Laboratory method for high-solids countercurrent fermentations

Equipment and procedures were developed to study the conversion of lignocel lulosic biomass to carboxylic acids using high-solids countercurrent fermen tations. Countercurrent fermentations of cattle manure yielded a rapid ferm entation (maximum 2.98 g of total acid/ [Ld]) with high acid concentrations (maximum of 32.5 g of total acid/L), but the acid yield tended to be low ( maximum of 0.24 g of total acid/g of volatile solids). Countercurrent ferme ntations of a mixture of 80% municipal solid waste/20% sewage sludge fermen ted more slowly (maximum of 1.98 g of total acid/[L.d]) with a lower acid c oncentration (maximum of 26.5 g of total acids/L), but higher acid yields w ere achieved (maximum of 0.34 g of total acid/g of volatile solids).