TY - JOUR
T1 - Isolation of key methanogens for global methane emission from rice paddy fields
T2 - A novel isolate affiliated with the clone cluster rice cluster
AU - Sakai, Sanae
AU - Imachi, Hiroyuki
AU - Sekiguchi, Yuji
AU - Ohashi, Akiyoshi
AU - Harada, Hideki
AU - Kamagata, Yoichi
N1 - Copyright:
Copyright 2009 Elsevier B.V., All rights reserved.
PY - 2007/7
Y1 - 2007/7
N2 - Despite the fact that rice paddy fields (RPFs) are contributing 10 to 25% of global methane emissions, the organisms responsible for methane production in RPFs have remained uncultivated and thus uncharacterized. Here we report the isolation of a methanogen (strain SANAE) belonging to an abundant and ubiquitous group of methanogens called rice cluster I (RC-I) previously identified as an ecologically important microbial component via culture-independent analyses. To enrich the RC-I methanogens from rice paddy samples, we attempted to mimic the in situ conditions of RC-I on the basis of the idea that methanogens in such ecosystems should thrive by receiving low concentrations of substrate (H 2) continuously provided by heterotrophic H2-producing bacteria. For this purpose, we developed a coculture method using an indirect substrate (propionate) in defined medium and a propionate-oxidizing, H 2-producing syntroph, Syntrophobacter fumaroxidans, as the H 2 supplier. By doing so, we significantly enriched the RC-I methanogens and eventually obtained a methanogen within the RC-I group in pure culture. This is the first report on the isolation of a methanogen within RC-I.
AB - Despite the fact that rice paddy fields (RPFs) are contributing 10 to 25% of global methane emissions, the organisms responsible for methane production in RPFs have remained uncultivated and thus uncharacterized. Here we report the isolation of a methanogen (strain SANAE) belonging to an abundant and ubiquitous group of methanogens called rice cluster I (RC-I) previously identified as an ecologically important microbial component via culture-independent analyses. To enrich the RC-I methanogens from rice paddy samples, we attempted to mimic the in situ conditions of RC-I on the basis of the idea that methanogens in such ecosystems should thrive by receiving low concentrations of substrate (H 2) continuously provided by heterotrophic H2-producing bacteria. For this purpose, we developed a coculture method using an indirect substrate (propionate) in defined medium and a propionate-oxidizing, H 2-producing syntroph, Syntrophobacter fumaroxidans, as the H 2 supplier. By doing so, we significantly enriched the RC-I methanogens and eventually obtained a methanogen within the RC-I group in pure culture. This is the first report on the isolation of a methanogen within RC-I.
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U2 - 10.1128/AEM.03008-06
DO - 10.1128/AEM.03008-06
M3 - Article
C2 - 17483259
AN - SCOPUS:34447540346
VL - 73
SP - 4326
EP - 4331
JO - Applied and Environmental Microbiology
JF - Applied and Environmental Microbiology
SN - 0099-2240
IS - 13
ER -