Differences down-under: alcohol-fueled methanogenesis by archaea present in Australian macropodids

Hoedt, Emily C., O Cuiv, Paraic, Evans, Paul N., Smith, Wendy J., McSweeney, Chris S., Denman, Stuart E. and Morrison, Mark (2016) Differences down-under: alcohol-fueled methanogenesis by archaea present in Australian macropodids. ISME Journal, 10 10: 2376-2388. doi:10.1038/ismej.2016.41

Author Hoedt, Emily C.
O Cuiv, Paraic
Evans, Paul N.
Smith, Wendy J.
McSweeney, Chris S.
Denman, Stuart E.
Morrison, Mark
Title Differences down-under: alcohol-fueled methanogenesis by archaea present in Australian macropodids
Journal name ISME Journal   Check publisher's open access policy
ISSN 1751-7362
Publication date 2016-03-29
Sub-type Article (original research)
DOI 10.1038/ismej.2016.41
Open Access Status Not Open Access
Volume 10
Issue 10
Start page 2376
End page 2388
Total pages 13
Place of publication London, United Kingdom
Publisher Nature Publishing Group
Collection year 2017
Language eng
Formatted abstract
The Australian macropodids (kangaroos and wallabies) possess a distinctive foregut microbiota that contributes to their reduced methane emissions. However, methanogenic archaea are present within the macropodid foregut, although there is scant understanding of these microbes. Here, an isolate taxonomically assigned to the Methanosphaera genus (Methanosphaera sp. WGK6) was recovered from the anterior sacciform forestomach contents of a Western grey kangaroo (Macropus fuliginosus). Like the human gut isolate Methanosphaera stadtmanae DSMZ 3091T, strain WGK6 is a methylotroph with no capacity for autotrophic growth. In contrast, though with the human isolate, strain WGK6 was found to utilize ethanol to support growth, but principally as a source of reducing power. Both the WGK6 and DSMZ 3091T genomes are very similar in terms of their size, synteny and G:C content. However, the WGK6 genome was found to encode contiguous genes encoding putative alcohol and aldehyde dehydrogenases, which are absent from the DSMZ 3091T genome. Interestingly, homologs of these genes are present in the genomes for several other members of the Methanobacteriales. In WGK6, these genes are cotranscribed under both growth conditions, and we propose the two genes provide a plausible explanation for the ability of WGK6 to utilize ethanol for methanol reduction to methane. Furthermore, our in vitro studies suggest that ethanol supports a greater cell yield per mol of methane formed compared to hydrogen-dependent growth. Taken together, this expansion in metabolic versatility can explain the persistence of these archaea in the kangaroo foregut, and their abundance in these ‘low-methane-emitting’ herbivores.
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: HERDC Pre-Audit
School of Chemistry and Molecular Biosciences
UQ Diamantina Institute Publications
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Created: Fri, 01 Apr 2016, 14:53:45 EST by Mrs Louise Nimwegen on behalf of School of Chemistry & Molecular Biosciences