Assessment of cellulase complex secretory capacity of trichoderma strains and morphological and molecular identification of the isolate with the highest enzymatic secretion capacity

Abstract

The bioconversion of lignocellulosic biomass into monomeric sugars is a key economic difficulty hindering the profitable use of plant biomass as energy. The production of cellulase is a main factor in the cellulose hydrolysis. Among the main cellulase producers are the filamentous fungi. Therefore, many efforts have been made in obtaining new microorganisms with high cellulase secretion capacity. The cellulase secretory capacity of 28 isolates of Trichoderma was qualitatively and quantitatively evaluated. The detection of cellulolytic fungi was correlated with both Congo red and the dinitrosalicylic acid reagent methods. Based on qualitatively assays, sixteen of the isolates revealed carboxymethyl cellulose degradation ability, where the Trichoderma POS7 isolate showed the highest increase in filter paper activity, endo-1,4-β-glucanases and β-glucosidases activities (p<0.05) in a short incubation time. This isolate was molecularly identified as Trichoderma koningiopsis, based on internal transcribed spacer sequences. Our results provide new information and reveal new microorganism in the hydrolysis of cellulose material. The phylogenetic analysis revealed close positioning of T. koningiopsis clade with T. viride, T. viridescens and T. petersenii clades in a closely related group, in concordance with the current taxonomic classification of Trichoderma genus.