ISOLATION AND CHARACTERIZATION OF AMYLASE PRODUCING FUNGI FROM BANANA PEEL AND PAPAYA RIND WASTES

Abstract

Efficient biodegradation of starch and lignocellulosic waste materials by fungi or bacteria leads to a number of processes of great economic importance. The present study was undertaken to isolate and characterize amylase producing fungi from banana peel and papaya rind wastes. The screening for amylase fungal isolates was conducted based on zone of inhibition followed by morphological identification of fungal species. The amylase activity was determined for fungal colonies using dinitro salicylic acid method. Optimization of parameters for amylase activity was conducted using different pH, temperature, carbon and nitrogen source and incubation time. Important microbial organisms for amylase production like Aspergillus, Penicillium and Rhizopus were indicated from banana peel and Aspergillus, Penicillium, Rhizopus and Saccharomyces were isolated from papaya rind. The effect of pH on amylase activity of the fungal isolates indicated that the maximum enzyme activity (141.51 U/min) was recorded for Aspergillus papaya rind isolate (PI), followed by Rhizopus PI (124.73 U/min) at pH7. The minimum enzyme activity (96.97) was recorded by Rhizopus BI at the same pH7 indicating that the optimum pH for the amylase activity was at around pH7 (neutral). The effect of temperature on amylase activity of the fungal isolates indicated that the maximum enzyme activity (206.05U/min) was recorded for Aspergillus PI and Aspergillus BI (150.06U/min) at 500c.The maximum enzyme activity for Rhizopus PI (150.54 U/min) and for Rhizopus BI (121.82 U/min) at 40oc. The effect of incubation time on amylase activity of the fungal isolates indicated that the maximum enzyme activity (217.51 U/min) was recorded for Aspergillus PI, and Aspergillus BI (116.34 U/min) at 72 hours incubation time while the maximum enzyme activity for Rhizopus PI (154.26 U/min) and Rhizopus BI (112.30 U/min) during 96 hours incubation time. The effect of carbon supplement on amylase activity of the fungal isolate found that Aspergillus BI has recorded the highest enzyme activity (93.10 U/min) with glucose supplement and Rhizopus BI isolate has recorded maximum enzyme activity (78.87 U/min) with lactose supplement. The effect of carbon source on papaya rind isolate has presented maximum enzyme activity (60.67U/min) with glucose supplement for Aspergillus PI while Rhizopus PI has recorded maximum enzyme activity (62.77 U/min) with lactose supplement. The effect of Nitrogen source on amylase activity of the fungal isolate presented that Aspergillus BI (92.94 U/min) and Rhizopus BI (67.45 U/min). The papaya rind isolate has presented maximum enzyme activity (113.59U/min) for Aspergillus PI and (68.58 U/min) for Rhizopus PI has recorded with peptone supplement. It can be concluded that the Aspergillus spp isolates were found to be superior in amylase activity over other isolates, and the papaya rind fungal isolates superior in the amylase activity than the banana peel fungal isolates. In light of significant enzyme imports, despite the potential in waste materials like banana peels and papaya rinds, this study advocates large-scale production for practical and sustainable utilization.