Quantification of syntrophic acetate-oxidizing microbial communities in biogas processes

Maria Westerholm, Jan Dolfing, Angela Sherry, Neil D. Gray, Ian M. Head, Anna Schnürer*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

102 Citations (Scopus)

Abstract

Changes in communities of syntrophic acetate-oxidizing bacteria (SAOB) and methanogens caused by elevated ammonia levels were quantified in laboratory-scale methanogenic biogas reactors operating at moderate temperature (37°C) using quantitative polymerase chain reaction (qPCR). The experimental reactor was subjected to gradually increasing ammonia levels (0.8-6.9gNH 4 +-Nl -1), whereas the level of ammonia in the control reactor was kept low (0.65-0.90gNH 4 +-Nl -1) during the entire period of operation (660 days). Acetate oxidation in the experimental reactor, indicated by increased production of 14CO 2 from acetate labelled in the methyl carbon, occurred when ammonia levels reached 5.5 and 6.9gNH 4 +-Nl -1. Syntrophic acetate oxidizers targeted by newly designed qPCR primers were Thermacetogenium phaeum, Clostridium ultunense, Syntrophaceticus schinkii and Tepidanaerobacter acetatoxydans. The results showed a significant increase in abundance of all these bacteria except T. phaeum in the ammonia-stressed reactor, coincident with the shift to syntrophic acetate oxidation. As the abundance of the bacteria increased, a simultaneous decrease was observed in the abundance of aceticlastic methanogens from the families Methanosaetaceae and Methanosarcinaceae. qPCR analyses of sludge from two additional high ammonia processes, in which methane production from acetate proceeded through syntrophic acetate oxidation (reactor SB) or through aceticlastic degradation (reactor DVX), demonstrated that SAOB were significantly more abundant in the SB reactor than in the DVX reactor.

Original languageEnglish
Pages (from-to)500-505
Number of pages6
JournalEnvironmental Microbiology Reports
Volume3
Issue number4
Early online date21 Mar 2011
DOIs
Publication statusPublished - 1 Aug 2011
Externally publishedYes

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