title: Ethanol/water pulps from sugar cane straw and their biobleaching with xylanase from Bacillus pumilus.
abstract: The influence of independent variables (temperature and time) on the cooking of sugar cane straw with ethanol/water mixtures was studied to determine operating conditions that obtain pulp with high cellulose contents and a low lignin content. An experimental 2(2) design was applied for temperatures of 185 and 215 degrees C, and time of 1 and 2.5 h with the ethanol/water mixture concentration and constant straw-to-solvent ratio. The system was scaled-up at 200 degrees C cooking temperature for 2 h with 50% ethanol-water concentration, and 1:10 (w/v) straw-to-solvent ratio to obtain a pulp with 3.14 cP viscosity, 58.09 kappa-number, and the chemical composition of the pulps were 3.2% pentosan and 31.5% lignin. Xylanase from Bacillus pumilus was then applied at a loading of 5-150 IU/g dry pulp in the sugar cane straw ethanol/water pulp at 50 degrees C for 2 and 20 h. To ethanol/water pulps, the best enzyme dosage was found to be 20 IU/g dry pulp at 20 h, and a high enzyme dosage of 150 IU/g dry pulp did not decrease the kappa-number of the pulp.
authors.affiliation: Departamento de Biotecnologia, Escola de Engenharia de Lorena-USP, PO box 116, 12600-970 SP, Lorena, Brazil.
authors.forename: Regina Y
authors.initials: RY
authors.lastname: Moriya
authors.forename: Adilson R
authors.initials: AR
authors.lastname: Gonçalves
authors.forename: Marta C T
authors.initials: MC
authors.lastname: Duarte
mesh_terms: D001407:Bacillus / Q000201:enzymology*; D020650:Combinatorial Chemistry Techniques / Q000379:methods*; D043364:Endo-1,4-beta Xylanases / Q000737:chemistry*; D000431:Ethanol / Q000737:chemistry*; D035261:Plant Components, Aerial / Q000737:chemistry*; D031786:Saccharum / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
chemical_list: D014867:Water; D000431:Ethanol; D043364:Endo-1,4-beta Xylanases