halanaerobiales halanaerobiales the halanaerobiales are an order of bacteria placed within the class clostridia, and encompassing two families, the halanaerobiaceae and the halobacteroidaceae. originally placed within the highly polyphyletic class clostridia, according to the ncbi and lpsn, it is now thought to lie outside the bacillota. halanaerobiales are halophilic obligate anaerobes with a fermentative or homoacetogenic metabolism. halanaerobiales scientific classification domain: bacteria phylum: bacillota class: "halanaerobiia" order: halanaerobialescorrig. rainey and zhilina 1995 families halanaerobiaceae oren et al. 1984 halobacteroidaceae zhilina and rainey 1995 phylogeny the currently accepted taxonomy is based on the list of prokaryotic names with standing in nomenclature (lpsn) and national center for biotechnology information (ncbi). 16s rrna based ltp_12_2021 gtdb 07-rs207 by genome taxonomy database anoxybacter halanaerobiaceae halarsenatibacter halothermothrix halocella halanaerobium halobacteroidaceae acetohalobium sporohalobacter fuchsiella zhilina et al. 2012 selenihalanaerobacter halanaerobaculum hedi et al. 2009 halobacteroides natroniella orenia (incl. halonatronum) halanaerobacter dy22613 dy22613 anoxybacter zeng et al. 2015 halanaerobiales "halothermotrichaceae" halocella simankova et al. 1994 halothermothrix cayol et al. 1994 "halarsenatibacteraceae" halarsenatibacter switzer blum et al. 2010 halanaerobiaceae halanaerobium corrig. zeikus et al. 1984 "halobacteroidales" "acetohalobiaceae" acetohalobium zhilina and zavarzin 1990 sporohalobacter oren et al. 1988 "ca.frackibacter" daly et al. 2016 selenihalanaerobacter switzer blum et al. 2001 halobacteroidaceae halobacteroides oren et al. 1984 halanaerobacter corrig. liaw & mah 1996 halonatronum zhilina et al. 2001 orenia rainey & stackebrandt 1995