Heavy metal pollution in the cold region is serious, affecting human health and aquatic ecology. This study investigated the ability of microalgae to remove heavy metals (HMs) and produce lipid at low temperature. The removal efficiency of different HMs (Cd2+, Cu2+, Cr3+ and Pb2+), cell growth and lipid synthesis of microalgae were analyzed at 15 °C. Moreover, addition of glycine betaine (GB) further enhanced the productivity of microalgae in treating HMs and lipid production, and simultaneously increased the antioxidant capacity of microalgae against environmental stresses. The results showed that the highest lipid productivity of 100.98 mg L−1 d−1 and the removal efficiency of 85.8 % were obtained under GB coupled with Cr3+. The highest glutathione content of 670.34 nmol g−1 fresh alga was achieved under GB coupled with Pb2+. In addition, lipidomics showed that GB was able to up-regulate the triglyceride and diglyceride content, influenced fatty acid composition to regulate the microalgal metabolism, and mediated lipid accumulation under 15 °C mainly through the regulation of glycerol ester metabolism. This study provided a new perspective on microalgal lipid production and the removal of HMs in cold regions and provided evidence for the use of phytohormones to improve the algal environmental resistance.

中文翻译：

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甘氨酸甜菜碱介导的低温胁迫缓解下微藻脂质产生和重金属吸附的脂质组学分析


寒区重金属污染严重，影响人体健康和水生生态。本研究调查了微藻在低温下去除重金属 （HMs） 和产生脂质的能力。在 15 °C 下分析不同 HMs （Cd2+、Cu2+、Cr3+ 和 Pb2+） 的去除效率、细胞生长和微藻的脂质合成。 此外，甘氨酸甜菜碱 （GB） 的添加进一步提高了微藻处理 HMs 和脂质产生的生产力，同时增加了微藻对环境胁迫的抗氧化能力。结果表明，在 GB 与 Cr3+ 耦合下，获得了最高的脂质生产率 100.98 mg L-1 d-1 和 85.8% 的去除效率。在 GB 与 Pb2+ 耦合下实现了 670.34 nmol g-1 新鲜藻类的最高谷胱甘肽含量。此外，脂质组学显示，GB 能够上调甘油三酯和甘油二酯含量，影响脂肪酸组成调节微藻代谢，主要通过调节甘油酯代谢介导 15 °C 下脂质积累。这项研究为寒冷地区微藻脂质的产生和 HMs 的去除提供了新的视角，并为使用植物激素提高藻类环境抵抗力提供了证据。