School of Environment, Tsinghua University, Beijing, 100084, China; Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, China.
School of Environment, Tsinghua University, Beijing, 100084, China; Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, China.
Chemosphere. 2022 Dec;308(Pt 1):136113. doi: 10.1016/j.chemosphere.2022.136113. Epub 2022 Aug 22.
Ultraviolet light-emitting diodes (UV-LEDs) are among the most compact devices and safest technologies in water disinfection systems. However, the validation of different assay methods to evaluate the disinfection performance of different wavelengths (265, 280, 285, and 300 nm) of UV-LEDs toward marine microalgae remains poorly characterized. In this study, several detection assays, namely the culture-based most probable number (MPN) assay, membrane integrity-based vital stain (VS) assay, chlorophyll fluorescence assay, and photochemical efficiency assay, were compared to assess the viability of the marine microalga Tetraselmis sp., with results indicating the MPN assay to be the most sensitive. In addition, this study compared the inactivation kinetics, inactivation efficiency, and energy efficiency of Tetraselmis sp. under different UV wavelengths, as assessed by the VS and MPN assays. The fluence-response curves of Tetraselmis sp. varied with assay and wavelength, with Geeraerd's model fitting all fluence-response microalgal inactivation curves. The results showed a non-significant difference in inactivation efficiency among different wavelengths of UV-LEDs (except for 300 nm) when using the VS assay. On the contrary, significant differences among all wavelengths were observed with respect to inactivation efficiency when using the MPN assay. The wavelength of 265 nm exhibited maximum inactivation efficiency, whereas 285 nm achieved optimal energy efficiency. The UV action spectrum of Tetraselmis sp. exhibited the peak at 265 nm, a finding which matched well with the absorbance spectrum of DNA. The observations from this study provide a theoretical basis and technical support for the application of the emerging UV-LED light sources in the algicidal treatment of marine water.
紫外线发光二极管 (UV-LED) 是在水消毒系统中最紧凑和最安全的技术之一。然而，不同波长 (265、280、285 和 300nm) 的 UV-LED 对海洋微藻的消毒性能的不同检测方法的验证仍未得到充分描述。在这项研究中，比较了几种检测方法，即基于培养的最可能数 (MPN) 检测法、基于膜完整性的活细胞染色 (VS) 检测法、叶绿素荧光检测法和光化学效率检测法，以评估海洋微藻 Tetraselmis sp. 的生存能力，结果表明 MPN 检测法最敏感。此外，本研究比较了 VS 和 MPN 检测法评估的不同 UV 波长下 Tetraselmis sp. 的失活动力学、灭活效率和能量效率。Tetraselmis sp. 的剂量-反应曲线因检测方法和波长而异，Geeraerd 模型拟合了所有的剂量-反应微藻灭活曲线。结果表明，在使用 VS 检测法时，除 300nm 外，不同 UV-LED 波长之间的灭活效率无显著差异。相反，使用 MPN 检测法时，所有波长之间的灭活效率存在显著差异。波长 265nm 表现出最大的灭活效率，而 285nm 则达到最佳的能量效率。Tetraselmis sp. 的 UV 作用光谱在 265nm 处出现峰值，这一发现与 DNA 的吸收光谱吻合较好。本研究的结果为新兴的 UV-LED 光源在海洋水的杀藻处理中的应用提供了理论依据和技术支持。
