Stimulating the Anaerobic Degradation of Aromatic Hydrocarbons in Contaminated Sediments by Providing an Electrode as the Electron Acceptor

Department of Microbiology, University of Massachusetts, Amherst, MA, USA.
Environmental Microbiology (Impact Factor: 6.2). 04/2010; 12(4):1011-20. DOI: 10.1111/j.1462-2920.2009.02145.x
Source: PubMed


The possibility that electrodes might serve as an electron acceptor to simulate the degradation of aromatic hydrocarbons in anaerobic contaminated sediments was investigated. Initial studies with Geobacter metallireducens demonstrated that although toluene was rapidly adsorbed onto the graphite electrodes it was rapidly oxidized to carbon dioxide with the electrode serving as the sole electron acceptor. Providing graphite electrodes as an electron acceptor in hydrocarbon-contaminated sediments significantly stimulated the removal of added toluene and benzene. Rates of toluene and benzene removal accelerated with continued additions of toluene and benzene. [(14)C]-Toluene and [(14)C]-benzene were quantitatively recovered as [(14)C]-CO(2), demonstrating that even though the graphite adsorbed toluene and benzene they were degraded. Introducing an electrode as an electron acceptor also accelerated the loss of added naphthalene and [(14)C]-naphthalene was converted to [(14)C]-CO(2). The results suggest that graphite electrodes can serve as an electron acceptor for the degradation of aromatic hydrocarbon contaminants in sediments, co-localizing the contaminants, the degradative organisms and the electron acceptor. Once in position, they provide a permanent, low-maintenance source of electron acceptor. Thus, graphite electrodes may offer an attractive alternative for enhancing contaminant degradation in anoxic environments.

