Page 66 - Microbial methane cycling in a warming world From biosphere to atmosphere Michiel H in t Zandt

Chapter 3. Metal corrosion protection potential of methanogenic communities
quality-processed read data sets. Protein blasts (BLASTP) resulted in the most AckA hits for DL to the Deltaproteobacterium bacterium HGW species from a groundwater metagenome study (11.6%) (Hernsdorf et al. 2017), whereas AS reads mostly mapped to the Bacteroidetes bacterium RBG from sediment metagenomes (11.0%) (Anantharaman et al. 2016) (Table S6). For ACS, most DL reads matched to Methanobacterium species from coal seam gas formation water (11.0%) (Rosewarne et al. 2013), Methanoregulaceae from sediment metagenomes (5.3%) (Dalcin Martins et al. 2018), and Bathyarchaeota (4.3%) (Anantharaman et al. 2016; Probst et al. 2018a). Of the ACS reads, 19.3% were most identical to HGW species from a groundwater metagenome study (Hernsdorf et al. 2017). For AS, 29.8% of the sequences showed highest identity to Bathyarchaeota ACS sequences from sediment metagenomes (Anantharaman et al. 2016), groundwater metagenomes (Probst et al. 2018b) and hot springs metagenomes (Wilkins et al. 2018). A total of 12.6% of the ACS reads mapped to Chloroflexi sequences from sediment metagenomes (Anantharaman et al. 2016) (Table S7). These findings are supported by 16S rRNA gene read analyses that indicate that Bathyarchaeota are more abundant and potentially have a central role in organic matter degradation in AS.
Potentially heterotrophic Bathyarchaeota and the candidate phylum Atribacteria (JS1) were more abundant in adjacent sediment
Bathyarchaeota are generally described as heterotrophic microorganisms with the genomic potential to metabolize cellulose, lignin, and aromatic compounds (Evans et al. 2015; He et al. 2016; Yu et al. 2018). They were previously detected in methanogenic communities, where they can have close spatial associations with Methanomicrobia (Narrowe et al. 2017; Xiang et al. 2017). Interestingly, a study by Xiang et al. (2017a) found a significant correlation between occurrence of Bathyarchaeota and Methanomicrobia, indicating a potential syntrophic association between the two phyla. Here, we also observed the cooccurrence of Methanomicrobiales (2.9% in DL and 1.1% in AS [sample 2]) and Bathyarchaeota (5.1% in DL and 14.7% in AS). Their role in methane cycling communities, however, still needs to be elucidated.
Candidate phylum Atribacteria (JS1) is found globally in anoxic marine sediments, deep biospheres and petroleum reservoirs (Webster et al. 2007; Rastogi et al. 2010; Nobu et al. 2016a). Genomic data mining indicates that candidate phylum JS1 species most probably have
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