Effect of pretreatment of woody biomass on ethanol yield

Wood samples from Pinus patula and Eucalyptus camaldulensis species were characterized according to procedures and protocols established by the National Renewable Energy Laboratory (USA), to determine their composition. Then, chips from these woods were pretreated by steam explosion, alkaline delignification, ammonia wet soaking, ozonolysis, dilute acid hydrolysis and organic solvent techniques, to condition the raw materials for the enzymatic hydrolysis step. This step was carried out with the commercial enzymatic pull Accellerase 1500 from Genecor followed by fermentation of the hydrolyzate using Saccharomyces cerevisiae Ethanol Red yeast in a simultaneous saccharification and fermentation configuration. The results of this step allowed selecting the better pretreatment method for woods. Alkaline delignification showed the best ethanol yields (2.17 g/L for Eucalyptus camaldulensis, and 2.61 g/L for Pinus patula).