Alkali-peroxide treatment of sugar cane bagasse : Effect of chemical charges on the efficiency of xylan isolation and susceptibility of bagasse to saccharification
Sugar cane is a promising raw material for the extraction of hemicelluloses. An alkali treatment of sugar cane bagasse under proper conditions followed by a precipitation using a reasonable quantity of ethanol can be an effective method to isolate these polysaccharides. In this work, bagasse is treated to obtain two products: (a) polymeric hemicellulose and (b) an enzymatic hydrolysate from the treated bagasse after hemicellulose extraction. The effects of charges of sodium hydroxide (10, 20, 40% w/w) and hydrogen peroxide (0, 10, 20% w/w) in the alkali treatment were evaluated. A 3² experimental design was considered under control of metal ions and inert atmosphere during alkaline treatment. An acceptable proportion of xylose plus arabinose could be extracted from bagasse (up to 18.4 g/100 g of bagasse). Both the alkali and peroxide showed strong effects on the yield of the extraction, as well as on the yield of the precipitation in ethanol-water solution. Besides, the susceptibility of bagasse for cellulolytic enzymatic hydrolysis is improved. The highest hemicellulose precipitation yield was 85% which corresponded to the treatment with the highest alkali charge without peroxide. The highest yield of enzymatic hydrolysis was obtained for the highest alkali and peroxide charges.Instituto de Fisiología VegetalInstituto de Botánica "Dr. Carlos Spegazzini
