Study On Isolation And Extracellular Electron Transfer Properties Of Electroporation Microorganisms In Iron Reduction System

Dissimilatory iron-reducing bacteria can restore a variety of metal ions during cellular respiration and growth,remove toxic organics and heavy metals,and transfer electrons that are metabolized by intracellular organic substances to extracellular electron receptors,especially solid state,through extracellular electron transfer mechanisms to reduce metal oxides.Therefore,iron-reducing bacteria play an important role in the geochemical cycle of metal elements and the recycling of energy.The typical dissimilatory iron-reducing bacteria are represented by Geobacter(strictly anaerobic bacteria)and Shewanella(facultative anaerobes).Their common feature is the ability to conduct extracellular electron transfer,which is the most studied production electrobacter.Iron reduction is considered to be the oldest form of microbial metabolism on earth,and it is closely related to the circulation of water,soil,and matter in sediments.The microbial reduction of iron is of great significance for the remediation of heavy metal pollution.The research on the characteristics of iron production during iron reduction can provide a basis for the study of extracellular electron transport mechanisms.The discovery of novel electrogenic bacteria with extracellular electron transfer characteristics is of great significance for revealing the mechanism of electricity production by the dissimilatory iron-reducing bacteria.In this paper,based on iron ore soil,enriched by two methods,we screen out iron reducing bacteria.The screened bacteria were assembled into a bipolar chamber MFC.The data acquisition device is used to collect data of the battery for at least three working cycles,and the electrochemical data such as polarization curves,CV curves,open circuit voltage curves,power density curves,and internal resistances of the MFC device are obtained.Based on the electrochemical data of common producing bacteria,three unreported strains of iron-reducingbacteria were screened out,codenamed F1,F2,and F3 respectively.The gene sequence was obtained by sequencing the 16 S rRNA gene,identifying bacterial species,making electron microscopy samples,and observing the differences in the morphology of the bacteria under conditions of unproduced electricity and production of electricity.The results show that the morphology of these bacterial cells changed during the operation of microbial fuel cells.In this paper,the selected strains were studied for iron reduction and chromium reduction,and the iron reduction and chromium reduction curves and the corresponding bacterial growth curves were plotted.Studies have found that the iron reducing capacity of bacteria has an effect on its chromium reduction ability.This article also studied the photocatalytic properties of the three strains of electrogenic bacteria.The carbon electrode was modified with titanium dioxide,and the modified electrode was used as a working electrode to assemble a half-cell.Half cells were assembled for each strain of bacteria.The I-T curves and bacteria of the battery under light and dark conditions were recorded by an electrochemical workstation and an ultraviolet spectrophotometer.Growth curve.The experimental results show that titanium dioxide can increase the extracellular electron transfer efficiency of these three bacteria in the presence of light.Simultaneously,whole genome sequencing analysis of B.cereus strain F1 was performed.Through detailed comparison of sequencing data with various genes and protein databases such as KEGG,COG,Swiss-Prot,etc.,we grasped the growth characteristics,metabolic mechanism,and homology of the bacteria.Species and other characteristics lay the foundation for the study of extracellular electron transport mechanisms.