Production of Fungal β-amylase and Amyloglucosidase on Some Nigerian Agricultural Residues

Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger, Helminthosporium oxysporium, and Penicillium frequestans isolated from common Nigerian agricultural residues like cassava, yam, banana, and plantain peels and brewery spent grains (BSG) were screened for their ability to produce beta-amylase and amyloglucosidase using submerged and solid-state cultivation regimens. Enzyme activity (EU) was determined by estimating the amount of reducing sugars produced as a result of the action of crude enzyme solutions on buffered starch solution. Results showed that A. niger liberated the highest level of beta-amylase (33.2 EU) on plantain peels medium using the static cultivation method, while it produced the highest amount of amyloglucosidase (29.8 EU) on yam peels substrate with solid-state cultivation regimen. Plantain peels favored beta-amylase production more than the other tested wastes supporting production of 33.2 and 9.8 EU of the enzyme in A. niger under solid-state and static cultivation methods, respectively. Yam peels favored liberation of 15.3 EU amyloglucosidase in each of the solid-state and the static cultivation regimens. Production of beta-amylase on BSG, yam, banana, and plantain peels was not significantly facilitated by static cultivation method (p > 0.05), while solid-state cultivation regimen favored amyloglucosidase production on cassava peels and BSG (p < 0.05). Optimal production yield of beta-amylase and amyloglucosidase were 16.6 and 14.9 EU g(-1) on plantain and yam waste media by the mold.