Activity of ?2-Amylase in Some Fungi StrainsIsolated from Forest Soil in South-WesternNigeria

摘要

Aims: The aim of this study was to isolate fungi species from Omo natural forest soil in Ogun State of Nigeria and study the amylases from the fungi species which are digestive enzymes that hydrolyze glycosidic bonds in starch to glucose, maltose, maltotriose and dextrin; and in particular determine the activities of β-amylase from the forest soil. Study Design: Nine different species of fungi were isolated from the Omo natural forest reserve soil (Gonatobotrrys simplex, Aspergillus niger, Spiromyces minutus, Aspergillus flavus, Articulospora inflata, Botrytis cenera, Penicillium italicum, Aspergillus fumigatus and Aspergillus flavus). Four species of the fungi (Aspergillus flavus, Aspergillus niger, Aspergillus fumigatus and Penicillum italicum) exhibited amylolytic activities maximally were obtained and screened for the production of beta-amylase (1,4-α-D-glucan maltohydrolase) for five days in liquid medium using 2% starch as carbon source. All the strains of fungi produced β-amylase optimally within the first 24 hours with progressive decreased production as the days gone by. Place and Duration of Study: Department of Biochemistry, Federal University of Technology, Akure, Ondo State, Nigeria, between February 2010 and March 2011.Methodology: We isolated many fungi species from forest reserve soil, four species (Aspergillus flavus, Aspergillus niger, Aspergillus fumigantus and Penicillum itallicum) were identified and assayed for β-amylase activity. Results: All the organisms produced β-amylase activity favorably at 40oC; all were observed to be thermally stable at between 30oC and 40oC with optimal pH in alkaline medium between pH 7.00 and 9.00. Conclusion: The results obtained in this study however showed that all the fungi strains are promising sources of β-amylase for potential applications in food and pharmaceutical industries and for biotechnological and industrial applications.