A Novel Miniature Culture System to Screen CO₂-Sequestering Microalgae

In this study, a novel 96-well microplate swivel system (M96SS) was built for high-throughput screening of microalgal strains for CO₂ fixation. Cell growth under different CO₂ supply conditions (0.2, 0.4, 0.8, and 1.2 gL⁻¹d⁻¹), residual nitrate, and pH value of <i>Chlorella</i> sp. SJTU-3,<i> Chlorella pyrenoidosa </i>SJTU-2, and<i> </i><i>Scenedesmus obliquus</i> SJTU-3 were examined in the M96SS and traditional flask cultures. The dynamic data showed there was a good agreement between the systems. Two critical problems in miniature culture systems (intra-well mixing and evaporation loss) were improved by sealed vertical mixing of the M96SS. A sample screen of six microalgal species (<i>Chlorella</i> sp. SJTU-3,<i> Chlorella pyrenoidosa </i>SJTU-2,<i> </i><i>Selenastrum capricornutum</i>, <i>Scenedesmus obliquus</i> SJTU-3,<i> Chlamydomonas sajao</i>,<i> Dunaliella primolecta</i>) was carried out in flasks and the M96SS. <i>Chlamydomonas sajao</i> appeared to be a robust performer (highest cell density: 1.437 g L⁻¹) in anaerobic pond water with 0.8, and 1.2 gL⁻¹d⁻¹ CO₂. The reliability and efficiency of the M96SS were verified through a comparison of traditional flask culture, M96SS, Lukavský’s system, and a microplate shaker.