Selection of microalgae strains for bicarbonate-based integrated carbon capture and algal production system to produce lipid

Abstract

ABSTRACT Microalgae culture with a high concentration of bicarbonate has many advantages, but oleaginous algal strains tolerant to high alkalinity are very few. To obtain more strains with capabilities of both high lipid accumulation and high bicarbonate concentration tolerance, six strains of microalgae were investigated in this study. The results showed that Neochloris oleoabundans and Dunaliella tertiolecta could tolerate as high as 320 mM NaHCO3 concentration, while seawater Chlorella sp., Picochlorum oklahomensis and Chaetoceros calcitrans could tolerate 80 mM NaHCO3 concentration, and Isochrysis galbana was tolerant to only 40 mM. N. oleoabundans was selected for further study to optimize its lipid production. With Plackett-Burman design, it was found that MgSO4·7H2O and NaNO3 were significant factors for N. oleoabundans’ growth, while ZnSO4·7H2O and NaNO3 were significant factors against its lipid production. The optimal levels of significant factors in the Plackett-Burman design system were determined with a central composite design. Dry cell weight of N. oleoabundans under optimized condition was 1.56 g/L, and lipid content was 23.4%. This showed that N. oleoabundans is a promising strain for lipid production in a high bicarbonate concentration environment.