Optimization of pectinase enzyme production in Aspergillus fumigatus isolated from rotten fruits

Pectinase is one of the most important industrial enzymes which was isolated from a wide variety of microorganisms such as bacteria and filamentous fungi. This enzyme has been usually used in the juice and textile industry. In this study, the isolation and optimization of pectinase-producing fungi on decaying rotten fruits were studied. Isolation and screening of pectinase producing fungi have been done by plate culture on pectin medium and staining with Lugol's iodine solution. The best strain was identified by method of Pitt and Hocking as Aspergillus fumigates. The enzyme production was optimized by application of the factorial design which involves five factors, each at three levels. Five factors were carbon sources (whey, sugar, stevia) and ammonium sulfate, manganese sulfate, temperature, and pH). Pectinase concentration was measured by the Miller method. The results showed that the optimum condition for enzyme production was at 32 °C, PH = 6, 3g / L manganese sulfate, 2.75g / L of ammonium sulfate, 10g / L of each carbon source (whey, stevia, and glucose). Optimum of enzyme production was observed in the presence of 1.328 mg / ml of glucose. Molecular weight of enzyme was obtained about 40 kDa by SDS-PAGE.Discussion and The results demonstrated that this strain could grow in a wide range of carbon sources, PH and temperature. This study indicates that this strain is a good candidate for use in industrial application.