AbstractIn hydrocarbon fermentation, the efficiency of hydrocarbon uptake by cells ins one of the keys to the economical production of single‐cell protein. This work is concerned with characterization of cultures with two liquid phases for understanding the hydrocarbon uptake process by cells. Batch cultivation ofCandida lipolyticawas carried out in shaking flasks and in a tower fermentor with motionless mixers. Micorscopic observation and cell and hydrocarbon concentration distribution in batch cultivation showed that some cells are attached to the large oil drops ad others are free from them. Interfacial tension between oil and water and Sauter mean drop size decreased as cultivation proceeded. On the basis of the experimental results, the process of hydrocarbon uptake by cells is discusse