Mr. McGuire: I want to say one word to you. Just one word.
Benjamin: Yes, sir.
Mr. McGuire: Are you listening?
Benjamin: Yes, I am.
Mr. McGuire: Plastics.
Benjamin: Exactly how do you mean?
Mr. McGuire: There’s a great future in plastics. Think about it. Will you think about it?
“The Graduate,” (1967) United Artists. Directed by Mike Nichols, Written by Charles Webb, Calder Willingham, and Buck Henry.
In the roughly 70 years since plastic entered wide-spread use, it has swept the world as a raw material for the production of nearly every consumer good imaginable. In that time, over 8 billion metric tons of plastics have been made, with nearly 400 million tons more being produced annually.
But despite decades of pro-recycling efforts, only 9% of that total has been recycled, and, when China stopped accepting foreign plastics for recycling in 2018, many nations chose to halt their recycling efforts entirely.
These billions of tons of non-biodegradable petrochemical-derived products piling up in landfills, waterways, and oceans; in the stomachs and around the necks of wildlife; and even in our own food supply in the form of disintegrated microparticles impact the global economy to the tune of an estimated cost of $13 billion per year, and that’s just accounting for the marine economy.
The market is ripe for an alternative that can provide the same long-term durability during a product’s lifespan without persisting for millennia afterwards and that can compete with the price and availability of petrochemicals.
Currently, the frontrunner for filling this niche can be described in just one word. Bioplastics.
Agricultural bioscience company Yield10 may have come a step closer to this great future. Soon, they may be growing smartphone cases, wall plates, and plastic utensils next to rows of corn and soybeans. On January 19, the company announced the successful completion of field trials of multiple lines of genetically modified Camelina sativa, an oilseed crop. The plants were genetically modified with undisclosed bacterial genes to produce polyhydroxyalkanoates, PHAs, a polymer produced by some bacterial and archaea species as an energy store.
When harvested and processed, however, PHAs can be used to create biodegradable bioplastics while remaining stable enough for plastic materials destined for long-term use. That’s according to Oliver Peoples, PhD, CEO at Yield10.
“It’s basically like wood,” he says. “If you have untreated wood and build a deck with it, it will be there forever. If you put that out into compost or bury it the soil or it wrongly ends up in the river, you know it’s eventually just going to go away.”
Grown in small plots in the U.S. and Canada, the Camelina lines produced PHA at up to 6% of the mature seed weight, a peak level which Yield10 believes can be pushed up to 20% with further development. Peoples and his team believe a 5–20% PHA concentration would be necessary for most commercial bioplastic applications.
“It can go into all the things that are made using injection molding; box packaging, flatware, knives, forks, all that kind of thing,” he says, as well as outlet wall plates, lamp shades, and other durable household goods.
One of six field-tested traits
PHA production is just one of the six traits Yield10 field-tested in Camelina in 2020. The others include several transgenic traits designed to maximize seed yield and two CRISPR genome-edited traits designed to boost oil content.
Relatedly, Yield10 has also worked on ways to increase the efficiency of photosynthesis, according to Peoples. “The plant only fixes so much carbon, and if you’re making an extra product that’s based on the carbon that’s fixed, then obviously that can change the way the plant grows,” he says. “When we tried [making PHA] in leaves, you actually got smaller plants because you were using the building blocks for building the plant to make PHA.”
The plants in the field tests did take longer to mature than control plants but grew well after they were established.
What Yield10 has accomplished is a fairly sophisticated feat of plant bioengineering, according to Steven Burgess, PhD, an assistant professor of plant biology at the University of Illinois at Urbana-Champaign, whose own research focuses on increasing photosynthesis efficiency.
“They had to use specific promoters that turn genes on and off in certain conditions, either only in the seed or in certain developmental stages,” he says. “By doing this they have also increased the amount of this product while also gaining viable seed.”
That was by design, according to Peoples.
“The way we look at the Camellia seed is, once you process the seed you get three products. You get the protein that is normally present in an oilseed. You get oil, vegetable oil, which is actually an interesting feedstock for renewable diesel, and then you get the PHA bioplastic,” he says.
“With those three components you really get the integrated economics that drives the cost to an attractive place.” The most important property in plastics is not, in the end, durability or biodegradability, Peoples adds, it’s price. “I learned that the hard way.”
Yield10 is the second act for Peoples and his colleagues. The company previously went by the name of Metabolix and began producing PHA bioplastics in a bioreactor fermentation process in the early 2000s. That led to a 2010 partnership with Archer Daniels Midland in an Iowa facility that could produce tens of thousands of tons of PHA plastics annually. The facility closed within a couple of years, the partnership dissolved, and Metabolix sold its fermentation technology to a South Korean company.
Their PHA bioplastics never caught on with the market, Peoples says, because they just couldn’t compete with petroplastics on price. “Our plastics were around $2.50 per pound and we were going head-to-head with something that was .50 cents.”
Things may be different now, and not just because Metabolix is now called Yield10 and taking an agriscience approach to bioplastics. Sensing the opportunity in the rising concern over plastic waste and climate change, more than a dozen new and established firms such as Mitsubishi Chemical have now entered the bioplastics space, and the global market is projected to grow to more than $6 billion by 2023.
Most are following in Metabolix’s footsteps and using some form of bioreactor fermentation to produce PHA. Mango Materials, in Redwood City, CA, for instance, is using methane as a feedstock in a bacterial gas fermentation process.
The Harvard Wyss Institute’s Project Circe, meanwhile, is developing a bacterial gas fermentation process using CO2 and hydrogen as inputs, according to Marika Ziesack, PhD, a research scientist working on the project.
“What we are trying to do,” she says, “is actually avoid the agriculture supply chain as much as possible and just go directly from CO2 and hydrogen into our bioreactors.”
Both Peoples and Ziesack note the value in technologies that are potentially carbon neutral, if not carbon negative.
“[Polyethylene terephthalate], PET emits about four kilograms of CO2 per kilogram of plastic produced,” Ziesack says, and making bioplastics from alternative sources can reduce that carbon footprint.
Both gas fermentation and Yield10’s genetically engineered crop approach to bioplastics require more development.
“We can’t give you a kilogram of what we’re doing today,” Ziesack says. Yield10, meanwhile, hopes to begin serious commercialization by 2026, with a goal of millions of acres under cultivation, and millions of pounds of PHA being produced by 2030.
In the meantime, the diversity of approaches in the burgeoning PHA field can only be a good thing overall, according to Peoples.
“We are very much cheerleading for all these companies,” he says. “It continues to build the market. It builds experience with the materials, and it starts to work out some of the kinks in the system.”
The future is in bioplastics. Are you listening?