Biobased Polymers

Consumers who are paying close attention will soon notice a change in products they use every day. Some diapers, clothing, athletic shoes, and automobile tires currently made from petroleum will instead be made entirely from plants. Yet the quality and performance of these products will be identical to those made the old-fashioned way.

Thanks to many years of work on engineered microbes and new catalysts, the reach of biobased chemicals into consumer items is expanding. A host of biobased intermediates are approaching commercialization, and others are on the horizon. They include raw materials for such common polymers as polyester, spandex, synthetic rubber, and nylon.

Biobased polymers are being tackled by start-up firms and industrial giants, and announcements of progress are gaining in frequency and substance. Invista and Genomatica both say they will pursue making nylon intermediates from sugar. A partnership of BASF, Cargill, and Novozymes has selected a method to make biobased acrylic acid for superabsorbent polymers. And Coca-Cola, pleased with progress toward a 100% biobased soda bottle, has upped its funding of partner Virent, maker of a key raw material.

Still, the flurry of announcements does not mean a large-scale shift to biobased polymers is inevitable. Needed raw materials must first become available at competitive prices and in large quantities. They then have to enter a complicated and entrenched supply chain that evolved over decades to efficiently find homes for the products of ethylene cracking and petroleum refining. Unless biobased chemicals are embraced by both consumers and the commodity world, they’ll become mere curiosities, fit only for niche applications.

Figuring out how to elbow into the supply chain is an overarching concern for the biobased polymers industry, says Ronald F. Cascone, a principal at advisory firm Nexant. Consumer product companies are supporting many of the efforts, but their participation will go only so far.

“Brand owners say they want the materials, but they are not going to buy the intermediate; someone else has to buy it and convert it,” Cascone emphasizes. And, he adds, consumer product firms are certainly not going to construct commodity-scale manufacturing facilities for raw materials.

By examining case studies involving the polymer intermediates 1,4-butanediol (BDO), p-xylene, acrylic acid, and succinic acid, it is possible to clear away some of the fog and see how the pieces of a supply chain might successfully link up to deliver biobased products to consumers. One thing is clear: Commercializing a biobased polymer is not something that any one company can do on its own. It requires sustained, parallel progress on several fronts including technology development, end-product verification, market demand, and robust business acumen.

Invista, the synthetic fibers maker that was once part of DuPont, wants to make biobased polymers look effortless. In May, the company introduced a new version of its Lycra brand spandex that it touts as being 70% from dextrose derived from corn. Responding to a sports apparel industry looking for more Earth-friendly materials, Invista highlighted the fibers’ reduced CO₂ footprint in its press release.

What Invista didn’t highlight was the series of events and partnerships that made the new stretchy fiber possible. The key was starting the multistep spandex manufacturing process with biobased BDO sourced from the chemical giant BASF. BASF, in turn, made the bio-BDO with technology it licensed from the biotech firm Genomatica, which announced a fermentation route to the chemical in September 2008.

Now that BASF has commercialized bio-BDO, Genomatica will license the technology for making it to other manufacturers. It is also demonstrating a process for producing biobased butadiene, which could be used in synthetic rubber. And it has engineered microbes to make caprolactam, used in nylon 6, and adipic acid and hexamethylenediamine, used in nylon 6,6.

Industry watchers are impressed with the company’s progress. “Genomatica is a good example of a platform that lends itself to multiple products,” says Steven Slome, a senior consultant at Nexant. “They seem to be doing a very good job of bringing different products up and commercializing them quickly—it’s a good sign for them and for the industry itself.”

To attract licensees, Genomatica has had to work with companies throughout the supply chain to validate each intermediate in each potential application—to prove that a final product made from it will be indistinguishable from one made with its petroleum-derived cousin. This is true even though Genomatica’s biobased version is the same molecule.

“It’s important to publish the profile of the entire product you are sending over. Even trace materials in parts per million can affect, say, the color of the product,” says Steve Weiss, Genomatica’s head of marketing. But that’s not enough, he adds. “The only way to validate that something really is the exact same is with actual material use.”

For example, DSM tested Genomatica’s BDO in its Arnitel brand thermoplastic copolyester elastomer and published detailed results. The Dutch firm found the biointermediate was of higher purity than petroleum-derived BDO and deemed it a complete replacement. Similarly, initial research at Invista has shown that biobased raw materials are in most cases indistinguishable from, and match the performance of, petroleum-derived materials, reports Gary Smith, Invista’s vice president of sustainability.

Invista’s role now is to market the biobased alternative to clothing makers, an exchange that Genomatica will be left out of. “Our partners will make those decisions based on how they see the competitive landscape,” Weiss says. It’s clearly a work in progress because, at the moment, an Internet search for “sustainable yoga pants” turns up only styles made with organic cotton and regular spandex.

Invista claims to be opening a supply channel for biobased raw materials for more than just reasons of marketing or environmental sustainability. It wants options, particularly if those options may be cheaper. “We believe biotechnology has the potential to significantly improve the cost and availability of several chemicals and raw materials that we use to produce our products,” Smith maintains.

