Population dynamics of methanogenic archaeas in codigestion systems

Abstract

Anaerobic co-digestion is a useful tool to improve the biogas production and can be developed from the use of several types of waste, especially recalcitrant waste with high contamination power, such as industrial waste. Ricotta cheese whey is a polluting residue due to its high lactose concentration. Residual sludge of brewery is a waste equally dangerous to the environment, with a high organic load. It is believe that the association of these residues from the food industry with bovine manure can contribute to improving biogas production. The objective was to analyze the population dynamics of methanogenic archaea operated in co-digestion systems under different concentrations of industrial waste in association with bovine manure. DNA extraction from influent and effluent samples was perform. To analysis the archaeal community, it was performed the sequencing of the V4 region of the 16s rRNA gene. The genera highlighted in the co-digestion of ricotta cheese whey were Methanosaeta and Methanosarcina. The most abundant genera during the co-digestion of residual sludge of brewery were Methanosaeta, Methanocorpusculum, and Methanobrevibacter. The results show that the co-digestion of ricotta cheese whey with bovine manure is permissible in a system operating with up to 80% of the co-substrate, in contrast to the residual sludge of brewery, it is only possible to use up to 20% of the co-substrate.