U.S. scientists say they can turn E.coli, a strain of bacteria present in the human digestive tract, into a fuel that is twice or three times more efficient than ethanol. The scientists, attached to theUniversity of California in Los Angeles (UCLA) managed to create a strain for the first time that generates alcohol with five carbon atoms per molecule instead of the regular two or three. That´s important because the larger, longer chain molecules contain more energy, something of a "holy grail" for the fuel industry.