The production of total lipids in five microalgal species was induced by absence of nitrogen. The microalgae Ankistrodesmus sp., Ankistrodesmus nannoselene, Chlorella sp., Scenedesmus sp. and Scenedesmus quadricauda were cultured in CHU10 medium with and without nitrogen. They were evaluated during six days. The microalgae density was daily determined by a Neubahuer chamber. The average growth, total biomass and total lipids were also determined. The total lipids were extracted with chloroform: methanol (2:1). The results indicated that species with production greater amount of total lipids were Ankistrodesmus sp. (263.6 mg/g dry biomass), Ankistrodesmus nannoselene (316 mg/g dry biomass) and Scenedesmus sp. (243.3 mg/g dry biomass) when grown in media without nitrogen. Scenedesmus quadricauda and Chlorella sp. when grown in media with nitrogen showed higher amount of dry biomass (159.1 mg/g dry biomass and 221.1 mg/g dry biomass respectively) compared to those which were grown in media without nitrogen. The growth rate was variable between species grown in both conditions. In conclusion, Ankistrodesmus sp. microalgae experienced the highest growth rate (0.77 day-1) in medium without nitrogen. Under the same culture conditions, Scenedesmus sp., had the highest biomass production in dry weight (174.7 mg/l) and Ankistrodesmus nannoselene accumulated the highest percentage of total lipids.
- Growth rate