structural evaluation of sugar cane bagasse steam pretreated in the presence of co2 and so2结构评价甘蔗蔗渣蒸汽预处理的二氧化碳和二氧化硫.pdf

Corrales et al. Biotechnology for Biofuels 2012, 5:36 /content/5/1/36 RESEARCH Open Access Structural evaluation of sugar cane bagasse steam pretreated in the presence of CO2 and SO2 1 1 1 Roberta Cristina Novaes Reis Corrales , Fabiana Magalhães Teixeira Mendes , Clarissa Cruz Perrone , 2,3 2,3 2 4 1,4* Celso Sant’Anna , Wanderley de Souza , Yuri Abud , Elba Pinto da Silva Bon and Viridiana Ferreira-Leitão Abstract Background: Previous studies on the use of SO2 and CO2 as impregnating agent for sugar cane bagasse steam treatment showed comparative and promising results concerning the cellulose enzymatic hydrolysis and the low formation of the inhibitors furfural and hydroxymethylfurfural for the use of CO2 at 205°C/15 min or SO2 at 190°C/5 min. In the present study sugar cane bagasse materials pretreated as aforementioned were analyzed by scanning and transmission electron microscopy (SEM and TEM), X-Ray Diffraction (XRD) and Infrared (FTIR spectroscopy) aiming a better understanding of the structural and chemical changes undergone by the pretreated materials. Results: SEM and TEM data showed that the structural modifications undergone by the pretreatment with CO2 were less pronounced in comparison to that using SO2, which can be directly related to the combined severity of each pretreatment. According to XRD data, untreated bagasse showed, as expected, a lower crystallinity index (CI = 48.0%) when compared to pretreated samples with SO2 (CI = 65.5%) or CO2 (CI = 56.4%), due to the hemicellulose removal of 68.3% and 40.5%, respec