rhizobium hainanense rhizobium hainanense rhizobium hainanense is a gram negative root nodule bacteria. strain ccbau 57015 (166) is the type strain. rhizobium hainanense scientific classification domain: bacteria phylum: pseudomonadota class: alphaproteobacteria order: hyphomicrobiales family: rhizobiaceae genus: rhizobium species: r. hainanense binomial name rhizobium hainanensechen et al. 1997