The optimization of fermentation conditions for Neurospora crassa resulted in yields of 5.5 and 10 g l−1of ethanol from 1% Avicel and 2% alkali-treated cellulose powder corresponding to 100 and 90% conversion, respectively, in 4 days. N. crassa also has the ability to ferment d-mannose, d-galactose, d-xylose and d-arabinose to ethanol. The direct fermentation of d-xylan, gum arabic and treated bagasse yielded from 60 to 90% conversion of cellulose to ethanol.