That cost advantage doesn’t come just from a ready microbial workforce and good process engineering. Firms such as Invista are affected by the impact of the shale gas revolution on chemical intermediates, both four-carbon chemicals such as BDO and higher-carbon aromatics. Running low-priced ethane rather than petroleum through ethylene crackers results in fewer by-products that are four carbons and higher. In this environment, some biobased chemicals are more competitive.

The flip side, though, is that making ethylene from shale gas is cheap, meaning polyethylene and ethylene glycol made from sugar are becoming less competitive. Coca-Cola’s effort to grow a commodity-scale stable of intermediates for polyethylene terephthalate (PET) packaging illustrates how the biobased economy is, to some degree, hostage to fossil-fuel commodities.

PET is produced by reacting ethylene glycol with terephthalic acid. To date, Coca-Cola’s PlantBottle program has relied on biobased ethylene glycol, supplied by India Glycols and made from ethanol shipped from Brazil. Another Indian firm, JBF Industries, had planned to construct a large glycol plant in Brazil but eventually canceled the project, citing poor economics.

But the situation looks rosier on the terephthalic acid side of the PET equation. Virent is working with Coca-Cola to supply p-xylene, a terephthalic acid precursor, for use in the firm’s soda bottles.

Virent’s technology makes gasoline, diesel, and chemicals by catalytically converting soluble sugars, in a process not unlike standard refining. In the fuels business Virent has partnered with the oil giant Shell. Virent’s vision is to build biorefineries that turn a profit by making both fuels and aromatic chemicals including p-xylene, benzene, and toluene.

As petroleum-derived aromatics become scarce, scaled-up biorefineries can “ultimately compete with those materials coming only from crude oil,” says Virent’s chief executive officer, Lee Edwards.

Coca-Cola seems to see this logic. In September, it added fresh funds to support the scale-up of separation and purification capacity at Virent’s p-xylene demonstration plant in Madison, Wis. Looking ahead, Edwards says Virent will use Coke’s commitment to attract chemical manufacturing partners. “The companies we are gravitating to are aspirational. They want to be leaders and see growth in this industry as a key way of getting there.”

The Coke-Virent partnership links a giant with a fledgling. In contrast, the biobased chemical partnership of BASF, Cargill, and Novozymes combines multi-billion-dollar leaders in the fields of chemicals, agriculture, and enzymes to produce a biobased version of the polymer intermediate acrylic acid.

In August, the group reported making 3-hydroxypropionic acid from sugar and converting the intermediate, known as 3-HP, to glacial acrylic acid. They will now build a pilot plant to support BASF, the world’s largest acrylic acid producer, in its plans to market acrylic-based superabsorbent polymers for products such as diapers.

“To bring together the three best companies you could in this field—I can’t think of anything that would be smarter to do,” remarks Henrik Meyer, Novozymes’s senior director of business building. Novozymes is supplying the microbes that convert sugar into 3-HP.

“Companies with good science also need to understand the whole process and the scale-up and have a full understanding of the competitive nature of what they are actually making,” Meyer says. Financing manufacturing facilities also becomes much more realistic with three large companies, he adds.

Even after a biobased enterprise grows beyond the demonstration facility stage, it will continue to learn about the needs of its customers, and that might mean adjusting the strategy. For example, biobased succinic acid maker Reverdia started up its commercial plant in late 2012. It has now added a licensing option.

Succinic acid, made from sugar, is an adaptable molecule that can be used as a feedstock for BDO, polyester polyols for polyurethanes, biodegradable plastics, composite resins, and as a replacement for the polymer ingredient adipic acid. Unlike biobased BDO or acrylic acid, however, it is not an exact replacement for a petroleum-derived commodity chemical.

Customer interest in succinic acid has been high, but customers want assurances about future costs and availability, says Marcel Lubben, Reverdia’s president. Potential users in cost-competitive polymer markets started asking the company about licensing the technology so they could make the raw material themselves.

In the meantime, Reverdia has made progress getting its monomer into the supply chain for polybutylene succinate, a biodegradable polymer used in food packaging, disposable cups, and cutlery. In contrast, segments such as polyurethanes, resins, and coatings are taking longer because it is more difficult to change up those supply chains, Lubben acknowledges.

Indeed, when the shift to biobased polymers really gets started, consumers will likely first see it in biobased PET bottles, diapers, and packaging. And that actually makes sense from a consumer’s viewpoint, according to Nexant’s Cascone. “Disposables are where people are concerned we’re throwing away oil,” he observes.

For many consumers, the first hint of the biobased revolution has already arrived in the form of Coca-Cola’s PlantBottle, made with up to 30% biobased content. When that level moves higher, possibly with ingredients from Virent, it will be because another piece of the puzzle has dropped into place.

Shoppers can track how well the revolution is doing by scrutinizing the labels on products they buy. Of course, economics and supply chains are critical to making biobased polymers work. But ultimately, it’s the consumer’s embrace of polymers made without petroleum that will determine if they take off or remain mere curiosities of the chemical world.