Microbial fuel cell in enhancing anaerobic biodegradation of diesel

Abstract Microbial fuel cell (MFC) technology can potentially be applied to enhance subsurface bioremediation of contaminants such as petroleum hydrocarbons by providing an inexhaustible source of terminal electron acceptors to a groundwater environment that is likely depleted in thermodynamically favorable electron acceptors such as oxygen and nitrate. Results indicate that anaerobic biodegradation of diesel range organics (compounds eluting with n-alkane markers ranging in size from C-8 to C-25) was significantly enhanced (P = 0.007) in an MFC (82% removal) as compared to an anaerobically incubated control cell (31% removal) over 21 days at 30 °C, meanwhile, as much as 31 mW/m2 cathode of power was generated during diesel degradation (as measured during a polarization curve experiment). The microbial consortium on the anode of a diesel-degrading MFC was characterized by cloning and sequencing 16S rRNA genes. The majority of the clone sequences showed >98% similarity to bacteria capable of denitrification, such as Citrobacter sp., Pseudomonas sp., and Stenotrophomonas sp. The remaining clone sequences showed high similarity with organisms capable of using a wide range of electron acceptors, including sulfate, arsenate, and chlorinated inorganics. In particular, Shewanella sp. and Alishewanella sp. were found, which are typically capable of using multiple electron acceptors. This study suggests that MFC technology may be used for enhancing biodegradation of petroleum contaminants in anoxic environments, thus, eliminating the need to amend terminal electron acceptors such as oxygen.