The Use of Corn Starch for Growth and Production of α-amylase from Bacillus subtilis

摘要

Thirteen thermophilic bacterial strains were isolated from garden soil at NRCRI Umudike Nigeria. One strain was selected based on its ability to produce significant amylolytic activity on nutrient agar medium containing 1% soluble starch. The organism was identified as Bacillus subtilis based on its morphological, biochemical and physiological properties. Maximum amylase activity of 10.4±1.3 U mg~(-1) was obtained on corn starch mineral salts medium on the 3~(rd) day of the 6–day fermentation period which corresponded with the late exponential phase of the organism. Soluble starch mineral salts medium produced 9.40±0.71 U mg~(-1). A pH and temperature optimum of 6.5 and 65℃ respectively were observed when the organism expressed its highest amylase activity. The new strain may offer an attractive source of enzymes for application in food and brewing industries.