Scientific classification
Kingdom: Bacteria
Division: Firmicutes
Class: Clostridia Rainey 2010
Order: Thermoanaerobacterales Wiegel 2010
  • Thermoanaerobacteraceae Wiegel 2010
    • Ammonifex Huber and Stetter 1996 emend. Miroshnichenko et al. 2008
    • Caldanaerobacter Fardeau et al. 2004
    • Caldanaerobius Lee et al. 2008
    • Caloribacterium cisternae Slobodkina et al. 2012
    • Carboxydothermus Svetlichny et al. 1991 emend. Novikov et al. 2011
    • Desulfovirgula Kaksonen et al. 2007
    • Gelria Plugge et al. 2002
    • Moorella Collins et al. 1994
    • Tepidanaerobacter Sekiguchi et al. 2006
    • Thermacetogenium Hattori et al. 2000
    • Thermanaeromonas Mori et al. 2002
    • Thermoanaerobacter Wiegel and Ljungdahl 1982 emend. Lee et al. 2007
  • Thermodesulfobiaceae Mori et al. 2004
    • Coprothermobacter Rainey and Stackebrandt 1993
    • Thermodesulfobium Mori et al. 2004
  • Thermoanaerobacterales Family III. Incertae Sedis
    • Caldanaerovirga Wagner et al. 2009
    • Caldicellulosiruptor Rainey et al. 1995 emend. Onyenwoke et al. 2006
    • Syntrophaceticus Westerholm et al. 2011
    • Thermoanaerobacterium Lee et al. 1993 emend. Cann et al. 2001
    • Thermosediminibacter Lee et al. 2006
    • Thermovenabulum Zavarzina et al. 2002
    • Thermovorax Mäkinen et al. 2012
  • Thermoanaerobacterales Family IV. Incertae Sedis
    • Mahella Bonilla Salinas et al. 2004

The Thermoanaerobacteriales are a polyphyletic order of bacteria placed within the polyphyletic class clostridia, and encompassing three families, the Thermoanaerobacteraceae, the Thermodesulfobiaceae, Thermoanaerobacterales Family III. Incertae Sedis and various unplaced genera. This order is noted for the species abilities to survive in environments of extreme elevated temperature. An example organism in this order is Thermoanaerobacterium autearoensis.[1]


The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) [2] and National Center for Biotechnology Information (NCBI)[3] and the phylogeny is based on 16S rRNA-based LTP release 111 by The All-Species Living Tree Project [4]

The Thermoanaerobacteriales as previously mentioned are polyphyletic, and consists of over six morphologically and physiologically similar clades:

  • Clostridium thermoamylolyticumKatkocin et al. 1985
  • Gelria
  • Caldicellulosiruptor
  • Desulfovirgula thermocuniculi Kaksonen et al. 2007
  • Thermanaeromonas toyohensis Mori et al. 2002
  • Thermodesulfobiaceae
  • Thermoanaerobacteraceae


?T. acetatoxydansWesterholm et al. 2011

T. syntrophicus Sekiguchi et al. 2006 (type sp.)


T. gondwanense Ogg et al. 2010

T. ferriorganovorum Zavarzina et al. 2002 (type sp.)


T. litoriperuensis Lee et al. 2006

T. oceani Lee et al. 2006 (type sp.)

Fervidicola ferrireducens Ogg and Patel 2009

Caldanaerovirga acetigignens Wagner et al. 2009

Thermovorax subterraneus Mäkinen et al. 2012


?M. perchloratireducensBalk et al. 2008

M. thermoacetica (Fontaine et al. 1942) Collins et al. 1994 (type sp.)

M. thermoautotrophica (Wiegel et al. 1982) Collins et al. 1994

M. humiferrea Nepomnyashchaya et al. 2012

M. glycerini Slobodkin et al. 1997

M. mulderi Balk et al. 2005

Syntrophaceticus schinkii Westerholm et al. 2011

Thermacetogenium phaeum Hattori et al. 2000


C. pertinax Yoneda et al. 2012

C. islandicus Novikov et al. 2011

C. siderophilus Slepova et al. 2009

C. ferrireducens (Slobodkin et al. 1997) Slobodkin et al. 2006

C. hydrogenoformans Svetlichny et al. 1991 (type sp.)

Mahella australiensis Bonilla Salinas et al. 2004


C. fijiensis Lee et al. 2008 (type sp.)

C. polysaccharolyticus (Cann et al. 2001) Lee et al. 2008

C. zeae (Cann et al. 2001) Lee et al. 2008

Caloribacterium cisternae Slobodkina et al. 2012


?T. bryantiiStroot et al. 2002

?T. islandicumOrlygsson & Baldursson 2006

T. aotearoense Liu et al. 1996

T. thermostercoris Romano et al. 2011

T. thermosaccharolyticum (McClung 1935) Collins et al. 1994

Thermohydrogenium kirishiense Zacharova et al. 1996

T. aciditolerans Kublanov et al. 2007

T. saccharolyticum Lee et al. 1993

T. thermosulfurigenes (Schink and Zeikus 1983) Lee et al. 1993 (type sp.)

T. xylanolyticum Lee et al. 1993

International Journal of Systematic Bacteriology or International Journal of Systematic and Evolutionary Microbiology (IJSB/IJSEM) published species that are in press.
♠ Strains found at the National Center for Biotechnology Information (NCBI) but not listed in the List of Prokaryotic names with Standing in Nomenclature (LPSN).