Development of a Mixotrophic Strategy for Efficient Cultivation of a Coccolithophore, Chrysotila roscoffensis

Coccolithophores have unique ability of dual carbon fixation（photosynthesis and biocalcification） and can accumulate bioactive compounds effectively, thereby showing huge potential for CO2 bioremediation and simultaneous production of valueadded substances. However, biotechnological exploration of these microalgae is still very limited. In order to develop efficient cultivation strategies of these organisms, we tested the abilities of Chrysotila roscoffensis, a coccolithophore, to grow under mixotrophic and heterotrophic cultivation conditions. It was confirmed that only glycerol stimulated the cell growth of this microalga in the presence of light. To study the physiological significance of mixotrophy, we conducted cell culture experiments both autotrophically and mixotrophically, the only difference of which was optimal amount of glycerol was added under mixotrophic conditions. The results showed that the addition of glycerol substantially enhanced the lipids and monounsaturated fatty acids accumulation of C. roscoffensis, but imposed slight influences on the photosynthetic capacity, pigments content, polyunsaturated fatty acids content, and biocalcification. We concluded that mixotrophy might be an appropriate strategy for exploration of this species for production of high value molecules.