T. S. WATHORE AND M.B. PATIL
Abstract
Indigenously isolated Aspergillus furnigatus was found to produce thermostable alkaline proteinase in a medium containing wheat bran after 8 days of incubation at 30°C with initial pH 10. Additional carbon sources like arabinose, pectin and inulin and nitrogen sources such as ammonium nitrate, ammonium phosphate and yeast extract increased enzyme production. Metal ions like K+, Zn41 and Mn++ stimulated the synthesis of proteinase production. However sodium, potassium and ZSM salts of zeolites and EDTA inhibited enzyme synthesis. The partially purified enzyme exhibited broad range of pH stability from pH 9 to pH 11 at 60°C. The optimum pH and temperature was found to be 10.5 and 55°C, respectively. The enzyme was stable at 80°C for 20 minutes. The heavy metal ions like CO, Pb++, Mn++ and Zn++ did not inhibit the enzyme activity. It was stable with the organic solvents like petroleum ether followed by isoamyl alcohol. The partially purified proteinase also exhibited compatibility with detergents. It was found to retain 100% activity with Active wheel and Vim at 37°C for 30 minutes indicating the possible suitability of its exploitation in detergent industries.