Harnessing the Power of ... Bacteria?

Most people associate Escherichia coli (E. coli) with food poisoning, but Thomas Wood, a professor in Texas A&M University’s chemical engineering department, may have found a use for the bacteria. It could prove to be a viable source of energy for our cars, homes and more.

Using genetics, Wood has changed a strain of E. coli to produce substantial amounts of hydrogen. By deleting six specific genes in E. coli’s DNA, Wood has enhanced the bacteria’s naturally occurring glucose-conversion process on a massive scale. According to an article in “Microbial Biotechnology,” this means a new strain produces 140 times more hydrogen than natural E. coli.

Hydrogen is the key ingredient in fuel-cell technology. Today, separating hydrogen from the oxygen in water creates most of the hydrogen produced globally, but the process is expensive and requires vast amounts of energy.

With sugar as its main power source, this strain of E. coli now can take advantage of existing and ever-expanding scientific processes aimed at producing sugar from certain crops, such as corn, Wood said. E. coli produce hydrogen through fermentation.

“Biological methods such as this are likely to reduce energy costs since these processes don’t require extensive heating or electricity,” Wood said.

Of course, making a new pipeline to transport the gas would be expensive, and transporting it poses dangers. However, Wood suggests converting the hydrogen on-site.

“The main thing we think is you can transport things like sugar, and if you spill the sugar there is not a huge catastrophe,” Wood said. “The idea is to make the hydrogen where you need it.”

Wood also said, in chemical engineering terms, it is relatively easy to get the product.

“In this case, it’s very easy because the hydrogen is a gas, and it just bubbles out of the solution,” Wood said. “You just catch the gas as it comes out of the glass. That’s it. You have pure hydrogen.”

However, Wood concedes that there still is much work to be done before E. coli can be used for any kind of commercial application, but initial successes could prove to be a significant step in the direction of a hydrogen-based economy.

According to Wood, the size of the reactor necessary in the method’s current state would be less than the size of a 250-gallon fuel tank found in the typical East Coast home. He intends, however, to make the reactor size much smaller.

“I’m not finished with this yet, but at this point, if we implemented the technology right now, you or a machine would have to shovel in about the weight of a man every day so that the reactor could provide enough hydrogen to take care of the average American home for a 24-hour period,” Wood said. “We’re trying to make bacteria so it’s doesn’t require 80 kilograms. It will be closer to 8 kilograms.”


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