The effects of glucose, sodium thiosulphate and a combination of these two compounds in culture medium on growth kinetics and fatty acid production of Chlorella sp. were investigated. Two different concentrations (2.5 mmol and 5.0 mmol) of both components in culture medium were used. Results showed that glucose induced an increase in cell concentration and sodium thiosulphate enhanced accumulation of fatty acids in the cells. When cells were grown in a medium containing both glucose and sodium thiosulphate, the production of fatty acids depended on the concentration of these two components. At a given glucose concentration, an increase in fatty acid production was obtained by increasing the sodium thiosulphate concentration. In contrast, an increase in glucose concentration caused a decrease in fatty acid production when the sodium thiosulphate concentration was fixed. These results suggest that an appropriate concentration of glucose in combination with sodium thiosulphate can enhance the accumulation of lipids of Chlorclla sp. cells. (C) 2004 Elsevier Ltd. All rights reserved.