Saccardo Alberto, Bezzo Fabrizio, Sforza Eleonora
CAPE-Lab (Computer-Aided Process Engineering Laboratory), Department of Industrial Engineering, University of Padova, Padova, Italy.
Department of Industrial Engineering, University of Padova, Padova, Italy.
Front Bioeng Biotechnol. 2022 Aug 11;10:977429. doi: 10.3389/fbioe.2022.977429. eCollection 2022.
To disclose the net effect of light on microalgal growth in photobioreactors, self-shading and mixing-induced light-dark cycles must be minimized and discerned from the transient phenomena of acclimation. In this work, we performed experiments of continuous microalgal cultivation in small-scale photobioreactors with different thicknesses (from 2 to 35 mm): working at a steady state allowed us to describe the effect of light after acclimation, while the geometry of the reactor was adjusted to find the threshold light path that can discriminate different phenomena. Experiments showed an increased inhibition under smaller culture light paths, suggesting a strong shading effect at thicknesses higher than 8 mm where mixing-induced light-dark cycles may occur. A Haldane-like model was applied and kinetic parameters retrieved, showing possible issues in the scalability of experimental results at different light paths if mixing-induced light-dark cycles are not considered. To further highlight the influence of mixing cycles, we proposed an analogy between small-scale operations with continuous light and PBR operations with pulsed light, with the computation of characteristic parameters from pulsed-light microalgae growth mathematical modeling.
为了揭示光照对光生物反应器中微藻生长的净效应，必须将自遮荫和混合引起的光暗循环降至最低，并将其与适应的瞬态现象区分开来。在这项工作中，我们在不同厚度（2至35毫米）的小型光生物反应器中进行了微藻连续培养实验：在稳定状态下工作使我们能够描述适应后光照的影响，同时调整反应器的几何形状以找到能够区分不同现象的临界光程。实验表明，在较小的培养光程下抑制作用增强，这表明在厚度高于8毫米时存在强烈的遮荫效应，此时可能会出现混合引起的光暗循环。应用了类似Haldane的模型并获取了动力学参数，结果表明，如果不考虑混合引起的光暗循环，不同光程下的实验结果在可扩展性方面可能存在问题。为了进一步突出混合循环的影响，我们提出了连续光照下的小规模操作与脉冲光照下的光生物反应器操作之间的类比，并通过脉冲光微藻生长数学模型计算特征参数。
