ECOLOGICALLY JUSTIFIED METHODS OF SELECTION OF STRAINS OF MICROMYCETES WITH HIGH CELLULASE ACTIVITY

Abstract

The article presents information concerning the established interrelations between a number of ecological and physiological parameters of cultures of soil mycelial fungi and their productive capacity. These interrelations can be used as a basis for individual selection of strains with high lignocellulasic potential. The technological point of expanding the range of cultures with rich enzymatic potential is to create a reserve of strains to be included in complexes of cellulose-degrading microorganisms. This can be used for the destruction of cellulose-containing wastes, as well as for composting processes of crop residues. The paper contains information about original approaches to individual selection and selection of cultures of mycelial fungi obtained on the basis of natural strains collected from gray forest soil extract. The selection criteria were resistance to elevated temperature and enzymatic activity. Cultures were allocated to the Sabouraud medium, and individual colonies were divided. After the sporulation, the generic assignment and then the species of the cultures were determined. Later, monosporous sifting was carried out, and the monosporous cultures were risen, the parameters of which were evaluated. Screening was performed using modified Getchinson’s medium. Cellulase activity was determined at the level of qualitative assessment (using the Congo red indicator). The pigmentation degree of colonies during sporulation was estimated visually. We established positive correlations between the pigmentation intensity of the colony, its thermal stability and enzymatic activity. Having selected three species of promising strains, we studied their enzymatic activity. We assessed the stability of physiological and morphological characteristics and enzymatic activity of cultures to spontaneous dissociation in a series of ten passages. As a result of the research, we developed methods of express selection of promising strains and obtained four promising cultures for inclusion in a complex of decomposers for composting cellulose-containing wastes and crop residues.

Keywords

• selection of microorganisms
• individual selection
• ecology of mycelial fungi
• bioconversion of wastes
• enzymes
• cellulose