Scientists at the University of California, Berkeley have discovered that a long-abandoned process, once used to turn starch into explosives, can be used to efficiently produce diesel fuel from plant sources such as corn, sugar cane, grasses and other fast-growing plants or trees.

The process of bacterial fermentation was discovered nearly 100 years ago by Chaim Weizmann, a chemist who later became the first president of Israel. It uses a bacterium, clostridium acetobutylicum, to ferment sugars and turn them into acetone, butanol and ethanol. This process was used by the British to manufacture cordite for explosives during the First World War and, later, in the manufacture of synthetic rubber.

By the 1960s, the bacterial fermentation process had been replaced by fossil fuel-based processes.

The researchers used a catalyst to convert the acetone and butanol, produced by the fermentation process, into diesel.

Harvey Blanch, a professor of chemical engineering at Berkeley said that "It's a much more efficient way (of creating biofuel) than many of the other products being considered. This product is one that may be closest to commercialization."

The researchers expect that it will take about five years for the process to be perfected to the stage where fuel will be available for sale to the public.