bacillus gibsonii bacillus gibsonii bacillus gibsonii is a facultative anaerobe bacterium. it is a gram positive, alkaliphilic and alkalitolerant, aerobic endospore-forming bacteria. bacillus gibsonii scientific classification domain: bacteria phylum: bacillota class: bacilli order: bacillales family: bacillaceae genus: bacillus species: b. gibsonii binomial name bacillus gibsoniinielsen et al. 1995 this species has been recently transferred into the genus alkalihalobacillus. the correct nomenclature is alkalihalobacillus gibsonii.