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Selective fractionation and enzymatic hydrolysis of Eucalyptus nitens wood

Penín, L., Peleteiro, S., Santos, V., Alonso, J. L., Parajó, J. C.
Cellulose 2019 v.26 no.2 pp. 1125-1139
Eucalyptus nitens, biorefining, cellulose, delignification, enzymatic hydrolysis, fractionation, glucose, hot water treatment, hydrolysis, lignin, processing stages, raw materials, wood, xylan
Eucalyptus nitens, a fast growing species with remarkable resistance to plagues and ability to grow in frosting zones, was employed as a raw material for chemical fractionation following a selected biorefinery scheme. E. nitens wood samples were assayed for composition, and subjected to consecutive stages of hydrothermal processing (to solubilize the hemicellulosic fraction), organosolv delignification (for obtaining sulfur-free, soluble lignin fragments and a cellulose-enriched solid phase) and swelling. The various fractions from the processing stages were assayed for yield and composition. Operating under selected conditions, the hydrothermal stage allowed the recovery of 80.7% of the initial xylan as soluble hydrolysis or hydrolysis–dehydration products. The solid leaving the swelling stage contained 88.3% cellulose, and accumulated 90.2% of the cellulose present in the native wood. Near total cellulose conversion into glucose was achieved when the swelled solid was employed as a substrate in enzymatic hydrolysis experiments performed under selected operational conditions.