This work presents an acetic acid mediated energy-efficient process that integrates mixotrophic cultivation of extremophilic microalga Chlorella sorokiniana at the photobioreactor (macro) scale, with algal lipid accumulation at the molecular (micro) scale, and rapid biomass harvesting at the algal particle (meso) scale, followed by multiple recycling of nutrient-rich harvested broth. Chlorella sorokiniana is grown mixotrophically in Tris-Acetate-Phosphate medium using Tris buffer as nitrogen source, CO₂ and acetic acid as inorganic and organic carbon sources, respectively, at light intensities of 5600–11,000 lx and an optimized photoperiod of 18:6 (Light: Dark) in 25-l bubble-column photobioreactors for 138 h. Acetic acid is used as an organic carbon source to integrate the processes occurring at the three scales; acetic acid ionizes to acetate ions in the culture media, which are enzymatically assimilated inside the alga's cytosol to acetyl-CoA that enhance fatty acid synthesis at the molecular scale and biomass yield at the reactor scale. The excess acetate ions in the culture medium react with the ions formed by the hydrolysis of potash alum to form complexes that react with the ions on algal cell surfaces to facilitate rapid flocculation at the meso (particle) scale. This multiscale integration results in maximum biomass and overall productivity 4.16 g/L and 0.70 g/L/day, respectively, with 25.8% lipid content, obtained at 2% CO₂ and 11,000 lx, while reducing the harvesting time to 18–28 min, at a harvesting efficiency and cost of 98%, and 0.064$ per kg of dry biomass, respectively. The first and the second recycles of nutrient-rich broth lower the biomass yield by 9.8% and 14.2%, respectively, while increasing the harvesting time by 8.2% and 15.3%, respectively, as compared to fresh broth. Such multiscale integration of algal growth, macromolecular synthesis and biomass harvesting, followed by broth recycling, offers a novel, cost-effective technology for mixotrophic mass cultivation of extremophilic microalgae.

这项工作提出了一种乙酸介导的节能过程，该过程整合了在光生物反应器（宏观）规模上嗜极端微藻小球藻的混合营养培养，在分子（微观）规模上的藻类脂质积累以及在藻类颗粒（中观）上的快速生物质收获。）规模，然后多次回收富含营养的收获肉汤。使用Tris缓冲液作为氮源（CO _2）在Tris-乙酸盐-磷酸盐培养基中混合营养生长小球藻在25l气泡柱光生物反应器中，分别以5600–11,000 lx的光强度和18：6（亮：暗）的优化光周期分别在5600–11,000 lx的光照强度和乙酸作为无机和有机碳源。乙酸被用作有机碳源，以整合在三个规模上发生的过程。乙酸在培养基中离子化为乙酸根离子，然后在藻类的细胞质内被酶同化为乙酰辅酶A，从而在分子水平上增强脂肪酸合成，在反应器范围内提高生物质产率。培养基中过量的乙酸根离子与钾盐明矾水解形成的离子发生反应，形成与藻类细胞表面的离子发生反应的络合物，从而促进中观溶液快速絮凝（粒子）规模。这种多尺度的集成可最大程度地提高生物量和总生产率，分别为每天4.16 g / L和0.70 g / L /天，脂质含量为25.8％（在2％CO ₂和11,000 lx下获得），同时将收获时间缩短至18-28分钟，收获效率和成本分别为98％和每公斤干生物质0.064美元。与新鲜肉汤相比，富含营养的肉汤的第一次和第二次循环分别使生物量产量降低了9.8％和14.2％，而收获时间分别增加了8.2％和15.3％。藻类生长，大分子合成和生物质收获的这种多尺度整合，然后是肉汤回收，为极端嗜热性微藻的混合营养大规模培养提供了一种新颖，具有成本效益的技术。