Production optimization using Plackett-Burman and Box-Behnken designs with partial characterization of amylase from marine actinomycetes

Abstract

Amylase is an industrial enzyme that is used in the food and biofuel industries. We screened four actinomycetes strains for amylase biosynthesis. The Streptomyces rochei strain had a larger hydrolytic zone (24 mm) on starch agar plates, than the other isolates. Plackett-Burman’s experimental design was implemented to optimize the conditions for amylase production by the selected strains. Growth under optimized culture conditions led to 1.7, 9.8, 7.7, and 3.12 -fold increases for the isolates S. griseorubens, S. rochei, S. parvus, and Streptomyces sp., respectively, in the specific activity measurement in comparison with growth under primary conditions. When applying the Box-Behnken design on S. rochei using the most significant parameters starch, K2HPO4, pH, and temperature, there was a 12.22-fold increase in the specific activity measurement: 7.37 U/mg. The optimal fermentation medium formula was kept at 30.6°C for seven days. The amylase from S. rochei was partially purified, and its molecular weight was determined using Sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The molecular weight was found to be 45, 43, and 53 kDa. Amylase was particularly active at pH 6 and 65°C. The purified enzyme was most active at 65°C and a pH of 6, thermal stability of 70°C for 40 min and salt concentration of 1 M with a Km and Vmax of 6.58 mg/ml and 21.93 mg/ml/min, respectively. The amylase improved by adding Cu + 2, Zn + 2, and Fe + 2 (152.21%, 207.24%, and 111.89%). Increased production of amylase enzyme by Streptomyces rochei KR108310 attracts the production of industrially significant products.

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

“…Therefore, this study is aimed at investigating the production of α -amylase from different marine actinomycetes isolates belonging to the genus Streptomyces , the enhancement of α -amylase production, and the characterization of this enzyme for various industrial processes. This manuscript has been submitted as a preprint to the Research Square site [ 16 ].…”