Fungal fuel

Jack Newman, senior vice president of research and co-founder of biotech company Amyris, once believed algae would serve as the next biofuel. As a young postdoc in the lab of University of California, Berkeley, synthetic biologist Jay Keasling, Newman floated the idea of starting an algal biofuel company at one of the informal pitch parties Keasling would hold for his students at his house.

But as Newman and his colleagues continued to brainstorm, they saw a major hurdle. Evolution hasn't achieved ultimate photosynthetic efficiency in plants and algae - only a small percentage of solar energy is converted to biomass - so human efforts to do so would be quixotic. "Nature's been trying to do that for billions of years," Newman says. "Wow, that's really hard."

Plus, he adds, the algal genome is a veritable black box compared to the DNA of more familiar laboratory organisms. "The timeline for introducing a single change in algae is months."

Newman eventually cofounded Amyris with Keasling, Kinkead Reiling, and Neil Renninger to make ultra-low-cost antimalarial drugs using yeast cells. They also received funding from the Gates Foundation. Working with such a tractable and well-studied organism, Newman and his colleagues "got really good at building hydrocarbons," by feeding genetically modified yeast cells carbon and letting them do their thing. So they thought, why not use the yeast as a source of biofuels? "All the pieces are in the bug," Newman says. "It's a matter of fine-tuning."

The company performed scores of genetic manipulations, inserting genes from land plants into yeast cells and targeting a dozen or so steps in the Acetyl CoA glycolitic pathway to polymerize hydrocarbons into chains of optimal lengths for fuels. Then, about two years ago, Amyris scientists peered into their first test tube filled with yeast-produced diesel. The cells dine on inexpensive (and according to Newman, sustainably grown) sugarcane from Brazil, "eating" the carbon-rich, simple sugars, and converting them into more complex hydrocarbons called isoprenoids, along well-characterized metabolic pathways.

Now Amyris is going at full tilt. As beakers filled with murky liquid shimmy on automatic mixing machines in the company's laboratories in Emeryville, Calif., scientists there continue to tinker with thousands of strains of yeast cells per day to arrive at the most optimal characteristics for growth and hydrocarbon production. "We're beyond the single gene, but we're not at the level of the genome," Newman says. The bottleneck now, he explains, is in achieving the higher yields necessary to take a technology like Amyris's from laboratory beakers into commercial-scale production.

Amyris opened a pilot plant last November across the street from their Emeryville labs. Last fall, it was merely a large open space that had the sterile look of a milk processing plant, with workers shuffling around large fermenting tanks where more would soon stand. But by late 2009, the plant is supposed to have the capacity to pump out approximately 158 gallons of Amyris's "renewable diesel fuel" per day. The company plans to validate the quality of the fuel, and conduct emissions and engine testing using the pilot plant's output. The fuel can be blended with existing transportation fuels at a mixture of up to 50%, and by partnering with a biofuel producer in Brazil, from which Amyris sources its low-cost sugarcane feedstock, the company plans to have at least one million gallons of their yeast-derived fuel on the market, at about $60-70 per barrel, by 2011. (In mid-December, the cost of a barrel of oil was at $45.)

The trouble is, mixing a yearly output of one million gallons of Amyris fuel with existing fuels produces no more than two million gallons of useable diesel fuel per year. And Americans consume more than 140 billion gallons of gasoline annually.