Download full-text


Available from: Tian Zhang,
  • Source
    • "We hypothesized that the groundwater microbial community would use the anode of an MFC as an electron acceptor after forming a biofilm on it. Geobacter sp. are often dominant in MFCs fed by acetate (Kiely et al., 2011) but can also degrade aromatic compounds (Bond et al., 2002; Zhang et al., 2010). Phenolic compounds and/or acetate could therefore serve as electron donors for electricity production . "
    [Show abstract] [Hide abstract]
    ABSTRACT: This is the first study demonstrating the biodegradation of phenolic compounds and their organic metabolites in contaminated groundwater using bioelectrochemical systems (BESs). The phenols were biodegraded anaerobically via 4-hydroxybenzoic acid and 4-hydroxy-3-methylbenzoic acid, which were retained by electromigration in the anode chamber. Oxygen, nitrate, iron(III), sulfate and the electrode were electron acceptors for biodegradation. Electro-active bacteria attached to the anode, producing electricity (~1.8mW/m(2)), while utilizing acetate as an electron donor. Electricity generation started concurrently with iron reduction; the anode was an electron acceptor as thermodynamically favorable as iron(III). Acetate removal was enhanced by 40% in the presence of the anode. However, enhanced removal of phenols occurred only for a short time. Field-scale application of BESs for in situ bioremediation requires an understanding of the regulation and kinetics of biodegradation pathways of the parent compounds to relevant metabolites, and the syntrophic interactions and carbon flow in the microbial community.
    Bioresource Technology 10/2015; 200:426-434. DOI:10.1016/j.biortech.2015.09.092 · 4.49 Impact Factor
  • Source
    • "Other recent studies have shown that lab-scale microbial fuel cells, typically using carbon-based anodes and catalyzed cathodes exposed to air, can be used to accelerate the biodegradation of oil hydrocarbons in contaminated soil and sediment (Morris and Jin, 2012; Lu et al., 2014a,b). In principle, the use of electrodes to stimulate the microbiological oxidation of hydrocarbons in subsurface environments is extremely appealing since they can potentially serve as permanent, low-cost, low maintenance source of electron acceptor capacity (Zhang et al., 2010). The aim of this study is to present the proof-of-concept of a novel bioelectrochemical approach to accelerate hydrocarbons biodegradation in anoxic marine sediment. "
    [Show abstract] [Hide abstract]
    ABSTRACT: This study presents the proof-of-concept of the "Oil-Spill Snorkel": a novel bioelectrochemical approach to stimulate the oxidative biodegradation of petroleum hydrocarbons in sediments. The "Oil-Spill Snorkel" consists of a single conductive material (the snorkel) positioned suitably to create an electrochemical connection between the anoxic zone (the contaminated sediment) and the oxic zone (the overlying O2-containing water). The segment of the electrode buried within the sediment plays a role of anode, accepting electrons deriving from the oxidation of contaminants. Electrons flow through the snorkel up to the part exposed to the aerobic environment (the cathode), where they reduce oxygen to form water. Here we report the results of lab-scale microcosms setup with marine sediments and spiked with crude oil. Microcosms containing one or three graphite snorkels and controls (snorkel-free and autoclaved) were monitored for over 400 days. Collectively, the results of this study confirmed that the snorkels accelerate oxidative reactions taking place within the sediment, as documented by a significant 1.7-fold increase (p = 0.023, two-tailed t-test) in the cumulative oxygen uptake and 1.4-fold increase (p = 0.040) in the cumulative CO2 evolution in the microcosms containing three snorkels compared to snorkel-free controls. Accordingly, the initial rate of total petroleum hydrocarbons (TPH) degradation was also substantially enhanced. Indeed, while after 200 days of incubation a negligible degradation of TPH was noticed in snorkel-free controls, a significant reduction of 12 ± 1% (p = 0.004) and 21 ± 1% (p = 0.001) was observed in microcosms containing one and three snorkels, respectively. Although, the "Oil-Spill Snorkel" potentially represents a groundbreaking alternative to more expensive remediation options, further research efforts are needed to clarify factors and conditions affecting the snorkel-driven biodegradation processes and to identify suitable configurations for field applications.
    Frontiers in Microbiology 09/2015; 6:881. DOI:10.3389/fmicb.2015.00881 · 3.99 Impact Factor
  • Source
    • "Recently, it was reported that microbial anodes in METs can effectively enhance the anaerobic biodegradation of petroleum hydrocarbons (e.g. benzene, toluene), providing potential applications for the bioremediation of anaerobic sediment or groundwater contaminated with petroleum hydrocarbons (Zhang et al., 2010; Wang et al., 2012; Wu et al., 2013). In addition to converting the chemical energy of pollutants into electricity , METs were used as biosensors for on-line monitoring of wastewater treatment or anaerobic digestion processes, such as MFC-based sensors for measuring the biological oxygen demand (BOD) (Di Lorenzo et al., 2009; Liu et al., 2011). "
    [Show abstract] [Hide abstract]
    ABSTRACT: A bench-scale constructed wetland combined with microbial electrochemical technology (MET-CW) was run for 400days with groundwater contaminated with benzene, methyl-tert-butyl ether (MTBE), and ammonium (NH4(+)). Four vertically stacked anode modules were embedded into a sand bed and connected with a stainless steel cathode placed in an open water pond. In the zone of presence of anode modules, significantly more benzene and MTBE were removed in the MET-CW compared to the control CW without MET in the first 150 operation days. Benzene was identified as primary electron donor at the anode. Benzene removal and current densities were linearly correlated, implying the potential of the system for electrochemically monitoring benzene biodegradation. Compound-specific isotope analysis (CSIA) indicated that benzene was initially activated by monohydroxylation forming intermediates which were subsequently oxidized accompanied by extracellular electron transfer, leading to current production. NH4(+) removal was not stimulated by MET. Copyright © 2015 Elsevier Ltd. All rights reserved.
    Bioresource Technology 08/2015; 196. DOI:10.1016/j.biortech.2015.07.111 · 4.49 Impact Factor
Show more