Multiple parameter optimization for the maximization of hydrogen production by Enterobacter cloacae DM11

The study deals with the optimization of multiple operational parameters to maximize H 2 production using Enterobacter cloacae DM11 grown on MYG (malt extract-yeast extract-glucose) medium in a batch system. A three-factor Box-Behnken factorial design followed by regression analysis and study of contour plots was employed for experimental design and analysis of results. Independent variables (process parameters) were: Inoculum age (5, 10 and 15 h); Initial glucose concentration in growth medium (0.8, 1.0 and 1.2 % w/v); and Initial pH of the growth medium (4, 6 and 8). Dependent variable was amount of H 2 (in millimoles) produced in 10 h. Optimum values for inoculum age, initial glucose concentration and initial pH were found to be 12.96 h, 1.06 % (w/v) and 6.06, respectively.