Methane production and microbial community characteristics of anaerobic codigestion of straws and chicken manure

Abstract

AbstractPrevious studies showed that chicken manure and straws can be used as a feedstock in the production of methane during anaerobic digestions. The objective was to determine the best mixture of chicken manure and straw in the production of methane during anaerobic digestion. In this study the effect of three volatile solid (VS) rations on methane output, pH, hydrolase activity, and microbial community structure was determined. The optimal manure–straw VS ratio was M2 (9:1), where cumulative methane output reached a maximum of 227,660 ml kg–1 in 50 d. The cellulose activity was higher in the chicken manure to straw ratio of 9 than 4 or 1. The research showed that Megasphaera and Bacteroides were important cellulose‐secreting bacteria. The results show: (a) during anaerobic digestion the cellulose and lignin contents were completely degraded; (b) protease, amylase, and lipase activities were higher in M2 (9:1) than M1 (1:0) or M3 (4:1); and (c) increasing amount of straw decreased bacteria and archaea diversity. Due to the addition of straw, the unidentified_Prevotellaceae had good physiological activity in the acidic environment between 5 and 30 d, Candidatus_Cloacimonas, unidentified_Lentimicrobiaceae, and Ruminiclostridium were the main archaea between 40 and 50 d.