The Electricity Production Research Of Zymomonas Mobilis And Enhancement Of Microbial Fuel Cells

Microbial fuel cell(MFC)convokes microorganism to convert biomass into electricity.However,most well-known electrogenic strains can not directly use glucose to produce valuable products,which restricts these strains’applications.Zymomonas mobilis,a promising bacterium for ethanol production,owns branchless Entner-Doudoroff pathway without redundant by-products and the low energy-coupling respiration,making Z.mobilis a potential exoelectrogen.For Z.mobilis,reduction of oxidation-reduction potential(ORP)is observed during ethanol production.Based on this feature,a glucose-consumed MFC is constructed by inoculating Z.mobilis.By comparing the trends of voltage and oxidation-reduction potential,it is proved that the electricity is derived from the difference of ORP between anode and cathode chambers.And the maximum power density is 2.0 m W/m~2.Besides,in terms of ORP and glucose consumption rate,two-type electricity generation is observed as glucose-independent process and glucose-dependent process.This mechanism is unique and has never been reported in other major exoelectrogens.For the sake of enhancing MFC efficiency,extracellular and intracellular strategies are implemented.Extracellular strategies contain biofilm removal and addition of electron shuttles and surfactant.Intracellular strategies include addition of electron precursor and overexpressing genes of redox-related enzymes.Biofilm removal and addition of c-type cytochrome benefit electricity performance,and Tween 80accelerates the electricity generation.Perturbation of cellular redox balance compromises the electricity output,indicating that redox homeostasis is the principal requirement to reach ideal voltage.This study identifies potential features of electricity activity for Z.mobilis and provides multiple strategies to enhance the electricity output.Z.mobilis not only uses low-cost substrate to produce ethanol,but also recovers thermal energy in the form of electrical energy,not affecting ethanol production.Combining electricity generation and ethanol production in Z.mobilis helps expand theories and practices of renewable energy source production.