psychrobacter aquaticus psychrobacter aquaticus psychrobacter aquaticus is a gram-negative, psychrophilic, halotolerant, nonmotile bacterium of the genus psychrobacter which was isolated from the mcmurdo dry valley region of antarctica. psychrobacter aquaticus scientific classification domain: bacteria phylum: pseudomonadota class: gammaproteobacteria order: pseudomonadales family: moraxellaceae genus: psychrobacter species: p. aquaticus binomial name psychrobacter aquaticusshivaji et al. 2005 type strain cip 108799, cms 56, dsm 15339, mtcc 4386