. However, previously a cis-element in the promoter of the main xylanase-encoding gene was identified as binding site for a putative repressor. Subsequently, three candidate repressors were identified in a pull-down approach. The expression of the most promising candidate, Xpp1 (Xylanase promoter-binding protein 1), was reported to be up-regulated on the repressing carbon source d-glucose and to bind the cis-element in vitro. RESULTS In this study, Xpp1 was deleted and over-expressed in T. reesei. An in vivo DNA-footprint assay indicated that Xpp1 binds a palindromic sequence in the xyn2 promoter. Comparison of the deletion, the over-expression, and the parent strain demonstrated that Xpp1 regulates gene expression of xylanolytic enzymes at later cultivation stages. Xpp1 expression was found to be up-regulated, additionally to d-glucose, by high d-xylose availability. These findings together with the observed xyn2 transcript levels during growth on xylan suggest that Xpp1 is the mediator of a feedback mechanism. Notably, Xpp1 has neither influence on the d-xylose metabolism nor on the expression of cellulases. CONCLUSIONS Xpp1 as regulator acting on the expression of xylanases, but not cellulases, is a highly promising candidate for knowledge-based strain design to improve the cellulases-to-xylanases ratio during industrial cellulase production.
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Affiliation(s)
- Christian Derntl
- />Department for Biotechnology and Microbiology, Institute of Chemical Engineering, TU Wien, Gumpendorfer Str. 1a, 1060 Vienna, Austria
| | - Alice Rassinger
- />Department for Biotechnology and Microbiology, Institute of Chemical Engineering, TU Wien, Gumpendorfer Str. 1a, 1060 Vienna, Austria
| | - Ewald Srebotnik
- />Department of Biochemical Engineering, Institute of Chemical Engineering, TU Wien, Gumpendorfer Str. 1a, 1060 Vienna, Austria
| | - Robert L Mach
- />Department for Biotechnology and Microbiology, Institute of Chemical Engineering, TU Wien, Gumpendorfer Str. 1a, 1060 Vienna, Austria
| | - Astrid R Mach-Aigner
- />Department for Biotechnology and Microbiology, Institute of Chemical Engineering, TU Wien, Gumpendorfer Str. 1a, 1060 Vienna, Austria
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Valkonen M, Penttilä M, Benčina M. Intracellular pH responses in the industrially important fungus Trichoderma reesei. Fungal Genet Biol 2014; 70:86-93. [PMID: 25046860 DOI: 10.1016/j.fgb.2014.07.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Revised: 07/07/2014] [Accepted: 07/08/2014] [Indexed: 12/14/2022]
Abstract
Preserving an optimal intracellular pH is critical for cell fitness and productivity. The pH homeostasis of the industrially important filamentous fungus Trichoderma reesei (Hypocrea jecorina) is largely unexplored. We analyzed the impact of growth conditions on regulation of intracellular pH of the strain Rut-C30 and the strain M106 derived from the Rut-C30 that accumulates L-galactonic acid-from provided galacturonic acid-as a consequence of L-galactonate dehydratase deletion. For live-cell measurements of intracellular pH, we used the genetically encoded ratiometric pH-sensitive fluorescent protein RaVC. Glucose and lactose, used as carbon sources, had specific effects on intracellular pH of T. reesei. The growth in lactose-containing medium extensively acidified cytosol, while intracellular pH of hyphae cultured in a medium with glucose remained at a higher level. The strain M106 maintained higher intracellular pH in the presence of D-galacturonic acid than its parental strain Rut-C30. Acidic external pH caused significant acidification of cytosol. Altogether, the pH homeostasis of T. reesei Rut-C30 strain is sensitive to extracellular pH and the degree of acidification depends on carbon source.
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Affiliation(s)
- Mari Valkonen
- VTT Technical Research Centre of Finland, Espoo, Finland.
| | - Merja Penttilä
- VTT Technical Research Centre of Finland, Espoo, Finland
| | - Mojca Benčina
- Laboratory of Biotechnology, National Institute of Chemistry, 1000 Ljubljana, Slovenia; Centre of Excellence EN-FIST, 1000 Ljubljana, Slovenia.
