Isolation and Characterization of Amylase Producing Bacteria from Soils and Optimization Conditions for Enzyme Production

Abstract

Starch hydrolyzing enzymes are currently in high demand for a wide range of starch-based products used in a variety of industries. Although starch hydrolyzing enzymes (amylases) are already available from a range of sources, microbial sources have been preferred due to their inexpensive production costs. The goal of this research was to isolate and characterize amylase-producing bacteria from soil, as well as to analyseamylase enzyme production at different temperatures, pH levels, and incubation times.Soil samples were gathered from eight study sites at tullu korma foreast in adisalem town and sent to Ambo University's College of Natural and Computational Sciences' Biology laboratory, where they were serially diluted and plated on starch agar to isolate amylase producing bacteria..The amylase-producing potential of the isolated bacteria was evaluated by an iodine test on starch agar media by measuring the clean zone diameter, and the elite amylase-producing isolates were selected for optimization of conditions for amylase production using the DNS method.A total of 35 bacterial isolates were obtained on starch agar media in this investigation, from which 13 bacterial isolates showed amylase activity on the starch agar media.The majority of the bacterial isolates had large colony sizes and circular colony forms, and the gram reactions of the various bacterial isolates revealed gram positive and gram-negative in equal proportions.The majority of the isolates tested were negative for oxidase, Simmon citrate test, and method test but positive for catalase. The different bacterial isolates showed different clean zone diameters. Isolate Grasl s1 had the largest clean zone diameter (3.5 cm) of all the bacteria tested for starch breakdown, followed by isolates Farmland S1, Grassland white 1, Farmlan S11, Sotalo S31, and Farm Land S10, each with a clean zone diameter of 3 cm. and the smallest clean zone diameter was measured from the isolate Log S2 1.5 cm. . Bacterial isolate Log 36 had the highest amylase activity of all the bacteria tested in all of the incubation temperatures tested)OD=2.646±0.001) at an incubation temperature of 28 and the lowest at an incubation temperature of 37 (1.92± 0.001)followed by the bacterial isolate log, which had 1.698±0.002 at temperature 20 and 1.254 at temperature 37.Bacterial isolate Graslandred had the lowest enzyme activity (0.805±0.001 at 20 degrees centigrade and 0.621) at 37 degrees centigrade), followed by bacterial isolate Farmland 12 (0.992±0.002) at 20 degrees centigrade and 0.754±0.001) at 37 degrees centigrade). When enzyme activity from different bacterial isolates was evaluated at different temperatures and incubation durations, the results indicated less variance. Grassland isolate nor showed the highest enzyme activity at incubation time 96hrs OD= 0.798±0.001)and other bacterial isolate tested also showed highest enzyme activity at incubation time 96hrs. this study revealed that amylase-producing bacteria could be isolated from varicose sources for the production of this enzyme for various industrial applications.