Comparative Characterization and Amylase Activity Assessment of Certain Garden Bacterial Isolates

Background: Microorganisms are the most important sources of enzymes because of their stability and reduced price in production. The enzyme, amylase has a wide spectrum of application in biotechnology including food, fermentation, textile and laundry, paper and pulp industries. As the use of amylase is increased, it is necessary to search for a new source to produce amylase with better productivity in continuous practice. Method: In our present investigation, amylase producing bacteria were screened by starch hydrolysis test as bacteria are more potent in amylase production than other microorganisms. The bacteria were identified by Bergey's manual of systematic bacteriology. Enzyme assay and optimization of enzyme activity were performed by the 3,5-dinitrosalicylic acid method. Results: A total of eight bacterial isolates were identified with starch degrading capabilities and they were presumptively placed in the genus, Bacillus due to their characteristic features. All the isolates have potential for amylase activity. At any temperature (25°C, 35°C, 45°C, 50°C and 55°C), pH (6, 7, 8) and starch concentrations (0.5%, 1% and 1.5%), the highest amylase activity was observed by isolate 1A followed by isolate 2C, 1B, 3A, 4B, 3B, 4A, and 4C. Optimum conditions for the highest amylase activity in our laboratory for isolate 1A was 35°C (4.105 U/ml), pH 6 (3.343 U/ml) and 1.5% starch concentration (4.381 U/ml). Conclusion: Our study reveals that the isolates, collected from garden soil, are good amylase producers and they could be exploited in different industries in optimized conditions.