gemmobacter caeni gemmobacter caeni gemmobacter caeni is a gram-negative, rod-shaped, non-spore-forming, strictly aerobic and motile bacterium from the genus of gemmobacter which has been isolated from activated sludge from a butachlor waste water treatment system in nantong in china. gemmobacter caeni scientific classification domain: bacteria phylum: pseudomonadota class: alphaproteobacteria order: rhodobacterales family: rhodobacteraceae genus: gemmobacter species: g. caeni binomial name gemmobacter caeni(zheng et al. 2011) chen et al. 2013 type strain cgmcc 1.7745, dca-1, dsm 21823 synonyms catellibacterium caeni