A team of Harvard bioengineers recently announced they have successfully created a bacterium to absorb carbon dioxide and hydrogen and excrete several types of biofuels. The team has an upcoming paper in Science describing their experiments with the modified bacteria and the results they’ve gotten so far.
The lead researcher behind the development, Daniel Nocera, stated in a press conference that the bacteria could potentially be a self-sustaining energy source:
I can just let the bugs grow exponentially. They’re eating hydrogen, that’s their only food source, and then they breathe in CO2, and they keep multiplying. They procreate, and that goes into an exponential growth curve.
The bacterium, Ralstonia eutropha, was genetically modified in order to alter its production of adenosine triphosphate, or ATP. ATP is a molecule often referred to as the currency of energy for metabolic processes. It's produced by the enzyme ATP synthases, primarily in plants cells called chloroplasts where photosynthesis and ATP synthesis take place.
ATP is usually recycled and replenished by organisms, but Ralstonia eutropha was modified to convert its ATP into several alcohols and excrete them. The bacteria also produces several byproducts that can be burned as biofuel, providing even more energy. While plants convert sunlight into energy at around 1% efficiency, Ralstonia eutropha bacteria can produce energy with about 6% efficiency.
Despite the fact that burning biofuels produced by the bacteria actually releases carbon dioxide into the atmosphere, Ralstonia eutropha could ultimately be a carbon neutral fuel source since it uses CO2 in respiration. The bacterium is being eyed as a possible fuel source for developing countries such as India where fuel options are scarce, forcing many to turn to burning dirty fossil fuels like coal.
While many have high hopes for the bacteria to solve the carbon and fuel crises, those hopes should be tempered by the results of the same researchers’ last project, a genetically modified leaf that can produce high levels of hydrogen. They had hoped that this hydrogen could be used to power fuel cells and be the next big clean energy source, but as of today, hydrogen cells have yet to be embraced on a large scale.