Production of Amylase in a Corn Steep Liquor-Soya Bean Meal Medium by a Strain of Baccillus Stearothermophilus

Abstract

Corn grains (Zea mays, yellow variety) were steeped in water for 10 days and parameters such as pH, protein, amino acids, lipid, soluble starch and reducing sugar content were measured at 2 day intervals in the steep liquor. The pH decreased from 7.0 to 5.4 during the steeping period. The protein content ranged between 1.25 and 11.25 mg/ml; lipid content ranged between 0.3 and 3.2 mg/ml. The soluble starch concentration increased from 212 to 530 mg/ml, and the reducing sugar concentration reduced from 2.54 to 1.13 mg/ml. A fermentation medium was compounded from 2-day old liquor to cultivate an amylolytic strain of Bacillus stearothemophilus. Peak production of amylase occurred at 240 h while the highest cell density occurred at 144 h. Various concentrations of soluble starch (0.5-5%, w/v) and soya bean meal (0.1-0.5 %, v/v) were used in cultivating the organism. The highest amylase activity was recorded with 2 % (w/v) starch, while 0.5 % (v/v) of soya bean meal supported the greatest growth. The medium could be exploited for industrial amylase production.