Background Cultivation of microalgae in wastewater could significantly contribute to wastewater treatment, biodiesel production, and thus the transition to renewable energy. However, more information on effects of environmental factors, including light intensity, on their growth and composition (particularly fatty acid contents) is required. Therefore, we investigated the biomass and fatty acid production of four microalgal species, isolated in the Northern hemisphere and grown at three light intensities (50, 150 and 300 μE m-2 s-1). Results Increases in light intensities resulted in higher biomass of all four species and, importantly, raised fatty acid contents of both Desmodesmus sp. and Scenedesmus obliquus. Fourier-transform IR spectrometry analysis showed that the increases in fatty acid content were associated with reductions in protein, but not carbohydrate, contents. Assessment of fatty acid composition revealed that increasing light intensity led to higher and lower contents of oleic (18:1) and linolenic (18:3) acids, respectively. The microalgae consumed more than 75% of the nitrogen and phosphorus present in the wastewater used as growth medium. Conclusion The results show the importance of optimizing light intensities to improve fatty acid production by microalgae and their quality as sources of biodiesel. In addition, increase in fatty acid content is associated with decrease in protein content.

中文翻译：

---

光照强度对废水中生长的微藻生长和脂质产生的影响。

背景在废水中培养微藻可以显着促进废水处理、生物柴油生产，从而向可再生能源过渡。然而，需要更多关于环境因素（包括光强度）对其生长和组成（特别是脂肪酸含量）影响的信息。因此，我们研究了在北半球分离并在三种光强度（50、150 和 300 μE m-2 s-1）下生长的四种微藻物种的生物量和脂肪酸产量。结果 光强度的增加导致所有四个物种的生物量增加，重要的是，增加了两种 Desmodesmus sp。的脂肪酸含量。和斜角栅藻。傅里叶变换红外光谱分析表明，脂肪酸含量的增加与蛋白质的减少有关，但不是碳水化合物，含量。对脂肪酸组成的评估表明，光强度的增加分别导致油酸 (18:1) 和亚麻酸 (18:3) 的含量升高和降低。微藻消耗了用作生长培养基的废水中超过 75% 的氮和磷。结论结果表明优化光强度对提高微藻脂肪酸产量及其作为生物柴油来源的质量的重要性。此外，脂肪酸含量的增加与蛋白质含量的降低有关。微藻消耗了用作生长培养基的废水中超过 75% 的氮和磷。结论结果表明优化光强度对提高微藻脂肪酸产量及其作为生物柴油来源的质量的重要性。此外，脂肪酸含量的增加与蛋白质含量的降低有关。微藻消耗了用作生长培养基的废水中超过 75% 的氮和磷。结论结果表明优化光强度对提高微藻脂肪酸产量及其作为生物柴油来源的质量的重要性。此外，脂肪酸含量的增加与蛋白质含量的降低有关。