Enzymatic hydrolysis of steam-exploded hardwood using short processing times.
Woody materials are generally resistant to enzymatic saccharification unless they undergo harsh fiber disrupting pre-treatments such as steam explosion. In this study, enzymatic hydrolysis of steam-exploded hardwood was investigated using various conditions and commercial cellulase preparations. Hydrolysis times were kept below 24 h in order to approach industrially realistic conditions. The optimal conditions for enzymatic hydrolysis were found to be 55 degrees C and a pH of about 4.5. During enzymatic hydrolysis, acetate was released from the hemicellulose fraction. Increasing the dry matter concentration had a negative effect on glucose yields. Using fermentors with pH control, 66% of the cellulose in steam-exploded hardwood could be hydrolyzed to glucose within 12 h using an enzyme dose of 25 filter paper units (FPU)/g of dry matter. For 24 h hydrolysis maximum cellulose saccharification (71%) was observed at 25 FPU/g, and increasing the enzyme dose further did not increase the sugar yield.
Horn
Svein J
SJ
Department of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences, As, Norway. svein.horn@umb.no
Eijsink
Vincent G H
VG
D000085:Acetates / Q000378:metabolism; D002480:Cellulase / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007700:Kinetics; D032107:Populus / Q000378:metabolism; D013227:Steam; D013696:Temperature; D014242:Trichoderma / Q000201:enzymology; D014934:Wood; D014994:Xylose / Q000378:metabolism
D000085:Acetates; D013227:Steam; D014994:Xylose; D002480:Cellulase