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Illustration: Mike Pick
It’s difficult to exaggerate the ubiquity of plastics in our lives: from toothbrush bristles (polyamides) to computer keyboards (acrylonitrile butadiene styrene) to water bottles (polyethylene), there is scarcely a thing we use that isn’t made—in whole or in part—of the petroleum-based product. Since 1909, when Leo Hendrik Baekeland first combined phenol and formaldehyde to create “Bakelite,” the world’s first synthetic polymer, plastics production has soared: the North American and European industries alone produce more than $730 billion-worth of plastic goods per year.
But the very characteristics that have made plastic a wild success—extreme durability and resistance to degradation—also make it a huge environmental liability. It’s estimated that half a billion kilograms of plastic waste have been discarded since the 1950s, creating a burden that may persist for thousands of years. Incinerating the waste is not a viable solution either, as burning plastics can release carcinogenic fumes. And now of particular concern are the enormous quantities that get dumped at sea, where they coalesce in vast ocean gyres and accrue in the stomachs of unfortunate sea life.
Oliver Peoples, founder and chief scientific officer of the bioscience company Metabolix, is convinced that there is a natural solution to these myriad problems. Inside the company’s labs in Cambridge, Massachusetts, his engineers have spent the past 15 years refining a catalytic process in which engineered microbes spin a variety of sugars into fatty-acid globules. This bioplastic, trademarked as “Mirel,” is functionally identical to the petrochemical variety—except that it dissolves harmlessly in both water and soil.
Recently, Metabolix has partnered with agribusiness giant Archer Daniels Midland to build a $200 million production facility in Clinton, Iowa, the heart of the Corn Belt. In advance of the plant’s opening later this year, Seed editor Maywa Montenegro spoke with Peoples about turning microbes into plastic factories, Mirel’s environmental profile, and competition in the cutthroat plastics industry.
Seed: How is Mirel different from other bioplastics on the market?
OP: There are really two other types of bioplastics out there. One is polylactic acid, or PLA, produced by Cargill’s NatureWorks. PLA is a polyester and is very useful for certain applications, but it’s limited in performance. For instance, it doesn’t have very good heat stability. You want to be able to pour boiling water or hot coffee into a plastic cup, and you can’t do that with PLA. The other class is starches, one of the most abundant polymers in the world, and completely biologically produced. But starches have no value in terms of resistance to water.
Mirel, on the other hand, is not a single material. It’s a family of materials produced in a common manufacturing process. The technical term is polyhydroxyalkanoate, or PHA. What’s very different about PHA is that it can be used in a very wide range of applications—everything from hard items like inkjet printer cartridges to soft, “elastic-y” materials like films for bags.
Seed: In 2005, Metabolix received the Presidential Green Chemistry Challenge Award for the first commercialization of plastics that uses “living biocatalysts to convert renewable raw materials all the way to the finished polymer product.” What is this biocatalytic process?
OP: The new Clinton facility is based on corn, a starch that when processed in a wet mill yields sugar. We take this sugar and feed it into a large reactor, which is sort of like a beer-making tank. Inside that reactor are the microbes into which we’ve introduced an entire enzyme-catalyzed reaction pathway—these are the biocatalysts. They take the sugar into their cells and convert it into the bioplastics. Once they’re filled up with the polymer, we extract it and formulate it into resin pellets. Depending on the formulation, we can sell it for film, for card and sheet plastic, and for injection-molded things like pens.
Seed: When did you first start incubating the idea of using microbes to make plastic?
OP: A long, long time ago. I’m a molecular biologist by training, from Aberdeen, Scotland. I went to MIT in 1984 to work on a basic genetic problem associated with an enzyme—that enzyme happened to be the first one involved in the production of bioplastic and quite common in nature. Few people realize this, but bioplastic production happens in microorganisms all throughout the environment, everywhere from deep-sea vents to sewage plants to the root nodules of soybeans. It forms as a carbon- and energy-storage material, much like starch, glycogen, or vegetable oil.
But although I was a molecular biologist, I was not very academically inclined. And I realized that we could use genetic engineering to make a production system in which we could really control the economics and the performance of bioplastics. That was the beginning of Metabolix.
Seed: You opened your first labs in Cambridge in 1994. We’re now more than 15 years down the road. What have been some of the hurdles to scaling up production?
OP: The petroleum industry, which delivers nearly 450 billion pounds per year of plastics has done a tremendous job of delivering a material of superb functional use at pretty attractive costs. That’s why you see plastic pretty much everywhere.
So our first challenge was developing engineered organisms that were very robust and scalable. The second was developing the ability to make not a single material, but a family of materials with that same basic organism system. The next big hurdle is how to simplify all that into a scalable industrial manufacturing process where we can deliver these molecules to the marketplace reproducibly, routinely, and at low cost.
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