Metagenomics analysis on the microbiota of chicken manure anaerobic digestion materials in biogas production

Abstract

Abstract Identifying the microbial composition in the evaluation of the effectiveness of anaerobic digestion for complex systems still poses a challenge with regard to the first three phases (hydrolysis, acidogenesis and acetogenesis). These phases are crucial in creating substrates for the methanogens to take in, which will affect biogas production. In this study, the microbial composition of the various chambers in the anaerobic digestion of chicken manure was investigated. The optimal living conditions of the microorganisms in the chambers corresponds well with their respective operating conditions (aerobic hydrolysis chamber to anaerobic digester chambers). Diversity of the microbial community for chicken manure was relatively simpler, consisting of mainly the genus of Lactobacillus compared to the main digestion chambers of a more complex community containing more class of Clostridia. This change in microbial diversity composition indicates on the amount and degree of anaerobic digestion occurring (chicken manure only has hydrolysis phase occurring while the main digesters has the first three phases of anaerobic digestion (hydrolysis, acidogenesis and acetogenesis) occurring). A comparison of the metagenomics vs metaproteomics mode of analysis revealed that the bacterial compositions between these two modes of analysis were quite comparable, with the main difference being the quantity of unclassified microorganisms each due to different database and techniques used. The quantity of volatile fatty acids detected in each respective chamber suggested the effectiveness of the microorganisms in assimilating the metabolites for their growth. Successful integration of these study modes would present a better understanding of the anaerobic digestion of complex systems.