title: A study on the pretreatment of a sugarcane bagasse sample with dilute sulfuric acid.
abstract: Experiments based on a 2(3) central composite full factorial design were carried out in 200-ml stainless-steel containers to study the pretreatment, with dilute sulfuric acid, of a sugarcane bagasse sample obtained from a local sugar-alcohol mill. The independent variables selected for study were temperature, varied from 112.5°C to 157.5°C, residence time, varied from 5.0 to 35.0 min, and sulfuric acid concentration, varied from 0.0% to 3.0% (w/v). Bagasse loading of 15% (w/w) was used in all experiments. Statistical analysis of the experimental results showed that all three independent variables significantly influenced the response variables, namely the bagasse solubilization, efficiency of xylose recovery in the hemicellulosic hydrolysate, efficiency of cellulose enzymatic saccharification, and percentages of cellulose, hemicellulose, and lignin in the pretreated solids. Temperature was the factor that influenced the response variables the most, followed by acid concentration and residence time, in that order. Although harsher pretreatment conditions promoted almost complete removal of the hemicellulosic fraction, the amount of xylose recovered in the hemicellulosic hydrolysate did not exceed 61.8% of the maximum theoretical value. Cellulose enzymatic saccharification was favored by more efficient removal of hemicellulose during the pretreatment. However, detoxification of the hemicellulosic hydrolysate was necessary for better bioconversion of the sugars to ethanol.
authors.affiliation: Department of Biotechnology, Engineering College of Lorena, University of São Paulo, P.O. Box 116, CEP 12.602-810, Lorena, São Paulo, Brazil.
authors.forename: Larissa
authors.initials: L
authors.lastname: Canilha
authors.forename: Victor T O
authors.initials: VT
authors.lastname: Santos
authors.forename: George J M
authors.initials: GJ
authors.lastname: Rocha
authors.forename: João B
authors.initials: JB
authors.lastname: Almeida e Silva
authors.forename: Marco
authors.initials: M
authors.lastname: Giulietti
authors.forename: Silvio S
authors.initials: SS
authors.lastname: Silva
authors.forename: Maria G A
authors.initials: MG
authors.lastname: Felipe
authors.forename: André
authors.initials: A
authors.lastname: Ferraz
authors.forename: Adriane M F
authors.initials: AM
authors.lastname: Milagres
authors.forename: Walter
authors.initials: W
authors.lastname: Carvalho
mesh_terms: D002482:Cellulose / Q000032:analysis / Q000737:chemistry* / Q000378:metabolism; D006868:Hydrolysis; D008031:Lignin / Q000032:analysis; D011134:Polysaccharides / Q000032:analysis; D031786:Saccharum / Q000737:chemistry; D013464:Sulfuric Acids / Q000494:pharmacology*; D013696:Temperature; D014994:Xylose / Q000032:analysis
chemical_list: D011134:Polysaccharides; D013464:Sulfuric Acids; C007916:hemicellulose; D002482:Cellulose; D008031:Lignin; C027433:bagasse; D014994:Xylose; C033158:sulfuric acid