From Nasty Bacteria to Eco-Friendly Bugs


By Olga Kharif Kevin O'Connor, a microbiologist at the University College in Dublin, Ireland, has long felt that bacteria have achieved a villainous reputation over the years -- undeservedly so. Doctors warn hospital patients of bacteria called pseudomonas -- living in soil and marshes, but also thriving on human tissue -- that can cause infections on burns and open wounds. It's nasty stuff, resistant to antibiotics and able to thrive in the harshest possible conditions. Basically, pseudomonas is a pain to eradicate.

But that resilience is exactly why O'Connor believes the bacteria can save the world from toxic waste. He found that instead of dying from exposure to toxins such as styrene, a byproduct of rubber manufacturing, pseudomonas can convert it into biodegradable, relatively cheap plastic.

O'Connor is one of the pioneers in the emerging field of so-called white biotechnology, which is expected to take industry by storm in the next few years by harnessing nature's tools, like bacteria, for industrial production.

TOXIC TRASH. The revolution is already under way: The U.S. government has just proposed building its first large-scale bio-refinery. A slew of startups are beginning to produce green plastics by feeding bacteria starches, such as those found in corn. And researchers in India have used bacteria to turn food waste into plastics.

The beauty of white biotechnology is, "this step, of using the bacteria, is very inexpensive," says Eugene Stevens, professor of physical chemistry at Binghamton University in Binghamton, N.Y., and the author of a book on green plastics. "This can be done on a large scale, and the technology is sustainable." But none of the earlier developments in the field created a two-fer like O'Connor's -- disposing of toxins and creating biodegradable plastic at the same time.

The implications of O'Connor's discovery, which will be described in the April issue of The American Society for Microbiology's Applied & Environmental Microbiology Journal, are huge. About 126 million pounds of styrene waste are released in the U.S. each year -- most of it into the ground, water, and air. A low percentage is recycled. A small part is bottled into canisters, which are buried in the ground. But the majority of styrene, which is carcinogenic, never makes it to formal disposal.

"MAJOR STEP FORWARD." If O'Connor has his way, that will change. Within five years, he believes his pseudomonas will be able to convert a pound of styrene into half a pound of polymers, which are used in making disposable plates, cups, and salad containers. So, in a perfect world, those 126 million pounds of styrene waste produced each year could be converted into 63 million pounds of plastic. That's about as much as Americans buy in plastic goods each year.

Chemical companies producing styrene as a byproduct could then actually make money on it, instead of paying for its disposal. The resulting plastic could find a mass market, since it could probably be manufactured for $1 a pound, says O'Connor.ost of today's plastics produced by bacteria cost closer to $4 a pound, way more than petroleum-based plastic, which costs less than 50 cents a pound. "That [lower price] would be a major step forward," says Chris Somerville, professor of plant biology at Stanford University.

Also, unlike petroleum-based plastics, O'Connor's would be biodegradable: When exposed for several weeks to air, soil, or water, it would fall apart just like a banana peel. And styrene is just the beginning. O'Connor thinks he can genetically modify his bacteria to process other types of toxins and create different kinds of biodegradable plastic.

GENETIC UPGRADES. Here's how O'Connor's method works: He places styrene and pseudomonas, immersed in a water-based solution, into a fermenter, similar to the device used to turn grape juice into wine. The bacteria then "eats" the styrene, by breaking down its chemical bonds and forming plastics in its cells. After that, O'Connor only needs to sprinkle the bacteria with a mild detergent for the pseudomonas' cells to break down and release the plastic.

Of course, this process is still far from being commercially viable. O'Connor has yet to increase the bacteria's efficiency: Today, his pseudomonas makes 100 grams of plastic out of 1 kilogram of styrene, using the rest of the styrene for energy. But O'Connor believes he can genetically modify his bacteria to reach 50% efficiency in less than five years.

What's more, separating the plastic from the detergent and the bacteria's dead cells can be complicated, says Stevens. And transporting styrene to a fermenter where it can be converted into plastics is tricky: The liquid is highly volatile and flammable. Still, O'Connor believes these obstacles can be overcome. He has already been contacted by chemical companies, several of them located in the U.S.

With a bit more work, O'Connor hopes his bacteria will prove crucial in negotiating a win-win pact between business and the environment. Kharif is a reporter for BusinessWeek Online in Portland, Ore.


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