Since temperature is an important factor affecting microalgal growth, photosynthetic rate and biomass composition, this study has accordingly focused on its effects on biomass yield and nighttime biomass loss, as well as photochemical changes, using Nannochloropsis oceanica as model species, grown in two outdoor 50-L tubular photobioreactors (PBR). In two independent trials, cultures were subjected to a diurnal light:dark cycle, under a constant temperature of 28 °C and, on the second trial, at 18 °C. Changes in culture performance were assessed by measuring growth, lipid and fatty acid composition of the biomass in both morning and evening. Our results revealed that N. oceanica shows a wide temperature tolerance with relevant nighttime biomass loss, that decreased at lower temperatures, at the expenses of its daily productivity. Fluorescence measurements revealed reversible damage to photosystem II in cells growing in the PBR under optimal thermal conditions, whereas microalgae grown at suboptimal ones exhibited an overall lower photosynthetic activity. Lipids were partially consumed overnight to support cell division and provide maintenance energy. Eicosapentaenoic acid (EPA) catabolism reached a maximum after the dark period, as opposed to their saturated counterparts; whereas lower temperatures led to higher EPA content which reached the maximum in the morning. These findings are relevant for the production of Nannochloropsis at industrial scale.

由于温度是影响微藻生长，光合速率和生物量组成的重要因素，因此，本研究以Nannochloropsis oceanica为模型物种，在两个室外50上生长，重点研究了其对生物量产量和夜间生物量损失以及光化学变化的影响。-L管状光生物反应器（PBR）。在两项独立的试验中，将培养物置于昼夜光照：黑暗周期，恒定温度为28°C，第二次试验为18°C。通过在早晨和晚上测量生物量的生长，脂质和脂肪酸组成来评估培养性能的变化。我们的结果表明，N。oceanica表现出宽广的温度耐受性和相关的夜间生物量损失，在较低的温度下会以每天的生产力为代价而降低。荧光测量显示，在最佳温度条件下，在PBR中生长的细胞对光系统II的可逆损伤，而在次优条件下生长的微藻则显示出总体较低的光合作用活性。过夜消耗脂质以支持细胞分裂并提供维持能量。在黑暗期之后，二十碳五烯酸（EPA）的分解代谢达到了最大值，与饱和状态相反。而较低的温度导致较高的EPA含量，该含量在早晨达到最高。这些发现与工业规模生产拟南芥有关。