Isolation and Characterization of Industrially Important Alkaline Protease Producing Bacteria from Soil of Sludge disposal site and Sediment around Adama City, Ethiopia

Abstract

There are various microorganisms which are capable of producing the alkaline protease enzyme. Among them, bacterial proteases are most important when compared with plants and animals proteases due to their short generation time, cultivate in small space and easy for genetically manipulated to generate new enzymes. Bacterial proteases are the most important enzymes used in laundry, food, leather, and silk industry due to high production capacity and catalytic activity. The aim of this study was to isolate and characterize industrially important alkaline protease producing bacteria from soil of sludge disposal site and sediment around Adama City, Ethiopia. Five hundred gram of each soil samples were collected separately form sludge disposal sites at Adama Science and Technology University waste water treatment plant site and sediment soil at Modjo Tannery Share Company. One gram of soil sample was taken and carried out with serial dilution techniques and spread plate method using alkaline media (Skim milk agar). A total of 16 bacteria species were isolated the soil and screened for proteolytic activity on skim milk agar based on the zone of proteolysis. Four bacterial isolates showed high proteolytic activity were selected for enzymatic study. The isolates were identified by biochemical characterization 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%). Bacillus spp. were the dominant source for alkaline protease production. The crude alkaline protease enzyme produced by different bacterial isolates could promising for the application in the dehairing activity and destaining as detergent additives of which Bacillus carboniphilus was shown best activity. Based on this finding Bacillus carboniphilus was selected as most potent protease producing bacteria for both dehairing activity and destaining ability.