Microbiology and Metabolic Engineering of Key Laboratory of Sichuan Province, College of Life Sciences, Sichuan University, Chengdu, 610064, China.
College of Life Sciences, Sichuan Agricultural University, Ya'an, 625014, China.
Chemosphere. 2020 Mar;243:125166. doi: 10.1016/j.chemosphere.2019.125166. Epub 2019 Nov 1.
Microorganisms and microbial products can be highly efficient in uptaking soluble and particulate forms of heavy metals, particularly from solutions. In this study, the removal efficiency, oxidative damage, antioxidant system, and the possible removal mechanisms were investigated in Rhodobacter (R.) sphaeroides SC01 under mercury (Hg), lead (Pb) and cadmium (Cd) stress. The results showed that SC01 had the highest removal rates (98%) of Pb among three heavy metals. Compared with Hg and Cd stress, Pb stress resulted in a lower levels of reactive oxygen species (ROS) and cell death. In contrast, the activities of four antioxidant enzymes in SC01 under Pb stress was higher than that of Hg and Cd stress. Furthermore, the analysis from fourier transform infrared spectroscopy indicated that complexation of Pb with hydroxyl, amid and phosphate groups was found in SC01 under Pb stress. In addition, X-ray diffraction analysis showed that precipitate of lead phosphate hydroxide was produced on the cell surface in SC01 exposed to Pb stress. Therefore, these results suggested that SC01 had good Pb removal ability by biosorption and precipitation and will be potentially useful for removal of Pb in industrial effluents.
微生物及其产物在摄取可溶性和颗粒态重金属方面非常高效，特别是从溶液中。在这项研究中，研究了小球藻（R.）sphaeroides SC01 在汞（Hg）、铅（Pb）和镉（Cd）胁迫下的去除效率、氧化损伤、抗氧化系统和可能的去除机制。结果表明，在三种重金属中，SC01 对 Pb 的去除率最高（98%）。与 Hg 和 Cd 胁迫相比，Pb 胁迫导致活性氧（ROS）和细胞死亡水平较低。相比之下，Pb 胁迫下 SC01 中四种抗氧化酶的活性高于 Hg 和 Cd 胁迫。此外，傅里叶变换红外光谱分析表明，在 Pb 胁迫下 SC01 中发现 Pb 与羟基、酰胺和磷酸盐基团形成配合物。此外，X 射线衍射分析表明，在 Pb 胁迫下暴露的 SC01 细胞表面生成了磷酸铅氢氧化物沉淀。因此，这些结果表明，SC01 通过生物吸附和沉淀具有良好的 Pb 去除能力，将有望用于去除工业废水中的 Pb。
