Key Laboratory of Coastal Biology and Bioresource Conservation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China.
State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, China.
Bioelectrochemistry. 2018 Jun;121:65-73. doi: 10.1016/j.bioelechem.2018.01.005. Epub 2018 Jan 10.
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) 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（EAMs）被称为异化铁还原菌（DIRB），它们可以将铁作为电子受体来接受电子，从而在呼吸过程中传递电子。先前的研究表明，磁化率（χlf）可以用作 DIRB 活性的指标。然而，χlf 与 EAMs 的电活性之间的关系尚不清楚。在这里，我们报告说，在富含非晶铁的沙河沉积物中进行富集后，富集培养物的 χlf 显著增加。接种 χlf 较高的富集培养物的反应器更早开始，峰值电压（0.228 V）更高，功率密度（310.14 mW m）更高，库仑效率（10.16%）更高。细菌 16S rRNA 基因扩增子的测序和 χlf 测量表明，在沉积物中，变形菌门的相对丰度随着 χlf 值的增加而增加。对循环伏安曲线和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 性能的提高可能是由于微生物群落具有高度的电活性，而 162 bp 末端限制片段（TRFs）则来自该群落。我们的结果表明 χlf 与 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有前途的途径。
