University of Massachusetts, Microbiology, 639 North Pleasant St., Morrill IV North, Amherst, MA 01003, USA. Naval Research Laboratory, CBMSE, Room 304, 4555 Overlook Avenue, SW, Building 42, Code 6900, Washington, DC 20375, USA. University of Massachusetts, Environmental Engineering, 224 Marston Hall, Amherst, MA 01003, USA.
Environ Microbiol Rep. 2010 Apr;2(2):289-94. doi: 10.1111/j.1758-2229.2009.00118.x. Epub 2010 Jan 5.
Electrodes poised at potentials low enough to serve as an electron donor for microbial respiration, but high enough to avoid the production of hydrogen, have been proposed as an alternative to the use of soluble electron donors for stimulating the bioremediation of chlorinated contaminants and/or metals. However, this form of respiration using pure cultures of microorganisms has only been reported in Geobacter species. To further evaluate this bioremediation strategy studies were conducted with Anaeromyxobacter dehalogenans, which has previously been reported to reductively dechlorinate 2-chlorophenol to phenol with acetate as the electron donor. Anaeromyxobacter dehalogenans could oxidize acetate with electron transfer to a graphite electrode poised at a positive potential, demonstrating its ability to directly exchange electrons with electrodes. Anaeromyxobacter dehalogenans attached to electrodes poised at -300 mV versus standard hydrogen electrode reductively dechlorinated 2-chlorophenol to phenol. There was no dechlorination in the absence of A. dehalogenans and electrode-driven dechlorination stopped when the supply of electrons to the electrode was disrupted. The findings that microorganisms other than Geobacter species can accept electrons from electrodes for anaerobic respiration and that chlorinated aromatic compounds can be dechlorinated in this manner suggest that there may be substantial potential for treating a diversity of contaminants with microbe-electrode interactions.
已提出将电极置于足够低的电位以充当微生物呼吸的电子供体，但又足够高以避免产生氢气，以此替代使用可溶性电子供体来刺激氯化污染物和/或金属的生物修复。然而，这种使用纯微生物培养物的呼吸形式仅在 Geobacter 物种中得到报道。为了进一步评估这种生物修复策略，对先前已报道过的能够用乙酸盐作为电子供体将 2-氯苯酚还原脱氯为苯酚的 Anaeromyxobacter dehalogenans 进行了研究。Anaeromyxobacter dehalogenans 可以将电子转移到正电位的石墨电极上，从而氧化乙酸盐，证明其能够直接与电极交换电子。Anaeromyxobacter dehalogenans 附着在相对于标准氢电极为-300 mV 的电极上，将 2-氯苯酚还原脱氯为苯酚。在没有 A. dehalogenans 的情况下没有脱氯，并且当向电极供应电子中断时，电极驱动的脱氯停止。发现除了 Geobacter 物种之外的微生物可以从电极接受电子进行厌氧呼吸，并且可以以这种方式脱氯氯化芳烃化合物，这表明通过微生物-电极相互作用处理多种污染物可能具有很大的潜力。
