Renewable fuels-wizard James Dumesic, who wields his chemical engineering magic at the University of Wisconsin, Madison, has come up with yet another route for converting biomass directly into liquid petrol (gasoline) without getting any biologists’ messy enzymes involved. (His previous efforts have borne fruit in companies such as Virent).

This one centres on the sweet-odoured small ring-shaped molecule gamma-valerolactone (GVL), which occurs naturally in beer, cocoa, coffee and mango, and is also used as a food additive. In itself this can be blended with petrol, performing about as well as ethanol, though other problems limit its widespread use. Some chemists have proposed using GVL as a large-scale intermediate energy-storage molecule (akin to liquid hydrogen). Its chemical properties mean it’s easy and safe to store and move around.

But Dumesic’s team has found catalysts that will convert GVL extremely efficiently to liquid hydrocarbons, which can be used directly in petrol (gasoline) or jet fuel – no ethanol-style ‘blending’ required. What is more, Dumesic points out, the carbon dioxide that the reactions necessarily strip out of the GVL comes off in a fairly pure, pressurized stream, so it is easily captured for possible burial.

The link to biomass? GVL itself is created from two acids which are formed when other acids are used to break down cellulose into sugars. If you thought that sounded a little roundabout – it is, and somebody needs to find a better way to produce the lactone in large quantities from biomass. Get to work.

Dumesic’s latest paper is here (J. Bond et al, Science, 327, 1110-1114; 2010). A 7 October Nature article [subscription required] summarises other efforts to make liquid fuels directly from biomass.