Isolation and identification of amylase-producing bacteria from soil in Nasinuan community forest, Maha Sarakham, Thailand

Abstract

© 2019 Oriental Scientific Publishing Company. All rights reserved. This study aimed to isolate and identify bacteria that can produce amylase enzyme from the unexplored Nasinuan Forest, Kantarawichai District, Mahasarakham Province, Thailand. Thirteen bacterial isolates with amylase-producing capacity on 1% starch agar were identified using 16S rRNA sequencing. Twelve bacteria were gram-positive, rod shaped and identified as Bacillus spp. and one bacterium with gram-negative and rod shaped character was Enterobacter cloacae. Their closest relatives were found in India, China, Korea, Indonesia, Argentina, Italy, Israel, USA, Argentina and South Africa. These bacteria were tested for specific amylase activity after 1-3 days enzyme induction with 1% starch at 37°C. The results showed the highest specific activity at day 2 incubation in the order: Bacillus cereus 3.5AL2 > 3.4AL1 > 1.4AL3 and thus 2-day enzyme induction was chosen for further analysis. Bacillus sp. 3.5AL2 was found to exhibit the highest specific amylase enzyme activity of 1.97 ± 0.41 U/mg protein at the optimal conditions of 60°C and pH 7.0 after 30 min incubation with 1% starch in 0.05 M PBS buffer. This amylase-producing bacterial strain offers great potential for applications in food and agricultural industries in Thailand.