The α-Amylase Producing Bacteria From Bishoftu Lakes: Extraction, Purification and Application

Abstract

Objective Alpha-amylase is a crucial hydrolase enzyme that breaks down complex carbohydrates, specifically hydrolyzing starch into sugars (maltose and glucose) and has wide applications in detergent, food, paper, textile, and pharmaceutical industries. This study involved the isolation, characterization and optimization of alpha-amylase-producing bacteria (APB) from Bishoftu lakes, Ethiopia. Methodology Isolation and characterization of bacteria from water and soil samples were conducted using conventional methods. Amylase-producing isolates were screened by starch-hydrolysis test. The best amylase producing bacterial isolates were optimized using different physiological parameters. The crude enzyme activity was further optimized against various enzymological factors, and its activity was measured under the standard enzyme assay protocols. Finally, partial purification of the amylase was carried out using ammonium sulfate precipitation, and the purity was checked using SDS-PAGE. Results A total of 60 APB were isolated; among them, 3 potential isolates were selected and identified as Bacillus cereus (B1W1), Aeromonas rivipollensis (G2W1) and Klebsiella pasteurii (G3W1) via 16S rRNA gene sequence analysis. Glucose was identified as a suitable carbon source, whereas beef extract, tryptone, and ammonium chloride were identified as suitable nitrogen sources. B. cereus produced a maximum crude enzyme activity of 4.0 U/mL at 45°C and pH 7. The partially purified alpha-amylase from this strain had an estimated molecular weight of 55 kDa with specific activity of 10.1 U/mg, which is 2.35-fold higher than the crude enzyme activity. Detergent made by this enzyme had successfully cleaned the cloth stained with potato waste. Conclusion α-Amylase extracted from B . cereus has potential biotechnological applications in food and detergent industries.