Abstract：
Microalgae biofilm emerged as a solid alternative to conventional suspended cultures which present high operative costs and complex harvesting processes. Among several designs, rotating biofilm-based systems stand out for their scalability, although their primary applications have been in wastewater treatment and aquaculture. In this work, a rotating system was utilized to produce a high-value compound (astaxanthin) using Haematococcus pluvialis biofilms. The effect of nitrogen regime, light intensity, and light history on biofilm traits was assessed to better understand how to efficiently operate the system. Our results show that H. pluvialis biofilms follow the classical growth stages described for bacterial biofilms (from adhesion to maturation) and that a two-stage (green and red stages) allowed to reach astaxanthin productivities of 204 mg m-2 d-1 . The higher light intensity applied during the red stage (400 and 800 µmol m-2 s-1 ) combined with nitrogen depletion stimulated similar astaxanthin productivities. However, by training the biofilms during the green stage, using mild-light intensity (200 µmol m-2 s-1 ), a process known as priming, the final astaxanthin productivity was enhanced by 40% with respect to biofilms pre-exposed to 50 µmol m-2 s-1 . Overall, this study shows the possibility of utilizing rotating microalgae biofilms to produce high-value compounds laying the foundation for further biotechnological applications of these emerging systems.
摘要：
微藻生物膜作为传统悬浮培养物的固体替代品出现，传统悬浮培养物存在高操作成本和复杂的收获过程。在几种设计中，基于生物膜的旋转系统因其可扩展性而脱颖而出，尽管它们的主要应用是废水处理和水产养殖。在这项工作中,利用旋转系统使用雨生红球菌生物膜生产高价值的化合物（虾青素）。氮制度的影响，光强度,并评估了生物膜特征的光照历史，以更好地了解如何有效地操作系统。我们的结果表明，雨生H.pulvialis生物膜遵循针对细菌生物膜描述的经典生长阶段（从粘附到成熟），并且两个阶段（绿色和红色阶段）允许虾青素生产率达到204mgm-2d-1。在红色阶段施加的更高的光强度（400和800µmolm-2s-1）加上氮消耗刺激了相似的虾青素生产率。然而,通过在绿色阶段训练生物膜，使用弱光强度(200μmolm-2s-1)，一个被称为启动的过程，相对于预先暴露于50µmolm-2s-1的生物膜，最终虾青素生产率提高了40％。总的来说,这项研究显示了利用旋转微藻生物膜产生高价值化合物的可能性，为这些新兴系统的进一步生物技术应用奠定了基础。
