Optimization of cultivation conditions for the production of phytate-degrading enzymes by Enterobacter sakazakii ASUIA279 isolated from Malaysian maize root

The production of extracellular phytase by Enterobacter sakazakii ASUIA279 was optimized using response surfacemethodology with full-factorial faced centred central composite design. Two sets of experiments were carried out tooptimize the five most profound factors of the cultivation conditions in order to maximize phytase production.Incubation temperature, initial pH of the media and percentage of rice bran supplemented into the media wereoptimized in Erlenmeyer flasks while agitation and aeration effect were controlled in a bioreactor. This designreduced the number of actual experiment performed to optimize phytase production and allowed the study ofpossible interactions among the factors. In the first set of experiments linear and quadratic effect of initial pH wasdetermined to be the most significant factor affecting phytase production. In the bioreactor both linear effects ofagitation and aeration, were identified to be highly significant (> 99 %) in respect to phytase yields. Optimalphytase production was observed at a incubation temperature of 39.7 oC, an initial pH of 7.1, supplementation with13.6 % rice bran , 320 rpm of agitation and 0 vvm of aeration.