"They have been instrumental to this project," he said. "In four years, with two postdocs, we beat everybody, even groups with dozens of members."
San said the researchers screened hundreds of strains of E. coli and genetically combined the best qualities to reach a high yield. "Other scientists thought we couldn't come close to a maximum yield," San recalled. "They said E. coli only needs to build enough lipid (fat) for its membrane and would stop."
That, as it turned out, was not true. "In fact, one of the strains we developed is very interesting: Instead of excreting the fatty acid, it wants to keep it inside. So more than 70 percent of the weight of these cells is fatty acid. These are obese E. coli," San said.
Since the project began, the researchers have increased their production 100-fold, San said. "We started with a titer of 0.4 grams per liter, and we were excited when we first produced 1 gram. Now we're up to 14 grams per liter and looking at ways to fine-tune the process. But at this point, the bug will not change that much."
Still, it will take time to scale up. "We have to be sure the bug is perfected and robust enough for industry," San said. "Strains that behave well in the lab may not do as well in an industrial setting." He said the development path will involve testing by independent labs to make sure the process is repeatable, and then initial scaling by a pilot plant in two or three years.
"I think this is a very rich area," San said. "When we started this project four years ago, nobody had paid attention to fatty
|Contact: David Ruth|