Ethanol production from AFEX-treated forages and agricultural residues

Lignocellulosic materials derived from forages, namely timothy grass, alfalfa, reed canary grass, and agricultural residues, such as corn stalks and barley straw, were pretreated using ammonia fiber explosion (AFEX) process. The pretreated materials were directly saccharified by cellulolytic enzymes. Sixty to 80% of theoretical yield of sugars were obtained from the pretreated biomasses. Subsequent ethanolic fermentation of the hydrolysates by Pachysolen tannophilus ATCC 32691 resulted in 40-60% of theoretical yield after 24 h, based on the sugars present in the hydrolysates. The uptake of sugars was not complete, indicating a possible inhibitory effect on P. tannophilus during the fermentation of these substrates.