Screening of soil microorganisms for amylase production

Abstract

Soil microbes were isolated to determine their potential to produce amylase. The microbes were isolated and identified from soils of bakery waste, local flourmill waste, using pour plate method. The organism identified includes Bacillus subtilis, Bacillus licheniformis, Aspergillus niger, Aspergillus fumigatus, Escherichia coli, Micrococcus sp., Staphylococcus aureus and Mucor. The organisms were screened for amylase production and only B. licheniformis; B. subtilis, A. niger and A. fumigatus showed positive result to screening. Amylase activity was assayed using 3, 5-Dinitrosalicyclic acid (DNSA) method. All strains yielded high amount of amylase at optimum temperature and pH. Optimum temperature of amylase produced by B. subtilis, B. licheniformis, A. niger, and A. fumigatus was at 700C, 700C, 700C, 400C respectively with amylase activity ranging from 0.00083 0.00457 mg/ml/sec. The optimum pH for all the isolate was pH 7 with amylase activity ranging from 0.000471 0.00457 mg/ml/sec. The data obtained from optimization of amylase activity assay condition was subjected to Pearson Correlation Statistical analysis which showed that the organisms (B. subtilis, B. licheniformis, A. niger, A. fumigatus) have significant growth with moderate temperature but decrease with increase in temperature. Generally, as the incubation time increases enzyme activity increase also increase in pH decreases the enzyme activity except for B. licheniformis. The result obtained reveals that these isolates are good producers of amylase and could be exploited for production of amylase in food, brewery, textile and detergent industry.