Isolation and Characterization of polygalacturonase producing thermophilic Aspergillus spp. isolated from decayed tomato fruits

In this study, a polygalacturonase-producing fungus was isolated from decaying tomatoes. Based on colony morphology and hyphal characteristics, this fungus has been identified as Aspergillus sp. The fungus was used in solid-state fermentation to produce an acidic polygalacturonase enzyme. The crude extract obtained from solid-state fermentation had an activity of 94.6 U/mL. The enzyme was then purified using ammonium sulphate precipitation and column chromatography. Ammonium sulphate precipitation increased the enzyme's specific activity from 6.89 U/mg to 12.42 U/mg. Sephadex G-200 was used to purify the enzyme 3.58 times, and its specific activity was determined to be 24.66 U/mg. The Sephacryl S-100 column was responsible for achieving a final fold purification of 9.93 and a specific activity of 68.41 U/mg. When polygalacturonic acid was used as a substrate, the purified enzyme showed the best performance. The enzyme's optimum temperature and pH were found to be 55°C and 5, respectively. CaCl ₂ was found to be the best chelating ion for the enzyme. This enzyme is recommended for use in a variety of industrial applications.