AbstractBatch and continuous cultivations were used to investigate the single cell protein (SCP) production byCephalosporium eichhorniae152 in an air‐lift reactor. The fungus was grown in an 8L air‐lift fermenter. The culture medium consisted of cassava as a sole‐carbon source, (NH4)2SO4as a nitrogen source and KH2PO4as a buffering agent. The pH of the medium was adjusted to 3.8 and was controlled during fermentation by using an automatic pH‐controller via 0.5 N NaOH. In batch fermentation, 1% of cassava gave the highest yield of 0.4. The optimum condition for continuous fermentation was 1% cassava in feed medium at a dilution rate of 0.4 h‐1(396 ml/h where 0.35 was the final yield. The productivity of continuous culture was found to be higher than that of the batch culture (0.135 g/l.h versus 0.04 g/lh).