Blue-green algae can be 'tricked' into producing butanol
13 March 2013
In the search for the fuels of tomorrow, Swedish researchers are finding inspiration in the sea. Not in offshore oil wells, but in the water where blue-green algae thrive.
The building blocks of blue-green algae – sunlight, carbon dioxide and bacteria – are being used by researchers at KTH Royal Institute of Technology in Stockholm to produce butanol, a hydrocarbon-like fuel for motor vehicles. The advantage of butanol is that the raw materials are abundant and renewable, and production has the potential to be 20 times more efficient than making ethanol from corn and sugar cane.
Using genetically-modified cyanobacteria, the team linked butanol production to the algae’s natural metabolism, says Paul Hudson, a researcher at the School of Biotechnology at KTH who leads the research. “With relevant genes integrated in the right place in cyanobacteria’s genome, we have tricked the cells to produce butanol instead of fulfilling their normal function,” he says.
The team demonstrated that it can control butanol production by changing the conditions in the surrounding environment. This opens up other opportunities for control, such as producing butanol during specific times of day, Hudson says. However, Hudson warns that it could be a decade before production of biofuel from cyanobacteria is a commercial reality.
“We are very excited that we are now able to produce biofuel from cyanobacteria. At the same time we must remember that the manufacturing process is very different from today's biofuels,” he says. “We need to improve the production hundredfold before it becomes commercially viable.
Already, there is a demonstrator facility in New Mexico for producing biodiesel from algae, which is a more advanced process, Hudson says.
One of Sweden's leading biotechnology researchers, Professor Mathias Uhlén at KTH, has overall responsibility for the project. He says that the use of engineering methods to build genomes of microorganisms is a relatively new area. A bacterium that produces cheap fuel by sunlight and carbon dioxide could change the world.
Hudson agrees. “One of the problems with biofuels we have today [corn ethanol] is that the price of corn rises slowly while jumping up and down all the time and it is quite unpredictable,” he says. “In addition, there is limited arable land and corn ethanol production is also influenced by the price of oil, since corn requires transport.
“Fuel based on cyanobacteria requires very little ground space to be prepared. And the availability of raw materials - sunlight, carbon dioxide and seawater - is in principle infinite,” Hudson says.
He adds that some cyanobacteria also able to extract nitrogen from the air and thus do not need any fertilizer.
The next step in the research is to ensure that cyanobacteria produce butanol in larger quantities without it dying of exhaustion or butanol, which they cannot withstand particularly well. After that, more genes will have to be modified so that the end product becomes longer hydrocarbons that can fully function as a substitute for gasoline. And finally, the process must be executed outside of the lab and scaled up to work in industry.
There are also plans to develop fuel from cyanobacteria that are more energetic and therefore particularly suitable for aircraft engines.