There has been an increasing drive toward better valorising raw biological materials in the context of the sustainability of bio-based industries and the circular economy. As such, microalgae hold the ability to biosynthesise valuable metabolites, which are sought after within the bioenergy, pharmaceuticals, cosmetics or nutrition sectors. Owing to their bioactivities, the xanthophyll pigment fucoxanthin and the omega-3 polyunsaturated fatty acid eicosapentaenoic acid (EPA) have fostered increasing interests in terms of sustainably refining them from natural sources, such as microalgae. Together with the suitability of individual species to industrial cultivation, a key challenge resides in optimizing the yields of these compounds within the microalgal biomass they are retrieved from. The marine diatom Stauroneis sp. LACW24 was batch cultivated into its stationary phase of growth prior to being subjected at high cell density (1 × 10⁶ cells mL⁻¹) to seven different regimes of light exposure in replenished medium and under nutritional limitation (silica and nitrate) for 12 days. The highest EPA proportions and yields were obtained under blue LED in f/2 medium (16.5% and 4.8 mg g⁻¹, respectively), double the values obtained under red LED illumination. The fucoxanthin yield was the highest when cells were subjected to blue LEDs (5.9 mg g⁻¹), a fourfold increase compared to the nitrogen-limited treatment under white LEDs. These results indicate that a two-stage approach to the batch cultivation of this diatom can be used for enhancing the production of the high-value metabolites fucoxanthin and EPA post-stationary phase.

中文翻译：

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海洋硅藻 Stauroneis sp. 对 EPA 和岩藻黄质产生的不同反应。在不同的栽培条件下

在生物基产业的可持续性和循环经济的背景下，人们越来越倾向于更好地评估生物原料的价值。因此，微藻具有生物合成有价值的代谢物的能力，这些代谢物在生物能源、制药、化妆品或营养领域受到追捧。由于它们的生物活性，叶黄素色素岩藻黄质和 omega-3 多不饱和脂肪酸二十碳五烯酸 (EPA) 在从天然来源（如微藻）中可持续提炼它们方面引起了越来越多的兴趣。连同单个物种对工业栽培的适用性，一个关键挑战在于优化这些化合物在它们从中回收的微藻生物质中的产量。海洋硅藻Stauroneissp。LACW24在高细胞密度（1×10 ^{6 个} 细胞mL ^-1）下在补充培养基和营养限制（二氧化硅和硝酸盐）下经受七种不同的光照方案12天之前，分批培养到其生长的稳定期. 在 f/2 介质中的蓝色 LED 下获得最高的 EPA 比例和产率（分别为 16.5% 和 4.8 mg g ^-1），是红色 LED 照明下获得的值的两倍。当细胞受到蓝色 LED (5.9 mg g ^{-1 ) 时，岩藻黄质产量最高})，与白色 LED 下的限氮处理相比增加了四倍。这些结果表明，这种硅藻的分批培养的两阶段方法可用于提高高价值代谢物岩藻黄质和 EPA 后固定阶段的产量。