Chloracidobacterium thermophilum gen. nov., sp. nov. An anoxygenic microaerophilic chlorophotoheterotrophic acidobacterium

Marcus Tank, Donald A. Bryant

Research output: Contribution to journalArticlepeer-review

71 Scopus citations


A novel anoxygenic photoheterotrophic member of the phylum Acidobacteria, Chloracidobacterium thermophilum strain B sp. nov., was isolated from a cyanobacterial enrichment culture derived from microbial mats associated with Octopus Spring, Yellowstone National Park, WY. C. thermophilum sp. nov. was a Gram-stain-negative rod (diameter, approximately 0.8–1.0 mm; variable length, approximately 2.5 mm), which formed greenish-brown liquid suspension cultures. It was a moderately thermophilic microaerophile and grew in a defined medium at 51 6C (Topt ; range 44 to 58 6C) and in the pH range 5.5 to 9.5 (pHopt 5~7.0). The DNA G+C content was 61.3 mol%, and phylogenetic analysis, based on the 16S rRNA sequence, showed that C. thermophilum sp. nov. belongs to subdivision 4 (Acidobacteriaceae) of the Acidobacteria. C. thermophilum sp. nov. was unable to synthesize branched-chain amino acids, L-lysine, and vitamin B12 , which were required for growth. Although the organism lacked genes/enzymes for autotrophic carbon fixation, bicarbonate was required. Growth was stimulated by other amino acids and 2-oxoglutarate. Cells produced chlorosomes containing a diverse mixture of bacteriochlorophyll (BChl) c derivatives, and additionally, synthesized BChl aP , Chl aPD, and Zn-BChl a9P , which occurred in type-1 homodimeric reaction centres. The carotenoids included echinenone, canthaxanthin, lycopene, c-carotene and b-carotene. C. thermophilum sp. nov. produced iso-diabolic acid as its major fatty acid and synthesized three hopanoids (diploptene, bacteriohopanetetrol and bacteriohopanetetrol cyclitol ether). Based upon its phenotypic and genotypic properties, the name Chloracidobacterium thermophilum gen. nov., sp. nov. is proposed for this isolate; the type strain is C. thermophilum strain BT (ATCC BAA26475JCM 30199).

Original languageEnglish (US)
Pages (from-to)1426-1430
Number of pages5
JournalInternational journal of systematic and evolutionary microbiology
Issue number5
StatePublished - Jun 27 2015

All Science Journal Classification (ASJC) codes

  • Microbiology
  • Ecology, Evolution, Behavior and Systematics


Dive into the research topics of 'Chloracidobacterium thermophilum gen. nov., sp. nov. An anoxygenic microaerophilic chlorophotoheterotrophic acidobacterium'. Together they form a unique fingerprint.

Cite this