High-lipid density culture of chlorella sp. ABC-001

Abstract

Global warming is a critical issue caused by excessive use of fossil fuel. Bio-fuel produced from the lipids of microalgae with no carbon footprint has become a promising alternative to fossil fuel, which can significantly contribute to the prevention of climate-change like global warming. Microalgae are also a promising source of a variety of valuable biochemicals. The production of biofuel and/or biochemical from microalgae consists of many process steps such as strain development, cultivation, harvesting, oil extraction, and conversion. Among them, a high level of lipid productivity at the step of cultivation is critical to produce biofuel at a reasonable price. Up to date, photoautotrophic cultivation has been widely used. However, it is not cost effective mainly because of its low lipid productivity. On the other hand, heterotrophic cultivation by using an organic carbon source is expected very effective in realizing a high lipid productivity. In this study, three different strategies of heterotrophic cultivation of Chlorella ABC001 on glucose were tested and compared one another: batch culture, fed-batch culture with one-time intermittent feeding and fed-batch culture with multi-step divided feeding. With the multi-step feeding strategy, the highest biomass productivity and lipid productivity of 4.5 g/L/day and 1.3 g/L/day, respectively were obtained. Effects of trace metals were also examined.