Desulfitobacterium: Pollution-Eating Bacteria that Produce Electricity

By | September 4, 2008

Microbiologists seeking ways to eliminate pollution from waterways with microbes instead discovered that some pollution-eating bacteria commonly found in freshwater ponds can generate electricity. They present their findings today at the 105th General Meeting of the American Society for Microbiology.”The bacteria are capable of continuously generating electricity at levels that could be used to operate small electronic devices. As long as the bacteria are fed fuel they are able to produce electricity 24 hours a day,” says Charles Milliken of the Medical University of South Carolina, who conducted the research with colleague Harold May. … these bacteria … are the first known spore-forming bacteria shown to continuously generate electricity. A bacterial spore is a dormant stage of growth for the organism and is highly resistant to heat, radiation and drying.

…. Until now, Desulfitobacterium (pictured) was not known to have the capacity to generate electricity. These bacteria are most commonly known for their ability to breakdown and detoxify some of the most problematic environmental pollutants, including PCBs and some chemical solvents. – terradaily

Desulfitobacterium hafniense strain DCB2 generates electricity in microbial fuel cells (MFCs) when humic acids or the humate analog anthraquinone-2,6-disulfonate (AQDS) is added as an electron-carrying mediator. When utilizing formate as fuel, the Gram-positive, spore-forming bacterium generated up to 400 mW/m2 of cathode surface area in a single-chamber MFC with a platinum-containing air-fed cathode. Hydrogen, lactate, pyruvate, and ethanol supported electricity generation, but acetate, propionate, and butyrate did not. Scanning electron microscopy indicated that strain DCB2 colonized the surface of a current-generating anode but not of an unconnected electrode. The electricity was recovered fully within minutes after the exchange of the medium in the anode chamber and within a week after an exposure of a colonized anode to 90°C for 20 min. Of the six strains of Desulfitobacteria tested, all of which would reduce AQDS, only D. hafniense strain DCB2 continued to reduce AQDS and generate electricity for more than 24 h, indicating that reduction of the humate analog alone is insufficient to sustain electrode reduction. – springlnk

Read more about microbial fuel cells (MFCs). I don’t read Russian, but I think this photo is related to Desulfitobacteria somehow. It would be great if we could buy sealed MFCs for home use.

Scientists at the University of Massachusetts at Amherst announced yesterday that they have built a novel device that uses bacteria to turn garbage into electricity. At the heart of the advance, which will be described in the October issue of the journal Nature Biotechnology, is a newly discovered organism that is part of a group of bacteria known as “iron breathers,” so called because they rely on iron instead of oxygen. Yesterday’s announcement is part of a broader effort to tap the unusual properties of various iron breathers, now being discovered across the far reaches of the planet, to generate power or clean up oil spills or other pollutants. – bestview

A large number of a Geobacter species known as Desulfuromonas acetoxidans use iron as their terminal electron acceptor. Researchers at the University of Massachusetts reported in this week’s issue of the journal Science that these microorganisms can transform organic matter commonly found at the bottom of the ocean into electrical energy.  What the researchers did was give the Desulfuromonas acetoxidans a graphite electrode instead of iron to serve as their terminal electron acceptor. Even though graphite does not occur naturally in the sediment at the bottom of Boston Harbor, Desulfuromonas acetoxidans was happy to use it as a terminal electron acceptor. These bacteria made so many electrons the researchers were able to produce enough electrical current to power a lightbulb or a simple computer. – suite101

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