Production and recovery of volatile fatty acids from fermentation broth

Abstract

The production of volatile fatty acids (VFAs) by anaerobic fermentation of wheat milling waste residues (akalona) either as a solid or hydrolyzate and whey was studied using fresh rumen fluid as a mixed culture for anaerobic digestion of the organic residues. Maximum VFAs production was obtained from akalona followed by whey after 8 days. The lower VFAs production was obtained from akalona hydrolyzate after 7 days. VFAs recovery from fermentation broth by liquid–liquid extraction using a mixed solvent (tri- n-octylphosphine oxide in kerosene) followed by a pure solvent was studied. Experiments were run covering the extraction kinetics of tri- n-octylphosphine in the diluent kerosene under the optimum conditions for extraction of VFAs with mixed solvent and with pure solvent only, and the per cent recovery of VFAs was calculated in both steps.