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Liu Z, Xu J, Duan S, Zhang J, Zheng K, Feng X, Cheng L. Expression of modified xynA gene fragments from Bacillus subtilis BE-91. ANN MICROBIOL 2014. [DOI: 10.1007/s13213-013-0642-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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Li J, Lin L, Li H, Tian C, Ma Y. Transcriptional comparison of the filamentous fungus Neurospora crassa growing on three major monosaccharides D-glucose, D-xylose and L-arabinose. BIOTECHNOLOGY FOR BIOFUELS 2014; 7:31. [PMID: 24581151 PMCID: PMC4015282 DOI: 10.1186/1754-6834-7-31] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Accepted: 02/14/2014] [Indexed: 05/09/2023]
Abstract
BACKGROUND D-glucose, D-xylose and L-arabinose are the three major monosaccharides in plant cell walls. Complete utilization of all three sugars is still a bottleneck for second-generation cellulolytic bioethanol production, especially for L-arabinose. However, little is known about gene expression profiles during L-arabinose utilization in fungi and a comparison of the genome-wide fungal response to these three major monosaccharides has not yet been reported. RESULTS Using next-generation sequencing technology, we have analyzed the transcriptome of N. crassa grown on L-arabinose versus D-xylose, with D-glucose as the reference. We found that the gene expression profiles on L-arabinose were dramatically different from those on D-xylose. It appears that L-arabinose can rewire the fungal cell metabolic pathway widely and provoke the expression of many kinds of sugar transporters, hemicellulase genes and transcription factors. In contrast, many fewer genes, mainly related to the pentose metabolic pathway, were upregulated on D-xylose. The rewired metabolic response to L-arabinose was significantly different and wider than that under no carbon conditions, although the carbon starvation response was initiated on L-arabinose. Three novel sugar transporters were identified and characterized for their substrates here, including one glucose transporter GLT-1 (NCU01633) and two novel pentose transporters, XAT-1 (NCU01132), XYT-1 (NCU05627). One transcription factor associated with the regulation of hemicellulase genes, HCR-1 (NCU05064) was also characterized in the present study. CONCLUSIONS We conducted the first transcriptome analysis of Neurospora crassa grown on L-arabinose and performed a comparative analysis with cells grown on D-xylose and D-glucose, which deepens the understanding of the utilization of L-arabinose and D-xylose in filamentous fungi. The dataset generated by this research will be useful for mining target genes for D-xylose and L-arabinose utilization engineering and the novel sugar transportes identified are good targets for pentose untilization and biofuels production. Moreover, hemicellulase production by fungi could be improved by modifying the hemicellulase regulator discovered here.
