Optimization of process variables for enhanced lactic acid production utilizing paneer whey as substrate in SMF

<p>The production of lactic acid from dairy by-product (<em>paneer whey</em>) via SMF by <em>Lactobacillus delbruckii</em> was optimized in the present study. Three process variables viz; inoculum size, temperature and pH were optimized using CCRD. Design Expert 8.0.2.0 trial depicted that an optimum concentration of 8.00 % (v/v) size of inoculum, 5.50 pH and 36.53 °C temperature gave lactic acid and biomass yield of 5.61 g/L and 4.27 g/L, respectively. Lactic acid production was scale up in 7.5 L bioreactor under optimized conditions and it gave lactic acid and biomass yield of 39.2± 1.4 and 47.6 ±0.8 g/L, respectively. µ_g, Y_P/S,Y_P/X and productivity were found to be 0.14 h^-1, 0.66 g/g, 0.70 g/g and 1.98 g/L^.h, respectively. <em>Leudking Piret</em> equation deduced that lactic acid production was growth associated which varies from earlier reports. Lactic acid was characterized by FTIR and HPLC.