Abstract:
We investigated the biological characteristics of the alga
Eustigmatos vischeri Hibberd, and explored the effects of four cultivation modes (batch, two-stage, fed-batch and bicarbonate-addition culture) on its growth and lipid accumulation. We cultured
E.
vischeri by supplying different initial sodium nitrate, which was replaced with fresh medium, with a small amount of sodium nitrate and low concentrations of sodium bicarbonate or ammonium bicarbonate added. The biomass concentration in the batch culture reached 8.41 g/L, while the highest total lipid content was 65.16% and productivity was 0.30 g·L
-1·d
-1. Compared to the batch culture, the two-stage and fed-batch cultures had no significant effect on lipid accumulation in
E.
vischeri. However, the bicarbonate-addition culture did have a significant effect on growth and lipid accumulation, especially maximum biomass concentration in the NaNO
3+NH
4HCO
3 group, which reached 11.56 g/L, and total lipid content reached 60.92%. Thus, the biomass concentration and total lipid content increased by almost 1.0 g/L and 10%, respectively, compared with that in the batch culture under the same nitrogen concentration. In addition, the productivity of total lipids also increased (0.39 g·L
-1·d
-1). Our results indicated that
E. vischeri is an oleaginous microalga with high development and utilization value. Moreover, the addition of a low concentration of ammonium bicarbonate promoted the growth and lipid accumulation of
E. vischeri, and is thus a suitable method for cultivation.