Immobilization in Spheres of a Cocktail Rich in Xylanase Produced by the Fungus <i>Fusarium sp</i>. EA 1.3.1 for Hydrolysis of Sugarcane Bagasse

Second generation ethanol is produced from the degradation of lignocellulosic biomass using enzymes as catalysts, with emphasis on xylanases. These biocatalysts are often costly, but stable at high temperatures, and their reuse is of great value, so the immobilization of the enzymes can increase their applicability on an industrial scale. We sought to immobilize a cocktail rich in xylanase produced by the fungus Fusarium sp. EA 1.3.1 in alginate spheres, optimize the immobilization method, characterize the immobilized derivatives, improve their physical-chemical characteristics, and perform the hydrolysis of sugarcane bagasse to release sugars. The Fusarium sp. EA 1.3.1 has been identified and used for cocktail rich in xylanase production that was immobilized in alginate spheres. During this process, the drip equipment, and the concentration of the solutions of sodium alginate and calcium chloride were evaluated. The best results were obtained with the glass rod and with concentrations of 3.14% and 2.10% for the solutions, respectively. The apparent optimum conditions of pH and temperature reaction were studied, and the values of pH 6.5 and 60°C were obtained. The immobilized conjugate also presented greater stability at this temperature than that of the soluble cocktail. The conjugate could be recycled up to six times, and its activity was maintained after 75 days of storage. Finally, the hydrolysis in natural sugarcane bagasse was achieved, and greater amounts of reducing sugars were obtained in the reaction with the conjugate. Thus, the cocktail rich in xylanase produced by the fungus Fusarium sp. EA1.3.1 was successfully immobilized on alginate spheres and possesses the potential to be used as a catalyst in industrial processes such as the lignocellulosic ethanol industry.

Hydrolysis of cellobiose catalyzed by zeolites—the role of acidity and micropore structure

The roles of acidity and micropore structure of zeolite were studied in the hydrolysis of the model oligosaccharide of cellulose–cellobiose. HZSM-5, HY, HMOR and Hβ zeolites were selected as model catalysts for the hydrolysis of cellobiose. The effect of acidity of zeolite, including the strength, type and location, on its catalytic activity was investigated. The strong Br？nsted acid sites located in micropores are the active sites for the hydrolysis of cellobiose to glucose. Meanwhile, the catalytic performance of zeolite is also dependent on the micropore size of zeolite.

Preparation of furfural and reaction kinetics of xylose dehydration to furfural in high-temperature water

Factors influencing dehydration of xylose to furfural,such as catalyst and extract agents,were investigated.Results indicated that high-temperature water may substitute for solid and liquid acid as a catalyst,and ethyl butyrate improved furfural yield for the high distribution coefficient.A furfural yield of 75 % was obtained at200 °C for 3 h in ethyl butyrate/water.The reaction kinetics of xylose dehydration to furfural was investigated and it was found that the reaction order was 0.5,and the activation energy was 68.5 k J/mol.The rate constant k showed a clear agreement with the Arrhenius law from160 to 200 °C.