Many electroactive microorganisms (EAMs) are known as dissimilatory iron-reducing bacteria (DIRB) which can access iron as an electron acceptor to transfer electrons during the process of respiration. Previous research has shown that magnetic susceptibility (χlf) could be used as an indicator of DIRB activities. However, the relationship between χlf and electroactivity of EAMs is still unclear. Here, we report that after sediments of the Sha River enriched with amorphous iron, the χlf of enrichment cultures increased dramatically. The reactor inoculated with higher χlf enrichment cultures started earlier and had a higher peak voltage (0.228 V), higher power density (310.14 mW m⁻²) and higher coulombic efficiency (10.16%) than lower χlf cultures. Sequencing of bacterial 16S rRNA gene amplicons and χlf measurement revealed that relative abundance of dominant phyla Proteobacteria increased with χlf values in sediments. Further analysis of cyclic voltammetry curves and bacterial terminal-restriction fragment length polymorphism (T-RFLP) of bacterial rRNA genes indicated that the improved performance of the MFCs might be due to a highly electroactive microbial community that the 162 bp terminal restriction fragments (TRFs) originated from. Our results suggested a potential correlation between χlf and presence of EAM indicating a promising route for fast screening in complex environments.

许多电活性微生物（EAM）被称为异化还原铁细菌（DIRB），可以在呼吸过程中利用铁作为电子受体来转移电子。先前的研究表明，磁化率（χlf）可以用作DIRB活性的指标。但是，χlf与EAMs的电活性之间的关系仍不清楚。在这里，我们报告说，在沙河的沉积物中富含无定形铁之后，富集培养物的xlf急剧增加。接种了较高xlf富集培养物的反应堆较早开始，并且具有较高的峰值电压（0.228 V），较高的功率密度（310.14 mW m ^-2））和比较低的lf培养物更高的库仑效率（10.16％）。细菌16S rRNA基因的扩增子和χlf测量的测序表明主导门类其相对丰度变形菌门与沉积物χlf值增高。循环伏安曲线和细菌rRNA基因的细菌末端限制性片段长度多态性（T-RFLP）的进一步分析表明，MFCs的性能改善可能是由于具有162 bp末端限制性片段（TRF）的高度电活性微生物群落来源于。我们的结果表明χlf和EAM的存在之间存在潜在的相关性，这表明在复杂环境中进行快速筛选的一种可行途径。