Application of Aspergillus niger Hemicellulases to Chemically Treated Sugarcane Bagasse for Bioethanol Production

K. RODRIGUEZ-ALBAVERA, M. Mendez-Melendez, L-A. Garcia-Vallejo, A-B. Pérez-Zapata, L-W. Granados-Baeza, H. Alonso-Jiménez, F. Hernández-Campos, A. Alvarez-Castillo, M-J. Granados-Baeza, A. Román-Toledo


Background: Currently the lignocellulosic biomass waste from agroindustrial processes has become a potencial source for biofuels (bioethanol) production. The material must be first delignified and then hydrolyzed with a chemical or biological process. For enzymatic hydrolysis, there are many studies related to cellulases, but hemicellulases are also interesting. The objective of this work was the application of commercial hemicellulases from Aspergillus niger to chemically delignified sugarcane bagasse, for fermentable reducing sugars production.Methods: The sugarcane bagasse was collected from Ingenio Emiliano Zapata (Zacatepec Morelos, Mexico). This material was milled and delignified with an alkaline method using hydrogen peroxide. The treatment with hydrogen peroxide increases the susceptibility to enzymatic hydrolysis because lignin content is reduced. The enzymatic hydrolysis was carried out with commercial hemicellulases from Aspergillus niger (1.5 U/mg solid). The parameters studied were particle size (1.0 and 0.5 mm), enzyme units (100, 300 and 500 U/g delignified bagasse) and agitation speed (175 and 250 rpm). All the experiments were run at pH 4.8, 50°C and incubation time was 96 h. Reducing sugars (RS) obtained were determined by the 3, 5-dinitrosalicylic acid method. The data collected was statistically analyzed using the Minitab 16 Statistical Software. Results: The results showed that there only the enzyme concentration and the agitation speed affect statistically the generation of RS. When the different enzyme concentrations and agitation speeds were analyzed, no significance among the different values was found. From this, the selected parameters were: 500 U/g, 175 rpm and 1.0 mm particle size, rendering 25.97 mg glucose/mL, at 96 h. Conclusions: We can conclude that hemicellulases were able to generate a large amount of RS, and the best parameters were selected satisfactorily. These enzymes can be used along with cellulases to hydrolyze completely sugarcane bagasse.

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Full conference title: 

American Society for Microbiology General Meeting
    • ASM 112th (2012)