Production of xylooligosaccharides (XOS) from delignified sugarcane bagasse by peroxide-HAc process using recombinant xylanase from Bacillus subtilis

Xylan is a structural component of the plant cell wall, the most abundant hemicellulose in the nature and generally is considered as an agricultural waste. However, due to upcoming environmental changes, and the excess of residues generated by industrial process, sustainable methods are being applied in the waste management. The world interest in the utilization of agricultural residues as a source to produce biofuel and other products is increasing. Brazil is the biggest producer of sugarcane in the world generating around 110 million tons of dried bagasse. The hemicellulose in sugarcane bagasse is rich in xylan and can be used to produce xylose, xylitol, second-generation ethanol and xylooligosaccharides (XOS). This work, investigated the combination of the pre-treatment with hydrogen peroxide and acetic acid followed by the application of a recombinant xylanase from Bacillus subtilis to produce XOS from sugarcane bagasse. The main products released by the xylanase after the exposure of sugarcane bagasse to different periods of pre-treatment were xylotriose (X3), xylotetraose (X4), xylopentaose (X5) and also is less amounts xylooligomers up to 11 mers (X11), suggesting that is an endo-acting xylanase. The process yielded was 113 and 119 mg/g of xylooligomers from sugarcane bagasse pre-treated with peroxide-HAc for 7 and 8 h, respectively. The hydrolyzed xylooligomers were identified and quantified by HPAE-PAD validating the efficiency of both methods applied to XOS production from sugarcane bagasse. (C) 2013 Elsevier B.V. All rights reserved.