Effects of Synthetic Quinones as Electron Shuttles on Geothite Reduction and Current Generation by Klebsiella pneumoniae L17

摘要

Quinone groups in exogenous electron shuttles (ES) can accelerate extracellular electron transfer from bacteria to insoluble terminal electron acceptor such as Fe(Ⅲ) oxide and electrode,which is considered to relate to their redox properties.This study examined the effects of a series of synthetic quinones (SQ) on geothite reduction and current generation by a fermenting bacterium Klebsiella pneumoniae L17,and tested the electron-accepting capabilities (EAC) and electron-donating capabilities (EDC) of SQ using chronoamperometry.The results showed that most of the tested SQ could significantly enhance the Fe(Ⅱ) production rates and current outputs by K.pneumoniae L17.However,5-HNQ showed only small effects,and Car showed no effects.The EAC and EDC of different SQ were ranked as follows:AQC ＞ AQS ＞ AQDS ≈ 2-HNQ ≈ 5-HNQ ＞ Ali ＞ Car.Generally,the effects of the SQ on microbial Fe(Ⅲ) reduction and current generation were found to correlate with the EAC and EDC of the SQ.These results suggest that the microbial Fe(Ⅲ) oxide reduction and current generation mediated by exogenous ES is controlled by their electron transfer capabilities.