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Affiliation(s)
- Jingen Li
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Liangcai Lin
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
| | - Huiyan Li
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
| | - Chaoguang Tian
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
| | - Yanhe Ma
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
- Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
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Novello M, Vilasboa J, Schneider WDH, Reis LD, Fontana RC, Camassola M. Enzymes for second generation ethanol: exploring new strategies for the use of xylose. RSC Adv 2014. [DOI: 10.1039/c4ra00909f] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
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35
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Liao H, Li S, Wei Z, Shen Q, Xu Y. Insights into high-efficiency lignocellulolytic enzyme production by Penicillium oxalicum GZ-2 induced by a complex substrate. BIOTECHNOLOGY FOR BIOFUELS 2014; 7:162. [PMID: 25419234 PMCID: PMC4239378 DOI: 10.1186/s13068-014-0162-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 10/21/2014] [Indexed: 05/15/2023]
Abstract
BACKGROUND Agricultural residue is more efficient than purified cellulose at inducing lignocellulolytic enzyme production in Penicillium oxalicum GZ-2, but in Trichoderma reesei RUT-C30, cellulose induces a more efficient response. To understand the reasons, we designed an artificially simulated plant biomass (cellulose plus xylan) to study the roles and relationships of each component in the production of lignocellulolytic enzymes by P. oxalicum GZ-2. RESULTS The changes in lignocellulolytic enzyme activity, gene expression involving (hemi)cellulolytic enzymes, and the secretome of cultures grown on Avicel (A), xylan (X), or a mixture of both (AX) were studied. The addition of xylan to the cellulose culture did not affect fungal growth but significantly increased the activity of cellulase and hemicellulase. In the AX treatment, the transcripts of cellulase genes (egl1, egl2, egl3, sow, and cbh2) and hemicellulase genes (xyl3 and xyl4) were significantly upregulated (P <0.05). The proportion of biomass-degrading proteins in the secretome was altered; in particular, the percentage of cellulases and hemicellulases was increased. The percentage of cellulases and hemicellulases in the AX secretome increased from 4.5% and 7.6% to 10.3% and 21.8%, respectively, compared to the secretome of the A treatment. Cellobiohydrolase II (encoded by cbh2) and xylanase II (encoded by xyl2) were the main proteins in the secretome, and their corresponding genes (cbh2 and xyl2) were transcripted at the highest levels among the cellulolytic and xylanolytic genes. Several important proteins such as swollenin, cellobiohydrolase, and endo-beta-1,4-xylanase were only induced by AX. Bray-Curtis similarity indices, a dendrogram analysis, and a diversity index all demonstrated that the secretome produced by P. oxalicum GZ-2 depended on the substrate and that strain GZ-2 directionally adjusted the compositions of lignocellulolytic enzymes in its secretome to preferably degrade a complex substrate. CONCLUSION The addition of xylan to the cellulose medium not only induces more hemicellulases but also strongly activates cellulase production. The proportion of the biomass-degrading proteins in the secretome was altered significantly, with the proportion of cellulases and hemicellulases especially increased. Xylan and cellulose have positively synergistic effects, and they play a key role in the induction of highly efficient lignocellulolytic enzymes.
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Affiliation(s)
- Hanpeng Liao
- National Enginnering Research Center for Organic-based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waste Utilization, College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing, 210095 China
| | - Shuixian Li
- National Enginnering Research Center for Organic-based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waste Utilization, College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing, 210095 China
| | - Zhong Wei
- National Enginnering Research Center for Organic-based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waste Utilization, College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing, 210095 China
| | - Qirong Shen
- National Enginnering Research Center for Organic-based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waste Utilization, College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing, 210095 China
| | - Yangchun Xu
- National Enginnering Research Center for Organic-based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waste Utilization, College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing, 210095 China
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Glass NL, Schmoll M, Cate JH, Coradetti S. Plant Cell Wall Deconstruction by Ascomycete Fungi. Annu Rev Microbiol 2013; 67:477-98. [DOI: 10.1146/annurev-micro-092611-150044] [Citation(s) in RCA: 244] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
| | - Monika Schmoll
- Austrian Institute of Technology GmbH (AIT), Health and Environment, Bioresources, 3430 Tulln, Austria
| | - Jamie H.D. Cate
- Molecular and Cellular Biology Department, and
- Chemistry Department, University of California, Berkeley, California 94720;
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Xing S, Li G, Sun X, Ma S, Chen G, Wang L, Gao P. Dynamic changes in xylanases and β-1,4-endoglucanases secreted by Aspergillus niger An-76 in response to hydrolysates of lignocellulose polysaccharide. Appl Biochem Biotechnol 2013; 171:832-46. [PMID: 23900618 DOI: 10.1007/s12010-013-0402-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Accepted: 07/16/2013] [Indexed: 11/30/2022]
Abstract
Aspergillus niger is an effective secretor of glycoside hydrolases that facilitate the saprophytic lifestyle of the fungus by degrading plant cell wall polysaccharides. In the present study, a series of dynamic zymography assays were applied to quantify the secreted glycoside hydrolases of A. niger cultured in media containing different carbon sources. Differences in the diversity and concentrations of polysaccharide hydrolysates dynamically regulated the secretion of glycoside hydrolases. The secretion of β-1,4-endoglucanase isozymes was observed to lag at least 24 h behind, rather than coincide with, the secretion of xylanase isozymes. Low concentrations of xylose could induce many endoxylanases (such as Xyn1/XynA, Xyn2, and Xyn3/XynB). High concentrations of xylose could sustain the induction of Xyn2 and Xyn3/XynB but repress Xyn1/XynA (GH10 endoxylanase), which has a broad substrate specificity, and also triggers the low-level secretion of Egl3/EglA, which also has a broad substrate specificity. Mixed polysaccharide hydrolysates sustained the induction of Egl1, whereas the other β-1,4-endoglucanases were sustainably induced by the specific polysaccharide hydrolysates released during the hydrolysis process (such as Egl2 and Egl4). These results indicate that the secretion of glycoside hydrolases may be specifically regulated by the production of polysaccharide hydrolysates released during the process of biomass degradation.
