Utilization of oilseed residues and oat bran as substrates for Beta-glucosidase production by Zygomycetous fungi

Abstract

Utilization of agro- and food-industrial residues has special importance today. One possible way of the applications is the production of industrially interesting microbial hydrolases, for which, solid-state fermentation is a low-cost and environmental friendly biotechnological technique. Since most filamentous fungi are able to biodegrade the cellulosic content of these natural materials, high-yield production of extracellular P-glucosidases can be obtained during the fermentation. In this study, zygomycetous fungal strains representing Rhizomucor miehei, Rhizopus stolonifer, Mucor corticolus, Mortierella echinosphaera and Umbelopsis autotrophica were grown in solid cultures containing various oilseed residues and oat bran as carbon sources to assess the production of their P-glucosidases. Among the oilseed residues, pumpkin seed proved to be the best inductor for P-glucosidase activity. Enzyme production of R. miehei and U. autotrophica was further enhanced when oat bran was used as support. Effect of minerals salts on the enzyme yield was also assayed, in which P-glucosidase production of the investigated strains was generally stimulated after moisturizing the substrates by mineral salt solution.