Lactic acid production is carried out in submerged fermentation using agro waste as substrates by lactobacillus plantarum. Various agro wastes are selected and pretreated using acid and alkali. The results show that the alkali treated banana peel and acid treated press mud yields better results. Experiments were performed with the selected substrates. Initial screening of nutrient was performed using Plackett–Burman design and the variables with statistically significant effects on lactic acid were identified. Peptone, MnSO₄ and CaCl₂ were found to influence lactic acid production significantly for banana peel. Peptone, MnSO₄, CaCl₂, sodium acetate and MnCl₂.7H₂O were found to influence lactic acid production significantly for pressmud. These variables were selected for further optimization studies using Box-Behnken design (BBD). At the optimized conditions, validation of model was carried out. At these conditions a maximum lactic acid production of 42 and 55 g/L for pressmud and banana peel respectively was achieved.
Keywords: Lactic Acid; Lactobacillus Plantarum; Plackett–Burman; Box-Behnken