anaerobutyricum hallii anaerobutyricum hallii anaerobutyricum hallii (formerly eubacterium hallii) is an anaerobic bacterium that lives inside the human digestive system. anaerobutyricum hallii scientific classification domain: bacteria phylum: bacillota class: clostridia order: eubacteriales family: lachnospiraceae genus: anaerobutyricum species: a. hallii binomial name anaerobutyricum halliishetty et al. 2018 synonyms eubacterium hallii