roseomonas lacus roseomonas lacus roseomonas lacus is a species of gram negative, strictly aerobic, coccobacilli-shaped, pale pink-colored bacterium. it was first isolated from a freshwater sediment from lake tai in jiangsu province, china, and the species was first proposed in 2006. the species name comes from latin lacus (lake). roseomonas lacus scientific classification domain: bacteria phylum: pseudomonadota class: alphaproteobacteria order: rhodospirillales family: acetobacteraceae genus: roseomonas species: r. lacus binomial name roseomonas lacusjiang 2006 the optimum growth temperature for r. lacus is 30 °c, but can grow in the 15-40 °c range. the optimum ph is 7.0, and can grow in ph 6.0-9.0.