Researchers Love E. Coli Because They Can Make It Poop Plastic

Jeggings, styrofoam cups, makeup, tampons, gasoline—virtually all of humanity's synthetic wonders are made from refined crude oil. We're hardly able to feed or clothe ourselves without fracking the shit out of the planet. Which is why researchers have been working on making all of those marvellous things, not with oil, but agricultural waste.

Their tool of choice: genetically engineered bacteria that eat up abundant resources such as glucose, glycerol or wood pulp and spit valuable plastic precursors out the other end. But one bacteria in particular swims a flagellum above the rest. E. coli, perhaps best known for causing violent diarrhea and ruining family barbecues, is the darling of the biotech world. Cutting-edge research often relies on mutant strains of the infamous germ.

E. coli requires minimal energy to do its job, and produces few harmful byproducts. Some believe that, if we can grow them cheaply enough, and on a large enough scale, these mutant microbes have the potential to help us radically reduce our carbon footprint, without giving up the products that have come to typify the Western way of life.

In particular, E. coli-based plastic production has been on the horizon for decades—but thus far, companies have managed to get E. coli to make only a limited number of chemicals on anything near an industrial scale. In one of the first commercially viable projects, DuPont's Loudon, Tennessee plant has been using 600,000 litre tanks full of E. coli to make 1,3-propanediol, which goes into fibres for carpets and clothing. A company representative told Motherboard that they're currently making 140 million pounds of propanediol per year, using 40 percent less energy and releasing 40 percent less greenhouse gasses than tradition methods. As of 2008, soon after the project began, total production of the compound in the US was only about 100 million pounds.

Over the next year, researchers at the University of Toronto will move their own E. coli projects from small 5-litre research reactors to much larger industrial-scale tanks, working up to 100 and perhaps 1,000 litre tanks. The aim is to make significant quantities of bio-manufactured nylon precursors, including adipic acid, bringing down costs and showing industry that it can be done at a profit.

Professor Radhakrishnan Mahadevan of the university's Chemical Engineering and Applied Chemistry department told Motherboard that the processes his team is working on have the potential to be virtually carbon neutral, since they use little energy and don't require fossil fuels. Some, he says, can even be carbon negative, feeding E. coli from derivatives of CO2 that's already been released into the atmosphere.

"There will always be a requirement for plastics," he said. "The idea would be, let's not make them from what we dig out of the ground, but from CO2 that we've already put out there."

Mahadevan estimates that, if done on a large scale, bioengineered microbes could process 5 to 10 percent of the CO2 humans have emitted so far, permanently storing it in household objects that we'd produce anyway. However, only photosynthetic microbes can suck CO2 directly out of the atmosphere—and since E. coli can't do photosynthesis, the team has to convert CO2 into a chemical called formate first. It's a drawback, but one that Mahadevan believes is more than made up by the bacteria's myriad advantages.

E. coli grows quickly, for example, doubling its numbers every 20 minutes in good conditions, and can survive on a wide range of food sources. Conventional ways of producing adipic acid use petroleum-derived benzene and release nitrous oxide, a greenhouse (and laughing) gas that destroys the ozone layer. E. coli doesn't.

Most importantly, its genome has been completely mapped out, so researchers are much better able to predict how knocking out, overexpressing or replacing certain genes will change the bacteria's metabolism, making it churn out exactly the chemical they need.

"There's no other organism that has as much knowledge and papers as E. coli," said Mahadevan. "It's just a very well studied and characterized model organism."

With this knowledge in hand, Mahadevan's PhD students have substituted E. coli's genes with DNA from all sorts of other organisms. With a bit of tweaking, they believe they can get hybrid E. coli to manufacture virtually any organic compound that occurs somewhere in nature—at least in theory.

PhD student Christian Euler is taking genes from Listeria—another bacteria that occasional kills people who accidently eat it—to create an E. coli strain that makes flavonoids, the delicious compounds found in fruits and vegetables. Euler and Mahadevan told Motherboard that genetically modified E. coli can also make insulin, vitamins, vanilla, tylenol, face creams and possibly chemical weapons like Ricin ("I would never do that," Euler said).

Euler is currently focused on getting more value out of less glucose—and that's a challenge for every biotech project. If E. coli is going to change the world by making processed foods taste more like apples or turning CO2 into pleather, the process has to be cost-effective. That's not a problem when the end-product is expensive enough and the food being fed to the microbes is suitably cheap (it helps that cellulosic sugars made from grass, wood or the inedible parts of plants sell for as low as 28 cents per kilogram). But with the price of oil at record lows, it's hard for biochemical processes to compete with traditional fossil fuel-based production.

Mahadevan said that the cutoff for the private market is about $2 per kilogram. Any petroleum derivative worth more than that will probably be made using E. coli or other microbes within five years. But anything less expensive might need government support to get off the ground.

"There are some compounds that are very, very cheap. That's tough," he told Motherboard. "Fuel is about $1 dollar per kilogram, so we will need some incentives to get that part of the process filled in."

But if those incentives are put in place, either through subsidies or a tax on fossil fuels, Mahadevan said manufacturers could produce as much as 30 percent of materials previously reliant on oil using bacteria within a decade or so. Once the initial investments are in place, the process could be just as cost-effective as the current petroleum industry, if not more so.

"Technologically I can't see any barriers," Mahadevan said. "It's a policy issue."

With the right incentives, and enough buy-in from industry, Euler thinks it could be the start of a "biotech revolution."

"I see a future where we replace all of these environmentally destructive processes with biological solutions," Euler said. "And we'll never get there without E. coli."