Morita M, Watanabe Y, Okawa T, Saiki H
Bio-Science Department, Abiko Research Laboratory, Central Research Institute of Electric Power Industry (CRIEPI), 1646 Abiko, Abiko-shi, Chiba 270-1194, Japan.
Biotechnol Bioeng. 2001 Jul 20;74(2):136-44. doi: 10.1002/bit.1103.
The characteristics of the flow of culture medium significantly affects the photosynthetic productivity of bioreactors incorporating microalgae. Therefore, in order to optimize the performance of a conical helical tubular photobioreactor (CHTP) designed to be useful in practical applications, we characterized the flow pattern of the culture medium through the reactor. The effects of medium flow conditions on the photosynthetic productivity of Chlorella sp. were investigated using several different CHTP units with 0.50-m2 installation areas which were designed to vary the direction and rate of flow driven by airlift. In addition, the performance of two- and four-unit systems constructed by combining individual CHTP units was evaluated. We found that when medium flowed from the bottom to the top of the photostage, it exhibited smoother flow of culture medium than when flowing from top to bottom, which led to higher photosynthetic productivity by the former. Consistent with theoretical calculations, varying the lengths of vertical flow passages caused flow rates to vary, and higher flow rates meant smoother circulation of medium and better photosynthetic performance. Flow of medium through a four-unit CHTP system was similar to that in single units, enabling a photosynthetic productivity of 31.0 g-dry biomass per m2-installation area per day to be achieved, which corresponded to a photosynthetic efficiency of 7.50% (photosynthetically active radiation (PAR; 400-700 nm)). This high photosynthetic performance was possible because smoother medium flow attained in single units was also attained in the four-unit system.
培养基的流动特性显著影响包含微藻的生物反应器的光合生产力。因此，为了优化设计用于实际应用的锥形螺旋管光生物反应器（CHTP）的性能，我们对培养基通过该反应器的流动模式进行了表征。使用几个不同的CHTP装置（安装面积为0.50平方米，设计用于改变气升驱动的流动方向和速率）研究了培养基流动条件对小球藻光合生产力的影响。此外，还评估了通过组合单个CHTP装置构建的两单元和四单元系统的性能。我们发现，当培养基从光阶段的底部流向顶部时，其流动比从顶部流向底部时更顺畅，这使得前者具有更高的光合生产力。与理论计算一致，改变垂直流动通道的长度会导致流速变化，流速越高意味着培养基循环越顺畅，光合性能越好。培养基通过四单元CHTP系统的流动与单个单元中的流动相似，能够实现每平方米安装面积每天31.0克干生物量的光合生产力，这相当于7.50%的光合效率（光合有效辐射（PAR；400 - 700纳米））。这种高光合性能是可能的，因为在四单元系统中也实现了与单个单元中一样顺畅的培养基流动。
