Asian Journal of Biotechnology and Genetic Engineering

Amylase are enzymes that catalyze the hydrolysis of glycosidic bonds present in starch to release simple sugars and produce different monomeric products. Microbial amylase are essential enzymes compared with animals and plants amylases in industrial applications. Thus, in Eastern Nigeria, pap processing wastes (pap residues) from maize are generated in large amount during pap processing. This study was aimed to isolate, screen and identify potential fungi strains producing amylase from pap processing wastes (pap residue) and also utilize the pap residue for the production of reducing sugar. Fungi were isolated from the residue using standard microbiological procedures. Five (5) samples were collected from different places (Obikabia, Obete, Omoba, Eziama and Umuotuu) in Isiala Ngwa Abia state and were transported to the laboratory using a serial container for each. The samples were allowed to decomposed for 2 weeks. A 10-fold serial dilution were done by suspending 1 g of the sample in 9 ml of sterile distilled water. Thereafter, 0.1 ml dilution of each sample was plated on PDA plate and incubate at room temperature (25° c) for four days during which they were monitored and examined. The isolated fungi were tested for amylolytic activity using 1 ml of iodine solution and soluble starch containing PDA to screen for amylase production. Those that showed hydrolytic activity on the soluble agar were selected and identified microscopically by slide culture technique and lactophenol stain. The amylase activity was determined by submerged fermentation. Out of 21 fungal isolates obtained from pap residue, 15 showed clear zone of hydrolysis. Out of the 15 fungal strains, some were the same fungi but different zone diameters as they were gotten from different places. Those that showed zone of hydrolysis with the corresponding number of fungal strains were; Aspergillus fumigatus (3) Penicillin sp. (2), Mucor sp. (1), Trichophyton terrestre (2), Aspergillus niger (1), Aspergillus flavus (3), Microsporum canis (1), Sporothrix schenckii (1), White mould (1), Fusarium lichenicola (1). Furthermore, the best five fungal isolates with the highest amylolytic potentials were selected for amylase production interms of glucose or reducing sugars released from the sweet potato peel during submerged fermentation. They include; Aspergillus fumigatus, Sporothrix schenckii, Trichophyton terrestre (E), Aspergillus flavus, Trichophyton terrestre (O). Among them, Aspergillus flavus had the highest glucose concentration at 8.387 mg\ml after 120 hrs of incubation. This result show that pap processing waste (residue) is a good source of amylolytic fungi and equally a good substrate for amylase production interms of glucose.