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.

Solid-State Fermentation with Trichoderma reesei for Cellulase Production

Abstract: Cellulase yields of 250 to 430 IU/g of cellulose were recorded in a new approach to solid-state fermentation of wheat straw with Trichoderma reesei QMY-1. This is an increase of ca. 72% compared with the yields (160 to 250 IU/g of cellulose) in liquid-state fermentation reported in the literature. High cellulase activity (16 to 17 IU/ml) per unit volume of enzyme broth and high yields of cellulases were attributed to the growth of T. reesei on a hemicellulose fraction during its first phase and then on a cellulose fraction of wheat straw during its later phase for cellulase production, as well as to the close contact of hyphae with the substrate in solid-state fermentation. The cellulase system obtained by the solid-state fermentation of wheat straw contained cellulases (17.2 IU/ml), β-glucosidase (21.2 IU/ml), and xylanases (540 IU/ml). This cellulase system was capable of hydrolyzing 78 to 90% of delignified wheat straw (10% concentration) in 96 h, without the addition of complementary enzymes, β-glucosidase, and xylanases.

Tracking the roots of cellulase hyperproduction by the fungus Trichoderma reesei using massively parallel DNA sequencing

Abstract: Trichoderma reesei (teleomorph Hypocrea jecorina) is the main industrial source of cellulases and hemicellulases harnessed for the hydrolysis of biomass to simple sugars, which can then be converted to biofuels such as ethanol and other chemicals. The highly productive strains in use today were generated by classical mutagenesis. To learn how cellulase production was improved by these techniques, we performed massively parallel sequencing to identify mutations in the genomes of two hyperproducing strains (NG14, and its direct improved descendant, RUT C30). We detected a surprisingly high number of mutagenic events: 223 single nucleotides variants, 15 small deletions or insertions, and 18 larger deletions, leading to the loss of more than 100 kb of genomic DNA. From these events, we report previously undocumented non-synonymous mutations in 43 genes that are mainly involved in nuclear transport, mRNA stability, transcription, secretion/vacuolar targeting, and metabolism. This homogeneity of functional categories suggests that multiple changes are necessary to improve cellulase production and not simply a few clear-cut mutagenic events. Phenotype microarrays show that some of these mutations result in strong changes in the carbon assimilation pattern of the two mutants with respect to the wild-type strain QM6a. Our analysis provides genome-wide insights into the changes induced by classical mutagenesis in a filamentous fungus and suggests areas for the generation of enhanced T. reesei strains for industrial applications such as biofuel production.

A novel, small endoglucanase gene, egl5, from Trichoderma reesei isolated by expression in yeast.

Abstract: Summary A method is presented for the isolation of genes encoding hydrolytic enzymes without any knowledge of the corresponding proteins. cDNA made from the organism of interest is cloned into a yeast vector to construct an expression library in the yeast Saccharomyces cerevisiae. Colonies producing hydrolytic enzymes are screened by activity plate assays. In this work, we constructed a yeast expression library from the filamentous fungus Trichoderma reesel and isolated a new β-1,4-endoglucanase gene on plates containing β-glucan. This gene, eg15, codes for a previously unknown small protein of 242 amino acids. Despite its small size, the protein contains two conservative domains found in Trichoderma cellulases, namely the cellulose-binding domain (CBD) and the iinker region that connects the CBD to the catalytic core domain. Molecular modelling of the EGV CBD revealed some interesting structural differences compared to the CBD of the major celluiase CBHI from T. reesei. The catalytic core of EGV is unusually small for a ceiiulase and represents a new family of ceilulases (Family K) and of glycosyl hydrolases (Famlly 45) together with the endoglucanase B of Pseudomonas fluorescens and the endoglucanase V of Humicola insolens on the basis of hydrophobic ciuster anaiysis.

Crystal structure of the catalytic domain of a thermophilic endocellulase.

Abstract: One way to improve the economic feasibility of biomass conversion is to enhance the catalytic efficiency of cellulases through protein engineering. This requires that high-resolution structures of cellulases be available. Here we present the structure of E2cd, the catalytic domain of the thermophilic endocellulase E2 from Thermomonospora fusca, as determined by X-ray crystallography. The structure was solved by multiple isomorphous replacement at 2.6-A resolution and has been refined at 1.8-A resolution to an R-value of 18.4% for all reflections between 10- and 1.8-A resolution. The fold of E2cd is based on an unusual parallel beta-barrel and is equivalent to the fold determined for the catalytic domain of cellobiohydrolase II, an exocellulase from Trichoderma reesei [Rouvinen et al. (1990) Science 249, 380-385]. The active site cleft of the enzyme, approximately 11 A deep and running the entire length of the molecule, is seen to be completely free for ligand binding in the crystal. A 2.2-A resolution analysis of crystals of E2cd complexed with cellobiose, an inhibitor, shows how cellobiose binds in the active site and interacts with several residues which line the cleft. Catalytic roles are suggested for three aspartic acid residues at the active site. A comparison of the E2cd and CBHIIcd structures reveals a large difference in their active site accessibilities and supports the hypothesis that the main difference between endo- and exocellulases is the degree to which their active sites are accessible to substrate.