Waste Land

Halfway between Hawaii and California in the north Pacific Ocean sits the Great Pacific Garbage Patch, the world’s largest buildup of plastic. This floating mass, made up of an estimated 1.8 trillion pieces of plastic, will never disappear. Instead, aided by wind and sea currents, it will degrade into minute shards of microplastics, endangering even the smallest organisms and damaging entire ecosystems. It’s just one of six giant garbage patches swirling around in our seas.

Since 1950, when plastics became ubiquitous, humans have generated 8.3 billion metric tons of the stuff, and the vast majority of plastic waste ends up in landfills, oceans and other natural environments.

So far, recycling is the best available method to stop the world from accumulating more and more plastic trash, but even that doesn’t get us far. That’s because traditional recycling uses chemical or mechanical processes to break down products and reformulate them into a cheaper, less structurally sound plastic. (Like taking a polyethylene laundry basket and using it to make grocery bags.) These degraded products can’t be recycled infinitely, and eventually end up in the waste stream, making the process — known as “downcycling” — ultimately unsustainable.

Georgia State biologist Eric Gilbert is working on a way to change the game using “upcycling,” which transforms discarded materials into more valuable products. He’s doing it by thinking small — using tiny microorganisms, each thinner than a human hair, to gobble up the waste and turn it into a commercially viable substance.

Gilbert grew up in California in the 1960s, back when plastics were starting to work their way into every conceivable consumer product. He used to gaze out his bedroom window from his parents’ house high on the western slope of Berkeley Hills, watching the sun set — first over the Campanile bell tower at the University of California-Berkeley campus, then over the Golden Gate Bridge and the San Francisco Bay, and finally over mile after mile of ancient redwoods cloaked in coastal fog on the mountains of Marin County, a place where conservationist John Muir once tramped. With what Gilbert calls “big views,” his fascination with the natural world began.

The world is a beautiful place, he’d think. We need to take care of it.

He became an avid hiker and backpacker, and studied biology at the University of California-Santa Cruz. He chose the major after James Watt, President Ronald Reagan’s Secretary of the Interior, announced he planned to allow development of natural resources on public lands.

“I thought, I enjoy nature and yet I really don’t know anything about it,” he said. “But this is clearly something that needs our protection.”

In spring 1990, after graduating with a biology degree, Gilbert read an article in Discover magazine called “The Poison Eaters.” It was about the burgeoning field of bioremediation, a branch of biotechnology that uses living organisms to address water and soil pollution. The article included a description of the work of William T. Frankenberger, a now-retired University of California-Riverside professor, who was using microorganisms to clean up selenium pollution in oil spills.

“I had never heard of it, but I immediately knew it was what I wanted to do,” Gilbert said.

Five months later, he joined Frankenberger’s lab as a Ph.D. student. Ever since, he’s been searching for ways to protect the natural world with microorganisms.

Today, in his lab in the Natural Science Center at Georgia State’s downtown campus, Gilbert and his colleagues are using chemical processes to degrade plastic into its base components, and then feeding those components to yeast microbes that — over the course of about five days — transform the plastics into fatty acids. The digestion happens in beakers full of a soupy mix of plastic that’s been heated to 400 degrees Fahrenheit.

After ingesting the plastic, the yeast microbes become filled with palmitic and oleic acids: two fatty acids that are found in commercial products like shampoos, lubricants, biofuels and detergents. The team harvests these acids by breaking apart the microbes with tools in the lab. (Another environmental advantage of this work: extracting palmitic oil from microbes could eliminate the need for companies to deforest palm plantations.)

So far, they’ve had what scientists call “bench level” success; that is, success in the lab. The next step: scaling up the process.

“We’re currently working at the one-liter scale. We have our eyes set on moving two steps down the road, to 100 liters,” Gilbert said. (Engineers like to scale up in 10-fold steps, so from one to 10 to 100.) “As the size increases, new challenges sometimes show up. It’s a lot more challenging to create 1,000 liters of solution than 10 liters.”

Eventually, the volume needs to be large enough to make the process commercially viable.

“We need the yield of product to be sufficient so the whole thing becomes profitable at the end of the day,” said Gilbert, a slim 55-year-old whose voice still carries the casual cadence of his California childhood. Improving the process is key to taking their work out of the lab and into industry, where companies can use this technology to divert plastic from landfills.

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