Eco-Friendly Applications of Bacterial Extracellular Alkaline Protease

Abstract

Among the most important hydrolytic enzymes microbial alkaline protease have been extensively used since the advent of enzymology. It is produce by bacterium either extracellular or intracellular. Isolation and screening of sufficient extracellular alkaline protease producing bacterial strains are of great importance due to its wide spectrum applications in number of industries such as bio-remediation, food industries, leather processing, bio-film degradation, keratin degradation antifungal activity and number of other eco-friendly applications. The various samples, sea water, domestic water sludge, fish market soil and fermented fish were collected and used for enrichment, isolation and screening was done using screening medium and optimization for different physical and chemical parameters were carried out using CYP agar medium. Out of 18 isolates 16 were alkaline protease positive out of those; 4 isolates were able to produce sufficient amount of extracellular alkaline protease. The ratio of zone diameter to colony diameter from 4 isolates ranges from 3.11 to 8.41. Out of four efficient alkaline protease producers B.pumilus P1 showed significant enzyme activity. Optimizations of physical parameters were determined and found to be 72 hours of incubation period, 8.0 to 9.0 pH, 45 0 C incubation period. Optimization of chemical parameters were determined for variety of carbon and nitrogen sources, were found to be 1.5% of glucose, lactose, 2% of sucrose,0.7% of ammonium sulphate, gelatin in case of refined sources. Wheat bran, sugarcane baggase as carbon sources and soya bean meal, cotton stalk gave maximum enzyme activity at 10% concentration. Enzyme obtained from refined sources and crude sources having maximum enzyme activity 16.5U/ml and 8.3U/ml respectively. Crude as well as partially purified enzyme preparations were found to be excellent in dehairing, depilation, of raw leather, degradation of feather, bio-film degradation and antifungal activity.