Department of Chemistry, University of Science & Technology of China, Hefei 230026, China.
Bioresour Technol. 2013 May;136:711-4. doi: 10.1016/j.biortech.2013.02.072. Epub 2013 Mar 14.
Shewanella oneidensis MR-1 is an extensively studied dissimilatory metal-reducing bacterium with a great potential for bioremediation and electricity generation. It secretes flavins as electron shuttles which play an important role in extracellular electron transfer. However, the influence of various environmental factors on the secretion of flavins is largely unknown. Here, the effects of electron acceptors, including fumarate, ferrihydrite, Fe(III)-nitrilotriacetic acid (NTA), nitrate and trimethylamine oxide (TMAO), on the secretion of flavins were investigated. The level of riboflavin and riboflavin-5'-phosphate (FMN) secreted by S. oneidensis MR-1 varied considerably with different electron acceptors. While nitrate and ferrihydrite suppressed the secretion of flavins in relative to fumarate, Fe(III)-NTA and TMAO promoted such a secretion and greatly enhanced ferrihydrite reduction and electricity generation. This work clearly demonstrates that electron acceptors could considerably affect the secretion of flavins and consequent microbial EET. Such impacts of electron acceptors in the environment deserve more attention.
希瓦氏菌属 MR-1 是一种被广泛研究的异化金属还原菌，具有很大的生物修复和发电潜力。它分泌黄素作为电子穿梭体，在细胞外电子转移中起着重要作用。然而，各种环境因素对黄素分泌的影响在很大程度上尚不清楚。在这里，研究了电子受体（包括延胡索酸盐、水铁矿、Fe(III)-氮三乙酸（NTA）、硝酸盐和三甲胺氧化物（TMAO））对黄素分泌的影响。与延胡索酸盐相比，不同电子受体对希瓦氏菌属 MR-1 分泌的核黄素和黄素-5'-磷酸（FMN）水平有很大的影响。硝酸盐和水铁矿抑制了黄素的分泌，而 Fe(III)-NTA 和 TMAO 则促进了黄素的分泌，并大大增强了水铁矿的还原和发电。这项工作清楚地表明，电子受体可以显著影响黄素的分泌和随后的微生物 EET。电子受体在环境中的这种影响值得更多关注。
