Fuel from Bacteria, CO2, Water, and Solar Energy

Harvard University
Engineering a Bacterial Reverse Fuel Cell
Graphic of Harvard's technology, Shewanella
ARPA-E Award: 
Boston, MA
Project Term: 
07/01/2010 to 09/30/2013
Project Status: 
Technical Categories: 
Critical Need: 
Domestic biofuels are an attractive alternative to petroleum-based transportation fuels. Biofuels are produced from plant matter, such as sugars, oils, and biomass. This plant matter is created by photosynthesis, a process that converts solar energy into stored chemical energy in plants. However, photosynthesis is an inefficient way to transfer energy from the sun to a plant and then to biofuel. Electrofuels--which bypass photosynthesis by using self-reliant microorganisms that can directly use the energy from electricity and chemical compounds to produce liquid fuels--are an innovative step forward.
Project Innovation + Advantages: 
Harvard is engineering a self-contained, scalable electrofuels production system that can directly generate liquid fuels from bacteria, carbon dioxide (CO2), water, and sunlight. Harvard is genetically engineering bacteria called Shewanella, so the bacteria can sit directly on electrical conductors and absorb electrical current. This current, which is powered by solar panels, gives the bacteria the energy they need to process CO2 into liquid fuels. The Harvard team pumps this CO2 into the system, in addition to water and other nutrients needed to grow the bacteria. Harvard is also engineering the bacteria to produce fuel molecules that have properties similar to gasoline or diesel fuel--making them easier to incorporate into the existing fuel infrastructure. These molecules are designed to spontaneously separate from the water-based culture that the bacteria live in and to be used directly as fuel without further chemical processing once they're pumped out of the tank.
Impact Summary: 
If successful, Harvard would create a liquid transportation fuel that is cost competitive with traditional gasoline-based fuels and 10 times more efficient than existing biofuels.
Cost-competitive electrofuels would help reduce U.S. dependence on imported oil and increase the nation's energy security.
Widespread use of electrofuels would help limit greenhouse gas emissions and reduce demands for land, water, and fertilizer traditionally required to produce biofuels.
A domestic electrofuels industry could contribute tens of billions of dollars to the nation's economy. Widespread use of electrofuels could also help stabilize gasoline prices--saving drivers money at the pump.
ARPA-E Program Director: 
Dr. Ramon Gonzalez
Project Contact: 
Dr. Pamela Silver