Bacterial proteases are important enzymes used in detergent, food, leather, and silk industry. The aim of this study was to isolate and characterize industrially important alkaline protease-producing bacteria from a sludge disposal site and tannery waste sediment. Soil samples were collected separately from sludge disposal sites and tannery waste sediments. One-gram soil samples were serially diluted and spread plated on alkaline media (Skim milk agar). A total of 16 bacteria species were isolated and screened for proteolytic activity on skim milk agar based on the zone of proteolysis. Four bacterial isolates showed high proteolytic activity and were selected for the enzymatic study. The isolates were characterized based on biochemical activities using bioMerieux API kits and ABIS online software. The results indicated that the isolated bacteria were E. coli (99.69%), Pseudomonas putrefaciens (Shewanella putrefaciens) (91.61%), Bacillus carboniphilus (92.78%), and Lysinibacillus sphaericus (98.4%). The crude alkaline protease enzyme produced by these bacterial isolates showed promising results for application in dehairing and destaining as detergent additives. Bacillus carboniphilus showed the best activity and was selected as the most potent protease producing bacteria for both dehairing and destaining ability. Soils of sludge disposal sites and sediments around tannery wastes could be good sources for isolating alkaline protease producing bacteria.
Keywords: Alkaline protease, Dehairing, Destaining, Hydrolysis, Sediment