(89e) Production of Carboxylic Acids From Acidogenic Fermentation of Algefiber® (Sea Weed Sludge) Using a Mixed Culture of Marine Microorganisms

Seaweed (Macro algae) has an increasing concern as a biomass source for biofuel production. In this study, carboxylic acids were produced from seaweed derived biomass using the MixAlco? process. Produced carboxylic acids were neutralized with calcium carbonate and ammonium bicarbonate to form carboxylate salts that can be chemically upgraded to higher alcohols liquid biofuel. Algefiber^® was used as the biomass source which is an alkaline pretreated waste biomass from seaweed processing (FMC Biopolymer). Algefiber^® derived from red seaweed (Eucheuma spinosum) was anaerobically digested using a mixed culture of marine-derived microorganisms. The fermentation was carried out at two temperatures of 35⁰C (mesophilic) and 55⁰C (thermophilic) in bench scale batch fermenters. The acidogenic digestion and suppression of methanogenesis were achieved by adding small doses of iodoform. Calcium carbonate and ammonium bicarbonate were used as buffers to maintain the pH of the fermentation. The produced carboxylic acids ranged from 2 to 7 carbons. The total carboxylic acid production was found to be higher at lower temperature. Acetic acid was the prominent acid at both temperatures but the proportion of acetic acid in the mixture was greater at thermophilic temperature.