Effect of ferric tartrate/sodium hydroxide solvent pretreatment on enzyme hydrolysis of cellulose in corn residue

Lignocellulose containing 62% cellulose was prepared from corn residue by dilute acid hydrolysis using 5% H(2)SO(4) at 90 degrees C. The lignocellulose was then treated with a cellulose solvent consisting of a ferric sodium tartrate complex in 1.5N sodium hydroxide at levels ranging from 4:1 to 12:1 (solvent volume: corn residue lignocellulose) or a 1.5N sodium hydroxide solution alone. Subsequent hydrolysis with cellulase enzymes from Trichoderma reesei gave cellulose conversions which were two to three times higher than untreated lignocellulose (30%) and approached 90% conversion after 24 h in the best cases. It was found that increasing cellulase enzyme levels from 3.74 lU/g lignocellulose to 7.71 lU/g lignocellulose increased cellulose conversion by 50% at all pretreatment conditions, while an increase from 7.71 to 10.1 lU/g gave only an additional 5-10% increase. Pretreatment with sodium hydroxide resulted in 5-25% lower conversions than observed for cellulose treated with the solvent, depending on enzyme levels and treatment levels. At high enzyme levels, sodium hydroxide pretreatment is almost as effective in enhancing cellulose conversion after 24 h as is pretreatment using the cellulose solvent.