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Affiliation(s)
- Sheng Xing
- State Key Laboratory of Microbial Technology, Shandong University, 27 Shandanan Rd, Jinan, 250100, People's Republic of China,
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Ren A, Li MJ, Shi L, Mu DS, Jiang AL, Han Q, Zhao MW. Profiling and quantifying differential gene transcription provide insights into ganoderic acid biosynthesis in Ganoderma lucidum in response to methyl jasmonate. PLoS One 2013; 8:e65027. [PMID: 23762280 PMCID: PMC3676390 DOI: 10.1371/journal.pone.0065027] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Accepted: 04/21/2013] [Indexed: 01/09/2023] Open
Abstract
Ganoderma lucidum is a mushroom with traditional medicinal properties that has been widely used in China and other countries in Eastern Asia. Ganoderic acids (GA) produced by G. lucidum exhibit important pharmacological activities. Previous studies have demonstrated that methyl jasmonate (MeJA) is a potent inducer of GA biosynthesis and the expression of genes involved in the GA biosynthesis pathway in G. lucidum. To further explore the mechanism of GA biosynthesis, cDNA-Amplified Fragment Length Polymorphism (cDNA-AFLP) was used to identify genes that are differentially expressed in response to MeJA. Using 64 primer combinations, over 3910 transcriptionally derived fragments (TDFs) were obtained. Reliable sequence data were obtained for 390 of 458 selected TDFs. Ninety of these TDFs were annotated with known functions through BLASTX searching the GenBank database, and 12 annotated TDFs were assigned into secondary metabolic pathways by searching the KEGGPATHWAY database. Twenty-five TDFs were selected for qRT-PCR analysis to confirm the expression patterns observed with cDNA-AFLP. The qRT-PCR results were consistent with the altered patterns of gene expression revealed by the cDNA-AFLP technique. Additionally, the transcript levels of 10 genes were measured at the mycelium, primordia, and fruiting body developmental stages of G. lucidum. The greatest expression levels were reached during primordia for all of the genes except cytochrome b2 reached its highest expression level in the mycelium stage. This study not only identifies new candidate genes involved in the regulation of GA biosynthesis but also provides further insight into MeJA-induced gene expression and secondary metabolic response in G. lucidum.
