derxia derxia derxia is a genus of gram-negative, nitrogen-fixing bacteria from the family of alcaligenaceae. derxia scientific classification domain: bacteria phylum: pseudomonadota class: betaproteobacteria order: burkholderiales family: alcaligenaceae genus: derxiajensen et al. 1960 type species derxia gummosa species d. gummosa d. lacustris