APPLICATION OF PLACKETT-BURMAN EXPERIMENTAL DESIGN TO OPTIMIZE THE COLD-ACTIVE ALPHA AMYLASE BIOSYNTHESIS BY PSYCHROTROPHIC STREPTOMYCES 4 ALGA

The aim of this work was to optimize the cultural and production parameters through the statistical approach for the synthesis of cold active alpha amylase by Streptomyces 4 Alga in submerged fermentation. The process parameters influencing the enzyme production were identified using Plackett-Burman design. Among the various variables screened, the yeast extract and CaCl2 were the most significant. The optimum levels of these significant parameters were determined employing the Response Surface Methodology and the Central Composite Design. The most significant variables were determined as follows: yeast extract (5.00 g%) and CaCl2 (0.25 g%). By using the optimal fermentation medium, the cold-active alpha amylase production was increased up to 23.96 AU, an approximate 4.4-fold improvement over the previous production (5.44 AU) with un-optimized medium. The cold-active alpha amylases could be used in bioethanol production at lower temperatures, waste- water treatment and bioremediation in cold climates.