Power Up With Magnetic Bacteria
A 16-year-old high school student has invented a new way of producing electricity by harnessing the brawny power of bacteria.
Kartik Madiraju, an 11th-grader from Montreal, was able to generate about half the voltage of a normal AA battery with a fifth of an ounce of naturally occurring magnetic bacteria. And the bacteria kept pumping current for 48 hours nonstop.
“No one has ever used magnetic bacteria to produce an electrical current before,” Madiraju said.
The experiment is being presented this week at the Intel International Science and Engineering Fair, an über-science geek competition in which the chipmaker annually hands out $4 million in prize money to students. Winners will be announced Friday.
Magnetotactic or magnetic bacteria have extremely small crystals of magnetite inside their bodies. Only discovered in 1975, these aquatic bacteria are quite common and found in fresh water and saltwater around the world.
A bit of a science whiz kid, Madiraju was browsing through the science journal Nature and happened to see something about magnetic bacteria while trying to think of a project to benefit the environment. “I knew that spinning windmills use a magnetic generator to produce electricity and wondered if I got the magnetic bacteria spinning they might generate a current and be a clean, alternative energy source,” he said.
Madiraju put the free-floating bacteria, which are essentially tiny magnets, into plastic boxes less than a fifth of a cubic inch. Metal strips on two sides act as electrodes and get them spinning, generating a magnetic field and an electric current. Current and power were sustained at 25 microamps and 5.5 microwatts, respectively, beyond 48 hours at a resistance of 10 kohms.
“I was one of the most surprised when it worked the very first time,” said John Sheppard, a professor in the Department of Bioresource Engineering at Montreal’s McGill University.
“I’m optimistic about the practical applications; he’s developed the technology quite a bit just working on weekends,” said Sheppard.
Madiraju envisions clean-running underwater power plants in the developing world. “The latter is long-term of course, but not too far-fetched,” he said.
Micro-energy sources in nanotechnology or biosensors would be easier to do and are more likely uses, said Sheppard, who was Madiraju’s mentor under the strict conditions of two big science contests, the Intel competition and Canada’s Sanofi-Aventis Biotech Challenge. Madiraju has won in various categories previously and on May 10, his magnetic bacteria battery demonstration placed third in the Canadian competition.
Results aside, as a science fair project, inventing a new clean and green source of electricity sure tops the old papier-mâché volcano.
In nature, organisms use a variety of methods to figure out where they are and where they need to be going. Plants use sunlight and the force of gravity to determine which direction they should grow, birds migrate in part using the sun and stars to guide their path, and we humans can simply ask for directions at the nearest gas station. Some organisms use the earth’s geomagnetic field to orient themselves and navigate through their environment. Organisms that use the earth’s geomagnetic field have some type of internal compass. The smallest organisms that use this navigational method are called magnetotactic bacteria.
Magnetotactic bacteria were discovered in 1975 by Richard P. Blakemore. Blakemore noticed that some of the bacteria that he observed under a microscope always moved to the same side of the slide. If he held a magnet near the slide, the bacteria would move towards the north end of the magnet. These bacteria are able to do this because they make tiny, iron-containing, magnetic particles. Each of these particles is a magnet with a north pole and a south pole. The bacteria arrange these tiny magnets in a line to make one long magnet. They use this magnet as a compass to align themselves to the earth’s geomagnetic field.
Why would these bacteria need a compass? Like many other types of bacteria, magnetotactic bacteria don’t like oxygen very much. They will move away from areas with high oxygen and toward areas with low or no oxygen. In an aquatic environment, the level of oxygen decreases as one moves deeper into the water. So, magnetotactic bacteria like to live in the deeper parts of their aquatic environments. They use their magnetic compass to tell them which way is down.
How do they do this? It has to do with the direction of the geomagnetic field. In the Northern Hemisphere; the geomagnetic north actually points down at an angle. So, magnetotactic bacteria that are aligned to this field are also pointing down. By moving north along this field, they move deeper into the water, and into areas with less oxygen. Interestingly, in the Southern Hemisphere, the geomagnetic north actually points up and at an angle. So, magnetotactic bacteria in this half of the world are “south-seeking”, which points them downward. At the equator, the geomagnetic north doesn’t point up or down, so the magnetotactic bacteria found there are a mixture of north-seeking and south-seeking bacteria.
Scientists are also interested in practical applications involving these magnetic microbes. While it isn’t likely we’ll be using these bacteria to stick notes to our refrigerators, they could prove to be useful to humans. The tiny magnets that these simple organisms make are far superior to those produced by people. So, scientists and engineers are trying to develop ways to use this magnetic material in places where tiny magnets are much better than big magnets.
Intel International Science and Engineering Fair
Encouraging Youth in Scientific Discovery and Innovation
Great ideas start with opportunities. At the Intel International Science and Engineering Fair (Intel ISEF), a program of Society for Science & the Public , the world’s largest pre-college science competition, students have a chance to dream and create big ideas like: a better way to get fresh water to victims of natural disasters, a way to help the blind and disabled access the Internet, or illustrate ground-breaking mathematical theory. These innovations, and more than a thousand like them, are on display every year at Intel ISEF, a global celebration of scientific excellence.
Intel ISEF brings together over 1,500 leading young scientists from more than 50 countries, regions and territories to compete for more than USD 4 million in scholarships and prizes.
Students’ projects encompass a wide range of issues and disciplines, often addressing issues that have stumped scientists for years. In 2008, more than 20 percent of the young scientists competing at Intel ISEF either had or had applied for a patent for their work.
Intel ISEF finalists come from a field of more than 65,000 students who participated in more than 550 regional Intel ISEF-affiliated science fairs around the world.
Every year, more than 1,200 science, engineering, and industry professionals volunteer to travel to Intel ISEF to judge the projects and determine the winners.
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