azoarcus anaerobius azoarcus anaerobius azoarcus anaerobius is a gram-negative, strictly anaerobic, catalase-negative, nitrate-reducing, rod-shaped bacterium from the genus of azoarcus. azoarcus anaerobius scientific classification domain: bacteria phylum: pseudomonadota class: betaproteobacteria order: rhodocyclales family: rhodocyclaceae genus: azoarcus species: a. anaerobius binomial name azoarcus anaerobiusspringer et al. 1998 type strain dsm 12081, lufres1