The Effects of Aniline-Promoted Electron Shuttle-Mediated Goethite Reduction by Shewanella oneidensis MR-1 and theDegradation of Aniline

The biological reduction of Fe (III) is common in underground environments. This process not only affects the biogeochemical cycle of iron but also influences the migration and transformation of pollutants. Humic substances are considered effective strategies for improving the migration and transformation of toxic substances and enhancing the bioavailability of Fe (III). In this study, the electron shuttle anthraquinone-2-sulfonate (AQS) significantly promoted the bio-reduction of Fe (III). On this basis, different concentrations of aniline were added. The research results indicate that at an aniline concentration of 3 mu M, the production of Fe (II) in the reaction system was 2.51 times higher compared to the microbial reaction group alone. Furthermore, the degradation of aniline was most effective in this group. The increased consumption of sodium lactate suggests that aniline, under the mediation of AQS, promoted the metabolism of Shewanella oneidensis MR-1 cells and facilitated the involvement of more electrons in the reduction process. After the reaction, the solid mineral Fe (II)-O content increased to 41.32%. This study provides insights into the reduction mechanism of Fe (III) in the complex environment of microorganisms, iron minerals, electron shuttles, and pollutants. It aims to offer a theoretical basis for the biodegradation of aromatic hydrocarbon pollutants.

Automated summary

The biological reduction of Fe (III) in underground environments has significant impacts on the biogeochemical cycle of iron and the migration and transformation of pollutants. Humic substances, especially the electron shuttle anthraquinone-2-sulfonate (AQS), can effectively promote the bio-reduction of Fe (III) and enhance the bioavailability of Fe (III). This study demonstrated that aniline, when mediated by AQS, significantly increased the production of Fe (II) and promoted the metabolism of Shewanella oneidensis MR-1 cells, leading to more efficient degradation of aniline. The findings provide insights into the reduction mechanism of Fe (III) in complex environments and offer a theoretical basis for the biodegradation of aromatic hydrocarbon pollutants.