Is the hope for a cellulosic biofuel a lot of rot?

Compared with the small amount of fermentable sugars in corn kernels, lignocellulose obtained from agricultural waste products or non-food crops is an abundant natural resource that can be used for the production of ethanolbased biofuel. However, the rigid structure linking cellulose and hemicellulose to lignin, while rather handy for plants, restricts the availability of fermentable sugars necessary to produce ethanol. As a result, current biofuel production relies on expensive and toxic pretreatment to detach the cellulose from lignin and render it susceptible to hydrolysis (Scharf and Tartar, 2008). But alternative approaches recently have been deduced from the genomes of organisms that naturally convert lignocellulose into fermentable sugars. Several animals, such as termites and ruminant mammals, use symbiotic microbes to degrade lignin and cellulose. In all termites, this occurs in the digestive tract, but involves different types of symbionts in ‘lower’ and ‘higher’ termites: lower termites harbour both protozoa and bacteria, whereas higher termites only contain bacterial symbionts (Scharf and Tartar, 2008). To find