Bacteria have been a hot topic in research these days.  It turns out that the little guys, oft vilified for their pathogenic brethren, can provide exciting solutions to many alternative energy and material purification problems.  Researchers have used bacteria for everything from purifying water, to data storage, to microbial biofuel and hydrogen production.

Now researchers have made an exciting new microbiological breakthrough involving a very special type of bacteria.  It has been known for some time that the bacteria, Shewanella, found commonly in water and soil, produces electricity when it digests organic matter.  This led to researchers taking special interest in its potential as a natural generator.  However, a major roadblock to such alternative energy plans was the fact that it was unknown until now is exactly how the bacteria accomplished its electrical generation, or whether the process could be governed.

Researchers at the University of Minnesota have now discovered that the vitamin riboflavin (known commonly as vitamin B-2), provides the bacteria with much of its generating capabilities.  The research was led by Daniel Bond and Jeffrey Gralnick, of the University of Minnesota's BioTechnology Institute and Department of Microbiology.

Professor Bond explained the importance of their discovery, stating, "This is very exciting because it solves a fundamental biological puzzle.  Scientists have known for years that Shewanella produce electricity. Now we know how they do it."

Their research, which will be published in the March 3 issue of the “Proceedings of the National Academy of Sciences” opens the door to an exciting new chapter in alternative energy.  By boosting the Shewanella bacteria's riboflavin intake with vitamins, the bacteria's electrical output dramatically increases.  These bacteria can transform organic waste byproducts such as lactic acid into electricity, offering both a waste disposal and an alternative energy solution.

The research team discovered riboflavin's effects when bacteria growing on their electrodes began to increase in electrical output.  The team discovered that the increase was do to the accumulation of riboflavin on the electrodes, a substance the bacteria naturally produce.  As the riboflavin built up, the bacteria's electrical output increased to a maximum of 370 percent of the original levels.

Potential uses include waste water microbial fuel cells and, according to researchers, a natural fuel source for ocean floor probes.  Professor Bond remarks, "Bacteria could help pay the bills for a wastewater treatment plant."

The researchers do warn that in order for the technology to be cost-effective for home and business use or for transportation, significant biological and fuel cell design obstacles would have to be overcome.  For now, the technology provides a great deal of niche potential for the waste water industry, they say.

For those curious of why Shewanella outputs electrical current, here's why.  The bacteria needs to digest certain soil metals such as iron to survive and thrive.  In order to properly absorb them it directs electrons into the metals to change their properties, making them more digestible.   Says Profesor Gralnick, "Bacteria have been changing the chemistry of the environment for billions of years.  Their ability to make iron soluble is key to metal cycling in the environment and essential to most life on earth."

Such bacteria could also be applied to ship surfaces and used in a reverse process to prevent corrosion by outputting iron.  The U.S. Navy is interested enough in this application to provide the team with a grant to explore the technology further. 

The research was primarily funded by the Initiative for Renewable Energy and the Environment, the National Science Foundation, the National Institutes of Health and Cargill.  The University of Minnesota's College of Biological Sciences and the Institute of Technology were also involved with the project. 

The very useful Shewanella bacterium has also been found to produce carbon nanotubes under the proper conditions.