Asian Journal of Microbiology and Biotechnology

The study produced α-amylase from a bacterium isolated from decayed plantain peel with a view to obtaining a microorganism candidate for the production of the enzyme for industrial uses. The unripe plantains were purchased and allowed to decay, serially diluted and plated on agar plate. Isolates from the plates were screened for amylase activity using starch agar. The bacterium with the highest amylase activity was selected for enzyme production. Optimal conditions for enzyme production by the bacterium were determined. Five strains of Bacillus sp. were isolated from the decayed plantain peel. They were identified as Bacillus sp. The organism with highest amylolytic activity was further identified molecularly as Bacillus brevis RD8. The peak of amylase activity was at 32h of incubation (174 Units/ml). The optimum pH and temperature for the production of Bacillus brevis RD8 α-amylase is 7 and 35°C respectively. The result revealed that 1.5% plantain peel composition of the enzyme production medium produced the highest enzyme activity of 103.2 ± 1.3 Units/ml. Peptone as a nitrogen source gave a better enzyme activity of 185.5 ± 3.2 Units/ml. Soluble starch as a carbon source gave the highest activity of 164.5 ± 4.0 Units/ml. The study concluded that α-amylase synthesized by Bacillus brevis RD8 is moderately thermostable and able to degrade many cheap raw starches and can therefore find applications in the food industry.