Bioethanol production from hydrothermally pretreated Eucalyptus globulus wood.

Eucalyptus globulus wood samples were pretreated in aqueous media under non-isothermal conditions to reach maximal temperatures (T(MAX)) in the range 195-250 degrees C, in order to assess the effects of the pre-treatment severity on the fractionation of wood and on the susceptibility of processed samples toward enzymatic hydrolysis. Both the fraction of cellulose susceptible to hydrolysis and the hydrolysis rate increased with the severity of the pre-treatments, but the overall glucose yield decreased for substrates pretreated at T(MAX) above 220 degrees C owing to cellulose losses. Using substrates pretreated at T(MAX)=220 degrees C, up to 94% of polysaccharides were recovered in the hydrolysis media as mono- or oligo-saccharides. High glucose to ethanol conversions were obtained operating at low enzyme charges in Simultaneous Saccharification and Fermentation mode.