marinobacterium jannaschii marinobacterium jannaschii marinobacterium jannaschii is a gram-negative bacterium. the cells are straight rods. it was isolated from seawater. marinobacterium jannaschii scientific classification domain: bacteria phylum: pseudomonadota class: gammaproteobacteria order: alteromonadales family: alteromonadaceae genus: marinobacterium binomial name marinobacterium jannaschii(bowditch et al. 1984) satomi et al. 2002 synonyms oceanospirillum jannaschii