Supplementary Material for: Archaeal and Bacterial Community Structure in an Anaerobic Digestion Reactor (Lagoon Type) Used for Biogas Production at a Pig Farm

Biogas production from animal waste is an economically viable way to
reduce environmental pollution and produce valuable products, i.e.,
methane and a nutrient-rich organic waste product. An anaerobic
digestion reactor for biogas production from pig waste was sampled at
the entrance, middle (digestion chamber), and exit of a digester, while
the bacterial and archaeal community structure was studied by 16S rRNA
gene metagenomics. The number of bacterial operational taxonomic units
(OTU)-97% was 3-7 times larger than that of archaeal ones. Bacteria and
Archaea found in feces of animals (e.g., Clostridiaceae,
Lachnospiraceae, Ruminococcaceae, Methanosarcina, Methanolobus, Methanosaeta, and Methanospirillum)
dominated the entrance of the digester. The digestion chamber was
dominated by anaerobic sugar-fermenting OP9 bacteria and the syntrophic
bacteria Candidatus Cloacamonas (Waste Water of Evry 1; WWE1). The methanogens dominant in the digestion chamber were the acetoclastic Methanosaeta and the hydrogenothrophic Methanoculleus and Methanospirillum.
Similar bacterial and archaeal groups that dominated in the middle of
the digestion chamber were found in the waste that left the digester.
Predicted functions associated with degradation of xenobiotic compounds
were significantly different between the sampling locations. The
microbial community found in an anaerobic digestion reactor loaded with
pig manure contained microorganisms with biochemical capacities related
to the 4 phases of methane production.