Researchers have developed a new strain of E. coli bacteria that can produce an advanced biofuel directly from biomass.
The new strain of bacteria, engineered by researchers at the U.S. Department of Energy's Joint BioEnergy Institute, does not need chemical modifications to produce the biodiesel. That's important because it keeps costs down, allowing the process to scale and remain sustainable -- that is, economically feasible.
According to current research, liquid fuels derived from plant biomass are one of the best alternatives to crude oil -- but only if a cost-effective means of commercial production can be found.
Current research efforts are focused on fatty acids, called "nature's petroleum" thanks to their energy-rich composition. Fatty acids serve as the raw materials for a wide range of chemicals, including surfactants, solvents, lubricants and, of course, biodiesel.
Led by JBEI CEO and synthetic biologist Jay Keasling, the team also included members of LS9, a privately-held industrial biotechnology firm based in South San Francisco.
"The increased demand and limited supply of these oils has resulted in competition with food, higher prices, questionable land-use practices and environmental concerns associated with their production," Keasling said in a statement. "A more scalable, controllable, and economic alternative route to these fuels and chemicals would be through the microbial conversion of renewable feedstocks, such as biomass-derived carbohydrates."
E. coli is known for its ability to synthesize fatty acids, as well as for its flexibility to allow genetic manipulation.
By unlocking the microbes' natural regulation, the researchers were able to engineer them to produce an abundance of fatty acids that they could then convert to valuable chemicals. The team also engineered the E. coli to stop using fatty acids for energy.
After successfully diverting the bacteria's fatty acid metabolism, the researchers also engineered the bacteria strain to produce hemicellulases, enzymes that are able to ferment the complex sugars that are a major constituent of cellulosic biomass -- in other words, the keys to the energy trapped within plant cell walls.
Normally, those enzymes must be purchased and added, an expensive step that significantly increases the total cost of the process.
For now, the process is not yet commercially feasible, but the team is moving in the right direction. The researchers are currently working on maximizing the efficiency and speed of the biomass-to-biodiesel conversion.