The extensive use of roxarsone in the poultry and livestock industry has led to increasing arsenic contamination of soil and aquatic environments. Microbial activity, especially exoelectrogenic bacterium (EEB)-mediated roxarsone bioreduction, plays important roles in such a bioconversion. However, the biomolecular-level mechanism behind this process and the reduction pathways remain largely unclear. Herein, the rapid anaerobic reduction of roxarsone by several EEB was explored, and the degradation pathways were clarified by using Shewanella putrefaciens CN32 as the model. The knockout of undA/mtrC led to a 70% loss of the roxarsone bioreduction ability within the initial 48 h. Both extracellular and intracellular reductions occurred simultaneously, resulting in the production of As(III) as the main inorganic arsenic species. Adding anthraquinone 2,6-disulfonate as a mediator considerably increased the roxarsone reduction rate by 119%. Given the wide distribution of EEB in environments, our findings facilitate a better understanding of the transformation behaviors of arsenic compounds in natural environments and highlight the necessity of re-evaluating the environmental risks of roxarsone.

中文翻译：

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放氧细菌从罗沙松生物还原中快速释放砷

洛克沙酮在禽畜工业中的广泛使用已导致土壤和水生环境中砷的污染增加。微生物活性，特别是外生电细菌（EEB）介导的洛沙酮生物还原，在这种生物转化中起重要作用。然而，该过程背后的生物分子水平机制和还原途径仍不清楚。在本文中，探索了几种EEB快速厌氧还原洛克沙酮的方法，并以腐烂希瓦氏菌CN32为模型阐明了降解途径。und A / mtr的淘汰赛C在最初的48小时内导致了roxarsone生物还原能力的损失70％。细胞外和细胞内还原同时发生，从而导致As（III）作为主要的无机砷物质产生。加入蒽醌2，6-二磺酸盐作为介体可将洛沙酮的降低率显着提高119％。考虑到EEB在环境中的广泛分布，我们的发现有助于更好地理解砷化合物在自然环境中的转化行为，并强调了重新评估roxarsone的环境风险的必要性。