钝顶螺旋藻在不同光照条件下的放氧特性

Oxygen evolution characteristics of Spirulina platensis under various light conditions

钝顶螺旋藻在持续照光和中等频率（0.01-20 Hz）的光/暗交替照光下的放氧特性对光生物反应器的设计和操作具有重要意义。构建了一套可实现光/暗交替的光生物反应器系统对此进行研究,结果显示：根据与放氧速率的关系,可以将光强分为4个区：光限制区（0-335μmol/（m2.s））,过渡区（335-875μmol/（m2.s））,光饱和区（875-2 775μmol/（m2.s））以及光抑制区（2 775μmol/（m2.s）以上）。提高光/暗频率能否提高微藻光合速率取决于所采用的光强和光比例：低光强、低光比例下无明显提高;在光比例处于0.1-0.6之间时,光强越高,提高光/暗频率所带来的光合速率提高的幅度越大。研究结果对于实际生产的指导意义是,在午间高光强下提高藻液混合程度所带来的光合速率的提高相对于早晚低光强下更加明显,经济上更加可行。

The knowledge of oxygen evolution characteristics,which is a symbol of photosynthetic activity,under various light conditions is important for photobioreactor design and operation.In this study,we constructed a device to investigate oxygen evolution characteristics of Spirulina platensis under two different light regimes： 1） continuous illumination of various light intensities（14？6 500 μmol/（m2？s））;2） medium frequency L/D cycles of four different light intensities（69,505,1 330,4 265 μmol/（m2？s））.Light limited region,intermediate region,light saturated region and light inhibited region of light intensity were recognized according to their relationship with oxygen evolution rate（OER） under continuous illumination.Investigation of S.platensis under L/D cycles showed whether photosynthetic efficiency could be increased with increasing L/D frequency largely depended on the light intensity applied.The higher the light intensity,the larger the photosynthetic enhancement could be expected with the increase of L/D frequency.The largest light integration effect was found under L/D cycles of high light intensity（4 265 μmol/（m2？s）） and medium light fraction（k=0.6）,while light integration effect was totally absent under low light fractions（k0.2）.We also discussed their implications to the practical aspects of microalgae cultivation.