Development of a photobioreactor with volumetric illumination via resonant inductive coupling

微藻在制药、医药、精细化工、食品工业等领域具有广泛的应用前景。光养微生物生长最重要的过程参数是光，光在水中不分散，被培养的微生物大量吸收。这导致了一个高度不均匀的光分布在反应器的横截面上，这导致在反应器的不同部分的光供应急剧不同。因此，高表面体积比是实现高比光供应和最大生产力所必需的。现有光生物反应器（pbr）的主要限制是缺乏方便的放大解决方案。本项目的主要目标是设计一个具有均匀内部照明的搅拌槽反应器，用于培养光养微生物。这将通过使用无线光发射器（WLEs）来实现，通过谐振电感耦合无线供电。光将由具有适当光谱波长模式的发光二极管（led）产生。WLEs将具有与培养基几乎相同的密度，以保证整个流体内部的统计均匀分布，从而导致反应器内部均匀的光模式。反应堆将被一个主发射线圈包围，连接到频率发生器和功率放大器，在反应堆内部提供一个频繁的电磁场。WLEs将由连接到电容器的次级线圈和封装在塑料球体中的LED组成。发射线圈的频繁磁场将在多个接收线圈内感应电流并为LED供电。新的反应器系统将与生物过程工程研究所的PBR系统进行比较，重点关注生长行为和有价值产品的产量。此外，将完成并评估从小型1升反应器到50升反应器的规模扩大。这些反应堆将按照1991年开始的DECHEMA生物反应堆准则建造。这将证明这种新型照明方法的原理放大可能性。除了工程领域的目标外，高频电磁场对微藻的影响还需要进行基础研究。关于电磁场对光养微生物影响的研究成果很少。了解电磁场的潜在副作用是应用新反应器概念的基础，因为微生物在整个培养过程中都暴露在电磁场中。该项目的初步工作表明，两种选定的频率对模式绿藻莱茵衣藻没有显著影响，但尽管如此，有必要更详细地分析不同电磁场对更多光养微生物的影响，以便为工业光生物技术提供有价值和可靠的工具。

Microalgae could be sources for a multitude of products in pharmacy, medicine, fine chemistry, and food industry. The most important process parameter for the growth of phototrophic microorganisms is light, which is not dispersible in water and is absorbed drastically by the cultivated organisms. This leads to a highly inhomogeneous light distribution over the reactor cross section, which results in drastically differing light supply in different parts of the reactor. Therefore a high surface to volume ratio is necessary to achieve a high specific light supply and consequently a maximum productivity. The major limitation of existing photobioreactors (PBRs) is the lack of convenient scale-up solutions. The main goal of this project is to engineer a stirred tank reactor with a homogeneous internal illumination for cultivation of phototrophic microorganisms. This will be achieved by using wireless light emitters (WLEs), powered wirelessly via resonant inductive coupling. The light will be generated by light emitting diodes (LEDs) with an appropriate spectral wavelength pattern. The WLEs will have nearly the same density as the cultivation medium to guarantee a statistical homogeneous distribution inside the whole fluid and thus lead to a uniform light pattern inside the reactor. The reactor will be surrounded by a primary transmitting coil, connected to a frequency generator and a power amplifier, to provide a frequent electromagnetic field inside the reactor. The WLEs will consist of a secondary coil connected to a capacitor and a LED encapsulated in a plastic sphere. The frequent magnetic field of the transmitting coil will induce a current inside the multiple receiving coils and will power the LED. The new reactor system will be compared to the PBR systems at the Institute of Bioprocess Engineering, focusing on growth behavior and the yield of valuable products. Furthermore, a scale-up from small-scale 1 L reactors to a 50 L reactor will be done and evaluated. The reactors will be constructed according to the DECHEMA guidelines for bioreactors from 1991. This will prove the principle scaling-up possibilities of this novel illumination method. Besides the goals in the field of engineering, basic studies regarding the influence of frequent electromagnetic fields (EMF) on microalgae have to be done. There are only few results on the EMFs influence on phototrophic microorganisms published. The knowledge of potential side effects of EMF is fundamental to the application of the new reactor concept, as the microorganisms are exposed to that field during the whole cultivation process. Preliminary work concerning this project showed no significant influence of two selected frequencies on the model greenalga Chlamydomonas reinhardtii, but nevertheless, a more detailed analysis of the influence of different EMF on more phototrophic microorganisms is necessary to provide a valuable and reliable tool to industrial photobiotechnology.