Isolation and characterization of amylase producing Bacillus spp. from selected soil sample

Abstract

Amylases are among the most important enzymes and are of great significance in present day industry. Starch degrading bacteria are most important for industries such as food, fermentation, textile and paper. Amylase is a hydrolytic enzyme and in recent years, interest in its microbial production has increased dramatically due to its wide spread use in food, textile, baking and detergent industries. The selected soil samples were obtained (10gm) from Roorkee, Haridware district, Uttarakhand state, India. The collected soil samples were labeled as banana field (A), potato field (B) and sugarcane field (C) respectively. Soil samples were then serially diluted in normal saline and plated on sterile nutrient agar plates. The colonies obtained from higher dilutions were subjected to Gram staining and starch hydrolysis test. All isolated colonies were screened by activity zone techniques with iodine solution. Out of 10 bacterial strains, only 5 bacterial colonies showed positive results for amylase production and out of 5, Bacterial strains, B3 showed widest diameter i.e. 8mm was selected for further study. Different Biochemical tests were used to confirmed the Bacillus sp. Isolated Bacillus sp. (B3) were chosen for amylase potential screening and it has shown maximum zone of clearance on starch agar plates. Bacterial colony yielding positive starch hydrolysis test (Bacillus sp. B3 ) were subjected to Amylase activity test. The amylase activity was also carried with respect to time, temperature and pH of the media in which it was inoculated. The amylase activity decrease from 0.981 to 0.215 U/ml as the incubation time increase from 24 to 72 hours at 35 ±2°C. The amylase activity shown at different temperature from 35 to 45°C has gradual decrease from 0.992 U/ml to 0.545 U/ml. The amylase activity recorded at different pH from 5 to 10. It shows maximum amylase activity at pH 7 (0.998 U/ml). There is increase in amylase activity at basic pH5 = 0.910 U/ml whereas decrease in acidic medium pH10 = 0.089 U/ml.