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Affiliation(s)
- Ang Ren
- Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, Nanjing, Jiangsu, P.R. China
| | - Meng-Jiao Li
- Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, Nanjing, Jiangsu, P.R. China
| | - Liang Shi
- Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, Nanjing, Jiangsu, P.R. China
| | - Da-Shuai Mu
- Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, Nanjing, Jiangsu, P.R. China
| | - Ai-Liang Jiang
- Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, Nanjing, Jiangsu, P.R. China
| | - Qin Han
- Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, Nanjing, Jiangsu, P.R. China
| | - Ming-Wen Zhao
- Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, Nanjing, Jiangsu, P.R. China
- * E-mail:
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Derntl C, Gudynaite-Savitch L, Calixte S, White T, Mach RL, Mach-Aigner AR. Mutation of the Xylanase regulator 1 causes a glucose blind hydrolase expressing phenotype in industrially used Trichoderma strains. BIOTECHNOLOGY FOR BIOFUELS 2013; 6:62. [PMID: 23638967 PMCID: PMC3654998 DOI: 10.1186/1754-6834-6-62] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Accepted: 04/23/2013] [Indexed: 05/02/2023]
Abstract
BACKGROUND Trichoderma reesei is an organism involved in degradation of (hemi)cellulosic biomass. Consequently, the corresponding enzymes are commonly used in different types of industries, and recently gained considerable importance for production of second-generation biofuel. Many industrial T. reesei strains currently in use are derived from strain Rut-C30, in which cellulase and hemicellulase expression is released from carbon catabolite repression. Nevertheless, inducing substances are still necessary for a satisfactory amount of protein formation. RESULTS Here, we report on a T. reesei strain, which exhibits a very high level of xylanase expression regardless if inducing substances (e.g. D-xylose, xylobiose) are used. We found that a single point mutation in the gene encoding the Xylanase regulator 1 (Xyr1) is responsible for this strong deregulation of endo-xylanase expression and, moreover, a highly elevated basal level of cellulase expression. This point mutation is localized in a domain that is common in binuclear zinc cluster transcription factors. Only the use of sophorose as inducer still leads to a slight induction of cellulase expression. Under all tested conditions, the formation of cbh1 and cbh2 transcript level strictly follows the transcript levels of xyr1. The correlation of xyr1 transcript levels and cbh1/cbh2 transcript levels and also their inducibility via sophorose is not restricted to this strain, but occurs in all ancestor strains up to the wild-type QM6a. CONCLUSIONS Engineering a key transcription factor of a target regulon seems to be a promising strategy in order to increase enzymes yields independent of the used substrate or inducer. The regulatory domain where the described mutation is located is certainly an interesting research target for all organisms that also depend so far on certain inducing conditions.
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Affiliation(s)
- Christian Derntl
- Department for Biotechnology and Microbiology, Institute of Chemical Engineering, Vienna University of Technology, Gumpendorfer Str. 1a, Wien, A-1060, Austria
| | | | - Sophie Calixte
- Iogen Corp., 310 Hunt Club Rd., Ottawa, ON, K1V 1C1, Canada
| | - Theresa White
- Iogen Corp., 310 Hunt Club Rd., Ottawa, ON, K1V 1C1, Canada
| | - Robert L Mach
- Department for Biotechnology and Microbiology, Institute of Chemical Engineering, Vienna University of Technology, Gumpendorfer Str. 1a, Wien, A-1060, Austria
| | - Astrid R Mach-Aigner
- Department for Biotechnology and Microbiology, Institute of Chemical Engineering, Vienna University of Technology, Gumpendorfer Str. 1a, Wien, A-1060, Austria
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Controlled preparation of cellulases with xylanolytic enzymes from Trichoderma reesei (Hypocrea jecorina) by continuous-feed cultivation using soluble sugars. Biosci Biotechnol Biochem 2013; 77:161-6. [PMID: 23291768 DOI: 10.1271/bbb.120696] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The objective of this study was to develop an efficient production system for cellulase preparation with a high level of xylanolytic enzymes using soluble carbon sources. When xylose and arabinose were simultaneously fed with glucose and cellobiose, a mutant of Trichoderma reesei, M3-1, showed sufficient levels of cellulolytic and xylanolytic activities, indicating that xylose and arabinose are good inducers for the production of xylanolytic enzymes. In a continuous feeding experiment using glucose/cellobiose and glucose/xylose/cellobiose, cellulase preparations with various levels of xylanolytic enzymes were obtained by altering the feeding solutions and the timing of their addition. The volumetric production rates for xylanolytic activities at the glucose/xylose/cellobiose-feeding phase were significantly higher than at the glucose/cellobiose-feeding phase, while those for cellulolytic activities were comparable under the two conditions. Thus the composition of the enzyme preparation produced by the mutant was readily controlled by varying the inducers and the pattern of their addition, facilitating the tailored production of enzymes in a diversity of bioconversion processes.
