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

Microbial fuel cells(MFC)was a emerging technologies of generate electricity by using microorganisms oxidize organic or inorganic substrate.This study was to isolate and screen electricigens from seawater farm sediment in Xishan island,Zhoushan,Zhejiang province(respectively M01,M02,M03 and M04).Using anaerobic tube to culture and purify bacteria from sediment samples,and obtained 11 strains,respectively referred to as ME1,ME2,ME3~ME11.Combined the results of 16 s rDNA molecular identification and phylogenetic analysis that ME1 belonged to Microbacterium paraoxydans,ME2 and ME3 belonged to Shewanella haliotis,ME4 belonged to Sunxiuqinia elliptica,ME6,ME8 and ME10 belonged to Burkholderia contaminansz,ME7 belonged to Bacillus altitudinis,ME9 belonged to Exiguobacterium sp.,ME10 belonged to Clostridiales,and it couldn't be identified which genera belonged.In order to study the difference of microbial community structure in sediment and anode chamber in microbial fuel cell,The microbial diversity of four sediment samples using high-throughput sequencing were analyzed.The results showed that there were 24 phyla bacteria,and Proteobacteria was the dominant,followed by bacteroidetes and Chloroflexi.There was no significant difference in community diversity and relative abundance among all four samples.And there were three phyla fungi,concluded Ascomycota,Basidiomycota and Zygomycota.The community diversity and relative abundance existed differences among all four samples.Also found three phyla archaea,respectively were Crenarchaeota,Euryarchaeota and Parvarchaeota,and Crenarchaeota was dominant,there was no significant difference among all four samples in community diversity and relative abundance.Three two-chambered MFC had been designed in this study(respectively 01,02 and 03)to screen electricigens,with the sediment samples(respectively M01,M02 and M03)as the inoculums.And then the microbial diversity of anode biofilm and the sediment of anode chamber using high-throughput sequencing were analyzed.The results showed that there were 9 phyla bacteria in sediment of anode chamber,respectively were Proteobacteria,Planctomycetes,Gemmatimonadetes,Firmicutes,Chloroflexi,Chlorobi,Bacteroidetes,Actinobacteria and Acidobacteria.The relative abundance of Proteobacteria were 73.20%,66.47% and 73.20% respectively and was the dominant.Followed by Chloroflexi and Bacteroidetes.There were 6 phyla bacteria in anode biofilm,respectively were Proteobacteria,Firmicutes,Chloroflexi,Bacteroidetes,Actinobacteria and Acidobacteria.The relative abundance of Proteobacteria were all above 97% and was the significant dominant.Both anode biofilm and sediment of anode chamber included tree phyla archaea,respectively were Crenarchaeota,Euryarchaeota and Parvarchaeota,and Crenarchaeota was dominant.While the relative abundance of anode sediment was higher one or two order of magnitude than anode biofilm.Both anode biofilm and sediment of anode chamber included tree phyla fungi,respectively were Ascomycota,Basidiomycota and Zygomycota,and Ascomycota was dominant.The microbial community structure in sediment of inoculums,sediment of anode chamber and anode biofilm were changed,the results showed the relative abundance of Shewanella was significantly higher after MFC running,the microbial diversity in both sediment of anode chamber and anode biofilm were decreased,which verified the selective of MFC for the microbial community structure in anode.