Abstract

Five common Nigerian agricultural wastes: cassava peels, yam peels, banana peels, plantain peels, and Brewery Spent Grains (BSG) were formulated into media on which amylolytic fungal strains were isolated. These isolates were subsequently identified, characterized using standard mycological keys and were thereafter employed in production of α-amylase using submerged and solid-state cultivation regimens. Amount of α-amylase in enzyme unit (E.U.) liberated by each mould was quantified by estimating the amount of reducing sugars produced when specified quantity of starch was hydrolyzed after incubation at 40°C with known concentration of enzyme solution. Results showed the amylolytic isolates to be Helminthosporium oxysporium, Aspergillus niger, Aspergillus fumigatus, Aspergillus flavus, andPenicillium frequestans. The mould Helminthosporium oxysporium liberated 10.77 and 10.42 E.U of α-amylase on cassava and yam peels media respectively using submerged cultivation method while A. flavus produced 11.94 E.U. of the enzyme on cassava peels with submerged cultivation method. Production of α-amylase on cassava, yam and plantain peels was facilitated by submerged cultivation method. With exception of banana peels substrate, other investigated Nigerian agricultural wastes favoured α-amylase production at different rates.

Key words: Agricultural wastes, submerged cultivation, solid-state cultivation, α-amylase, fungal isolates.