Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of the Chinese Academy of Sciences, Beijing 100049, China.
Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of the Chinese Academy of Sciences, Beijing 100049, China.
J Hazard Mater. 2018 Oct 5;359:348-355. doi: 10.1016/j.jhazmat.2018.07.070. Epub 2018 Jul 18.
Iron oxides are reactive inorganic soil components that play an important role in the fate and transport of organic pollutants. Here, hematite was selected to investigate its effect on the biodegradation of benzo[a]pyrene (BaP) by Paracoccus sp. strain HPD-2. Approximately 60% of the total BaP was degraded in the absence of hematite after 7 days but only 30.8 and 20.8% of that was degraded after the addition of 10 and 20 mg mL hematite, respectively, indicating that the addition of hematite could significantly inhibit the biodegradation of BaP (P < 0.05). The hematite also lowered bacterium activity by coating the cells and by generating reactive oxygen species that destroyed the cells. Two-photon confocal laser scanning microscope images showed that the addition of hematite substantially decreased the amount of BaP combined with the bacterium, and this also enabled us to observe directly the migration and regression of BaP in the interaction between HPD-2 and hematite. Higher death ratio of HPD-2 might lower the BaP access to live cells because dead cells have a higher adsorption affinity for BaP than live cells. These observations enhance our understanding of the mechanisms by which metal oxides, organic pollutants and degrading-bacteria interact during the biodegradation process.
氧化铁是一种反应性无机土壤成分，在有机污染物的归趋和迁移中起着重要作用。在这里，选择赤铁矿来研究其对 Paracoccus sp. 菌株 HPD-2 降解苯并[a]芘（BaP）的影响。在没有赤铁矿的情况下，7 天后约有 60%的总 BaP 被降解，但添加 10 和 20 mg mL 赤铁矿后，分别只有 30.8%和 20.8%的 BaP 被降解，表明添加赤铁矿可显著抑制 BaP 的生物降解（P<0.05）。赤铁矿还通过包裹细胞和生成破坏细胞的活性氧来降低细菌活性。双光子共聚焦激光扫描显微镜图像显示，添加赤铁矿后，与细菌结合的 BaP 量大大减少，这也使我们能够直接观察到 HPD-2 和赤铁矿相互作用中 BaP 的迁移和回归。由于死细胞对 BaP 的吸附亲和力高于活细胞，因此 HPD-2 的更高死亡率可能会降低 BaP 进入活细胞的机会。这些观察结果增强了我们对金属氧化物、有机污染物和降解菌在生物降解过程中相互作用机制的理解。
