Kartik Madiraju attends school in Montreal. He reasoned that since some bacteria are magnetic, they should be able to serve as a source of electricity. His experiment generated half the power of a normal AA battery with 1/5 oz. of bacteria.

The “battery” kept producing for two days before wearing out. Amazingly, no one had ever thought to do this before.

Magnetic bacteria are distinguished by the fact that they include magnetite. They were discovered just a quarter century ago and are naturally occurring in all kinds of water. (The fact that such a widely dispersed class of organisms could have just been discovered recently should also give us pause.)

Future Dr. Madiraju devised an experiment in which he placed water filled with bacteria into tiny boxes. Each box is surrounded by electrically conductive metal strips on two sides. The metal strips interact with the “magnets” between them, causing the box to spin. This generates the electric current.

The experiment was vetted by professor John Sheppard, a bioresource engineer at McGill University, and has been entered in the Intel International Science and Engineering Fair.

“I’m optimistic about the practical applications,” said Sheppard. He expects it to eventually serve as a power source for nanotechnology devices with limited life and in biosensors.

As a practical matter, this is rich with potential. The bacteria used were selected almost randomly from the widely available types. Now that the phenomenon has been proven to work, it’s a safe bet that researchers such as Dr. Sheppard will actively seek to identify the best naturally occurring bacteria for these “batteries.”

Following that, the next logical step is to genetically engineer optimized organisms. There is almost certainly an ideal percentage of magnetite in each bacterium, and it’s improbable that nature happened to provide it — since these creatures did not evolve to be batteries.

Such optimization should at least double the power output. While a single AA battery may not sound like much, the “real estate” required is only a cube about 1/5 cubic inches in size. Such cubes may or may not be the optimal configuration, representing a further opportunity for optimization.

An additional opportunity lies in researching the “shelf life.” It may well be true that the bacteria died due to lack of continuing nutrition. A colony supplied with ambient food might be self-replicating and effectively immortal.

Regardless, the energy density is clearly comparable with that of commercially available alkaline batteries, potentially at far lower cost. Also, the “batteries” can be stacked and the power output added together for far greater power needs. I can envision a scenario in which they are housed in lattices by the thousands, with special nutrient water continually washing all of the cubes to keep the bacteria healthy and productive.

In addition, it may be desirable that the bacteria die after a short time. This could make them an ideal power source for tomorrow’s implantable nanotechnology devices, causing the nanites to shut off after a few days.

The era of microscopic machines is coming. It will be interesting to see the mix of technologies that wind up powering these tiny devices.

To your profitable future,
Jonathan Kolber
July 31, 2007

P.S.: Apart from this exotic discovery, my Emerging Capital Report happens to have another company in its portfolio along these lines. This company has designed a nanotechnology-sized battery based on radioactive tritium. Don’t worry: Tritium is safe within the body so long as it isn’t within cells.

Alternative Electricity Sources was originally featured in the Penny Sleuth.