Department of Chemical Engineering, Sungkyunkwan University, Suwon, 440-746, Korea.
Bioprocess Biosyst Eng. 2012 Jan;35(1-2):309-15. doi: 10.1007/s00449-011-0616-x. Epub 2011 Sep 10.
The unicellular green microalgae, Haematococcus pluvialis, has been examined as a microbial source for the production of astaxanthin, which has been suggested as a food supplement for humans and is also prescribed as an ingredient in eye drops because of its powerful anti-oxidant properties. In this study, we estimated the effects of the slope of a V-shaped bottom design, the volumetric flow rate of air, height/diameter (H/D) ratio, and diameter of an air sparger on the performance of a photo-bioreactor. These parameters were selected because they are recognized as important factors effecting the mixing that produces increased cell density in the reactor. The mixing effect can be measured by changes in optical density in the bioreactor over a period of time. A 6 L indoor photo-bioreactor was prepared in a short time period of 24 h for the performance study. A bioreactor designed with a V-shaped bottom with a slope of 60° showed an optical density change of 0.052 at 680 nm, which was sixfold less than the change in a photo-bioreactor designed with a flat bottom. Studies exploring the effects of bioreactor configuration and a porous metal sparger with a 10 μm pore size showed the best performance at an H/D ratio of 6:1 and a sparger diameter of 1.3 cm, respectively. The optimal rate of air flow was 0.2 vvm. The indoor culture of microalgae in the photo-bioreactor was subsequently carried for an application study using the optimal values established for the important factors. The indoor culture system was composed of a light source controlled according to cell phase, a carbon dioxide feeder, a bag-type reactor with an H/D ratio of 6:1, and a temperature controller. Results demonstrated the efficient production of microalgal cells and astaxanthin in the amounts of 2.62 g/L and 78.37 mg/L, respectively, when using adequate hydrodynamic mixing. Furthermore, the optimal design of a photo-bioreactor can be applied for the phototropic culturing of other microalgae for mass production.
单细胞绿藻雨生红球藻已被研究作为虾青素的微生物来源，虾青素被建议作为人类的一种食品补充剂，也被规定为眼药水的一种成分，因为它具有强大的抗氧化性能。在这项研究中，我们评估了 V 形底部设计的斜率、空气体积流量、高径比（H/D）和空气分布器直径对光生物反应器性能的影响。这些参数被选择是因为它们被认为是影响混合的重要因素，而混合可以增加反应器中的细胞密度。混合效果可以通过在一段时间内测量生物反应器中的光密度变化来衡量。在 24 小时内，我们快速制备了一个 6L 的室内光生物反应器，用于性能研究。与平底光生物反应器相比，设计为 60°V 形底部的生物反应器在 680nm 处的光密度变化为 0.052，变化小了六倍。研究探索了生物反应器结构和具有 10μm 孔径的多孔金属分布器的影响，结果表明，在 H/D 比为 6:1 和分布器直径为 1.3cm 时，性能最佳。最佳空气流速为 0.2vvm。随后，在建立了重要因素的最佳值的基础上，使用室内光生物反应器对微藻进行了室内培养应用研究。室内培养系统由根据细胞阶段控制的光源、二氧化碳进料器、H/D 比为 6:1 的袋式反应器和温度控制器组成。结果表明，在充分的水动力混合下，微藻细胞和虾青素的产量分别达到 2.62g/L 和 78.37mg/L。此外，光生物反应器的最佳设计可以应用于其他微藻的光培养，以实现大规模生产。
