hellea hellea hellea is a gram-negative, aerobic and heterotrophic genus of bacteria from the family of hyphomonadaceae with only one known species (hellea balneolensis). hellea scientific classification domain: bacteria phylum: pseudomonadota class: alphaproteobacteria order: caulobacterales family: hyphomonadaceae genus: helleaalain et al. 2008 species h. balneolensis