Tuesday, April 30, 2013
Exhibit Hall
Sugarcane bagasse was pretreated with dilute sulfuric acid (100 mg of acid/ g of dry bagasse) at 121 ºC for 20 min. This hemicellulosic hydrolysate after concentration by vacuum evaporation and detoxification with overliming showed 30.89 g/l xylose along with other products (0.32 g/l glucose, 2.31 g/l arabinose, 1.26 g/l acetic acid etc). The recovered cellulignin was subsequently delignified by sodium hydroxide (1.0 % w/v NaOH, 120 0C, 60 min) mediated pretreatment. The acid-base pretreated material showed 48.50 g/l total reducing sugars (0.91 g sugars/g pretreated bagasse) after enzymatic hydrolysis (15 FPU/g and 20 IU of β-glucosidase/g at 50 0C, 150 rpm for 96 h). Ultra-structural mapping of acid-base pretreated and enzyme hydrolysed SB by scanning electron microscopy, FTIR, FTNIR and NMR elucidated the molecular changes in hemicellulose, cellulose and lignin components of bagasse.
The detoxified hemicellulosic hydrolysate was fermented by Candida shehatae UFMG HM 52.2 and showed 9.11 g/l ethanol production (yield 0.38 g/g) after 48h of fermentation. Enzymatic hydrolysate when fermented by Saccharomyces cerevisiae 174 showed 8.13 g/l ethanol (yield 0.22 g/g) after 72 h of fermentation.
Acknowledgement: Financial support by Bioen-FAPESP, CNPq and CAPES, Brazil is gratefully acknowledged.