Sulfite pretreatment to overcome recalcitrance of lignocellulose (SPORL) for robust enzymatic saccharification of hardwoods


  • This work was conducted on official government employee time by Zhu and Gleisner and while Wang was a visiting scientist at the USDA Forest Products Laboratory.

  • This is a U.S. Government work and, as such, is in the public domain in the United States of America.


This study demonstrates sulfite pretreatment to overcome recalcitrance of lignocellulose (SPORL) for robust bioconversion of hardwoods. With only about 4% sodium bisulfite charge on aspen and 30-min pretreatment at temperature 180°C, SPORL can achieve near-complete cellulose conversion to glucose in a wide range of pretreatment liquor of pH 2.0–4.5 in only about 10 h enzymatic hydrolysis. The enzyme loading was about 20 FPU cellulase plus 30 CBU β-glucosidase per gram of cellulose. The production of fermentation inhibitor furfural was less than 20 mg/g of aspen wood at pH 4.5. With pH 4.5, SPORL avoided reactor corrosion problem and eliminated the need for substrate neutralization prior to enzymatic hydrolysis. Similar results were obtained from maple and eucalyptus. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009