Bacteria produce biofuel… in a test tube!

The DirectFuel consortium manipulates bacterial enzymes and metabolic pathways in an attempt to turn carbon into gas

Biofuels were once heralded as fuels of the future. But growing biomass for fuel consumes agricultural land and requires energy greedy processing – it fails to deliver. Water borne algae may be a superior alternative.

Despite common belief plants are not the only organisms able to photosynthesise: cyanobacteria – known as blue-green algae – have picked up the knack too. But while algal growth does not require farmland or fresh water, we cannot ferment or burn bacterial biomass. So how can energy be extracted?

International scientists are collaborating on the DirectFuel project to engineer bacterial enzymes and hack metabolic pathways to turn carbon - the end product of photosynthesis - into gasses such as propane.

At The University of Manchester Professor Nigel Scrutton and Professor David Leys from the Faculty of Life Sciences purify bacterial enzymes to profile their crystal structure and activity. “We have already manipulated an enzyme to produce propane gas from the precursor compound butyraldehyde,” says Professor Scrutton. “This will be one of the final reactions in a long metabolic pathway that will turn carbon into propane gas. It is a major step forward.”

Now Professor Scrutton and Professor Leys are working to optimize the enzyme to increase gas yields. They are combining knowledge of structural biology and chemistry to build computer models to predict which enzyme structures will work fastest. By mutating and screening hundreds of thousands of enzymes at once the researchers can then test their predictions.

“We are making significant progress but we want to do more than make our enzymes efficient – we want to outstrip natural photosynthesis,” enthuses Professor Scrutton. “Sugar cane, for example, has some of the most efficient photosynthesis reactions but only harvests 1-2% of the available energy. If we can manipulate cyanobacteria to harvest even a fraction more energy we will have a potent, cheap and absolutely sustainable fuel source.”

The DirectFuel project is unique in its focus on cyanobacteria. It holds the potential to put biofuels back at the forefront of the fuel sector.

Professor Scrutton concludes: “Is it exciting? Most definitely! The technology has the potential to transform the fuel sector.”

Project fact file

Project name: DirectFuel

Lead researchers: Professor Nigel Scrutton and Professor David Leys

Faculty: Faculty of Life Sciences

Research group: Biophysics and Structural Biology

Research institute: Manchester Institute of Biotechnology

Dates: October 2010 – September 2014

Funding: EU FP7

Partners: University of Turku (Finland); VTT (Finland); Albert Ludwigs University; Freiburg (Germany); Humboldt University; Berlin (Germany); University of Michigan (USA); Kobenhavns University (Denmark); Chemtex Italia SRL (Italy); Photon Systems Instruments (Czech Republic)

The technology has the potential to transform the fuel sector.

Did you know?

Even efficient plants only harvest 1-2% of the potential energy from photosynthesis.
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