Rhodococcus ruber colonies on nutrient agar: (A) strain IEGM 333, (B) strain IEGM 71; on mineral salts agar in the presence of n-hexadecane: (C) strain IEGM 235, (D) strain IEGM 231 or propane: (E) strain IEGM 231, (F) strain IEGM 333
