petrobacter petrobacter petrobacter is a genus of gram-negative, non-spore-forming bacteria from the family of rhodocyclaceae which belongs to the class of betaproteobacteria. so fare there is only one species known (petrobacter succinatimandens). petrobacter scientific classification domain: bacteria phylum: pseudomonadota class: betaproteobacteria order: rhodocyclales family: rhodocyclaceae genus: petrobacterbonilla salinas et al. species: petrobacter succinatimandens type species petrobacter succinatimandens