Peer-Reviewed Journal Details
Mandatory Fields
Madden, P,Al-Raei, AM,Enright, AM,Chinalia, FA,de Beer, D,O'Flaherty, V,Collins, G
2014
July
Frontiers In Microbiology
Effect of sulfate on low-temperature anaerobic digestion
Published
Altmetric: 1WOS: 8 ()
Optional Fields
biogas low-temperature anaerobic digestion sulfate sulfide methane methanogenesis wastewater WASTE-WATER TREATMENT VOLATILE FATTY-ACID 16S RIBOSOMAL-RNA TARGETED OLIGONUCLEOTIDE PROBES MICROBIAL COMMUNITY STRUCTURE POLYMERASE-CHAIN-REACTION IN-SITU HYBRIDIZATION REDUCING BACTERIA METHANOGENIC ACTIVITY BIOLOGICAL TREATMENT
5
The effect of sulfate addition on the stability of, and microbial community behavior in, low-temperature anaerobic expanded granular sludge bed-based bioreactors was investigated at 15 degrees C. Efficient bioreactor performance was observed, with chemical oxygen demand (COD) removal efficiencies of >90%, and a mean SO42- removal rate of 98.3%. In situ methanogensis appeared unaffected at a COD: SO42- influent ratio of 8:1, and subsequently of 3:1, and was impacted marginally only when the COD: SO42- ratio was 1:2. Specific methanogenic activity assays indicated a complex set of interactions between sulfate-reducing bacteria (SRB), methanogens and homoacetogenic bacteria. SO42- addition resulted in predominantly acetoclastic, rather than hydrogenotrophic, methanogenesis until >600 days of SO42--influenced bioreactor operation. Temporal microbial community development was monitored by denaturation gradient gel electrophoresis (DGGE) of 16S rRNA genes. Fluorescence in situ hybridizations (FISH), qPCR and microsensor analysis were combined to investigate the distribution of microbial groups, and particularly SRB and methanogens, along the structure of granular biofilms. qPCR data indicated that sulfidogenic genes were present in methanogenic and sulfidogenic biofilms, indicating the potential for sulfate reduction even in bioreactors not exposed to SO42-. Although the architecture of methanogenic and sulfidogenic granules was similar, indicating the presence of SRB even in methanogenic systems, FISH with rRNA targets found that the SRB were more abundant in the sulfidogenic biofilms. Methanosaeta species were the predominant, keystone members of the archaeal community, with the complete absence of the Methanosarcina species in the experimental bioreactor by trial conclusion. Microsensor data suggested the ordered distribution of sulfate reduction and sulfide accumulation, even in methanogenic granules.
10.3389/fmicb.2014.00376
Grant Details
Publication Themes