On The Subject of iLeafs And Cowborgs

In 1828, the German chemist Friedrich Wohler was experimenting with inorganic salts when he unintentionally created a curious white powder. Upon examining the powder, Wohler saw it was made of tiny crystals of urea, a waste chemical manufactured in the livers of animals and expelled through the kidneys in urine. Until Wohler’s discovery, scientists assumed that only living creatures could fabricate organic chemicals like urea. But then here was this dish of urea crystals on Wohler’s laboratory bench. “I must tell you,” he declared in a letter to a former teacher, “that I can prepare urea without requiring a kidney of an animal, either man or dog.”

It was a famous moment in the history of organic chemistry. Once people learned they could assemble organic molecules from inorganic compounds, it wasn’t long before the products of synthetic organic chemistry — plastics, glues, paints, dyes, pharmaceutical drugs, natural flavorings — transformed everyday life. In his new book, Biology is Technology: The Promise, Peril, And New Business of Engineering Life, Rob Carlson argues that we have recently passed a similar moment in the history of biology. “We are at the beginning of the development of synthetic biology,” he writes. “We are only beginning to understand the power at our fingertips.”

Synthetic biologists have been altering living cells using man-made genes and gene parts for more than a decade. They have programmed bacteria, for example, to ooze vaccines, to turn colors, and to sense the presence of toxins. When it comes to understanding how life is put together, however, biologists know very little. Given the daunting complexity of living organisms, there is some debate about whether synthetic biologists will ever engineer anything more complicated than a bacterium. But according to Carlson, who is a principal at the engineering, consulting and design company Biodesic in Seattle, Washington, “there is currently a revolution well under way.” And Carlson, for one, has very particular ideas about where this revolution is headed.

In an essay he submitted to The Economist’s “World in 2050 Essay Competition” in 2001, he wrote: “In fifty years, you may be reading The Economist on a leaf. The page will not look like a leaf, but it will be grown like a leaf.” The leaf reader — is it too presumptuous to call it the iLeaf? — will be engineered to display pictures and text, perhaps with genes inspired by those of the cuttlefish, which can quickly change color to hide from predators. And when a page gets old or ripped, why, just toss it in the compost. “Many of the artifacts produced in 50 years and used in daily living will have a similar appearance, and have similar origin,” Carlson concludes.

In his book, however, Carlson abandons his musings about futuristic gadgetry and instead lays out his predictions for an entire economy based on biology-inspired technology. It will start, he says, by transforming the fuel economy. Forget oil refineries, ethanol plants, even battery charging stations. “Cars themselves might become a production unit for the fuels they consume.” According to Carlson, the fueling process is fairly straightforward: “the consumer adds sugar or starch, the enzymes chew on it, and hydrogen gas bubbles out of the soup and is then used in a fuel cell to provide electrical power for the car.”

At this point, you may be thinking this sounds about as far-fetched as schemes to geo-engineer the planet with giant reflective mirrors or fleets of cloud-spewing ships. Are self-fueling cars really any closer to becoming a reality than, say, Freeman Dyson’s carbon-guzzling supertrees or John Martin’s plan to dump several billion tons of carbon-capturing iron dust into the oceans?

Actually, yes. In fact, the kind of technology that might eventually run these cars is already starting to be developed. Biological engineers at Virginia Tech published a paper in 2007 reporting that they’d constructed, using artificial chemicals, a sequence of 13 genes that code for 13 different enzymes. In the natural world, these enzymes perform different tasks in a variety of different organisms, including spinach, rabbits and yeast. But when the enzymes work together, which never happens naturally, they turn starch directly into hydrogen.

If scientists can engineer a single microbe to make all 13 enzymes at once — a challenging but not impossible feat given the tools of molecular biology — all you’d need to make fuel would be a gas tank full of bacteria. Your car would become, according to Carlson, “something of a cyborg, relying on living organisms to provide power to an inorganic shell.”

Not long after cyborg cars hit the market, Carlson warns, get ready for cowborgs. “Imagine robotic harvesters,” he writes, “equipped with bioprocessing modules slowly wandering around farmland, consuming a variety of feedstocks, processing that material into higher-value products like fuels and plastics, and delivering it to distribution centers.” The factories of the future, in other words, won’t be factories at all, at least not in the conventional sense. In a world run by biotechnology, factories are organisms. If Carlson is right, “our future production infrastructure could become indistinguishable from systems of microbes, insects, and cows.”

Carlson readily admits that synthetic biologists have a lot of work to do before vacationers will be cruising in half-living sedans past cow-like robots grazing on garbage piles and pooping out plastic soda bottles. “Current genetic ‘engineering’ techniques are quite primitive, akin to swapping random parts between cars to produce a better car,” he writes. Still, given the rate at which gene making and gene designing is advancing, perhaps it’s time we start taking biology-inspired solutions more seriously. Now that we know we can assemble living things from non-living parts, biology — as Carlson puts it — is in human hands. Is it really so foolish to assume our inventions will transform the world?