Corn converter

A patented process to pretreat corn-crop waste before conversion into ethanol means extra nutrients do not have to be added, cutting the cost of making biofuels from cellulose.

The AFEX (ammonia fibre expansion) pretreatment process, developed by Bruce Dale, university distinguished professor of chemical engineering and materials science at Michigan State University, uses ammonia to make the breakdown of cellulose and hemicellulose in plants 75 per cent more efficient than when conventional enzymes alone are used.

Cellulose in plants must be broken down into fermentable sugars before they can be turned into biofuel.

Dale said: 'It is possible to use AFEX to pretreat corn stover (cobs, stalks and leaves) and then hydrolyse and ferment it to commercially relevant levels of ethanol without adding nutrients to the stover.

'It's always been assumed that agricultural residues such as corn stover did not have enough nutrients to support fermentation. We have shown this isn't so.'