AbstractFermentations for the overproduction of citrate and isocitrate withS. lipolyticain media containing both glucose andn‐alkanes as mixed C‐source have been performed. Biomass and product yields strongly depend on the C‐source of the inoculation culture. If the inoculation culture had been taken from media containing glucose as sole C‐source both glucose andn‐alkanes were utilized for cell growth in the main culture whereas only glucose was utilized if the inoculation medium contained onlyn‐alkanes.For idiophasic citrate and isocitrate production both glucose andn‐alkanes were consumed independently of the C‐source of the inoculum but that C‐source was preferentially utilized which has been the C‐source of the inoculation culture.These findings are reflected by the activities of the isocitrate lyase and the pyruvate carboxylase, respectively. InS. lipolyticaboth anaplerotic pathways are coexisting but the C‐source of the inoculation culture determines the level of the specific activities even if the ratio of the cell‐mass of the inoculum to the cell‐mass of the main culture at the end of the g