Presence of a Novel Methanogenic Archaeal Lineage in Anaerobic Digesters Inferred from &lt;I&gt;mcrA&lt;/I&gt; and 16S rRNA Gene Phylogenetic Analyses

Saito, Yayoi; Aoki, Masataka; Hatamoto, Masashi; Yamaguchi, Takashi; Takai, Ken; Imachi, Hiroyuki

doi:10.2965/jwet.2015.279

Cited by 10 publications

(3 citation statements)

References 31 publications

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“…A methylotrophic methanogen was also detected at comparatively lower abundance in all cultures ( Methanomethylovorans ), but was most abundant in the n -alkane-amended cultures (0.14–0.62% of hexadecane and octadecane communities, respectively). In addition, the archaeon WCHA1-57 (possibly a novel lineage of methanogens, Saito et al, 2015 ) was also particularly abundant in the octadecane degrading culture ( Table 2 ).…”

Section: Resultsmentioning

confidence: 99%

Community Structure in Methanogenic Enrichments Provides Insight into Syntrophic Interactions in Hydrocarbon-Impacted Environments

2016

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The methanogenic biodegradation of crude oil involves the conversion of hydrocarbons to methanogenic substrates by syntrophic bacteria and subsequent methane production by methanogens. Assessing the metabolic roles played by various microbial species in syntrophic communities remains a challenge, but such information has important implications for bioremediation and microbial enhanced energy recovery technologies. Many factors such as changing environmental conditions or substrate variations can influence the composition and biodegradation capabilities of syntrophic microbial communities in hydrocarbon-impacted environments. In this study, a methanogenic crude oil-degrading enrichment culture was successively transferred onto the single long chain fatty acids palmitate or stearate followed by their parent alkanes, hexadecane or octadecane, respectively, in order to assess the impact of different substrates on microbial community composition and retention of hydrocarbon biodegradation genes. 16S rRNA gene sequencing showed that a reduction in substrate diversity resulted in a corresponding loss of microbial diversity, but that hydrocarbon biodegradation genes (such as assA/masD encoding alkylsuccinate synthase) could be retained within a community even in the absence of hydrocarbon substrates. Despite substrate-related diversity changes, all communities were dominated by hydrogenotrophic and acetotrophic methanogens along with bacteria including Clostridium sp., members of the Deltaproteobacteria, and a number of other phyla. Microbial co-occurrence network analysis revealed a dense network of interactions amongst syntrophic bacteria and methanogens that were maintained despite changes in the substrates for methanogenesis. Our results reveal the effect of substrate diversity loss on microbial community diversity, indicate that many syntrophic interactions are stable over time despite changes in substrate pressure, and show that syntrophic interactions amongst bacteria themselves are as important as interactions between bacteria and methanogens in complex methanogenic communities.

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Section: Resultsmentioning

confidence: 99%

Community Structure in Methanogenic Enrichments Provides Insight into Syntrophic Interactions in Hydrocarbon-Impacted Environments

2016

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“…However, one potentially class-level Euryarchaeota clade thought to be capable of methanogenesis, WSA2 (or Arc 1), (Hugenholtz 2002;Chouari et al, 2005) remains uncharacterized, despite the identification through 16S ribosomal RNA (rRNA) sequencing more than 15 years ago (Dojka et al, 1998). Moreover, members of this clade have been observed in a wide range of natural and engineered environments (for example, freshwater and marine sediments, contaminated groundwater and bioreactors; Dhillon et al, 2005;Cheng et al, 2012;Saito et al, 2015;Wilkins et al, 2015). To fill this gap in our understanding of methanogen phylogeny and WSA2's potential roles in anaerobic biogeochemical cycles, we construct the first WSA2 genomes through metagenomics of methanogenic bioreactors treating wastewater.…”

Section: Introductionmentioning

confidence: 99%

Chasing the elusive Euryarchaeota class WSA2: genomes reveal a uniquely fastidious methyl-reducing methanogen

et al. 2016

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The ecophysiology of one candidate methanogen class WSA2 (or Arc I) remains largely uncharacterized, despite the long history of research on Euryarchaeota methanogenesis. To expand our understanding of methanogen diversity and evolution, we metagenomically recover eight draft genomes for four WSA2 populations. Taxonomic analyses indicate that WSA2 is a distinct class from other Euryarchaeota. None of genomes harbor pathways for CO 2 -reducing and aceticlastic methanogenesis, but all possess H 2 and CO oxidation and energy conservation through H 2 -oxidizing electron confurcation and internal H 2 cycling. As the only discernible methanogenic outlet, they consistently encode a methylated thiol coenzyme M methyltransferase. Although incomplete, all draft genomes point to the proposition that WSA2 is the first discovered methanogen restricted to methanogenesis through methylated thiol reduction. In addition, the genomes lack pathways for carbon fixation, nitrogen fixation and biosynthesis of many amino acids. Acetate, malonate and propionate may serve as carbon sources. Using methylated thiol reduction, WSA2 may not only bridge the carbon and sulfur cycles in eutrophic methanogenic environments, but also potentially compete with CO 2 -reducing methanogens and even sulfate reducers. These findings reveal a remarkably unique methanogen 'Candidatus Methanofastidiosum methylthiophilus' as the first insight into the sixth class of methanogens 'Candidatus Methanofastidiosa'.

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“…After a significant decrease of the relative abundance to only 1% on day 150, the relative abundance of unassigned WCHA1-57 increases to dominates the archaeal community at the last stage of operation of the reactor. The uncultured archaeal group WCHA1-57 (also called WSA2 or ARC I) may represent a new order of hydrogenotrophic methanogens that contributes to methane production in anaerobic digesters (Saito et al, 2015).…”

Section: Archaeal Community Dynamicsmentioning

confidence: 99%

Energy conservation mechanisms and electron transfer in syntrophic propionate-oxidizing microbial consortia

Núñez¹,

Tonamellotl²

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Table of contents Chapter 1 General introduction and thesis outline Chapter 2 A genomic comparison of syntrophic and non-syntrophic butyrate-and propionate-degrading bacteria points to a key role of formate in syntrophy Chapter 3 Metabolic flexibility of Syntrophobacter fumaroxidans: Syntrophic vs sulfate-reducing lifestyle during growth on propionate Chapter 4 Comparative proteome analysis of propionate degradation by Syntrophobacter fumaroxidans in pure culture and in coculture with methanogens Chapter 5 Proteomic analyses of Methanospirillum hungatei and Methanobacterium formicicum grown in a syntrophic partnership with Syntrophobacter fumaroxidans and in pure culture with H2/CO2 or formate. Chapter 6 Microbial community analysis and performance of a mesophilic anaerobic membrane bioreactor treating pot ale Chapter 7 General discussion

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Presence of a Novel Methanogenic Archaeal Lineage in Anaerobic Digesters Inferred from <I>mcrA</I> and 16S rRNA Gene Phylogenetic Analyses

Cited by 10 publications

References 31 publications

Community Structure in Methanogenic Enrichments Provides Insight into Syntrophic Interactions in Hydrocarbon-Impacted Environments

Community Structure in Methanogenic Enrichments Provides Insight into Syntrophic Interactions in Hydrocarbon-Impacted Environments

Chasing the elusive Euryarchaeota class WSA2: genomes reveal a uniquely fastidious methyl-reducing methanogen

Energy conservation mechanisms and electron transfer in syntrophic propionate-oxidizing microbial consortia

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