Coproduction of lipids and carotenoids by the novel green alga Coelastrella sp. depending on cultivation conditions
Mizuki Saito, Haruka Watanabe, Mitsuki Sasaki, Madoka Ookubo, Takashi Yarita, Masakazu Shiraiwa, Munehiko Asayama
Abstract
A novel green alga Coelastrella sp. D3–1 was isolated, and its unique and significant lipid and carotenoid coproduction capability was characterised depending on cultivation conditions. The main component of produced lipids was triacylglycerol under nutrient depletion conditions, in which fatty-methyl-esters made up 20−44% of the dry cell weight (DCW) and consisted of abundant C16:0 and C18:1 fatty acids. The red (orange)-stage cells also produced a large portion of carotenoids (38.5% of the DCW) involving echinenone, canthaxanthin, and astaxanthin as major components accumulated over only 5–6 days under optimal conditions. Stress tests revealed resistance of the cells to pH 2–11, high temperatures (40–60 °C), ultraviolet irradiation, drought, and H2O2 treatment, thereby showing a robust nature. Both green- and red (orange)-stage cell extracts also showed antioxidant and anti-inflammatory abilities, implying that they have significant functions as useful biorefinery materials.