초록
<P><B>Abstract</B></P><P><B>BACKGROUND</B></P><P>Eucalyptus provides a promising feedstock for the bioconversion of lignocellulosic biomass to bio‐fuels. Pretreatment of lignocellulosic biomass is an essential step prior to enzymatic hydrolysis to sugars and bioconversion to other useful products.</P><P><B>RESULTS</B></P><P>In this work, during subcritical CO<SUB>2</SUB> pretreatment, the effects of CO<SUB>2</SUB> pressure, reaction time and temperature on compositional changes and subsequent enzymatic hydrolysis were determined. After the pretreatment of 5 MPa CO<SUB>2</SUB>, 80 min and 160 °C, the maximal xylose yield was 9.8 g (including 8.4 g oligomer) based on 100 g native material. When the pretreated eucalyptus were enzymatically hydrolyzed for 60 h, 42.4 g glucose based on 100 g native material could be obtained, representing 92.2% of glucose in eucalyptus. Under the most favourable pretreatment and enzymatic hydrolysis conditions, a maximum total sugar recovery of 50.6 g (including 8.5 g xylose and 42.1 g glucose) based on 100 g native material was obtained, which corresponds to 84.1% yield on the basis of total sugar in eucalyptus biomass. Characterization data were obtained for the pretreated eucalyptus using XRD and SEM analyses.</P><P><B>CONCLUSIONS</B></P><P>The results suggested that subcritical CO<SUB>2</SUB> pretreatment could enhance enzymatic digestibilities due to the removal of hemicelluloses. © 2014 Society of Chemical Industry</P>