title: Characterization of Electricity Generated by Soil in Microbial Fuel Cells and the Isolation of Soil Source Exoelectrogenic Bacteria.
abstract: Soil has been used to generate electrical power in microbial fuel cells (MFCs) and exhibited several potential applications. This study aimed to reveal the effect of soil properties on the generated electricity and the diversity of soil source exoelectrogenic bacteria. Seven soil samples were collected across China and packed into air-cathode MFCs to generate electricity over a 270 days period. The Fe(III)-reducing bacteria in soil were enriched and sequenced by Illumina pyrosequencing. Culturable strains of Fe(III)-reducing bacteria were isolated and identified phylogenetically. Their exoelectrogenic ability was evaluated by polarization measurement. The results showed that soils with higher organic carbon (OC) content but lower soil pH generated higher peak voltage and charge. The sequencing of Fe(III)-reducing bacteria showed thatClostridiawere dominant in all soil samples. At the family level,ClostridialesFamily XI incertae sedis were dominant in soils with lower OC content but higher pH (>8), whileClostridiaceae, Lachnospiraceae, andPlanococcaceaewere dominant in soils with higher OC content but lower pH. The isolated culturable strains were allied phylogenetically to 15 different species, of which 11 wereClostridium. The others wereRobinsoniella peoriensis, Hydrogenoanaerobacterium saccharovorans, Eubacterium contortum, andOscillibacter ruminantium. The maximum power density generated by the isolates in the MFCs ranged from 16.4 to 28.6 mW m-2. We concluded that soil OC content had the most important effect on power generation and that theClostridiaceaewere the dominant exoelectrogenic bacterial group in soil. This study might lead to the discovery of more soil source exoelectrogenic bacteria species.
authors.affiliation: Jiangsu Provincial Key Laboratory of Materials Cycling and Pollution Control, School of Geography Science, Nanjing Normal UniversityNanjing, China; Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and ApplicationNanjing, China.
authors.forename: Yun-Bin
authors.initials: YB
authors.lastname: Jiang
authors.affiliation: Jiangsu Provincial Key Laboratory of Materials Cycling and Pollution Control, School of Geography Science, Nanjing Normal UniversityNanjing, China; Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and ApplicationNanjing, China.
authors.forename: Wen-Hui
authors.initials: WH
authors.lastname: Zhong
authors.affiliation: Jiangsu Provincial Key Laboratory of Materials Cycling and Pollution Control, School of Geography Science, Nanjing Normal UniversityNanjing, China; Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and ApplicationNanjing, China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Han
authors.affiliation: Jiangsu Provincial Key Laboratory of Materials Cycling and Pollution Control, School of Geography Science, Nanjing Normal UniversityNanjing, China; Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and ApplicationNanjing, China; School of Environment, Nanjing Normal UniversityNanjing, China.
authors.forename: Huan
authors.initials: H
authors.lastname: Deng
keywords: Clostridiaceae; Fe(III)-reducing bacteria; Illumina pyrosequencing; polarization curve; soil property