Evidence of syntrophic acetate oxidation by Spirochaetes during anaerobic methane production.
To search for evidence of syntrophic acetate oxidation by cluster II Spirochaetes with hydrogenotrophic methanogens, batch reactors seeded with five different anaerobic sludge samples supplemented with acetate as the sole carbon source were operated anaerobically. The changes in abundance of the cluster II Spirochaetes, two groups of acetoclastic methanogens (Methanosaetaceae and Methanosarcinaceae), and two groups of hydrogenotrophic methanogens (Methanomicrobiales and Methanobacteriales) in the reactors were assessed using qPCR targeting the 16S rRNA genes of each group. Increase in the cluster II Spirochaetes (9.0±0.4-fold) was positively correlated with increase in hydrogenotrophic methanogens, especially Methanomicrobiales (5.6±1.0-fold), but not with acetoclastic methanogens. In addition, the activity of the cluster II Spirochaetes decreased (4.6±0.1-fold) in response to high hydrogen partial pressure, but their activity was restored after consumption of hydrogen by the hydrogenotrophic methanogens. These results strongly suggest that the cluster II Spirochaetes are involved in syntrophic acetate oxidation in anaerobic digesters.
School of Civil, Environmental and Architectural Engineering, Korea University, Seoul 136-714, South Korea.
Sang-Hoon
SH
Lee
School of Civil, Environmental and Architectural Engineering, Korea University, Seoul 136-714, South Korea; IT Convergence Materials R&D Group, Chungcheong Regional Division, Korea Institute of Industrial Technology, Chungnam 330-825, South Korea.
Jeong-Hoon
JH
Park
Department of Environmental Engineering, Daegu University, Gyeongbuk 712-714, South Korea.
Sang-Hyoun
SH
Kim
IT Convergence Materials R&D Group, Chungcheong Regional Division, Korea Institute of Industrial Technology, Chungnam 330-825, South Korea.
Byung Jo
BJ
Yu
IT Convergence Materials R&D Group, Chungcheong Regional Division, Korea Institute of Industrial Technology, Chungnam 330-825, South Korea.
Jeong-Jun
JJ
Yoon
School of Civil, Environmental and Architectural Engineering, Korea University, Seoul 136-714, South Korea. Electronic address: heedeung@korea.ac.kr.
Hee-Deung
HD
Park
D000085:Acetates / Q000378:metabolism*; D000693:Anaerobiosis / Q000502:physiology; D019149:Bioreactors / Q000382:microbiology; D008697:Methane / Q000302:isolation & purification / Q000378:metabolism*; D010084:Oxidation-Reduction; D013045:Species Specificity; D013142:Spirochaeta / Q000145:classification* / Q000235:genetics / Q000378:metabolism*; D013559:Symbiosis / Q000502:physiology*
D000085:Acetates; D008697:Methane
Anaerobic digester; Methanogen; Spirochaetes; Syntrophic acetate oxidation