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.

Factors influencing glycosylation of Trichoderma reesei cellulases. II: N-glycosylation of Cel7A core protein isolated from different strains

Abstract: A systematic analysis of the N-glycosylation of the catalytic domain of cellobiohydrolase I (Cel7A or CBH I) isolated from several Trichoderma reeseistrains grown in minimalmedia was performed. Using a combination of chromatographic, electrophoretic, and mass spectrometric methods, the presence of glucosylated and phosphorylated oligosaccharides on the three N-glycosylation sites of Cel7A core protein (from T. reesei strains Rut-C30 and RL-P37) confirms previous findings. With N-glycans isolated from other strains, no end-capping glucose could be detected. Phosphodiester linkages were however found in proteins from each strain and these probably occur on both the a1-3 and the a1-6 branch of the highmannose oligosaccharide tree. Evidence is also presented for the occurrence of mannobiosyl units on the phosphodiester linkage. Therefore the predominant N-glycans on Cel7A can be represented as (ManP)0‐1GlcMan7‐8GlcNAc2 for the hyperproducing Rut-C30 and RL-P37 mutants and as (Man1‐2P)0‐1‐2Man5‐6‐7GlcNAc2 for the wild-type strain and the other mutants. As shown by ESI-MS, random substitution of these structures on the N-glycosylation sites explains the heterogeneous glycoform population of the isolated core domains. PAG-IEF separates up to five isoforms, resulting from posttranslational modification of Cel7A with mannosyl phosphodiester residues at the three distinct sites. This study clearly shows that posttranslational phosphorylation of glycoproteins is not atypical for Trichoderma sp. and that, in the case of the Rut-C30 and RL-P37 strains, the presence of an end-capped glucose residue at the a1-3 branch apparently hinders a second mannophoshoryl transfer.

Proteomic analysis of the biomass hydrolytic potentials of Penicillium oxalicum lignocellulolytic enzyme system

Abstract: The mining of high-performance enzyme systems is necessary to develop industrial lignocellulose bioconversion. Large amounts of cellulases and hemicellulases can be produced by Penicillium oxalicum. Hence, the enzyme system of this hypercellulolytic fungus should be elucidated to help design optimum enzyme systems for effective biomass hydrolysis. The cellulolytic and xylanolytic activities of an SP enzyme system prepared from P. oxalicum JU-A10 were comparatively analyzed. Results indicated that the fungus possesses a complete cellulolytic-xylanolytic enzyme system. The cellobiohydrolase- and xylanase-specific activities of this system were higher than those of two other enzyme systems, i.e., ST from Trichoderma reesei SN1 and another commercial preparation Celluclast 1.5L. Delignified corncob residue (DCCR) could be hydrolyzed by SP to a greater extent than corncob residue (CCR). Beta-glucosidase (BG) supplemented in SP increased the ability of the system to hydrolyze DCCR and CCR, and resulted in a 64 % decrease in enzyme dosage with the same glucose yield. The behaviors of the enzyme components in the hydrolysis of CCR were further investigated by monitoring individual enzyme dynamics. The total protein concentrations and cellobiohydrolase (CBH), endoglucanase (EG), and filter paper activities in the supernatants significantly decreased during saccharification. These findings were more evident in SP than in the other enzyme systems. The comparative proteomic analysis of the enzyme systems revealed that both SP and ST were rich in carbohydrate-degrading enzymes and multiple non-hydrolytic proteins. A larger number of carbohydrate-binding modules 1 (CBM1) were also identified in SP than in ST. This difference might be linked to the greater adsorption to substrates and lower hydrolysis efficiency of SP enzymes than ST during lignocellulose saccharification, because CBM1 not only targets enzymes to insoluble cellulose but also leads to non-productive adsorption to lignin. Penicillium oxalicum can be applied to the biorefinery of lignocellulosic biomass. Its ability to degrade lignocellulosic substrates could be further improved by modifying its enzyme system on the basis of enzyme activity measurement and proteomic analysis. The proposed strategy may also be applied to other lignocellulolytic enzyme systems to enhance their hydrolytic performances rationally.

Partition of enzymes between the solvent and insoluble substrate during the hydrolysis of lignocellulose by cellulases

Abstract: The interfacial and interphasic behavior of enzyme plays an important role in heterologous biocatalysis, such as the enzymatic hydrolysis of lignocellulose. The solid-solution partition of the major cellulases from a highly effective Trichoderma reesei cellulolytic system was evaluated during the enzymatic cellulolysis of a pretreated corn-stover substrate. Upon mixing with the insoluble substrate, almost all of the enzymes (including CBH-I, CBH-II, EG-I, EG-II, and BG) were adsorbed, as shown by the protein and activity assay of the solution fraction. No significant desorption was detected during as well as after the cellulolysis, indicating the enzymes’ ability to function at the lignocellulose surface. The adsorption was attributed to the specific binding to and activating of cellulose during the cellulolysis, and to the non-specific binding to lignin, particularly after the cellulolysis. The presence of several representative cellulolysis enhancers, substances capable of enhancing the cellulase action on lignocellulosic substrate, led to a significant desorption of the adsorbed cellulases. The effect might be related to the enhancing effect of these substances on the cellulases.