Isolation and characterization of Amylase producing bacteria from Chitu Soda Lake East Shewa, Oromia, Ethiopia

Abstract

Enzymes are biological catalysts, which controls certain biochemical reactions. Amylases are among the most important enzymes that are widely utilized in different industries. Amylase could be produced from plant, animal, and microorganisms. Alkaliphilic Amylase producing bacteria were isolated from sediment soil samples obtained from Ethiopian soda lake in the Rift Valley area Lake Chitu. Starch-hydrolyzing isolates were selected on the basis of their activity on starch agar plate assay. Five isolates were chosen, characterized, and subjected to MALDI -TOF analysis. All the isolates were gram positive, urease, and catalase positive. All isolates except one were motile endospore forming rods and were found to be closely related to the Bacillus , being grouped with Bacillus cereus. The one exception had non- motile, non- endospore rod cells and was closely related to Cutibacterium acnes. The isolates were characterized for incubation period, effect of temperature, pH tolerance, nitrogen source preference, and effect of salt. The amylase activities were also characterized for effect of buffer, temperature, metal ions, and EDTA. All isolates grew optimally within 48 hours at temperature of 45°C and pH 9 when they grew on peptone as a nitrogen source that was supplemented with 15(w/v) NaCl. The maximum amylase activity was found at phosphate buffer pH 6. The amylase activities varied significantly across the presence of different metals.The amylase activity of all isolates inhibited in the presence of ethylenediaminetetraacetic acid (EDTA).