title: Temperature and solids retention time control microbial population dynamics and volatile fatty acid production in replicated anaerobic digesters.
abstract: Anaerobic digestion is a widely used technology for waste stabilization and generation of biogas, and has recently emerged as a potentially important process for the production of high value volatile fatty acids (VFAs) and alcohols. Here, three reactors were seeded with inoculum from a stably performing methanogenic digester, and selective operating conditions (37°C and 55°C; 12 day and 4 day solids retention time) were applied to restrict methanogenesis while maintaining hydrolysis and fermentation. Replicated experiments performed at each set of operating conditions led to reproducible VFA production profiles which could be correlated with specific changes in microbial community composition. The mesophilic reactor at short solids retention time showed accumulation of propionate and acetate (42 ± 2% and 15 ± 6% of CODhydrolyzed, respectively), and dominance of Fibrobacter and Bacteroidales. Acetate accumulation (>50% of CODhydrolyzed) was also observed in the thermophilic reactors, which were dominated by Clostridium. Under all tested conditions, there was a shift from acetoclastic to hydrogenotrophic methanogenesis, and a reduction in methane production by >50% of CODhydrolyzed. Our results demonstrate that shortening the SRT and increasing the temperature are effective strategies for driving microbial communities towards controlled production of high levels of specific volatile fatty acids.
authors: 1] Advanced Water Management Centre (AWMC), The University of Queensland, St Lucia, QLD 4072, Australia [2] Australian Centre for Ecogenomics (ACE), School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD 4072, Australia.
authors: Inka
authors: I
authors: Vanwonterghem
authors: Advanced Water Management Centre (AWMC), The University of Queensland, St Lucia, QLD 4072, Australia.
authors: Paul D
authors: PD
authors: Jensen
authors: 1] Advanced Water Management Centre (AWMC), The University of Queensland, St Lucia, QLD 4072, Australia [2] Laboratory for Microbial Ecology and Technology (LabMET), Ghent University, Coupure Links 653, 9000 Ghent, Belgium.
authors: Korneel
authors: K
authors: Rabaey
authors: 1] Advanced Water Management Centre (AWMC), The University of Queensland, St Lucia, QLD 4072, Australia [2] Australian Centre for Ecogenomics (ACE), School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD 4072, Australia.
authors: Gene W
authors: GW
authors: Tyson
mesh_terms: D000693:Anaerobiosis; D044822:Biodiversity; D019149:Bioreactors / Q000382:microbiology*; D005232:Fatty Acids, Volatile / Q000096:biosynthesis*; D064307:Microbiota; D013696:Temperature
chemical_list: D005232:Fatty Acids, Volatile