Metagenomics and Metabolomics Study on Microbial Diversity and Enzymatic Activities Changes on Cow Dung Based Low-Temperature Biogas Production by Entererococcus spp

Abstract

To fill the gap between the rise in demand for energy and decline in the traditional energy sources such as coal, natural gas and nuclear energy, other alternative sources such as biogas are necessary. Studies have shown that the existing conditions within the fermentation realm control the microbial characteristics in biogas production. However, there is inadequate insight between the duration of fermentation and the microbial diversity, and with specific emphasis to cow manure as the substrate under low temperature fermentation. This study aimed at providing additional insight on the effect of varying fermentation duration (0 to 60 days) on the composition of the dominant microbial flora on cow dung based low-temperature (15 °C) biogas fermentation using metagenomics and metabolomics analyses approach. The study results showed that the main dominant community in the process of methanogenesis are the Spirochaetae, Synergistetes and Chloroflexi, and are new flora in the methane phase. In the peak stage of low-temperature biogas fermentation, the dominant bacteria groups were Methanosarcina and after adding 10% concentration of L1 bacteria. The prediction of metabolic pathway was mainly carbohydrate metabolism and amino acid metabolism with succinyl-CoA synthase a subunit, lactaldehyde reductase and the glutamate-glyoxylate aminotransferase being the main unique enzymes. The study therefore supports the potential of involving the reported dominant microbial communities and related enzymatic activities for improved biogas production under low temperature conditions.