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Xylanase gene transcription in Trichoderma reesei is triggered by different inducers representing different hemicellulosic pentose polymers. EUKARYOTIC CELL 2013; 12:390-8. [PMID: 23291620 DOI: 10.1128/ec.00182-12] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The ascomycete Trichoderma reesei is a paradigm for the regulation and production of plant cell wall-degrading enzymes, including xylanases. Four xylanases, including XYN1 and XYN2 of glycosyl hydrolase family 11 (GH11), the GH10 XYN3, and the GH30 XYN4, were already described. By genome mining, we identified a fifth xylanase, XYN5, belonging to GH11. Transcriptional analysis reveals that the expression of all xylanases but xyn3 is induced by D-xylose, dependent on the cellulase and xylanase regulator XYR1 and negatively regulated by the carbon catabolite repressor CRE1. Impairment of D-xylose catabolism at the D-xylose reductase and xylitol dehydrogenase step strongly enhanced induction by D-xylose. Knockout of the L-xylulose reductase-encoding gene lxr3, which connects the D-xylose and L-arabinose catabolic pathways, had no effect on xylanase induction. Besides the induction by D-xylose, the T. reesei xylanases were also induced by L-arabinose, and this induction was also enhanced in knockout mutants in L-arabinose reductase (xyl1), L-arabitol dehydrogenase (lad1), and L-xylulose reductase (lxr3). Induction by L-arabinose was also XYR1 dependent. Analysis of intracellular polyols revealed accumulation of xylitol in all strains only during incubation with D-xylose and accumulation of L-arabitol only during incubation with L-arabinose. Induction by L-arabinose could be further stimulated by addition of D-xylose. We conclude that the expression of the T. reesei xylanases can be induced by both D-xylose and L-arabinose, but independently of each other and by using different inducing metabolites.
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d-Xylose concentration-dependent hydrolase expression profiles and the function of CreA and XlnR in Aspergillus niger. Appl Environ Microbiol 2012; 78:3145-55. [PMID: 22344641 DOI: 10.1128/aem.07772-11] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Aspergillus niger is an important organism for the production of industrial enzymes such as hemicellulases and pectinases. The xylan-backbone monomer, d-xylose, is an inducing substance for the coordinate expression of a large number of polysaccharide-degrading enzymes. In this study, the responses of 22 genes to low (1 mM) and high (50 mM) d-xylose concentrations were investigated. These 22 genes encode enzymes that function as xylan backbone-degrading enzymes, accessory enzymes, cellulose-degrading enzymes, or enzymes involved in the pentose catabolic pathway in A. niger. Notably, genes encoding enzymes that have a similar function (e.g., xylan backbone degradation) respond in a similar manner to different concentrations of d-xylose. Although low d-xylose concentrations provoke the greatest change in transcript levels, in particular, for hemicellulase-encoding genes, transcript formation in the presence of high concentrations of d-xylose was also observed. Interestingly, a high d-xylose concentration is favorable for certain groups of genes. Furthermore, the repressing influence of CreA on the transcription and transcript levels of a subset of these genes was observed regardless of whether a low or high concentration of d-xylose was used. Interestingly, the decrease in transcript levels of certain genes on high d-xylose concentrations is not reflected by the transcript level of their activator, XlnR. Regardless of the d-xylose concentration applied and whether CreA was functional, xlnR was constitutively expressed at a low level.
