Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences building, Indian Institute of Technology Madras, Chennai, 600036, India.
Centre for Nanobiotechnology, VIT University, Vellore, 632014, India.
Environ Sci Pollut Res Int. 2020 Aug;27(22):27394-27406. doi: 10.1007/s11356-019-06388-0. Epub 2019 Sep 7.
The occurrence of titanium dioxide nanoparticles (nTiO), in the effluents released from wastewater treatment plants, has raised concerns. The fate of nTiO and their potential impact on organisms from different ecosystems are widely investigated. For the first time, in this work, we report the responses of an oleaginous bacteria Rhodococcus opacus PD630, belonging to an ecologically important genus Rhodococcus to environmentally relevant concentrations of nTiO under dark and UV light conditions. We observed a dose-dependent increase in nTiO uptake by the bacteria that reached a maximum of 1.4 mg nTiO (g cell) under mid-log UV exposure, corresponding to 97% uptake. The nTiO induced oxidative stress in bacteria that increased from 25.1 to a maximum of 100.3, 44.1, and 51.7 μmol OH (g cell) under dark, continuous, and mid-log UV, respectively. However, nTiO did not affect bacterial viability. Further, due to oxidative stress, the triacylglycerol (biodiesel) content from bacteria increased from 30% to a maximum of 54% CDW. Based on our findings, we propose an application of R. opacus PD 630 in nTiO remediation due to their high nTiO uptake and resistance.
二氧化钛纳米颗粒（nTiO）在污水处理厂排放的废水中的出现引起了关注。nTiO 的命运及其对来自不同生态系统的生物体的潜在影响已得到广泛研究。在这项工作中，我们首次报道了属于生态重要属罗尔斯通氏菌属的产油细菌罗达斯氏菌 PD630 对环境相关浓度的 nTiO 在黑暗和紫外光条件下的反应。我们观察到细菌对 nTiO 的摄取量随剂量呈依赖性增加，在中对数紫外光暴露下达到最大 1.4mg nTiO（g 细胞），摄取率达到 97%。nTiO 诱导了细菌中的氧化应激，分别在黑暗、连续和中对数紫外光条件下，从 25.1 增加到最大的 100.3、44.1 和 51.7 μmol·OH（g 细胞）。然而，nTiO 并不影响细菌的生存能力。此外，由于氧化应激，细菌中的三酰基甘油（生物柴油）含量从 30%增加到最大 54% CDW。基于我们的发现，我们提出了由于 R. opacus PD630 具有高 nTiO 摄取和抗性，可将其应用于 nTiO 的修复。
