title: A lithotrophic microbial fuel cell operated with pseudomonads-dominated iron-oxidizing bacteria enriched at the anode.
abstract: In this study, we attempted to enrich neutrophilic iron bacteria in a microbial fuel cell (MFC)-type reactor in order to develop a lithotrophic MFC system that can utilize ferrous iron as an inorganic electron donor and operate at neutral pHs. Electrical currents were steadily generated at an average level of 0.6 mA (or 0.024 mA cm(-2) of membrane area) in reactors initially inoculated with microbial sources and operated with 20 mM Fe(2+) as the sole electron donor and 10 ohm external resistance; whereas in an uninoculated reactor (the control), the average current level only reached 0.2 mA (or 0.008 mA cm(-2) of membrane area). In an inoculated MFC, the generation of electrical currents was correlated with increases in cell density of bacteria in the anode suspension and coupled with the oxidation of ferrous iron. Cultivation-based and denaturing gradient gel electrophoresis analyses both show the dominance of some Pseudomonas species in the anode communities of the MFCs. Fluorescent in-situ hybridization results revealed significant increases of neutrophilic iron-oxidizing bacteria in the anode community of an inoculated MFC. The results, altogether, prove the successful development of a lithotrophic MFC system with iron bacteria enriched at its anode and suggest a chemolithotrophic anode reaction involving some Pseudomonas species as key players in such a system. The system potentially offers unique applications, such as accelerated bioremediation or on-site biodetection of iron and/or manganese in water samples.
authors.affiliation: Research group for Physiology and Applications of Microorganisms (PHAM group) at Center for Life Science Research, Vietnam National University - University of Science, Nguyen Trai 334, Thanh Xuan, Hanoi, Vietnam.
authors.forename: Thuy Thu
authors.initials: TT
authors.lastname: Nguyen
authors.forename: Tha Thanh Thi
authors.initials: TT
authors.lastname: Luong
authors.forename: Phuong Hoang Nguyen
authors.initials: PH
authors.lastname: Tran
authors.forename: Ha Thi Viet
authors.initials: HT
authors.lastname: Bui
authors.forename: Huy Quang
authors.initials: HQ
authors.lastname: Nguyen
authors.forename: Hang Thuy
authors.initials: HT
authors.lastname: Dinh
authors.forename: Byung Hong
authors.initials: BH
authors.lastname: Kim
authors.forename: Hai The
authors.initials: HT
authors.lastname: Pham
mesh_terms: D052818:Autotrophic Processes; D001674:Bioelectric Energy Sources; D004560:Electricity; D004566:Electrodes / Q000382:microbiology*; D005296:Ferrous Compounds / Q000378:metabolism*; D010084:Oxidation-Reduction; D011548:Pseudomonadaceae / Q000254:growth & development* / Q000378:metabolism*
chemical_list: D005296:Ferrous Compounds