By Erika Check Hayden of Nature magazine

When the synthetic biology industry was in its infancy a decade ago, it offered some world-changing opportunities. As researchers showed that microbes could be engineered to produce cheaper medicines, or to turn renewable feedstocks such as sugar cane into substitutes for fossil fuels, start-up companies rushed to exploit these possibilities.

But as the industry matures, it has become clear that it must diversify if it is to flourish. That means making some rather more prosaic products, such as cat food or face cream--or tires.

This week saw the latest announcement that exemplified the trend. Amyris, a synthetic-biology company in Emeryville, California, agreed to work with French tire manufacturer Michelin to produce isoprene, the chemical building block used to make synthetic rubber.

Amyris is most famous for producing a cheap, synthetic version of the anti-malarial drug artemisinin, the first batches of which are scheduled to be sold by Paris-based drug firm Sanofi next year. But Amyris no longer develops medicines, and has instead built itself into a synthetic chemical shop specializing in lubricants, fragrances, plastics ingredients and other products.

These products are usually made with chemicals derived from oil. Eighty-five percent of the volume of a barrel of oil is used to make fuel, but the chemicals that come from the remaining 15 percent account for 85 percent of the barrel's monetary value.

For a small biotechnology firm aiming to sell fuel, competing with giant petrochemical companies that have enormous, cost-effective operations has proved to be a tall order. "Everyone thought they were going to take on Exxon initially, but that's not the best model," says Rob Carlson, principal at Biodesic, an engineering and consulting company based in Seattle, Washington.

Instead, smaller companies are increasingly hoping to make a profit from higher-value specialist chemicals, often in collaboration with bigger partners. Bio-derived chemicals still account for just 1-2 percent of the overall chemicals market, but that is still expected to amount to about $1 billion next year, Carlson estimated in a report this year.

Palo Alto, California-based company Genencor, for example, has been working since 2008 with the Akron, Ohio-based Goodyear tire company to make isoprene that it expects to begin selling commercially by next year. Genencor is owned by the Copenhagen-based company, Danisco, which was bought earlier this year by US chemical giant DuPont for $5.8 billion.

Solazyme, of South San Francisco, California, which extracts oils from bioengineered algae, has a partnership with UK-based Unilever, which owns the Dove and Vaseline brands, to make cosmetic ingredients. And in April, Dow Chemical of Midland, Michigan partnered with Boulder, Colorado-based OPX Biotechnologies to make bio-derived acrylic, a component of many plastics. The list goes on.

Conventional chemicals companies such as Dow and DuPont are interested in part because bio-derived versions of their products can be marketed as 'green'. In many cases, they come from renewable sources that have a lower carbon footprint than petrochemicals. The rising cost of oil is also an important factor. "That's driving companies to look at renewables like isoprene," says Mark Bünger, Research Director at Lux Research in San Francisco.

Moving on, not giving up

Biofuels remain an important part of the portfolio of Amyris and other major synthetic biology companies, but they are years away from replacing petroleum-derived fuels. It will also take enormous amounts of feedstock to meet the world's energy demand.

And it's hard to predict when biofuels will become more cost-effective than petroleum, because they rely heavily on government loans or tax breaks that can wax or wane depending on political whims.

In contrast, companies can start making money from specialty chemicals now, and can depend on them as a source of revenue, says Christopher Ryan, president of Gevo, an Englewood, Colorado-based company that retrofits existing biofuels plants to make renewable isobutanol. "We can develop our business plans without uncertainty around what the government might do with regard to biofuel subsidies and things like that--that's the nice thing about the chemicals market," he says.

Bio-derived tires may not seem as world-changing as biofuels, but, as Carlson points out, "We have built our modern world on access to those petrochemicals, so replacing them is at least important as replacing petroleum with biofuels."

This article is reproduced with permission from the magazine Nature. The article was first published on September 30, 2011.