December 7, 2017 - 13:08 AMT
British scientists turn beer into fuel

Chemists at the University of Bristol have made the first steps towards making sustainable petrol using beer as a key ingredient, EurekAlert says.

It is commonly accepted that there is an urgent need for sustainable alternatives to fossil fuels for transportation to replace diesel and petrol.

One of the most widely used sustainable alternatives to petrol world-wide is bioethanol - in the United States gasoline is typically sold as a blend with up to 10 percent ethanol.

It is also know that ethanol is not an ideal replacement for petrol as it has issues such as lower energy density, it mixes too easily with water and can be fairly corrosive to engines.

A much better fuel alternative is butanol but this is difficult to make from sustainable sources.

Scientists from the University of Bristol's School of Chemistry have been working for several years to develop technology that will convert widely-available ethanol into butanol.

This has already been demonstrated in laboratory conditions with pure, dry ethanol but, if this technology is to be scaled up, it needs to work with real ethanol fermentation broths.

These contain a lot of water (about 90 percent) and other impurities, so the new technology has to be developed to tolerate that.

Professor Duncan Wass, whose team led the research, said: "The alcohol in alcoholic drinks is actually ethanol - exactly the same molecule that we want to convert into butanol as a petrol replacement.

"So alcoholic drinks are an ideal model for industrial ethanol fermentation broths - ethanol for fuel is essentially made using a brewing process.

"If our technology works with alcoholic drinks (especially beer which is the best model) then it shows it has the potential to be scaled up to make butanol as a petrol replacement on an industrial scale."