Microbial community structure and dynamics in two-stage vs single-stage thermophilic anaerobic digestion of mixed swine slurry and market bio-waste

Giuseppe Merlino, Aurora Rizzi, Andrea Schievano, Alberto Tenca, Barbara Scaglia, Roberto Oberti, Fabrizio Adani, Daniele Daffonchio*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

65 Scopus citations


The microbial community of a thermophilic two-stage process was monitored during two-months operation and compared to a conventional single-stage process. Qualitative and quantitative microbial dynamics were analysed by Denaturing Gradient Gel Electrophoresis (DGGE) and real-time PCR techniques, respectively. The bacterial community was dominated by heat-shock resistant, spore-forming clostridia in the two-stage process, whereas a more diverse and dynamic community (Firmicutes, Bacteroidetes, Synergistes) was observed in the single-stage process. A significant evolution of bacterial community occurred over time in the acidogenic phase of the two-phase process with the selection of few dominant species associated to stable hydrogen production. The archaeal community, dominated by the acetoclastic Methanosarcinales in both methanogen reactors, showed a significant diversity change in the single-stage process after a period of adaptation to the feeding conditions, compared to a constant stability in the methanogenic reactor of the two-stage process. The more diverse and dynamic bacterial and archaeal community of single-stage process compared to the two-stage process accounted for the best degradation activity, and consequently the best performance, in this reactor. The microbiological perspective proved a useful tool for a better understanding and comparison of anaerobic digestion processes.

Original languageEnglish (US)
Pages (from-to)1983-1995
Number of pages13
JournalWater Research
Issue number6
StatePublished - Apr 15 2013


  • Bacterial and archaeal anaerobic consortia
  • Bio-hydrogen
  • Bio-methane
  • Real-time PCR

ASJC Scopus subject areas

  • Ecological Modeling
  • Water Science and Technology
  • Waste Management and Disposal
  • Pollution

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