Screening of Cellulolytic and Amyloytic Fungi Associated with Corncobs in Refuse Dumps Within Jos, Nigeria

Abstract

Screening of cellulolytic and amylolytic fungi that colonize corncobs collected from fifteen refuse dumps in Jos Metropolis, Nigeria was undertaken. The samples were cultured on Potato Dextrose Agar and the fungi were isolated and identified. The isolates were then sub-cultured on Modified Starch Agar and Modified Cellulose Agar to determine their amylase- and cellulase producing abilities respectively. The starch-iodine reaction test was used to determine amylase activity while cellulase activity of the organisms was measured using the radial diameter of their colonies. The organisms were further cultured on modified agar prepared using various cellulosic wastes such as paper, cornstalk and wood sawdust. A mean fungal count of 1.17×106 cfu/g was obtained for the corncobs, showing no significant difference between the fungal loads in the locations (P≥0.05). A total of 15 different fungi and an actinomycetes were isolated. They were : Streptomyces sp. (actinomycetes) (15.93%), Aspergillus sp. (14.16%), Rhizopus sp. (11.50%), Mucor sp. (10.62%), Geotrichum sp. (9.74%), Trichophyton sp. (8.85%), Penicillium sp. (7.08%), Trichoderma sp. (6.2%), Microsporum sp. (5.31%), Fusarium sp. (4.43%), Chaetomium sp. (1.77%), Monilia sp. (1.77%), Nocardia sp. (0.88%), Aureobasidium sp. (0.88%), and Madurella sp. (0.88%) respectively with the percentage frequency of occurrence in parenthesis. While 8 (53.33%) of the isolated microorganisms had high amylolytic activity, 10 (66.67%) demonstrated cellulolytic activity when grown on modified starch agar and modified cellulose agar respectively. The results of this study implied that a high percentage of cellulolytic and amylolytic fungi could be obtained locally from corncobs and most of the microorganisms isolated hold varied industrial and bioremediation potentials.