A naturally occurring fruit lactone could prove useful as a new type of biofuel, say Hungarian scientists.  

Istvan Horvath and colleagues at Eotvos University in Budapest have found that -valerolactone has 'all the qualities of a good biofuel', including being easy and safe to store and transport.  

Horvath explained 'of course the quantity of -valerolactone found in fruits is very, very small and we would not want to use a food resource as a fuel, instead we plan to convert carbohydrates obtained from agricultural residues, wood and wood wastes directly to -valerolactone'.

The team tested the lactone and ethanol as 10% additive:90% gasoline mixtures and found that as fuel additives their properties were very similar. However, what makes -valerolactone attractive as an alternative to ethanol is that it is produced by a less energy demanding process, because unlike ethanol it is removed by distillation.  Additionally, 'its lower vapour pressure may also mean improved fuel performance', said Horvath. The lower vapour pressure means emissions of volatile organic compounds are minimised, and corrosion and instability which can be a problem during storage and transportation of fuels are avoided with -valerolactone, he said.

Robert Crabtree from the Centre for Green Chemistry and Green Engineering at Yale University explained that it is difficult, but critically important, to find sustainable biofuels. 'Horvath has taken the first step by showing that -valerolactone has many of the right properties. The challenge now is to find a synthetic route that can be run economically at the scale required and which does not compete with food resources.'  

Horvath has ambitious plans to improve the yields of -valerolactone obtained from biomass and to develop novel chemistries to enable it to be used as a feedstock for carbon-based chemicals.

Janet Crombie