Abstract
High Zn(2+) concentrations in microalgal cells that produce astaxanthin as a feed additive can reduce the symptoms of malnutrition in aquatic animals. Therefore, in this study, we analysed the effect of Zn(2+) in the culture medium on the growth of a newly isolated microalgal strain Dysmorphococcus globosus ZY24. Zn(2+) and white light stress altered the pigment content in microalgal cells. In addition, high Zn(2+) concentrations in the culture medium altered cell morphology and chlorophyll fluorescence and also increased intracellular Zn(2+) accumulation. Further, an optimal Zn(2+) concentration in the culture medium promoted the synthesis of astaxanthin and other pigments. When the concentration of Zn(2+) was 45.5 mg L(-1), Dysmorphococcus globosus ZY24 produced 0.31 mg g(-1) astaxanthin, whereas the total zinc content of the microalgae was 4337 mg kg(-1). This study confirmed that microalgae have a high capacity for Zn(2+) enrichment, providing a theoretical basis for studying Zn(2+) enrichment in microalgae. Furthermore, Zn(2+) supplementation to stimulate astaxanthin production in microalgae is a practical method to enhance their nutritional value.