CONVERSION OF LIGNOCELLULOSICS PRETREATED WITH LIQUID HOT-WATER TO ETHANOL

Lignocellulosic materials pretreated using liquid hot water (LHW) (220 degrees C, 5 MPa, 120 s) were fermented to ethanol by batch simultane ous saccharification and fermentation (SSF) using Saccharomyces cerevi siae in the presence of Trichoderma reesei cellulase. SSF of sugarcane bagasse (as received), aspen chips (smallest dimension 3 mm), and mix ed hardwood flour (-60 +70 mesh) resulted in 90% conversion to ethanol in 2-5 d at enzyme loadings of 15-30 FPU/g. In most cases, 90% of the final conversion was achieved within 75 h of inoculation. Comminution of the pretreated substrates did not affect the conversion to ethanol . The hydrolysate produced from the LHW pretreatment showed slight inh ibition of batch growth of S. cerevisiae. Solids pretreated at a conce ntration of 100 g/L were as reactive as those pretreated at a lower co ncentration, provided that the temperature was maintained at 220 degre es C.