As for cellulose, this polysaccharide was hardly affected by hydrothermal pretreatments so that in all LHW experiments the cellulose recovery was close to 100% (99.5% average), Fig. 2B. Therefore, the solubilisation of the hemicellulosic fraction in LHW assays led to the increase of the cellulose percentage in the pretreated solids from 27.9% to 43.0% when increasing temperature from 190 C to 230 C. For DSA pretreatments, the cellulose recovery remained almost constant (94.3%, 93.8% and 91.4%) until temperature reached 210 C, but beyond this value the cellulose yield decreased with temperature (80.3% and 45.5% for pretreatments carried out at 220 C and 230 C, respectively), Fig. 2B. The minimum percentages of cellulose in DSA pretreated solids were thereby obtained at 220 C (41.0%) and 230 C (26.6%). These
results show the higher capacity of LHW pretreatment, in comparison
to DSA hydrolysis, for removing hemicelluloses without
degrading cellulose.