2014-10-13

Autotrophic CO2 fixation is the most important biotransformation process in the biosphere. Research focusing on the diversity and distribution of relevant autotrophs is significant to our comprehension of the biosphere. In this study, a draft genome of a bacterium from candidate phylum SBR1093 was reconstructed with the metagenome of an industrial activated sludge. Based on comparative genomics, this autotrophy may occur via a newly discovered carbon fixation path, the hydroxypropionate-hydroxybutyrate (HPHB) cycle, which was demonstrated in a previous work to be uniquely possessed by some genera from Archaea. This bacterium possesses all of the thirteen enzymes required for the HPHB cycle; these enzymes share 30∼50% identity with those in the autotrophic species of Archaea that undergo the HPHB cycle and 30∼80% identity with the corresponding enzymes of the mixotrophic species within Bradyrhizobiaceae. Thus, this bacterium might have an autotrophic growth mode in certain conditions. A phylogenetic analysis based on the 16S rRNA gene reveals that the phylotypes within candidate phylum SBR1093 are primarily clustered into 5 clades with a shallow branching pattern. This bacterium is clustered with phylotypes from organically contaminated environments, implying a demand for organics in heterotrophic metabolism. Considering the types of regulators, such as FnR, Fur, and ArsR, this bacterium might be a facultative aerobic mixotroph with potential multi-antibiotic and heavy metal resistances. This is the first report on Bacteria that may perform potential carbon fixation via the HPHB cycle, thus may expand our knowledge of the distribution and importance of the HPHB cycle in the biosphere.

Wang, Z, Guo, F, Liu, L, Zhang, T. (2014). Data from: Evidence of Carbon Fixation Pathway in a Bacterium from Candidate Phylum SBR1093 Revealed with Genomic Analysis. [Data File]. The authors confirm that all data underlying the findings are fully available without restriction. Data are deposited on web of MG-RAST with accession number 4539207.3.
Click on “Linked Publications” to access the publication and access supporting information on figshare at https://figshare.com/articles/_Evidence_of_Carbon_Fixation_Pathway_in_a_Bacterium_from_Candidate_Phylum_SBR1093_Revealed_with_Genomic_Analysis_/1202840

autotrophic growth mode

HPHB cycle

Candidate Phylum SBR 1093 Revealed

enzyme

16 S rRNA gene

phylotype

biosphere

archaea

species

Carbon Fixation Pathway

bacterium

Genomic Analysis Autotrophic CO 2 fixation

carbon fixation path

identity

candidate phylum SBR 1093