Manufacture of Microcrystalline Cellulose from Eucalyptus globulus Wood Using an Environmentally Friendly Biorefinery Method

In this work, hemiceluloses and lignin were solubilized by successive steps of autohydrolysis and delignification, and the resulting solids were processed to obtain microcrystalline cellulose. Eucalyptus globulus wood chips were treated with hot, compressed water under selected conditions to cause the hydrolytic breakdown of heteroxylan into substituted saccharides. The xylan-depleted solids were treated with acetic acid under optimized conditions to remove lignin, leaving a solid phase with high cellulose content. This latter was subjected to Totally Chlorine Free (TCF) bleaching to yield microcrystalline cellulose. These sequence autohydrolysis-organosolv delignification-TCF bleaching enabled the selective separation of hemicelluloses (which were mainly converted into soluble saccharides), lignin (as compounds soluble into acetic acid), and microcrystalline cellulose, according to an environmentally friendly biorefinery method.