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.

Hydrolytic properties of two cellulases of Trichoderma reesei expressed in yeast

Abstract: Two cellulases of the filamentous fungus Trichoderma reesei, cellobiohydrolase II (CBHII, EC 3.2.1.91) and endoglucanase I (EGI, EC 3.2.1.4), produced in recombinant strains of the yeast Saccharomyces cerevisiae, were tested in the hydrolysis of cellulose, xylan and other polymeric substrates. Both enzymes were active against unsubstituted, insoluble cellulose. CBHII had greater activity than EGI against crystalline cellulose, whereas in the case of amorphous substrate the order was reversed. Evidence for synergism was obtained when mixtures of the two enzymes were used with a constant total protein dosage. The EGI was also active against soluble substituted cellulose derivatives, whereas the activity of CBHII against these substrates was insignificant. Both enzymes were active against barley (1-->3,1-->4)-beta-glucan, but were inactive against (1-->3,1-->6)-beta-glucan (laminarin). An apparent low mannan-degrading activity of EGI against locust-bean (Ceratonia siliqua) gum galactomannan was not confirmed when homopolymeric mannan was used as substrate in a prolonged hydrolysis test. EGI exhibited considerably greater activity against insoluble, unsubstituted hardwood xylan than against amorphous cellulose. Soluble 4-O-methyl-glucuronoxylan was also attacked by EGI, although to a somewhat lesser extent than the unsubstituted xylan. By comparison with two purified xylanases of T. reesei, EGI produced xylo-oligosaccharides with a longer mean chain length when acting on both substituted and unsubstituted xylan substrates. CBHII was inactive against xylan.

Rapid transformation of high cellulase-producing mutant strains of Trichoderma reesei by microprojectile bombardment.

Abstract: Intact conidia of three industrially relevant strains of Trichoderma reesei were effectively transformed by particle bombardment. Transformations were carried out individually with plasmids carrying either the fungal amdS or bacterial hph gene as a selectable marker and by cotransformation with both plasmids. Transformant yields with single plasmids were up to 11 stable transformants per µg DNA at the bombardment distance of 6 cm. Mitotic stability of the transformants was 75–100% and the cotransformation efficiency averaged 92% when the first selection was performed on hygromycin B plates. The entire procedure could be completed in 1 week with the hph marker.

Cloning and Expression of Trichoderma reesei Cellobiohydrolase I in Pichia pastoris

Abstract: Pichia pastoris was transformed with the Trichoderma reesei cbh1 gene, and the recombinant enzyme was purified and analyzed kinetically and by circular dichroism The P pastoris rCBH I was recognized by MoAb raised to T reesei CBH I but was found in multiple molecular weight species on SDS-PAGE gels Carbohydrate content determination and SDS-PAGE western analysis indicated that the recombinant protein was hyperglycosylated, although a species very similar in molecular weight to the T reesei enzyme could be isolated chromatographically The P pastoris rCBH I also demonstrated activity toward soluble and insoluble substrates (ie, pNPL and Sigmacell), although at a level significantly lower than the wild-type enzyme More seriously, the yeast-expressed enzyme showed non-wild-type secondary structure by circular dichroism We conclude that P pastoris may not serve as an adequate host for the site-directed mutagenesis of T reesei CBH I

Mathematical modeling and optimization of cellulase protein production using Trichoderma reesei RL-P37.

Abstract: The enzyme cellulase, a multienzyme complex made up of several proteins, catalyzes the conversion of cellulose to glucose in an enzymatic hydrolysis-based biomass-to-ethanol process. Production of cellulase enzyme proteins in large quantities using the fungus Trichoderma reesei requires understanding the dynamics of growth and enzyme production. The method of neural network parameter function modeling, which combines the approximation capabilities of neural networks with fundamental process knowledge, is utilized to develop a mathematical model of this dynamic system. In addition, kinetic models are also developed. Laboratory data from bench-scale fermentations involving growth and protein production by T. reesei on lactose and xylose are used to estimate the parameters in these models. The relative performances of the various models and the results of optimizing these models on two different performance measures are presented. An approximately 33% lower root-mean-squared error (RMSE) in protein predictions and about 40% lower total RMSE is obtained with the neural network-based model as opposed to kinetic models. Using the neural network-based model, the RMSE in predicting optimal conditions for two performance indices, is about 67% and 40% lower, respectively, when compared with the kinetic models. Thus, both model predictions and optimization results from the neural network-based model are found to be closer to the experimental data than the kinetic models developed in this work. It is shown that the neural network parameter function modeling method can be useful as a "macromodeling" technique to rapidly develop dynamic models of a process.