碳纳米管对嗜酸氧化亚铁硫杆菌的毒性效应及其作用机制

以嗜酸氧化亚铁硫杆菌（Acidithiobacillus ferrooxidans）为实验菌株,探讨不同条件下碳纳米管（CNTs）对其生长的影响,并采用SEM、EDS和FT-IR等手段分析CNTs对嗜酸氧化亚铁硫杆菌的毒性机制。实验结果表明,CNTs对Acidithiobacillus ferrooxidans生长有抑制作用,并随着CNTs剂量的增加,毒性增大。在CNTs投加量为500 mg/L时,培养40 h后菌株的生长量OD420达到最大值0.117,低于空白组的0.163。培养温度和培养基的pH对CNTs的细胞毒性效应有较大影响,在菌体生长的适宜条件下（pH 3.0,温度为30℃）,CNTs对菌体的毒性最强。SEM、EDS和FT-IR分析结果显示,CNTs附着在细胞表面,与细胞表面的羟基、氨基等基团相互作用,并可能诱发菌体细胞产生活性氧自由基（ROS）,从而导致细胞死亡。

Toxic effect of CNTs on growth of Acidithiobacillus ferrooxidans and mechanism of toxication

This present study investigated the effect of carbon nanotubes（CNTs） on the cell growth using Acidithiobacillus ferrooxidans as the experiment strain under different conditions and its toxic mechanism characterized by SEM,EDS and FT-IR.The results showed the presence of CNTs could inhibit the growth of A.ferrooxidans and the toxicity increased when dosages of CNTs increased.A significant decrease of cell numbers at 40 h was observed when CNTs concentration was 500 mg / L（OD 420 = 0.117） compared to the control（OD 420 = 0.163）.In addition,the solution pH and the temperature could impact obviously CNTs on the growth,the results showed that under the optimum conditions of 30℃,pH 3.0,CNTs had high toxicity to the growth of A.ferrooxidans.The SEM,EDS and FT-IR analyses showed that CNTs attached to the surface of cells,and reacted with —OH and N—H.Furthermore,the CNTs also could induce bacteria cells to produce reactive oxygen species（ROS） and lead to cell death.