Improvement of some chemical and biological methods for the efficient production of xylanases, xylooligosaccharides and lignocellulose from sugar cane bagasse

Abstract

The use of agroindustrial waste for chemicals, biofuels and food ingredients production has been studied considering limitations of natural resources. Therefore, sugarcane bagasse was studied to produce arabinoxylan, xylanases, xylooligosaccharides and lignocellulose by the improvement of some technologies. A comparison of two methods of extraction of arabinoxylan was performed. Arabinoxylan was obtained in a soluble fraction in a better extraction by KOH method with higher yield (72.1%) and efficiency (84%) than H2O2 method, which only produced 64.9 and 43.3%, respectively. Lignocellulose was obtained after filtration, as the solid fraction, representing 66.2% (KOH) and 78.8% (H2O2 method) of the total biomass. The endoxylanase was produced by Aspergillus fumigatus CCT7732 in submerged fermentation with bagasse culture medium reaching 40.2 U/mL in optimal conditions, pH 5.0 and 31.5 °C. In addition, NH4H2PO4 was efficient as phosphorus and nitrogen sources for xylanases production in the culture, when the more expensive salts K2HPO4 and KH2PO4 were replaced. An enzymatic hydrolysis of arabinoxylan in Xylooligosaccharides (XOS) by xylanases of A. fumigatus resulted in 3.3% (m/v) XOS, 46.9% yield using 7% arabinoxylan, 350 U/g of xylanases at 50 °C in 48 h. These methods provided a prebiotic XOS since mainly xylobiose and xylotriose were produced with potential applications for food and feed. The set of chemical and biological methods applied in bagasse indicated that these methods should be evaluated in scale up of an integrated biosystem including economic studies for industrial purposes.