Molina E, Fernández J, Acién F G, Chisti Y
Department of Chemical Engineering, University of Almería, E-04071 Almeria, Spain.
J Biotechnol. 2001 Dec 28;92(2):113-31. doi: 10.1016/s0168-1656(01)00353-4.
Principles of fluid mechanics, gas-liquid mass transfer, and irradiance controlled algal growth are integrated into a method for designing tubular photobioreactors in which the culture is circulated by an airlift pump. A 0.2 m(3) photobioreactor designed using the proposed approach was proved in continuous outdoor culture of the microalga Phaeodactylum tricornutum. The culture performance was assessed under various conditions of irradiance, dilution rates and liquid velocities through the tubular solar collector. A biomass productivity of 1.90 g l(-1) d(-1) (or 32 g m(-2) d(-1)) could be obtained at a dilution rate of 0.04 h(-1). Photoinhibition was observed during hours of peak irradiance; the photosynthetic activity of the cells recovered a few hours later. Linear liquid velocities of 0.50 and 0.35 m s(-1) in the solar collector gave similar biomass productivities, but the culture collapsed at lower velocities. The effect of dissolved oxygen concentration on productivity was quantified in indoor conditions; dissolved oxygen levels higher or lower than air saturation values reduced productivity. Under outdoor conditions, for given levels of oxygen supersaturation, the productivity decline was greater outdoors than indoors, suggesting that under intense outdoor illumination photooxidation contributed to loss of productivity in comparison with productivity loss due to oxygen inhibition alone. Dissolved oxygen values at the outlet of solar collector tube were up to 400% of air saturation.
流体力学原理、气液传质原理以及辐照度控制的藻类生长原理被整合到一种用于设计管状光生物反应器的方法中，在该反应器中培养物通过气升泵循环。使用该方法设计的一个0.2立方米的光生物反应器在三角褐指藻的连续室外培养中得到了验证。在不同的辐照度、稀释率和通过管状太阳能集热器的液体流速条件下对培养性能进行了评估。在稀释率为0.04 h⁻¹时，生物量生产力可达1.90 g·l⁻¹·d⁻¹（或32 g·m⁻²·d⁻¹）。在辐照度峰值时段观察到了光抑制现象；细胞的光合活性在数小时后恢复。太阳能集热器中0.50和0.35 m·s⁻¹的线性液体流速产生了相似的生物量生产力，但在较低流速下培养物崩溃。在室内条件下对溶解氧浓度对生产力的影响进行了量化；高于或低于空气饱和值的溶解氧水平都会降低生产力。在室外条件下，对于给定的氧过饱和水平，室外生产力下降幅度大于室内，这表明与仅因氧抑制导致的生产力损失相比，在强烈的室外光照下光氧化导致了生产力损失。太阳能集热器管出口处的溶解氧值高达空气饱和值的400%。
