R. Torget et Ta. Hsu, 2-TEMPERATURE DILUTE-ACID PREHYDROLYSIS OF HARDWOOD XYLAN USING A PERCOLATION PROCESS, Applied biochemistry and biotechnology, 45-6, 1994, pp. 5-22
A novel two-temperature dilute-acid prehydrolysis of hybrid poplar xyl
an that exploits the xylan biphasic kinetics at moderate temperatures
is described. A lower temperature (140 degrees C) is applied to hydrol
yze the easily hydrolyzable xylan, and a higher temperature (170 degre
es C) is subsequently applied to hydrolyze the remaining xylan. Using
a bench-scale percolation reactor, yields of soluble xylose expressed
in monomeric xylose equivalents as high as 92% of theoretical have bee
n achieved with only 2% of the xylan being degraded to furfural. The l
ignocellulosic substrate produced from the pretreatment is readily con
verted to ethanol at a yield of 94% of theoretical via a simultaneous
saccharification and fermentation process in 48 h. In terms of both yi
eld of xylose equivalents and ethanol production level and rate, these
improvements are far superior to those previously reported using a si
ngle-temperature dilute-acid pretreatment.