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Green chemistry and the future of biofuels

14 September 2012




As the importance of biofuels increase, scientists are working to refine the chemical methods of their production. Chris Lo explores some of the most promising recent innovations that are improving the chances of biofuels tapping into the mainstream.


New biochemical advances are paving the way for advanced biofuels of the future. The development of efficient fuels from sustainable sources has the potential to not only revolutionise the struggle against climate change, but also completely transform the fuel supply chain forever.

The huge implications of biofuel are reflected in predictions concerning the future health of the green chemistry and biofuels markets.

Based on company announcements and orders compiled in November 2011, Biofuels Digest has predicted that global advanced biofuels and green chemicals capacity will reach 5.11bn gallons by 2015, setting biofuels on track to become a $20bn market within the next three years.

World Biofuels Markets event director Claire Poole agreed with the market's healthy prognosis in a statement this month. "Manufacturers and consumers are seeking healthier, cleaner, more sustainable products, positioning the bio-based chemical and products industry to rapidly and drastically grow its market share over the next five to ten years," she said.

But in order for biofuels to achieve their immense potential, there is still some serious chemical legwork to be done. Here we look at some of the most promising recent innovations from scientific teams around the world that are improving the chances of biofuels tapping into the global mainstream.

Aalto University harnesses wood biomass

"These novel fatty acids would be a renewable resource to replace raw materials now derived from petroleum."

Of all the alcohol-based biofuel candidates, butanol has often been trumpeted as the most effective because it is water insoluble and contains more energy than ethanol.

Butanol's longer hydrocarbon chain also makes it chemically similar to gasoline, meaning larger ratios of butanol-based biofuels (more than 20%) can be used in internal combustion engines without the need for any modifications.

The most common biomass crops currently used for butanol production are food-based sources like starch and cane sugar, which can be problematic as biomass crops take capacity out of the food production cycle. Researchers at Aalto University, in Finland, have overcome this issue by developing a new process for butanol production, one that makes use of simple woodchips.

They use a modified method of wood pulping that saves all of the material's chemical compounds - cellulose, hemicellulose and lignin - for refining. The preservation of hemicellulose has particular implications for biofuels as it is an efficient microbe raw material for chemical production.

The project, run by Aalto University as part of the Finnish Funding Agency for Technology and Innovation's BioRefine programme, has unlocked the full potential of wood biomass as a future source of sustainable biobutanol fuel.

New discovery unlocks double bond placement

A groundbreaking chemical breakthrough by a scientific collaboration between the US-based Brookhaven National Laboratory (BNL) and the Karolinska Institute, in Sweden, has unlocked the long-standing mystery of what mechanism allows enzymes to select a location to insert a double bond when desaturating plant fatty acids.

"Microbubbles float algae particles to the surface of the water, making harvesting much easier."

The discovery, which was published in the Proceedings of the National Academy of Sciences journal in September 2011, could pave the way for new methods of engineering plant oils to replace petrochemicals.

This new knowledge could allow scientists to 'customise' enzymes to increase their control over plant biomass and potentially open up new efficiencies in biofuel production.

BNL research associate Ed Whittle was particularly optimistic about the implications of the discovery.

"Using what we've now learned, I am optimistic we can redesign enzymes to achieve new desirable specificities to produce novel fatty acids in plants," he said. "These novel fatty acids would be a renewable resource to replace raw materials now derived from petroleum."

Microbubbles: a boost for biofuel production

"Butanol's longer hydrocarbon chain is chemically similar to gasoline, so larger amounts can be used in internal combustion engines."

Despite the widely recognised efficiencies of algae for potential biofuel applications, commercial demonstrations of algal fuel production are still few and far between. However, new research at the University of Sheffield's Department of Chemical and Biological Engineering unveiled last month, January 2012, may have overcome one of the major stumbling blocks holding back the industrial-scale production of algae-based biofuel.

A team led by Professor Will Zimmerman has developed a solution to the challenge of cost-effectively harvesting and removing water from algae for it to be viably processed into oil for biofuel production.

The solution comes in the form of microbubbles, which float algae particles to the surface of the water, making harvesting much easier.

"We thought we had solved the major barrier to biofuel companies processing algae to use as fuel when we used microbubbles to grow the algae more densely," said Zimmerman.

"It turned out, however, that algae biofuels still couldn't be produced economically because of the difficulty in harvesting and dewatering the algae. We had to develop a solution to this problem and once again, microbubbles provided a solution."

Microbubbles have previously been used by water purification companies to float impurities out of water, but the method developed by Zimmerman's team requires around 1,000 times less energy, making it financially viable for biofuel producers.

The team now plans to develop a pilot plant to test the new method on a larger scale and expects to work with Tata Steel at its Scunthorpe site, using CO2 from its flue-gas stacks. If the method proves viable as an industrial-scale process, it could prove a major boost for biofuel production.

It's clear that biofuels are on course to become an increasingly important part of the world's fuel production mix. A European Union mandate requires that all fuel must contain at least a 10% biofuel component by 2020, while in the US, the Federal Government has set a requirement for the country's annual fuel output to include at least 36bn gallons of biofuels by 2022. New, innovative chemical methods of producing biofuels being developed today will undoubtedly help the industry meet both their environmental and financial obligations in the future.

Aalto University's wood biomass project uses modified pulping to ensure compounds are preserved.
Shanklin and Whittle of Brookhaven are part of the team working on enzyme double bond placement in plant fatty acids.
Researchers at Sheffield University devised a new method of separating algae from water.
Microbubbles could hold the key to a more efficient process when refining algae to a biofuel.