The Coupling Technology Of Electricity Production And Wastewater Purification By Halomonas Microbial Fuel Cells

Microbial fuel cell(MFC)is a biochemical reaction device that uses microorganisms to directly convert chemical energy stored in organic matter into electrical energy.The coupling technology of microbial fuel cell power generation and wastewater purification has the characteristics of low energy consumption,wide adaptability,efficient process,clean products.MFC can recover electrical energy in wastewater treatment at the same time Wastewater generally has a high salt content in dyes,textiles,leather,petroleum pesticides and other industries.MFC operation based on salty wastewater faces the following technical problems:high salt inhibits the growth metabolism and community diversity of anode electricigens,which in turn affects the MFC produce electricity.The current solution strategies and methods are acclimating salt-tolerant electricigens and adding salt-tolerant additives.However,the salt-tolerated electrode microbes are unstable,and the addition of salt-tolerant additives significantly increases the operating cost of MFC.It is of great significance to select strains that can produce electricity and decolorize-denitrify MFC under high salt conditions from moderate halophilic bacteria,and to study the coupling technology of electricity generation and wastewater purification.In this paper,a MFC high-efficiency electricity-producing strain Halomonas venusta DSM 4743T was selected from the moderate halophilic bacteria Halomonas strain.The strain can induce ectoine synthesis under high salt,resist environmental osmotic stress,and then release the inhibitory effect of high salt on the growth and metabolism of the strain.In this paper,the power generation conditions of H.venusta DSM 4743T are optimized.The results show that the most suitable power generation conditions are:sodium acetate 6 g/L,neutral red 50 ?M,pH 8,NaCl 30 g/L.The maximum output voltage of MFC under electrical conditions is 346 mV,and the maximum power density is 10.09 mW/m3.This strain synthesizes riboflavin and secretes it extracellularly,and clones the rib Grib A and rib C/rib R riboflavin synthase genes.Response surface analysis was used to optimize the decolorization conditions of H.venusta DSM 4743T.The optimal decolorization conditions were glucose 20,sodium glutamate 25,ammonium sulfate 8,yeast powder 0.5,K2HPO4·3H2O9,KH2PO4 3,MgSO4·7H2O 0.4,MnSO4·H2O 0.01,NaCl 30,trace element 2 mL,methylene blue 32 mg/L,pH 6.7,temperature 27?.The decolorization rate under optimized conditions is 91.0%.The high salt denitrification ability of the strain was investigated,and the maximum denitrification rate was 91.8%.H.venusta DSM 4743T under high salt(NaCl 30 g/L)MFC power generation and decolorization-denitrification coupling operation,the maximum output voltage reaches 224 mV,the methylene blue decolorization rate is 94.1%,and the nitrogen removal rate is 53.5%.