UNASSIGNED:电子航天飞机(ESs)在ShewanellaoneidensisMR-1的细胞外电子转移(EET)中起关键作用。然而,ES浓度之间的定量关系,生物膜的形成,生物电流的产生尚未得到澄清。
未经批准:在这项研究中,9,10-蒽醌-2-磺酸(AQS)介导的EET和生物膜的形成在生物电化学系统(BES)中的不同AQS浓度下进行了评估。
UNASSIGNED:生物膜生物量(9-至17倍)和生物电流(21-至80倍)均被外源AQS大大提高,表明AQS具有促进生物膜形成和电子穿梭的双重能力。然而,没有添加外源AQS,生物膜几乎没有生长,揭示了S.oneidensisMR-1的生物膜形成高度依赖于电子穿梭。生物膜生长在2,000μMAQS的BES中延迟,这可能是因为本体溶液中多余的AQS充当了可溶性电子受体并延迟了生物膜的形成。此外,不同浓度AQS的BESs的最大生物电流密度拟合为Michael-Menten方程(R2=0.97),证明微生物催化的ES生物还原是BES中最大生物电流密度的关键限制因素。这项研究提供了对ES介导的EET的基本理解,这可能有利于电活性生物膜的富集,微生物燃料电池(MFC)的快速启动,以及用于废水处理的BESs的设计。
UNASSIGNED: Electron shuttles (ESs) play a key role in extracellular electron transfer (EET) in Shewanella oneidensis MR-1. However, the quantification relationship between ES concentration, biofilm formation, and biocurrent generation has not been clarified.
UNASSIGNED: In this study, 9,10-anthraquinone-2-sulfonic acid (AQS)-mediated EET and biofilm formation were evaluated at different AQS concentrations in bioelectrochemical systems (BESs) with S. oneidensis MR-1.
UNASSIGNED: Both the biofilm biomass (9- to 17-fold) and biocurrent (21- to 80-fold) were substantially enhanced by exogenous AQS, suggesting the dual ability of AQS to promote both biofilm formation and electron shuttling. Nevertheless, biofilms barely grew without the addition of exogenous AQS, revealing that biofilm formation by S. oneidensis MR-1 is highly dependent on electron shuttling. The biofilm growth was delayed in a BES of 2,000 μM AQS, which is probably because the redundant AQS in the bulk solution acted as a soluble electron acceptor and delayed biofilm formation. In addition, the maximum biocurrent density in BESs with different concentrations of AQS was fitted to the Michaelis-Menten equation (R 2 = 0.97), demonstrating that microbial-catalyzed ES bio-reduction is the key limiting factor of the maximum biocurrent density in BESs. This study provided a fundamental understanding of ES-mediated EET, which could be beneficial for the enrichment of electroactive biofilms, the rapid start-up of microbial fuel cells (MFCs), and the design of BESs for wastewater treatment.