Prokaryotic diversity and dynamics in a full-scale municipal solid waste anaerobic reactor from start-up to steady-state conditions

▸ We identify and quantify microbiota of a full-scale MSW anaerobic reactor. ▸ Shifts in the diversity and abundance were observed from start-up to steady-state. ▸ Hydrogenotrophic methanogens dominated the methane production in the MSW reactor. ▸ Methanosarcina, Methanimicrococcus and Methanosaeta were identified in the reactor. ▸ Quantification of bacterial and archaeal by FISH and qPCR differ. The prokaryotic diversity of an anaerobic reactor for the treatment of municipal solid waste was investigated over the course of 2years with the use of 16S rDNA-targeted molecular approaches. The fermentative Bacteroidetes and Firmicutes predominated, and Proteobacteria, Actinobacteria, Tenericutes and the candidate division WWE1 were also identified. Methane production was dominated by the hydrogenotrophic Methanomicrobiales (Methanoculleus sp.) and their syntrophic association with acetate-utilizing and propionate-oxidizing bacteria. qPCR demonstrated the predominance of the hydrogenotrophic over aceticlastic Methanosarcinaceae (Methanosarcina sp. and Methanimicrococcus sp.), and Methanosaetaceae (Methanosaeta sp.) were measured in low numbers in the reactor. According to the FISH and CARD-FISH analyses, Bacteria and Archaea accounted for 85% and 15% of the cells, respectively. Different cell counts for these domains were obtained by qPCR versus FISH analyses. The use of several molecular tools increases our knowledge of the prokaryotic community dynamics from start-up to steady-state conditions in a full-scale MSW reactor.