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Trichoderma reesei

About: Trichoderma reesei is a research topic. Over the lifetime, 3832 publications have been published within this topic receiving 152877 citations. The topic is also known as: Trichoderma reesi.


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Journal ArticleDOI
TL;DR: Genetic expression of genes encoding enzymes involved in xylan degradation and two endoglucanases involved in cellulose degradation was studied at the mRNA level in the filamentous fungus Aspergillus niger, indicating that transcriptional regulation by XlnR goes beyond the genes encoding xylanolytic enzymes and includes regulation of two endglucanase-encoding genes.
Abstract: The two most abundant structural polysaccharides in nature are cellulose and the hemicellulose xylan, which are closely associated in plant cell walls (4). Filamentous fungi, particularly Aspergillus and Trichoderma species, are well-known and efficient producers of both cellulolytic and hemicellulolytic enzymes. The cellulase degradation system of these organisms consists of three classes of enzymes (2): endoglucanases (EC 3.2.1.4), cellobiohydrolases (EC 3.2.1.91), and β-glucosidases (EC 3.2.1.21). Members of all of these classes are necessary to degrade cellulose, a homopolymer of β-1,4-linked d-glucose. Xylan, however, is a heterogeneous polymer with a backbone consisting of β-1,4-linked d-xylose residues, which can be substituted at the C-2 and C-3 positions with various residues, such as acetic acid, α-l-arabinofuranose, (4-o-methyl)glucuronic acid, ferulic acid, and p-coumaric acid (5). Due to this heterogeneous composition, a more complex set of enzymes is required for xylan degradation. The following enzymes have been found to be necessary during the cooperative process of xylan breakdown: endoxylanase (EC 3.2.1.8), β-xylosidase (EC 3.2.1.37), acetylxylan esterase (EC 3.1.1.72), α-l-arabinofuranosidase (EC 3.2.1.55), arabinoxylan arabinofuranohydrolase, β-glucuronidase (EC 3.2.1.139), feruloyl esterase, and p-coumaroyl esterase (3). The expression of cellulose- and xylan-degrading enzymes by Aspergillus and Trichoderma species has been studied extensively at the cellular level (1, 20, 21, 25). It has been shown that xylanase- and cellulase-encoding genes are regulated at the transcriptional level (10, 23, 31, 43). In the presence of d-glucose the genes are not expressed, and it has been shown that the carbon catabolite repressor protein CreA is involved in transcriptional repression of xylanase-encoding (10) and arabinase-encoding (38) genes in Aspergillus species. It has been demonstrated that in Trichoderma reesei the CreA counterpart Cre1 causes repression of transcription of cellulase-encoding (22, 23) and xylanase-encoding (30, 31) genes. However, far less is known about the mechanism by which cellulase- and xylanase-encoding genes are induced. The inducing abilities of various saccharides have been tested, and some saccharides induce the synthesis of both xylanases and cellulases (10, 21, 31, 37, 48). Nevertheless, on the basis of biochemical data (1, 20, 21) and mRNA expression analysis data (23, 31), a separate induction mechanism has been proposed for these systems in both Aspergillus and Trichoderma. Recently, a selection system was developed to isolate Aspergillus niger strains having mutations in a transcription factor involved in induction of expression of xylanolytic genes. Complementation of such a mutation by transformation with a plasmid library led to the isolation of the A. niger xlnR gene, which encodes a transcriptional activator of the A. niger xylanolytic system (44). This xlnR gene encodes a zinc binuclear cluster protein, which is a member of the GAL4 family of transcription factors. Isolation of both the xlnR gene and A. niger xlnR loss-of-function mutants provided an opportunity to study the spectrum of genes that are controlled by XlnR at the transcriptional level.

