Enhanced production of protease by Pseudoalteromonas arctica PAMC 21717 via statistical optimization of mineral components and fed-batch fermentation

Abstract

The objective of this study was to statistically optimize the mineral components of the nutritional medium required for enhancing the production of a cold-active extracellular serine-type protease, W-Pro21717, by the Antarctic bacterium <em>Pseudoalteromonas arctica </em>PAMC 21717. Skim milk was identified as the major efficient inducer. Among the 12 components included in the unoptimized medium, skim milk, NaCl, Na₂SO₄, Fe(C₆H₅O₇) (ferric citrate), and KCl were determined, by the Plackett？Burman and Box？ Behnken design, to have a major effect on W-Pro21717 production. Fed-batch fermentation (5 L scale) using the mineral-optimized medium supplemented with concentrated skim milk (critical medium component) resulted in a W-Pro21717 activity of 53.4 U/L, a 15-fold increment in production over that obtained using unoptimized flask culture conditions. These findings could be applied to scale up the production of cold-active protease.