厌氧条件下Shewanella oneidensis MR-1对2,4-二硝基甲苯的还原转化

【目的】研究Shewanella oneidensis MR-1厌氧生物转化2,4-二硝基甲苯(2,4-DNT)的能力、转化过程和影响因素。【方法】以乳酸钠为电子供体, 2,4-DNT为电子受体, S. oneidensis MR-1为降解菌, 黄素为胞外电子载体, 设立四个不同的对照体系并监测各体系在转化过程中2,4-DNT及其产物的动态变化。同时研究不同2,4-DNT浓度下细胞的生长情况, 以及不同黄素浓度下2,4-DNT的降解情况。【结果】S. oneidensis MR-1菌能够高效还原转化2,4-DNT为4-氨基-2-硝基甲苯(4A2NT)和2-氨基-4-硝基甲苯(2A4NT), 并将其进一步还原为2,4-二氨基甲苯(2,4-DAT), 黄素能加速转化过程。【结论】S. oneidensis MR-1菌具备高效还原转化2,4-DNT的能力, 为实际环境中硝基苯污染的原位修复提供科学依据。

Reductive biotransformation of 2,4-dinitrotoluene by Shewanella oneidensis MR-1 under anaerobic conditions

Objective] Reductive biotransformation of 2,4-dinitrotoluene (2,4-DNT) by Shewanella oneidensis MR-1 was evaluated under anaerobic conditions. Methods] Four systems were set up where 2,4-dinitrotoluene (2,4-DNT), S. oneidensis MR-1 and flavins were used as electron acceptor, degrading bacteria and extracellular mediator, respectively. Concentrations of 2,4-DNT and its metabolites were monitored by time temporal sampling. Growth of S. oneidensis MR-1 under different concentrations of 2,4-DNT and biotransformation of 2,4-DNT under different concentrations of flavins were also studied. Results] S. oneidensis MR-1 could efficiently biotransform 2,4-DNT to 4-amino-2-nitrotoluene (4A2NT) or 2-amino-4-nitrotoluene (2A4NT), both of them were further reduced to 2,4-diaminotoluene (2,4-DAT). The presence of flavins could accelerate the biotransformation. Conclusion] S. oneidensis MR-1 showed a high capacity for biotransforming 2,4-DNT and could be further applied in the in situ bioremediation of nitrobenzene contaminations in the environment.