Keasling, chief executive officer of the U.S. Department of Energy's Joint BioEnergy Institute, has pioneered research in biofuels based on substances ranging from yeast to E.coli and expects E.coli fuel production to improve.
Already, a similar technology is using E.coli bacteria to make plastics that are finding their way to stores in products including carpets. Although there is nothing dangerous in E.coli plastic, companies usually don't mention the unusual origins to consumers, he said.
When ingested by humans, E.coli can be dangerous, even fatal. Earlier this year, an outbreak in Germany caused widespread illness and panic, and led to more than 30 deaths.
While biofuels eventually have enormous potential for reducing fossil-fuel consumption, "it's going to be a long time before biofuels are a serious challenge to petroleum," he said.
Reaching critical mass was likely to take at least two decades, he said.
(Reporting by Sarah McBride; Editing by Gary Hill)