BIOFUEL I NSPIRED BY BEER

At most US filling stations customers are pumping fuel with a 10 per cent mix of ethanol made from fermenting the sugars in corn. The biofuel blend reduces greenhouse gases, but it can slowly corrode your engine and blends poorly at higher ratios. Butanol is an ideal addition to gasoline. It’s easy on your engine and blends better-however, it’s more expensive to manufacture. But researchers at the University of Bristol in the United Kingdom have developed a catalyst, a substance that speeds up chemical reactions, that turns ethanol into butanol, using beer – also made of fermented sugars – as their model.

Professor Duncan Wass says his group wanted to find a catalyst that worked with an ethanol fermentation broth, an early step in ethanol production, because it would be significantly cheaper to convert to butanol. But the mixture of ethanol, water, and unfermented sugars contains other chemicals that can potentially stop the catalyst. When they attempted to buy broth to test their catalyst, they found prohibitive health and safety restrictions. “Our industry partners said ‘Why don’t you try beer? It’s literally the same mix of ethanol, water, and unfermented sugars,’ ” says Wass. The team then successfully used the catalyst to convert a pale lager (pictured), an IPA, and a Belgian ale into butanol. For the record, says Wass, no beer will be wasted in industrial applications of the catalyst.