School of Petrochemical Engineering & Environment, Zhejiang Ocean University, Zhoushan 316000, China; Zhejiang Key Laboratory of Petrochemical Environmental Pollution Control, Zhoushan, 316000, China.
Centre for Water, Energy and Waste, Harry Butler Institute, Murdoch University, Murdoch, WA 6150, Australia.
Water Res. 2024 Jan 1;248:120864. doi: 10.1016/j.watres.2023.120864. Epub 2023 Nov 13.
The utilization of seawater supplemented with wastewater nutrients for microalgae cultivation represents a promising and cost-effective approach that combines the benefits of wastewater treatment and microalgal resource recovery. However, the high salt content in seawater poses a significant challenge, hindering microalgal growth and reducing the removal of nitrogen and phosphorus on a large scale. The phytohormone indoleacetic acid (IAA) was used in this study to enhance stress resistance and lipid production of Chlorella pyrenoidosa grown in seawater-wastewater medium. Compared to the control groups involving regular wastewater and seawater-containing wastewater without IAA, Chlorella pyrenoidosa cultivated in the seawater-containing wastewater supplemented with IAA exhibited remarkable outcomes. Specifically, microalgae in IAA-enhanced seawater-containing wastewater achieved the highest lipid productivity (22.67 mg L d) along with impressive nitrogen (99.3 %) and phosphorus (97.3 %) removal rates. Moreover, their cell sedimentation ratio reached 76.6 %, indicating enhanced settling properties. Additionally, the physiological mechanism changes after exposure to seawater stress and IAA were revealed based on the changes in antioxidant enzymes, endogenous hormones, and fatty acid saturation. Furthermore, the transcriptomic analysis elucidated the molecular mechanisms underlying microalgal lipid synthesis and their response to antioxidant stress when exposed to seawater. The supplementation of IAA under seawater stress stimulated energy metabolism and the antioxidant response in microalgal cells, effectively mitigating the adverse effects of seawater stress and promoting overall algal lipid productivity. Overall, this study unveiled the potential of exogenous plant hormones, particularly IAA, in enhancing stress resistance and lipid productivity of microalgae grown in seawater-wastewater medium, which significantly contributed towards the efficient use of seawater resources for microalgae cultivation and biofuel production.
利用补充废水营养物质的海水来培养微藻是一种很有前景且具有成本效益的方法，它结合了废水处理和微藻资源回收的好处。然而，海水中的高盐含量是一个重大挑战，它会阻碍微藻的生长，并降低大规模去除氮和磷的效率。在这项研究中，植物激素吲哚乙酸（IAA）被用于增强在海水-废水培养基中生长的栅藻的抗逆性和产脂能力。与不添加 IAA 的常规废水和含海水的废水对照相比，在含 IAA 的海水补充废水中培养的栅藻表现出了显著的结果。具体来说，在 IAA 增强的含海水废水中培养的微藻的脂生产率最高（22.67mg L d），同时具有令人印象深刻的氮（99.3%）和磷（97.3%）去除率。此外，它们的细胞沉降比达到了 76.6%，表明沉降性能得到了增强。此外，基于抗氧化酶、内源性激素和脂肪酸饱和度的变化，揭示了微藻在暴露于海水胁迫和 IAA 后的生理机制变化。在海水胁迫下添加 IAA 刺激了微藻细胞的能量代谢和抗氧化应激反应，有效地减轻了海水胁迫的不利影响，提高了藻类的整体脂生产率。总的来说，这项研究揭示了外源植物激素，特别是 IAA，在增强海水-废水培养基中生长的微藻的抗逆性和产脂能力方面的潜力，这对高效利用海水资源进行微藻养殖和生物燃料生产具有重要意义。
