Dataset Information

Methanogenesis from methanol at low temperatures by a novel psychrophilic methanogen, "Methanolobus psychrophilus" sp. nov., prevalent in Zoige wetland of the Tibetan plateau.

ABSTRACT: The Zoige wetland of the Tibetan plateau is at permanent low temperatures and is a methane emission heartland of the plateau; however, cold-adaptive methanogens in the soil are poorly understood. In this study, a variety of methanogenic enrichments at 15 degrees C and 30 degrees C were obtained from the wetland soil. It was demonstrated that hydrogenotrophic methanogenesis was the most efficient type at 30 degrees C, while methanol supported the highest methanogenesis rate at 15 degrees C. Moreover, methanol was the only substrate to produce methane more efficiently at 15 degrees C than at 30 degrees C. A novel psychrophilic methanogen, strain R15, was isolated from the methanol enrichment at 15 degrees C. Phylogenetic analysis placed strain R15 within the genus Methanolobus, loosely clustered with Methanolobus taylorii (96.7% 16S rRNA similarity). R15 produced methane from methanol, trimethylamine, and methyl sulfide and differed from other Methanolobus species by growing and producing methane optimally at 18 degrees C (specific growth rate of 0.063 +/- 0.001 h(-1)) and even at 0 degrees C. Based on these characteristics, R15 was proposed to be a new species and named "Methanolobus psychrophilus" sp. nov. The K(m) and V(max) of R15 for methanol conversion were determined to be 87.5 +/- 0.4 microM and 0.39 +/- 0.04 mM h(-1) at 18 degrees C, respectively, indicating a high affinity and conversion efficiency for methanol. The proportion of R15 in the soil was determined by quantitative PCR, and it accounted for 17.2% +/- 2.1% of the total archaea, enumerated as 10(7) per gram of soil; the proportion was increased to 42.4% +/- 2.3% in the methanol enrichment at 15 degrees C. This study suggests that the psychrophilic methanogens in the Zoige wetland are likely to be methylotrophic and to play a role in methane emission of the wetland.

SUBMITTER: Zhang G

PROVIDER: S-EPMC2565969 | biostudies-literature | 2008 Oct

REPOSITORIES: biostudies-literature

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Methanogenesis from methanol at low temperatures by a novel psychrophilic methanogen, "Methanolobus psychrophilus" sp. nov., prevalent in Zoige wetland of the Tibetan plateau.

Zhang Guishan G Jiang Na N Liu Xiaoli X Dong Xiuzhu X

Applied and environmental microbiology 20080801 19

The Zoige wetland of the Tibetan plateau is at permanent low temperatures and is a methane emission heartland of the plateau; however, cold-adaptive methanogens in the soil are poorly understood. In this study, a variety of methanogenic enrichments at 15 degrees C and 30 degrees C were obtained from the wetland soil. It was demonstrated that hydrogenotrophic methanogenesis was the most efficient type at 30 degrees C, while methanol supported the highest methanogenesis rate at 15 degrees C. Moreo ...[more]

PMID: 18676698

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Project description:BACKGROUND:Tibetan sheep (TS) and Gansu Alpine Finewool sheep (GS) are both important plateau sheep raised and fed on the harsh Qinghai-Tibetan Plateau, China. Rumen methanogen and protozoal communities of plateau sheep are affected by their hosts and living environments, and play important roles in ruminant nutrition and greenhouse gas production. However, the characteristics, differences, and associations of these communities remain largely uncharacterized. RESULTS:The rumen methanogen and protozoal communities of plateau sheep were investigated by 16S/18S rRNA gene clone libraries. The predominant methanogen order in both sheep species was Methanobacteriales followed by Methanomassiliicoccales, which is consistent with those seen in global ruminants. However, the most dominant species was Methanobrevibacter millerae rather than Methanobrevibacter gottschalkii seen in most ruminants. Compared with GS and other ruminants, TS have more exclusive operational taxonomic units and a lower proportion (64.5%) of Methanobrevibacter. The protozoa were divided into Entodiniomorphida and Vestibuliferida, including nine genera and 15 species. The proportion of holotrich protozoa was much lower (1.1%) in TS than ordinary sheep. The most predominant genus was Entodinium (70.0%) in TS and Enoploplastron (48.8%) in GS, while the most common species was Entodinium furca monolobum (43.9%) and Enoploplastron triloricatum (45.0%) in TS and GS, respectively; Entodinium longinucleatum (22.8%) was only observed in TS. LIBSHUFF analysis indicated that the methanogen communities of TS were significantly different from those of GS, but no significant differences were found in protozoal communities. CONCLUSION:Plateau sheep have coevolved with unique rumen methanogen and protozoal communities to adapt to harsh plateau environments. Moreover, the host appears to have a greater influence on rumen methanogen communities than on rumen protozoal communities. The observed associations of methanogens and protozoa, together with the findings of previous studies on methane emissions from ruminant livestock, revealed that the lower proportion of Methanobrevibacter and holotrich protozoa may be responsible for the lower methane emission of TS. These findings facilitate our understanding of the rumen microbial ecosystem in plateau sheep, and could help the development of new strategies to manipulate rumen microbes to improve productivity and reduce the emission of greenhouse gases.

Project description:BACKGROUND:Methane emissions by methanogen from livestock ruminants have significantly contributed to the agricultural greenhouse gas effect. It is worthwhile to compare methanogen from "energy-saving" animal (yak) and normal animal (cattle) in order to investigate the link between methanogen structure and low methane production. RESULTS:Diversity of methanogens from the yak and cattle rumen was investigated by analysis of 16S rRNA gene sequences from rumen digesta samples from four yaks (209 clones) and four cattle (205 clones) from the Qinghai-Tibetan Plateau area (QTP). Overall, a total of 414 clones (i.e. sequences) were examined and assigned to 95 operational taxonomic units (OTUs) using MOTHUR, based upon a 98% species-level identity criterion. Forty-six OTUs were unique to the yak clone library and 34 OTUs were unique to the cattle clone library, while 15 OTUs were found in both libraries. Of the 95 OTUs, 93 putative new species were identified. Sequences belonging to the Thermoplasmatales-affiliated Linage C (TALC) were found to dominate in both libraries, accounting for 80.9% and 62.9% of the sequences from the yak and cattle clone libraries, respectively. Sequences belonging to the Methanobacteriales represented the second largest clade in both libraries. However, Methanobrevibacter wolinii (QTPC 110) was only found in the cattle library. The number of clones from the order Methanomicrobiales was greater in cattle than in the yak clone library. Although the Shannon index value indicated similar diversity between the two libraries, the Libshuff analysis indicated that the methanogen community structure of the yak was significantly different than those from cattle. CONCLUSION:This study revealed for the first time the molecular diversity of methanogen community in yaks and cattle in Qinghai-Tibetan Plateau area in China. From the analysis, we conclude that yaks have a unique rumen microbial ecosystem that is significantly different from that of cattle, this may also help to explain why yak produce less methane than cattle.

Dataset Information

Methanogenesis from methanol at low temperatures by a novel psychrophilic methanogen, "Methanolobus psychrophilus" sp. nov., prevalent in Zoige wetland of the Tibetan plateau.

Publications

Methanogenesis from methanol at low temperatures by a novel psychrophilic methanogen, "Methanolobus psychrophilus" sp. nov., prevalent in Zoige wetland of the Tibetan plateau.

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