The Screening Of Electrigens For Microbial Fuel Cell And The Study Of Microbial Community Structure

Microbial fuel cells(MFCs)Microbialfuelcells is an ideal biological instrument that microorganism directly can convert chemical energy into electricity.Researches show that MFCs have has great application prospect in wastewater treatment and environmental protection.Compared to traditional energy utilization technologies,the device of energy conversion forms more directly and avoiding a large amount of energy loss.Various factors in the application especially internal resistance greatly limits the output power of MFCs.Optimization is needed in MFCs device structure and electrode materials,screening active higher electrogenesis microorganism and so on.1?Biological samples were collected and screened from seawater aquaculture sludge in zhejiang shanxi island,to determine the performance of MFCs in producting electricity,the polyaniline,polyaniline-graphene modified anode carbon electrode were used to explore the effect of electrode materials to produce electric device performance.The samples were enriched,separated and cultured,and 31 facultative anaerobic microorganisms were finally isolated.They were respectively used as anode biocatalysts and applied to MFCs for preliminary measurement of electrical performance.The results showed that 11 microorganisms had the ability to produce electricity,which were respectively labeled as N1A-B?N1A-BW?N1C-BW?N1C-F?N1C-SW?N2A-W?N2B-BY?N2B-SY?N3B-R?N3B-SW?N3C-MIX,the output voltage of 4 strains(N1A_BW,N2B_BY,N3B_R,N3B_SW)was higher,the electricity generation is 0.068V,0.24V,0.31V and 0.056V respectively.16S rDNA molecular identification revealed strain N3B-R?N2B-SY?N2B-BY?N3B-SW belong to Shewanella sp.,N1A-BW?N1A-B?N1C-BW?N3C-MIX all belong to Vibrio sp.,N1C-SW belongs to Aliiglacie colacoringensis with NIC-F,and N2A-W belongs to Bacillus cereus.Physiological and biochemical identification(API 20NE)results are used to verify the results of molecular identification.2?Polyaniline and polyaniline-graphene composites were deposited on the surface of carbon cloth electrode by electrochemical polymerization as MFCs anode,Four typicaltwo-compartment microbial fuel cells were constructed with N3B-R used as anode bacteria.The results showed that the performance of the electrode can be improved by the modified carbon cloth.The output voltage curve showed that the maximum output voltage of polyaniline modified carbon cloth anode is about 2-6 times higher than the other three anodes.The cyclic voltammetry curve showed that carbon(polyaniline)/carbon anode electrode has an obvious redox peak.The output power density is517.5mW/m~2,The results of impedance spectra show that the diameter of carbon(polyaniline)/carbon anode in the high frequency region is the smallest,and the slope in the low frequency region is roughly the same,which indicated its charge transfer resistance is lower than other anodes among the four MFCs.