Resume

This study aimed to evaluate the effect of delignification with NaOH and H2O2 in the enzymatic hydrolysis yield of sugarcane bagasse pretreated by steam explosion (~ 203ºC/~6 min). A 2^2 factorial design was used to study the conditions of delignification in the following ranges: 0.5-10% NaOH (w/w) to 50-150 °C and 1.0 to 30% H2O2 (w/w) 40-100 °C. The tests were performed in a 500 mL Parr reactor with 10% (w/w) of bagasse. The enzymatic hydrolysis of pretreated- and delignified bagasse was performed in a rotating incubator at 50 °C, pH 4.8, 120 rpm for 24 h with 2% (w/w) of bagasse using the NS22074 enzyme complex (Novozymes). Statistical analysis of the delignification results with NaOH showed that the NaOH concentration has a greater effect than temperature on the lignin solubilization (SL) and on enzymatic hydrolysis yield increasing (YH). The best results were achieved in the condition of 100 ºC with 10% NaOH, being SL equal to 67.3% and 47.4% for YH (related to pretreated bagasse). There was an increase in the values of YH with an increasing in NaOH concentration, which are: 3.7%, 17.3% and 47.4% to 0.5%, 5.3% and 10% NaOH 100°C, respectively. Overall results of H2O2 delignification showed that the lignin solubilization under the studied conditions varied little, remaining between 25 and 39%, while in the process with NaOH the range was 4.1 - 67.3%. The best results of YH with hydrogen peroxide were obtained under the following conditions: 36.9% with 30% H2O2 at 70 ºC and 41.8% to 25.8% H2O2 at 91 °C. ഀ Supported by FAPESP/Oxiteno.ഀ