zoogloea caeni zoogloea caeni zoogloea caeni is a gram-negative, catalase and oxidase-positiv, facultatively aerobic, nitrogen-fixing, rod-shaped motile bacterium with a polar flagellum from the genus of zoogloea which was isolated from activated sludge of a domestic wastewater treatment plant in korea. zoogloea caeni scientific classification domain: bacteria phylum: pseudomonadota class: betaproteobacteria order: rhodocyclales family: rhodocyclaceae genus: zoogloea species: z. caeni binomial name zoogloea caenishao et al. 2009 type strain dsm 19389, emb43, kctc 22084