An investigation on the production of lactic acid bio hydrogen and bio methane from organic solid waste by anaerobic digestion

Abstract

Recently, the bio-transformation of organic wastes to value-added products has gained huge interests owing to waste management issues, exhaustion of fuels derived from hydrocarbon sources and its associated problems to the environment. This research work investigated the techniques to enhance the production of lactic acid, bio-hydrogen and bio-methane from organic wastes such as food waste, tannery limed fleshing waste and effluent from wastewater treatment plant through anaerobic digestion technology. Lactic acid is a multi-functional compound with extensive applications in polymer, food/beverage, medicine, cosmetic and clothing industries. Especially, the sudden increase in the utilization of biodegradable plastics has significantly escalated its global demand. However, the biggest obstacle in large scale fermentation of lactic acid is in achieving enhanced productivity with cheap resources in order to keep the price competitive. newlineThis study investigated the influence of selected bacterial strains for lactic acid production from food waste through simultaneous scarification and fermentation process at optimal conditions of pH 5.5 at 30o C. The highest lactic acid concentration of 47.21 g L-1 was obtained from Lactobacillus amylovorus DSM 20531 followed by 18.69 g L-1 from Lacobacillus manihotivorans DSM 13343, 17.03 g L-1 from Lactobacillus plantarum DSM 20174 and 15.88 g L-1 from mixed culture (mix of 16 strains) during fermentation of food waste. newline