微藻，作为阳光驱动的细胞工厂，具有生产高附加值生物活性化合物的重要潜力。近年来，微藻生物质生产引起了全球的广泛关注。能同时驱动自养与异养的混养模式因具有高生长速率和生物量产量的特性，是一种理想的微藻生物量生产方式，但目前对混养条件下的微藻促生机制还缺乏深入的认识。且混养模式尚未在微藻规模化生产中运行，这主要受限于生产和收获成本高以及有机碳源的添加引起的菌污染问题严重。本文以虾青素生产的有力候选者佐夫色绿藻（Chromochloris zofingiensis）为研究对象，从混养机制、控菌策略以及生物反应器放大培养三方面展开研究，得到的主要结论如下： （1）混养条件下佐夫色绿藻的生物量显著高于自养与异养条件下生物量之和。叶绿素荧光和转录组结果显示，与自养相比，混养藻细胞具有更好的光合作用性能，光呼吸和氧化损伤减少，葡萄糖代谢显著上调；与异养相比，混养藻细胞单位葡萄糖的生物量产量更高，但葡萄糖代谢下调。基于此我们提出了混养条件下光合作用和葡萄糖代谢的协同促生机制，即藻细胞不仅直接受益于外源有机碳代谢产生的能量，还受益于细胞内光合作用副产物CO2的再利用，反过来，光合作用产生的O2可以被葡萄糖代谢消耗，CO2和O2间高效的推拉效应促进生物量生产。 （2）分批实验结果表明，控制培养体系中碳氮磷的浓度均可以显著性的控制菌污染；补料分批实验结果表明，同时控碳氮磷浓度，即仅提供藻生长所需的碳氮磷营养可以达到最佳的控菌效果，这一结论在5 L生物反应器中也得到验证。营养限制的策略可以在不影响藻生长的前提下有效控制微藻混养培养中的菌污染。 （3）以干湿交替模式进行固定化附着培养，用水量小且收获简单。提高附着材料表面粗糙度后，生物量产量达到8.53 g/m2/d。培养方式的不同使藻生理及生化组成差异显著。固定化环境使附着藻能量消耗少，更多能量用于存储化学物质和进行细胞分裂，同时气相CO2的供给利于混养光合作用，进而提高附着培养生物量。将收集的藻进行高光、缺氮与盐胁迫协同诱导，最终虾青素含量达到2.0 mg/g。 本文围绕藻类规模化培养目标，开展了自养、异养与混养培养的比较研究并阐明了混养条件下快速生长的机制；针对混养培养易受菌污染的问题，提出了营养限制的控菌策略；最后运用混养及控菌策略，探究了干湿交替式固定化附着培养的效果和机制；研究结果为微藻工业化生产提供了技术支持。

Microalgae, known as light-driven cellular factories, are regarded as an important source of high-value-added bioactive compounds. In recent years, the production of microalgae biomass has attracted extensive attention worldwide. Mixotrophy, which can drive both photoautotrophy and heterotrophy, is an ideal method for microalgal biomass production because of its high growth rate and biomass yield. However, there is still a lack of in-depth understanding of the underlying growth-boosting mechanisms under mixotrophy. Moreover, the mixotrophy mode has not yet entirely operated in the large-scale production of microalgae, which is mainly limited by the high cost of production and harvest and the serious bacterial contamination caused by the addition of organic carbon sources during the cultivation process. We selected Chromochloris zofingiensis, a strong candidate for astaxanthin production, as the research object. From three aspects: mixotrophic mechanism, bacteria control strategy and bioreactor scale-up culture. The main conclusions obtained are as follows: （1） Mixotrophy yielded the highest biomass, which was significantly higher than the sum of photoautotrophic and heterotrophic cultivation, indicating a significant growth-boosting effect. The chlorophyll fluorescence and transcriptomics results confirmed that the highest biomass production under mixotrophy was attributed to a higher photosynthesis performance, decreased light damage and photorespiration, as well as significantly upregulated glucose metabolism compared to photoautotrophy. Compared to heterotrophy, mixotrophy consumed less glucose and had a lower glucose metabolic efficiency but led to higher biomass yield. Taken together, we propose a synergistic growth-promoting mechanism between photosynthesis and glucose metabolism under mixotrophy, in which cells not only directly benefit from extra energy from exogenous organic carbon metabolism but also the reutilization of the byproduct CO2 for photosynthesis. In return, O2 evolved from photosynthesis was consumed by glucose metabolism as well, and the efficient push-pull effect between CO2 and O2 promotes biomass production. （2） The results of batch experiments showed that controlling the concentration of carbon, nitrogen and phosphorus in the culture system can significantly control bacterial contamination; the results of fed-batch experiments show that controlling the concentration of carbon, nitrogen and phosphorus simultaneously, that is, providing only the nutrients required for algae growth, can achieve the best bacteria control effect, and this conclusion has also been verified in the 5 L bioreactor. The strategy of nutrient limitation can effectively control bacterial contamination in microalgae mixotrophic cultivation without affecting the growth of algae. （3） The immobilized culture is carried out in the alternating dry and wet mode, which has the advantages of less water consumption and simple harvest. After improving the surface roughness of the attached material, biomass production increased to 8.53 g/m2/d, which has certain competitiveness. Physiological and biochemical analysis showed that there were significant differences between attached and suspended algae. The immobilized environment made the attached alage comsume less energy and more energy was used for storing chemical substances and cell division. Meanwhile, the supply of gaseous CO2 in the alternating dry and wet mode was conducive to the mixotrophic photosynthesis, thus increasing the biomass. Finally, the collected algae were induced synergistically by high light, nitrogen deficiency and salt stress, and the final astaxanthin content reached 2.0 mg/g. The study focuses on the goal of large-sacle cultivation of microalgae, conductes a comparative study of photoautotrophic, heterotrophic and mixotrophic cultivation, and elucidate the growth-boosting synergistic mechanism under mixotrophy. To address the issue of bacterial contamination under mixotrophy, the strategy of nutrient limitation has been proposed. Finally, the effect and mechanism of dry-wet alternating immobilized culture were explored by using mixotrophy and bacterial control strategy. The results provide technical support for the industrial production of microalgae.