Enhanced Power Generation And Sensing Performance Of Microbial Fuel Cells By Cell-surface Modification And Quorum Sensing Regulation

Microbial fuel cells（MFCs）is a new technology that uses electroactive biofilms（EABs）to convert chemical energy in organic matter into electrical energy.MFCs has the advantages of simple construction and low cost,so it has been widely studied in the fields of pollutant degradation,energy recovery and biosensing.In recent years,researchers have conducted a lot of in-depth research on optimizing configuration,operation parameters,electrode materials of MFCs and exploring electron transfer mechanism in EABs.However,the direct influence of intrinsic properties of EABs on the performance MFCs has not been well understood.In this study,cell-surface modification and microbial quorum sensing regulation were used to manipulate the extracellular electron transfer capability,microbial biomass production,microbial metabolic activity and microbial community of EABs.And the interaction between the electroactivity of EABs and the performance of MFCs was analyzed.The main research contents and results of this study include:（1）Cell-surface modification was used to manipulate the extracellular electron transfer capacity and microbial biomass of EABs,so as to explore the effect of the electroactivity of EABs on the power generation ability of MFCs.A three-dimensional conductive biofilm was constructed by coating conductive polypyrrole（PPy）and adhesive polydopamine（PDA）on Shewanella oneidensis MR-1,and the effect of modification process on the metabolic activity and surface morphology of bacteria was explored by fluorescence spectrum analysis,SEM and TEM.The charge transfer resistance of PDA@PPy@Bacteria-MFCs was significantly lower than that of PPy@bacteria-MFCs and unmodified MFCs.Moreover,the maximum output voltage and maximum power density of PDA@PPy@Bacteria-MFCs were increased to 4.6 times and 11.8 times of unmodified MFCs,respectively.Finally,cyclic voltammetry,high performance liquid chromatography and anode surface biomass analysis were conducted to identify the mechanism of the influence of polymer modification on the performance of EABs.The results showed that polypyrrole modification significantly improved the direct electron transfer ability of Shewanella oneidensis MR-1.Meanwhile,high adhesive PDA increased the amount of microorganisms attached on the anode surface,hence the modification of PDA can optimize the effect of PPy on the conductivity of EABs.（2）Commercially available quorum sensing autoinducers and acylase were used to construct biofilm with different electroactivity,and the effect of the electroactivity of EABs on the sensing performance of MFCs was studied.Graphite plate was selected as anode of MFCs biosensor owing to its low charge transfer resistance and smooth surface.The results showed that the enhanced quorum sensing is conducive to construct a biofilm with higher redox activity and less charge transfer resistance.Meanwhile,biofilms formed in enhanced quorum sensing have higher ratio of live/dead cells and Geobacter abundance.As for the sensing performance of MFCs sensors,biofilm with high electroactivity led to higher sensing linearity to a wider range of Pb²⁺and better recovery capability after 10 mg/L Cu²⁺shock.In this work,we found a simple and effective way to manipulate the intrinsic electrochemical properties of EABs,and identified the direct influence of intrinsic properties on the performance of MFC sensor,which advanced the process of MFCs sensor application.