State Key Laboratory of Urban Water Resource and Environment, School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin, 150090, P R China.
Environ Sci Technol. 2013 May 21;47(10):5353-61. doi: 10.1021/es400933h. Epub 2013 May 6.
Chlorinated nitroaromatic antibiotic chloramphenicol (CAP) is a priority pollutant in wastewaters. A fed-batch bioelectrochemical system (BES) with biocathode with applied voltage of 0.5 V (served as extracellular electron donor) and glucose as intracellular electron donor was applied to reduce CAP to amine product (AMCl2). The biocathode BES converted 87.1 ± 4.2% of 32 mg/L CAP in 4 h, and the removal efficiency reached 96.0 ± 0.9% within 24 h. Conversely, the removal efficiency of CAP in BES with an abiotic cathode was only 73.0 ± 3.2% after 24 h. When the biocathode was disconnected (no electrochemical reaction but in the presence of microbial activities), the CAP removal rate was dropped to 62.0% of that with biocathode BES. Acetylation of one hydroxyl of CAP was noted exclusive in the biocatalyzed process, while toxic intermediates, hydroxylamino (HOAM), and nitroso (NO), from CAP reduction were observed only in the abiotic cathode BES. Electrochemical hydrodechlorination and dehalogenase were responsible for dechlorination of AMCl2 to AMCl in abiotic and microbial cathode BES, respectively. The cyclic voltammetry (CV) highlighted higher peak currents and lower overpotentials for CAP reduction at the biocathode compared with abiotic cathode. With the biocathode BES, antibacterial activity of CAP was completely removed and nitro group reduction combined with dechlorination reaction enhanced detoxication efficiency of CAP. The CAP cathodic transformation pathway was proposed based on intermediates analysis. Bacterial community analysis indicated that the dominate bacteria on the biocathode were belonging to α, β, and γ-Proteobacteria. The biocathode BES could serve as a potential treatment process for CAP-containing wastewater.
氯硝基本土霉素（CAP）是废水中的优先污染物。应用施加 0.5 V 电压的生物阴极（作为细胞外电子供体）和葡萄糖作为细胞内电子供体的分批补料生物电化学系统（BES）来将 CAP 还原为胺产物（AMCl2）。生物阴极 BES 在 4 小时内将 32mg/L 的 CAP 转化了 87.1±4.2%，并且在 24 小时内去除效率达到了 96.0±0.9%。相反，在没有生物阴极的 BES 中，24 小时后 CAP 的去除效率仅为 73.0±3.2%。当生物阴极断开时（没有电化学反应但存在微生物活性），CAP 的去除率下降到生物阴极 BES 的 62.0%。在生物催化过程中仅观察到 CAP 的一个羟基乙酰化，而在无生物阴极 BES 中仅观察到 CAP 还原的有毒中间体羟基胺（HOAM）和亚硝（NO）。电化学脱氯和脱卤酶分别负责在无生物和微生物阴极 BES 中将 AMCl2 脱氯到 AMCl。循环伏安法（CV）突出显示与无生物阴极相比，在生物阴极处 CAP 还原的峰值电流更高，过电势更低。在生物阴极 BES 中，CAP 的抗菌活性被完全去除，并且硝基还原与脱氯反应提高了 CAP 的解毒效率。基于中间产物分析，提出了 CAP 的阴极转化途径。细菌群落分析表明，生物阴极上占主导地位的细菌属于α、β和γ变形菌。生物阴极 BES 可作为处理含 CAP 废水的潜在工艺。
