Intracytoplasmic membrane induction by hexadecane in Acinetobacter calcoaceticus

Acinetobacter calcoaceticus 69‐V is capable of utilizing n‐alkanes as the sole carbon source. By conventional and high voltage electron microscopy the fine‐structure of these bacteria grown on hexadecane (with or without addition of DL‐carnitine), succinate or yeast extract was analysed. A. calcoaceticus grown on hexadecane exhibited intracytoplasmic unit membrane aggregates in contrast to controls grown on the nonhydrocarbon substrates. Probably these aggregates are formed by the cytoplasmic membrane. Most of these membranes are surrounding and penetrating hexadecane inclusions. Ultrastructurally no essential difference caused by addition of carnitine could be seen. The results suggest that the membrane aggregates are the sites of enzymes which are required for the utilization of hexadecane.