363 citations

Journal ArticleDOI
TL;DR: A whole-cell biocatalyst with the ability to induce synergistic and sequential cellulose-degradation reaction was constructed through codisplay of three types of cellulolytic enzyme on the cell surface of the yeast Saccharomyces cerevisiae, indicating that simultaneous and synergistic saccharification and fermentation of amorphous cellulose to ethanol can be efficiently accomplished.
Abstract: A whole-cell biocatalyst with the ability to induce synergistic and sequential cellulose-degradation reaction was constructed through codisplay of three types of cellulolytic enzyme on the cell surface of the yeast Saccharomyces cerevisiae. When a cell surface display system based on α-agglutinin was used, Trichoderma reesei endoglucanase II and cellobiohydrolase II and Aspergillus aculeatus β-glucosidase 1 were simultaneously codisplayed as individual fusion proteins with the C-terminal-half region of α-agglutinin. Codisplay of the three enzymes on the cell surface was confirmed by observation of immunofluorescence-labeled cells with a fluorescence microscope. A yeast strain codisplaying endoglucanase II and cellobiohydrolase II showed significantly higher hydrolytic activity with amorphous cellulose (phosphoric acid-swollen cellulose) than one displaying only endoglucanase II, and its main product was cellobiose; codisplay of β-glucosidase 1, endoglucanase II, and cellobiohydrolase II enabled the yeast strain to directly produce ethanol from the amorphous cellulose (which a yeast strain codisplaying β-glucosidase 1 and endoglucanase II could not), with a yield of approximately 3 g per liter from 10 g per liter within 40 h. The yield (in grams of ethanol produced per gram of carbohydrate consumed) was 0.45 g/g, which corresponds to 88.5% of the theoretical yield. This indicates that simultaneous and synergistic saccharification and fermentation of amorphous cellulose to ethanol can be efficiently accomplished using a yeast strain codisplaying the three cellulolytic enzymes.

362 citations

Journal ArticleDOI
TL;DR: The results lead to the proposal of a bifunctional organisation of the CBH I: one domain, corresponding to the carboxyterminal, acts as a binding site for insoluble cellulose and the other, localised in the core protein, contains the active (hydrolytic) site.

359 citations

Journal ArticleDOI
Rui Liu1, Ling Chen1, Yanping Jiang1, Zhihua Zhou1, Gen Zou1 
TL;DR: The results illustrate that the CRISPR/Cas9 system is a powerful genome-manipulating tool for T. reesei and most likely for other filamentous fungal species, which may accelerate studies on functional genomics and strain improvement in these filamentous fungi.
Abstract: Filamentous fungi have wide applications in biotechnology. The CRISPR/Cas9 system is a powerful genome-editing method that facilitates genetic alterations of genomes in a variety of organisms. However, a genome-editing approach has not been reported in filamentous fungi. Here, we demonstrated the establishment of a CRISPR/Cas9 system in the filamentous fungus Trichoderma reesei by specific codon optimization and in vitro RNA transcription. It was shown that the CRISPR/Cas9 system was controllable and conditional through inducible Cas9 expression. This system generated site-specific mutations in target genes through efficient homologous recombination, even using short homology arms. This system also provided an applicable and promising approach to targeting multiple genes simultaneously. Our results illustrate that the CRISPR/Cas9 system is a powerful genome-manipulating tool for T. reesei and most likely for other filamentous fungal species, which may accelerate studies on functional genomics and strain improvement in these filamentous fungi.

359 citations

Journal ArticleDOI
TL;DR: The activities of six purified Thermomonospora fusca cellulases and Trichoderma reesei CBHI and CBHII were determined on filter paper, swollen cellulose, and CMC.
Abstract: The activities of six purified Thermomonospora fusca cellulases and Trichoderma reesei CBHI and CBHII were determined on filter paper, swollen cellulose, and CMC. A simple method to measure the soluble and insoluble reducing sugar products from the hydrolysis of filter paper was found to effectively distinguish between exocellulases and endocellulases. Endocellulases produced 34% to 50% insoluble reducing sugar and exocellulases produced less than 8% insoluble reducing sugar. The ability of a wide variety of mixtures of these cellulases to digest 5.2% of a filter paper disc in 16 h was measured quantitatively. The specific activities of the mixtures varied from 0.41 to 16.31 micromol cellobiose per minute per micromole enzyme. The degree of synergism ranged from 0.4 to 7.8. T. reesei CBHII and T. fusca E3 were found to be functionally equivalent in mixtures. The catalytic domains (cd) of T. fusca endocellulases E2 and E5 were purified and found to retain 93% and 100% of their CMC activity, respectively, but neither cd protein could digest filter paper to 5.2%. When E2cd and E5cd were substituted in synergistic mixtures for the native proteins, the mixtures containing E2cd retained 60%, and those containing E5cd retained 94% of the original activity. Addition of a beta-glucosidase was found to double the activity of the best synergistic mixture. Addition of CBHI to T. fusca crude cellulase increased its activity on filter paper 1.7-fold.

353 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202373
2022177
2021134
2020141
2019138
2018142