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Deciphering transcriptional regulatory mechanisms associated with hemicellulose degradation in Neurospora crassa. EUKARYOTIC CELL 2012; 11:482-93. [PMID: 22345350 DOI: 10.1128/ec.05327-11] [Citation(s) in RCA: 132] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Hemicellulose, the second most abundant plant biomass fraction after cellulose, is widely viewed as a potential substrate for the production of liquid fuels and other value-added materials. Degradation of hemicellulose by filamentous fungi requires production of many different enzymes, which are induced by biopolymers or its derivatives and regulated mainly at the transcriptional level through transcription factors (TFs). Neurospora crassa, a model filamentous fungus, expresses and secretes enzymes required for plant cell wall deconstruction. To better understand genes specifically associated with degradation of hemicellulose, we applied secretome and transcriptome analysis to N. crassa grown on beechwood xylan. We identified 34 secreted proteins and 353 genes with elevated transcription on xylan. The xylanolytic phenotype of strains with deletions in genes identified from the secretome and transcriptome analysis of the wild type was assessed, revealing functions for known and unknown proteins associated with hemicellulose degradation. By evaluating phenotypes of strains containing deletions of predicted TF genes in N. crassa, we identified a TF (XLR-1; xylan degradation regulator 1) essential for hemicellulose degradation that is an ortholog to XlnR/XYR1 in Aspergillus and Trichoderma species, respectively, a major transcriptional regulator of genes encoding both cellulases and hemicellulases. Deletion of xlr-1 in N. crassa abolished growth on xylan and xylose, but growth on cellulose and cellulolytic activity were only slightly affected. To determine the regulatory mechanisms for hemicellulose degradation, we explored the transcriptional regulon of XLR-1 under xylose, xylanolytic, and cellulolytic conditions. XLR-1 regulated only some predicted hemicellulase genes in N. crassa and was required for a full induction of several cellulase genes. Hemicellulase gene expression was induced by a combination of release from carbon catabolite repression (CCR) and induction. This systematic analysis illustrates the similarities and differences in regulation of hemicellulose degradation among filamentous fungi.
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Jun H, Kieselbach T, Jönsson LJ. Enzyme production by filamentous fungi: analysis of the secretome of Trichoderma reesei grown on unconventional carbon source. Microb Cell Fact 2011; 10:68. [PMID: 21861877 PMCID: PMC3179704 DOI: 10.1186/1475-2859-10-68] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2011] [Accepted: 08/23/2011] [Indexed: 12/17/2022] Open
Abstract
Background Spent hydrolysates from bioethanolic fermentation processes based on agricultural residues have potential as an abundant and inexpensive source of pentose sugars and acids that could serve as nutrients for industrial enzyme-producing microorganisms, especially filamentous fungi. However, the enzyme mixtures produced in such media are poorly defined. In this study, the secretome of Trichoderma reesei Rut C-30 grown either on a spent hydrolysate model medium (SHMM) or on a lactose-based standard medium (LBSM) was explored using proteomics. Results Our results show that both the SHMM and LBSM serve as excellent growth media for T. reesei Rut C-30. In total, 52 protein spots on 2-D gels were identified by using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) and electrospray ionization liquid chromatography tandem mass spectrometry (ESI-LC MS/MS). As expected, a considerable number of the identified proteins were related to the degradation of lignocellulosic biomass. The enzyme production profiles in the two media were similar, but β-glucosidase and β-galactosidase were only produced in LBSM. The main cellobiohydrolases (Cel7A/Cel6A) and endoglucanases (Cel7B/Cel5A) were identified in both media and the cellobiohydrolases, i.e. Cel7A and Cel6A, were the most abundant cellulolytic enzymes. Moreover, both media can also serve as a potent inducer of xylanolytic enzymes. Several key enzymes involved in sugar assimilation and regulation of cellulase formation were identified, and were found to be differentially expressed in the two growth media. Conclusions This study not only provides a catalogue of the prevalent proteins secreted by T. reesei in the two media, but the results also suggest that production of hydrolytic enzymes using unconventional carbon sources, such as components in spent hydrolysates, deserves further attention in the future.
