Enhancing microalgal oil/lipid production from Chlorella sorokiniana CY1 using deep-sea water supplemented cultivation medium

Engineering strategies were applied in this study to promote the autotrophic growth and oil accumulation of an oil-rich indigenous microalga Chlorella sorokiniana CY1 using deep-sea water (DSW) as the medium. The addition of 20% DSW to the culture medium effectively enhanced the cell growth and oil accumulation of C. sorokiniana CY1, leading to an oil content and biomass concentration of 61.0% and 3.0 g/L, respectively. The microalga strain was also successfully grown in 5 L plastic bag-type photobioreactor on DSW-amended medium, obtaining an oil content, biomass concentration, and biomass productivity of 51.7%, 2.4 g/L, and 176.6 mg/L/d, respectively. The semi-batch cultivation resulted in stable biomass production, but the lipid production efficiency slightly decreased. The main fatty acids in the lipid produced from C. sorokiniana CY1 were palmitic acid (C16:0), stearic acid (C18:0), oleic acid (C18:1), linoleic acid (C18:2) and eicosenoic acid (C20:1). This lipid quality is suitable for biodiesel production.