Production and Partial Characterization of α -Amylase Enzyme from Marine Actinomycetes.

Amylase producing actinobacteria were isolated and characterized from terrestrial environment. There are a limited number of reports investigating the marine environment; hence, in the present study, four marine enzymes were tested for their amylase production ability. On starch agar plates, the Streptomyces rochei strain showed a higher hydrolytic zone (24 mm) than the other isolates. Growth under optimized culture conditions using Plackett-Burman's experimental design led to a 1.7, 9.8, 7.7, and 3.12-fold increase for the isolates S. griseorubens , S. rochei , S. parvus , and Streptomyces sp., respectively, in the specific activity measurement. When applying the Box-Behnken design on S. rochei using the most significant parameters (starch, K 2 HPO 4 , pH, and temperature), there was a 12.22-fold increase in the specific activity measurement 7.37 U/mg. The α -amylase was partially purified, and its molecular weight was determined using sodium dodecyl sulfate-polyacrylamide gel electrophoresis. α -Amylase was particularly active at pH 6 and 65°C. The purified enzyme was most active at 65°C and pH 6, thermal stability of 70°C for 40 min, and salt concentration of 1 M with Km and Vmax of 6.58 mg/ml and 21.93  μ mol/ml/min, respectively. The α -amylase was improved by adding Cu +2 , Zn +2 , and Fe +2 (152.21%, 207.24%, and 111.89%). Increased production of α -amylase enzyme by S. rochei KR108310 leads to production of significant industrial products.