Isolation and characterization of amylase-producing Bacillus sp. ACoL20 isolated from the gut of flying fish, Cheilopogon intermedius

: Bacterial enzymes associated with the gut of fish are known to aid in the digestion and nutrition of the host. In the present study, amylase-producing bacteria were isolated, identified, and characterized from the gut of flying fish (Cheilopogon intermedius). Isolation was performed on starch agar (SA) plates, and the isolated bacterial strains were qualitatively and quantitatively screened for amylase production. Among the isolates, strain ACoL20 exhibited the highest amylase activity, reaching 15.21 U.mg-1 protein. Morphological, biochemical, physiological, and molecular analysis revealed that the isolate belongs to the genus Bacillus (86% homologous to B. paramycoides). Further qualitative assessment, through the measurement of the zone of hydrolysis, indicated that optimum amylase production occurred at 36 h at 40°C, with a wide range of pH tolerance (pH 6-9) when cultured in starch agar supplemented with 1% NaCl. These findings highlight the amylolytic potential of Bacillus sp. ACoL20 and its possible application in enhancing fish nutrition and other biotechnological processes.