13-10: ATR-FTIR analysis of sugarcane bagasse after using ozone and ultrasound as pretretments for enzymatic hydrolysis for cellulosic ethanol production

Monday, April 29, 2013
Exhibit Hall
Olavo Perrone1, Eleni Gomes2, Roberto da Silva1, João Claudio Thoméo3 and Maurício Boscolo1, (1)Department of Chemistry and Environmental Science, UNESP, São José do Rio Preto, Brazil, (2)Department of Biology, UNESP, São José do Rio Preto, Brazil, (3)Department of Food engineer, UNESP, São José do Rio Preto, Brazil
Sugarcane ethanol is already useful in Brazil and other countries and the possibility of use the bagasse to produce cellulosic ethanol is dificulted by the recalcitrance of this vegetable fiber. To overcome this recalcitrance a pretreatment of the bagasse was performed under ozone atmosphere and then kept in suspension with NaOH and sonicated. Treated samples and controls were subjected to analysis by ATR-FTIR as well as enzymatic hydrolysis with commercial cellulase and total reducing sugars was quantyfied. The peaks located in the region of 1600, 1510 and 1440 cm-1 in the infrared spectra which are related due to the presence of lignin, while the peak observed at 833 cm-1 is related to the absorption of p-Hydroxyphenyl, one of the precursors of lignin. The peak observed at 897 cm-1 is related to β (1-4) linkages between glucose units, and peak 1158 cm-1 is due to the stretch of the group C-O-C of β (1-4) glycosidic bond. It was observed that the peaks related to the presence of lignin (1600, 1510, 1440 and 833 cm-1) were almost completely eliminated when the bagasse was pretreated, compared to the untreated samples. In the same way, the peaks related to the glycosidic β (1-4) suffered some modifications, indicating reduction of these bonds. This facilitated the access of the enzyme to the cellulose/hemicellulose, increasing the saccharification of bagasse which can be proven by the value of 638 ± 10 mg ART/g bagasse, versus 128 ± 7 mg ART/g of sugarcane bagasse.