ABSTRACT

This study was conducted to screen the most efficient amylase producing Bacillus sp. and compare the methods for the determination of amylase from Bacillus strains. Different strains of Bacillus species were procured from Microbial Type Culture Collection from Microbiology department of Michael Okpara University of Agriculture Umudike and grown on nutrient agar slants at 3 7°C. A total of three bacillus strains were subjected to qualitative determination of amylase activity by plating the three bacillus strains (Bacillus sp A, Bacillus sp B and Bacillus sp) on the Starch agar medium. Among them, the isolate (B) showed the highest zone of clearance of (14mm). The dextrinizing method of enzyme activity using different starch sources at different concentrations viz 2mM, 4mM, 6mM, 8mM and 10mM was determined. Potatoes substrate has the highest starch concentration ranging from 0.49U/ml to 2.66U/ml, while corn substrate has the least starch concentration ranging from 0.38U/ml to 2.44U/ml. The DNSA method of enzyme activity using reducing sugar. The activity of the u-amylase was recorded to be highest when potato is used as substrate with a value of 0.1 3U/ml, whereas least enzyme activity was observed when corn and rice-flake was used as substrate with a value of 0.09 U/ml. The effect of temperature on the enzyme activity carried out at various temperature viz., 10°C, 28°C, 37°C, 50°C and 70°C. It was found to be maximum at 37°C and dropped down from 50°C to 70°C. The effect of pH on amylase production by Bacillus sp. using different starch sources was carried out at various pH viz., 3.0, 5.0, 7.0, 9.0 and 12.0. The activity of the enzyme gradually increased from 3.0 to 7.0 reaching the maximum at pH, and dropped down from 9.0 to 12.0. Further increase in the pH resulted in the decrease in the activity of a-amylase.