Olive stones are an agro-industrial by-product in Mediterranean countries that can be regarded as a
potential source of bio-fuels and bioactive compounds. In this work, olive stones were pretreated with
liquid hot water (LHW), dilute sulphuric acid (DSA) and organosolv delignification at temperatures in the
range 190 Ce230 C. The resulting solids from pretreatments were subjected to simultaneous
saccharification and fermentation (SSF) with the yeast Saccharomyces cerevisiae IR2-9a for fuel-ethanol
production. The composition of prehydrolysates from LHW and DSA pretreatments were strongly
dependent of reactor temperature. The highest yields of D-xylose (0.21 kg kg1) and D-glucose
(0.11 kg kg1) were achieved in DSA assays at 200 C and 230 C, respectively, while LHW processes
provided the maximum oligosaccharide recovery (0.17 kg kg1) at 210 C. The addition of sulphuric acid
in organosolv pretreatments was particularly effective to increase the cellulose content of the pretreated
solids till percentages close to 83%. Finally, the maximum ethanol concentration achieved by SSF was
47.1 kg m3, and 13 kg ethanol were obtained from 100 kg of raw material