New strains of basidiomycetes for industrial conversion of lignocellulosic materials

Abstract

Here we characterize newly isolated basidiomycetes strains and describe biotechnological procedure of purification of lignocellulolytic enzyme complex from their liquid culture. Among 61 basidiomycetes strains spanning over 18 species of 17 generawe selected and explored 4 new cellulase-producing strains of Basidiomycetes. For the latter, determined optimal conditions for synthesis of cellulases (temperature and initial pH of medium), the dynamics of cellulolytic enzyme activity in the culture filtrates, optimal composition of the culture medium on sources of nitrogen and carbon. As a result, we developed a method of purifying enzymatic preparations of cellulases from the cultural medium of basidiomycetes. A fundamentally new to this method is the elution of cellulases from the liquid medium of basidiomycetes. Applying our method allows purification of the enzymatic preparations with a high degree of purification within 3 stages (salting out the proteins, dialysis, and gel chromatography). With this method of obtaining cellulase preparations, we obtained original products of basidiomycetes strains Irpex lacteus К-1, А-Дон-02, Д-1 and Daedaleopsis confragosa f. confragosa AnSc-1. Further, we compared some basic physical and chemical properties (pH- and thermolability, pH- and thermostability) and associated enzymatic activities of cellulases derived from the cultural liquids of basidiomycetes with the lower fungi’s one both commercial and laboratory origin was conducted. Thus we proved that cellulolytic enzymes from basidiomycetes are more active than those from lower fungi. The cellulases from both basidiomycetes and lower fungi were found to exhibit a number of associated enzymatic activities, but cellulolytic enzymes from basidiomycetes have significantly higher activity of enzymes that act on starch, pectin and lignin.