Sulfate-reduction in the anaerobic digestion of animal waste

Abstract

The relationship between sulfate-reduction and the oxidation of various intermediates of anaerobic digestion of animal waste was investigated by incubating cattle waste anaerobically in the presence or absence of sulfate. Propionate oxidation was strongly accelerated by the addition of sulfate, but acetate oxidation was not affected. Lactate, butyrate, and ethanol were oxidized rather rapidly irrespective of the presence of sulfate. Hydrogen gas stimulated both sulfate-reduction and methanogenesis, but it delayed the oxidation of fatty acids. When methanogenesis was inhibited by the addition of chloroform in the presence of sulfate, the sulfate was ordinarily reduced, while the acetate concentration increased. It was concluded that the contribution of acetate as an electron donor for sulfate-reduction was very low in cattle waste. Sulfate-reduction in pig waste and a ditch sediment was also investigated for comparison. © 1986, Applied Microbiology, Molecular and Cellular Biosciences Research Foundation. All rights reserved.