title: Dilute-acid hydrolysis for fermentation of the Bolivian straw material Paja Brava.
abstract: Hydrolysis of the straw material Paja Brava, a sturdy grass characteristic for the high plains of Bolivia, was studied in order to find suitable conditions for hydrolysis of the hemicellulose and cellulose parts. Dried Paja Brava material was pre-steamed, impregnated with dilute sulfuric acid (0.5% or 1.0% by wt), and subsequently hydrolyzed in a reactor at temperatures between 170 and 230 degrees C for a reaction time between 3 and 10 min. The highest yield of xylose (indicating efficient hydrolysis of hemicellulose) were found at a temperature of 190 degrees C, and a reaction time of 5-10 min, whereas considerably higher temperatures (230 degrees C) were needed for hydrolysis of cellulose. Fermentability of hemicellulose hydrolyzates was tested using the xylose-fermenting yeast species Pichia stipitis, Candida shehatae and Pachysolen tannophilus. The fermentability of hydrolyzates decreased strongly for hydrolyzates produced at temperatures higher than 200 degrees C.
authors.affiliation: Department of Chemical Engineering, Lund University, P.O. Box 124, 221 00 Lund, Sweden.
authors.forename: Gladys
authors.initials: G
authors.lastname: Sanchez
authors.forename: Linda
authors.initials: L
authors.lastname: Pilcher
authors.forename: Christian
authors.initials: C
authors.lastname: Roslander
authors.forename: Tobias
authors.initials: T
authors.lastname: Modig
authors.forename: Mats
authors.initials: M
authors.lastname: Galbe
authors.forename: Gunnar
authors.initials: G
authors.lastname: Liden
mesh_terms: D001838:Bolivia; D002241:Carbohydrates / Q000032:analysis; D002482:Cellulose / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D006868:Hydrolysis; D006109:Poaceae / Q000737:chemistry*; D011134:Polysaccharides / Q000737:chemistry*; D013464:Sulfuric Acids / Q000737:chemistry*; D013696:Temperature; D013997:Time Factors; D015003:Yeasts / Q000378:metabolism
chemical_list: D002241:Carbohydrates; D011134:Polysaccharides; D013464:Sulfuric Acids; D000431:Ethanol; C007916:hemicellulose; D002482:Cellulose; C033158:sulfuric acid