Lipid induction of Chlamydomonas reinhardtii CC-124 Using Bicarbonate Ion

Abstract

Algal oils, which can be converted into biofuels, are one of the few possible substitutes for fossil fuels that can be used in conventional transportation systems. The algae have the distinctive advantage of having an exceptionally high productivity much higher than that of terrestrial plant-based oil production. However, the commercial viability of algal oils can only be achieved if the algal lipid content and consequently their productivity are still further enhanced. In this study, bicarbonate ions were investigated for their potential as a lipid-inducing chemical because they are one of the first key substrates in triacylglycerol (TAG) biosynthesis in microalgae. To examine this hypothesis, Chlamydomonas reinhardtii CC-124 was chosen as a model microalgae species, and the TAG content in CC-124 was semi-quantitatively detected by the Nile Red staining method. The highest TAG accumulation was observed for 12.5 g L−1 sodium bicarbonate. At this concentration, the light intensity was found to have a more important role than the cultivation temperature. This result suggests that the simple addition of sodium bicarbonate to a harvested and concentrated algae solution could serve as a facile and effective method for boosting the biofuel productivity of algae.