Glucose addition-induced changes in the growth and chemical compositions of a freshwater microalga Chlorella kessleri

BACKGROUND In recent years, mixotrophic culture of algal cells has been gaining increasing interest, largely because it offers an efficient means of commercial production of lipids and other value-added products. In this work, the impacts of glucose addition on the biomass production, chemical composition and fatty acid profiles of Chlorella kessleri were investigated to exploit the relationships between extra organic carbon and changes in the distribution of chemical compositions in algal cells. RESULTS Results showed that C. kessleri grew fast in the mixotrophic cultures with a maximum algal biomass and specific growth rate of 4.46 g L-1 and 1.27 day(-1), respectively. Glucose in the cultures was absorbed and utilized effectively by this alga, whose uptake efficiencies ranged from 88.2% to 98.3%, but it had a negative impact on the synthesis of photosynthetic pigments. Additionally, the culture's pH and chemical composition, including pigments, carbohydrate, protein and lipids, in this alga varied with the change of glucose concentrations in the cultures. The fatty acid profiles of this alga indicated that its biomass could be used as live feeds in aquaculture or a good-quality feedstock for biodiesel production. CONCLUSIONS These results suggested that adding an extra organic carbon source (glucose) to a photoautotrophic culture was a potentially effective way to improve the performance in mixotrophically culture of microalgae, for example in terms of higher biomass and lipid production. (c) 2018 Society of Chemical Industry