title: Enhanced removal of petroleum hydrocarbons using a bioelectrochemical remediation system with pre-cultured anodes.
abstract: Bioelectrochemical remediation (BER) systems such as microbial fuel cells (MFCs) have recently emerged as a green technology for the effective remediation of petroleum hydrocarbon contaminants (PH) coupled with simultaneous energy recovery. Recent research has shown that biofilms previously enriched for substrate degrading bacteria resulted in excellent performance in terms of substrate removal and electricity generation but the effects on hydrocarbon contaminant degradation were not examined. Here we investigate the differences between enriched biofilm anodes and freshly inoculated new anodes in diesel fed single chamber mediatorless microbial fuel cells (DMFC) using various techniques for the enhancement of PH contaminant remediation with concomitant electricity generation. An anodophilic microbial consortium previously selected for over a year through continuous culturing with a diesel concentration of about 800mgl(-1) and which now showed complete removal of this concentration of diesel within 30days was compared to that of a freshly inoculated new anode MFC (showing 83.4% removal of diesel) with a simultaneous power generation of 90.81mW/m(2) and 15.04mW/m(2) respectively. The behaviour of pre-cultured anodes at a higher concentration of PH (8000mgl(-1)) was also investigated. Scanning electron microscopy observation revealed a thick biofilm covering the pre-cultured anodic electrode but not the anode from the freshly inoculated MFC. High resolution imaging showed the presence of thin 60nm diametre pilus-like projections emanating from the cells. Anodic microbial community profiling confirmed that the selection for diesel degrading exoelectrogenic bacteria had occurred. Identification of a biodegradative gene (alkB) provided strong evidence of the catabolic pathway used for diesel degradation in the DMFCs.
authors.affiliation: Centre for Environmental Risk Assessment and Remediation (CERAR), University of South, Australia; CRC for Contamination Assessment and Remediation of the Environment (CRCCARE), Mawson Lakes, SA5095, Australia.
authors.forename: Krishnaveni
authors.initials: K
authors.lastname: Venkidusamy
authors.affiliation: Centre for Environmental Risk Assessment and Remediation (CERAR), University of South, Australia; CRC for Contamination Assessment and Remediation of the Environment (CRCCARE), Mawson Lakes, SA5095, Australia; Global Centre for Environmental Remediation, Faculty of Science and Information Technology, The University of Newcastle, Callaghan, NSW 2308, Australia. Electronic address: megh.mallavarapu@newcastle.edu.au.
authors.forename: Mallavarapu
authors.initials: M
authors.lastname: Megharaj
authors.affiliation: Laboratory for Microbial Ecology and Technology (LabMET), Gent University, 9000 Gent, Belgium.
authors.forename: Massimo
authors.initials: M
authors.lastname: Marzorati
authors.affiliation: Centre for Environmental Risk Assessment and Remediation (CERAR), University of South, Australia; CRC for Contamination Assessment and Remediation of the Environment (CRCCARE), Mawson Lakes, SA5095, Australia.
authors.forename: Robin
authors.initials: R
authors.lastname: Lockington
authors.affiliation: Centre for Environmental Risk Assessment and Remediation (CERAR), University of South, Australia; CRC for Contamination Assessment and Remediation of the Environment (CRCCARE), Mawson Lakes, SA5095, Australia; Global Centre for Environmental Remediation, Faculty of Science and Information Technology, The University of Newcastle, Callaghan, NSW 2308, Australia.
authors.forename: Ravi
authors.initials: R
authors.lastname: Naidu
mesh_terms: D001419:Bacteria; D001673:Biodegradation, Environmental; D001674:Bioelectric Energy Sources / Q000382:microbiology; D018441:Biofilms; D004566:Electrodes; D006863:Hydrogen-Ion Concentration; D010084:Oxidation-Reduction; D010578:Petroleum / Q000032:analysis / Q000378:metabolism*; D059392:Petroleum Pollution; D012989:Soil Pollutants / Q000032:analysis / Q000378:metabolism*
chemical_list: D010578:Petroleum; D012989:Soil Pollutants
keywords: AlkB gene; Bioelectrochemical remediation; Diesel-fed microbial fuel cell; Pre-cultured MFC