Enhanced lipid production in Chlorella pyrenoidosa by continuous culture.

Usually microalgae growth and lipid accumulation do not run in parallel throughout cultivation, which necessarily lowers overall lipid productivity. However, we show through batch and feed-batch studies of Chlorella pyrenoidosa XQ-20044 that by varying the nitrate concentration, conditions which produce fairly high lipid content could be achieved without sacrificing algal growth. Simultaneous microalgae growth and lipid production was achieved in continuous chemostat culture when the specific nitrate input rate was in the range of 0.78-4.56mmolg(-1)d(-1). Moreover, the maximum lipid productivity (144.93mgL(-1)d(-1)) in the continuous culture was significantly higher than in batch culture (96.28mgL(-1)d(-1)), thus indicating the feasibility and great advantage of one-step production of microalgal lipids.