Enhancing the hydrolysis yield in thermophilic anaerobic digestion of cattle manure

Abstract

The purpose of the research is to improve the biogas production rate and yield during anaerobic digestion of cattle manure. Hydrolysis being an anaerobic digestion-limiting step, a literature study was carried out on the ways to improve it by varying the experimental conditions. Bioaugmentation, addition of surfactant and decreasing the pH to 7.0 were expected to enhance biogas production. Growth of selected organisms was studied for their addition into reactors. Two reactors were operated under pH-control at 7.0 but the experiment had to be stopped because of the acid addition that was excessive. Meanwhile, experiments were made to design an efficient protocol for extracting proteins from the reactor digestate and comparing produced hydrolytic enzymes depending of the conditions. It was shown that proteins are mostly present in the liquid fraction.