Preliminary study of phosphatases and β-glucosidases enzymes as biochemical indicators in the anaerobic codigestion of onion residues and manures

Abstract

This work is a preliminary study of phosphatases and β-glucosidases hydrolytic enzymes activity in co-digestion of wastes of onion and hen and cow manure with and without addition of inoculum (co-digested hen manure) anaerobic reactors, in order to determine their function as early indicators of co-digestion different stages. The tests were carried out in duplicate on 3 biodigesters of 2000 mL at temperatures between 22 and 24 °C. Enzymatic activities, volume of gas generated, pH and biogas chromatography were measured. The highest enzymatic activity was obtained for cow manure reactors, which could be considered to set the initial operating and control conditions in the hydrolytic phase in the co-digestion processes. The highest volume production of biogas was for reactors with hen manure with 69% methane generation.