Molecular insight into electron transfer properties of extracellular polymeric substances of electroactive bacteria by surface-enhanced Raman spectroscopy

作     者：TAN Bin ZHOU ShaoFeng WANG Yi ZHANG BeiPing ZHOU LiHua YUAN Yong 

作者机构：Guangzhou Key Laboratory of Environmental Catalysis and Pollution ControlGuangdong Key Laboratory of Environmental Catalysis and Health Risk ControlSchool of Environmental Science and EngineeringInstitute of Environmental Health and Pollution ControlGuangdongUniversity of TechnologyGuangzhou510006China Institute of Natural Medicine&Green ChemistrySchool of Chemical Engineering and Light IndustryGuangdong University of TechnologyGuangzhou510006China 

出 版 物：《Science China(Technological Sciences)》 (中国科学（技术科学英文版）)

年 卷 期：2019年第62卷第10期

页      面：1679-1687页

核心收录：

学科分类：07[理学] 09[农学] 0903[农学-农业资源与环境] 0713[理学-生态学] 

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.51678162,41877045,21876032) the Guangzhou City Science-Technology Project(Grant No.201707010250) the Major Scientific Project of Guangdong University(Grant No.2017KZDXM029) 

主　　题：electroactive bacteria extracellular polymeric substances redox properties SERS 

摘      要：Extracellular polymeric substances(EPS) extracted from electroactive bacteria show promising redox activity, but the electron transfer(ET) mechanism of the EPS has been rarely elucidated because of their structural complexity and lack of efficient methodologies. In this study, the charge transfer theory of surface-enhanced Raman spectroscopy(SERS) was applied to evaluate the redox properties of EPS adsorbed on Ni and Ag nanoparticles(NPs). These metal NPs were used to simultaneously magnify Raman signals and reduce/oxidize the redox moieties in EPS. As a result, the ET between EPS and metal NPs was evaluated through the changes in Raman signals. In this regard, we compared the redox activity of EPS extracted from two typical electroactive bacteria(Shewanella oneidensis and Geobacter sulfurreducens) and another two nonelectroactive strains(Escherichia coli and Bacillus subtilis). Electrochemical measurements show that the electroactive strains have higher redox capabilities than nonelectroactive strains. The SERS analysis shows that the porphyrin present in cytochrome c is the dominating redox moiety in the EPS of electroactive bacteria. The results of this study show that SERS with active metal substrates is a sensitive tool to probe the redox response of EPS, offering an opportunity to better understand the redox nature of biomolecules.