Zigui Ecological Station for Three Gorges Dam Project, State Key Laboratory of Soil and Sustainable Agriculture , Institute of Soil Sciences, Chinese Academy of Sciences , 71 East Beijing Road , Nanjing 210008 , China.
Department of Chemical and Environmental Engineering (ChEE) , 705 Engineering Research Center, University of Cincinnati , Cincinnati , Ohio 45221-0012 , United States.
Environ Sci Technol. 2019 Feb 5;53(3):1585-1594. doi: 10.1021/acs.est.8b04923. Epub 2019 Jan 18.
Researchers are devoting great effort to combine photocatalytic nanoparticles (PNPs) with biological processes to create efficient environmental purification technologies (i.e., intimately coupled photobiocatalysis). However, little information is available to illuminate the responses of multispecies microbial aggregates against PNP exposure. Periphytic biofilm, as a model multispecies microbial aggregate, was exposed to three different PNPs (CdS, TiO, and FeO) under xenon lamp irradiation. There were no obvious toxic effects of PNP exposure on periphytic biofilm as biomass, chlorophyll content, and ATPase activity were not negatively impacted. Enhanced production of extracellular polymetric substances (EPS) is the most important protection mechanism of periphytic biofilm against PNPs exposure. Although PNP exposure produced extracellular superoxide radicals and caused intracellular reactive oxygen species (ROS) accumulation in periphytic biofilm, the interaction between EPS and PNPs could mitigate production of ROS while superoxide dismutase could alleviate biotic ROS accumulation in periphytic biofilm. The periphytic biofilms changed their community composition in the presence of PNPs by increasing the relative abundance of phototrophic and high nutrient metabolic microorganisms (families Chlamydomonadaceae, Cyanobacteriacea, Sphingobacteriales, and Xanthomonadaceae). This study provides insight into the protection mechanisms of microbial aggregates against simultaneous photogenerated and nanoparticle toxicity from PNPs.
研究人员正在努力将光催化纳米粒子 (PNP) 与生物过程相结合，以创建高效的环境净化技术（即紧密耦合的光生物催化）。然而，对于多物种微生物聚集体对 PNP 暴露的反应，可用的信息很少。周质生物膜作为一种多物种微生物聚集体模型，在氙灯照射下暴露于三种不同的 PNP（CdS、TiO 和 FeO）下。PNP 暴露对周质生物膜没有明显的毒性作用，因为生物量、叶绿素含量和 ATP 酶活性没有受到负面影响。增强的胞外聚合物物质（EPS）的产生是周质生物膜抵御 PNP 暴露的最重要保护机制。尽管 PNP 暴露产生了细胞外超氧自由基，并导致周质生物膜细胞内活性氧（ROS）积累，但 EPS 和 PNP 之间的相互作用可以减轻 ROS 的产生，而过氧化物歧化酶可以减轻周质生物膜中生物 ROS 的积累。周质生物膜通过增加光养和高营养代谢微生物（Chlamydomonadaceae、Cyanobacteriacea、Sphingobacteriales 和 Xanthomonadaceae 科）的相对丰度，在存在 PNP 的情况下改变了它们的群落组成。本研究深入了解了微生物聚集体对同时产生的光和纳米颗粒毒性的保护机制。
