A Combination of Solid Mandels Medium, CMC, and Congo Red Technique for Rapid, Sensitive and Reproducible Screening of Cellulase-Producing Fungi

Abstract

The bioconversion of lignocellulosic biomass into monomeric sugars, by the action of cellulase enzymes, is the main economic problem hindering the profitable use of this abundant source of energy. Trichoderma genus is important biotechnologically due to their ability to produce a wide spectrum of cellulase enzymes and bioactive compounds. There are different techniques to detected qualitative and quantitative cellulase enzymatic secretion of fungal isolates. In this work, we have analyzed the cellulase secretion from four isolates of Trichoderma genus by qualitative and quantitative assays, with the aim to detect a rapid, sensitive and reproducible way for screening cellulase-producing fungi. Two solid medium in three conditions of pH: 3.5, 4.5 and 5.5 and two incubation time were assayed to evaluate the qualitative enzymatic secretion of fungal isolates. The synergic effect of cellulase complex was quantitatively determined by filter paper activity. The correlation between qualitative screening with Congo red technique and quantitative screening withthe DNS reagent method had already been reported, but not reported the composition of the medium to use for it.In this study, we could standardize a solid medium to detect qualitative cellulase activities with Mandels medium as a nitrogen complex at pH 4, CMC as only carbon source and Congo red technique. This method was rapid, sensitive and reproducible way for screening cellulase-producing fungi.