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Affiliation(s)
- He Jun
- Department of Chemistry, Umeå University, Umeå, Sweden.
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L-arabitol is the actual inducer of xylanase expression in Hypocrea jecorina (Trichoderma reesei). Appl Environ Microbiol 2011; 77:5988-94. [PMID: 21742908 DOI: 10.1128/aem.05427-11] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The saprophytic fungus Hypocrea jecorina (anamorph, Trichoderma reesei) is an important native producer of hydrolytic enzymes, including xylanases. Regarding principles of sustainability, cheap and renewable raw materials, such as d-xylose (the backbone monomer of xylan), have been receiving increasing attention from industries. Recently, it was demonstrated that small (0.5 to 1 mM) amounts of d-xylose induce the highest expression of xylanase in H. jecorina. However, it was also reported that active metabolism of d-xylose is necessary for induction. In this report, we demonstrate that xylitol, the next intermediate in the pentose pathway after d-xylose, does not trigger transcription of xylanase-encoding genes in H. jecorina QM9414. The highest level of transcription of xylanolytic enzyme-encoding genes occurred in an xdh1 (encoding a xylitol dehydrogenase) deletion strain cultured in the presence of 0.5 mM d-xylose, suggesting that a metabolite upstream of xylitol is the inducer. The expression levels of xylanases in an xdh1-lad1 double-deletion strain were lower than that of an xdh1 deletion strain. This observation suggested that l-xylulose is not an inducer and led to the hypothesis that l-arabitol is the actual inducer of xylanase expression. A direct comparison of transcript levels following the incubation of the H. jecorina parental strain with various metabolites of the pentose pathway confirmed this hypothesis. In addition, we demonstrate that xyr1, the activator gene, is not induced in the presence of pentose sugars and polyols, regardless of the concentration used; instead, we observed low constitutive expression of xyr1.
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Kanna M, Yano S, Inoue H, Fujii T, Sawayama S. Enhancement of β-xylosidase productivity in cellulase producing fungus Acremonium cellulolyticus. AMB Express 2011; 1:15. [PMID: 21906369 PMCID: PMC3222308 DOI: 10.1186/2191-0855-1-15] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Accepted: 06/30/2011] [Indexed: 11/10/2022] Open
Abstract
Enzymatic hydrolysis is one of the most important processes in bioethanol production from lignocellulosic biomass. Acremonium cellulolyticus is a filamentous fungus with high cellulase production but productivity of hemicellulase, especially β-xylosidase, is lower than other filamentous fungi. We identified 2.4 Kb β-xylosidase gene in the A. cellulolyticus genome sequence information and it encoded 798 amino acids without introns. To enhance hemicellulase productivity in A. cellulolyticus, we transformed this fungus with the identified β-xylosidase gene driven by the cellobiohydrolase Ι (cbh1) promoter, using the protoplast-polyethyleneglycol (PEG) method, and obtained a transformant, YKX1. Hydrolysis rate of xylooligosaccharides was more than 50-fold higher using culture supernatant from YKX1 than that from the parental strain, Y-94. Total cellulase activity (measured by filter paper assay) in YKX1 was not affected by the cbh1 promoter used for expression of β-xylosidase, and induced by cellulose. Since YKX1 can produce larger amount of β-xylosidase without affecting cellulase productivity, it is considered to be beneficial for practical monosaccharide recoveries from lignocellulosic biomass.
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Rojas-Rejón OA, Poggi-Varaldo HM, Ramos-Valdivia AC, Martínez-Jiménez A, Cristiani-Urbina E, de la Torre Martínez M, Ponce-Noyola T. Production of cellulases and xylanases under catabolic repression conditions from mutant PR-22 of Cellulomonas flavigena. J Ind Microbiol Biotechnol 2010; 38:257-64. [DOI: 10.1007/s10295-010-0821-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2010] [Accepted: 07/26/2010] [Indexed: 11/29/2022]
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