IBB-Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710057 Braga, Portugal.
Appl Biochem Biotechnol. 2010 May;161(1-8):218-26. doi: 10.1007/s12010-009-8783-9. Epub 2010 Feb 21.
The slow development of microalgal biotechnology is due to the failure in the design of large-scale photobioreactors (PBRs) where light energy is efficiently utilized. In this work, both the quality and the amount of light reaching a given point of the PBR were determined and correlated with cell density, light path length, and PBR geometry. This was made for two different geometries of the downcomer of an airlift PBR using optical fiber technology that allows to obtain information about quantitative and qualitative aspects of light patterns. This is important since the ability of microalgae to use the energy of photons is different, depending on the wavelength of the radiation. The results show that the circular geometry allows a more efficient light penetration, especially in the locations with a higher radial coordinate (r) when compared to the plane geometry; these observations were confirmed by the occurrence of a higher fraction of illuminated volume of the PBR for this geometry. An equation is proposed to correlate the relative light intensity with the penetration distance for both geometries and different microalgae cell concentrations. It was shown that the attenuation of light intensity is dependent on its wavelength, cell concentration, geometry of PBR, and the penetration distance of light.
微藻生物技术的发展缓慢是由于在设计能够有效利用光能的大规模光生物反应器（PBR）时失败了。在这项工作中，确定了到达 PBR 给定点的光的质量和数量，并将其与细胞密度、光程长度和 PBR 几何形状相关联。这是使用光纤技术对两种不同的气升式 PBR 降液管几何形状进行的，光纤技术允许获得有关光模式定量和定性方面的信息。这很重要，因为微藻利用光子能量的能力因辐射的波长而异。结果表明，与平面几何形状相比，圆形几何形状允许更有效的光穿透，特别是在具有更高径向坐标（r）的位置；对于这种几何形状，PBR 的被照亮体积的分数更高，这证实了这些观察结果。提出了一个方程来关联两种几何形状和不同微藻细胞浓度的相对光强与穿透距离。结果表明，光强度的衰减取决于其波长、细胞浓度、PBR 几何形状和光的穿透距离。
