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

ABSTRACT

In the present study lactic acid production was enhanced by optimizing the three process variables viz; inoculum size, temperature and pH using three factor five level CCRD [central composite rotatable design] by Lactobacillus delbruckii under SMF [submerged fermentation process]. Paneer [dairy byproduct] whey was used as sole substrate for lactic acid production. Design Expert 8.0.2.0 software depicted that an optimum concentration of 8% [v/v] size of inoculum, 5.50 pH and 36.53°C temperature gave lactic acid and biomass yield of 5.61 g/L[-1] and 4.27 g/L[-1], 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[-1], respectively. micro[g], Y[P/S], Y[P/X] and productivity were found to be 0.14 h[-1], 0.66 g/g, 0.7 g/g and 1.98 g/L[-1] h, respectively. Leudking Piret equation deduced that lactic acid production was growth associated which varies from earlier reports. Lactic acid was characterized by FTIR [Fourier transform infrared spectroscopy] and HPLC