Biogas production and Archaea composition in the co-fermentation biogas system of corn stalks and pig manure

Abstract

In order to investigate the dynamics of Archaea community during co-fermentation, the mesophilic batch cofermentation of pretreated cornstalks and pig manure was studied, with samples of different fermentation periods collected for community analysis using 454 pyrosequencing. The results showed very fast start-up of co-fermentation. The daily biogas production reached the maximum of 1.46 L L-1 d-1 on 4th day. The biogas and methane yield was 356.55 mL/g VS and 208.0 mL/g VS respectively in 46 days. The 454 pyrosequencing analysis showed that the Archaea in the co-fermentation reactor belonged to Euryarchaeota (97.83%-100%) and Crenarchaeota (0%-2.17%). With proceeding of fermentation, the content of Methanobacteria decreased rapidly from 69.84% to 0.14%, while the contents of Miscellaneous Crenarchaeotic Group and Thermoplasmata gradually increased from 0% and 1.05% to 2.17% and 20.68%, respectively. At the same time the content of Methanomicrobia sharply increased from 29.84% to 96.14% and remained at high level. It showed that co-fermentation of corn stalk and pig manure can quickly start up and the diversity of archaeal gradually increases during co-fermentation.