Abstract: This invention relates to new Rhodococcus wratislaviensis CNCM I-4088 bacteria or Rhodococcus aetherivorans CNCM I-4089 bacteria that can degrade multiple petroleum compounds in solution in aqueous effluents. The invention also relates to a process for treating aqueous effluents comprising a complex mixture of substances containing native hydrocarbons of gasolines and additives that are present in gasolines or diesel fuel, in which process said bacteria are grown under aerobic conditions in the presence of a growth substrate containing said mixture as a carbon source, and said mixture is at least partially degraded by the bacteria down to the final degradation products—carbon dioxide, water and biomass.