title: Low temperature alkali pretreatment for improving enzymatic digestibility of sweet sorghum bagasse for ethanol production.
abstract: A low temperature alkali pretreatment method was proposed for improving the enzymatic hydrolysis efficiency of lignocellulosic biomass for ethanol production. The effects of the pretreatment on the composition, structure and enzymatic digestibility of sweet sorghum bagasse were investigated. The mechanisms involved in the digestibility improvement were discussed with regard to the major factors contributing to the biomass recalcitrance. The pretreatment caused slight glucan loss but significantly reduced the lignin and xylan contents of the bagasse. Changes in cellulose crystal structure occurred under certain treatment conditions. The pretreated bagasse exhibited greatly improved enzymatic digestibility, with 24-h glucan saccharification yield reaching as high as 98% using commercially available cellulase and β-glucosidase. The digestibility improvement was largely attributed to the disruption of the lignin-carbohydrate matrix. The bagasse from a brown midrib (BMR) mutant was more susceptible to the pretreatment than a non-BMR variety tested, and consequently gave higher efficiency of enzymatic hydrolysis.
authors.affiliation: Carbohydrate Laboratory, Food Resource Division, National Food Research Institute, National Agriculture and Food Research Organization (NARO), 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642, Japan.
authors.forename: Long
authors.initials: L
authors.lastname: Wu
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Arakane
authors.forename: Masakazu
authors.initials: M
authors.lastname: Ike
authors.forename: Masahisa
authors.initials: M
authors.lastname: Wada
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Takai
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Gau
authors.forename: Ken
authors.initials: K
authors.lastname: Tokuyasu
mesh_terms: D056804:Biofuels; D002480:Cellulase / Q000378:metabolism; D002482:Cellulose / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D003080:Cold Temperature; D000431:Ethanol; D006868:Hydrolysis; D008031:Lignin / Q000378:metabolism*; D045868:Sorghum / Q000378:metabolism*; D013464:Sulfuric Acids; D014961:X-Ray Diffraction; D014990:Xylans / Q000378:metabolism; D001616:beta-Galactosidase / Q000378:metabolism
chemical_list: D056804:Biofuels; D013464:Sulfuric Acids; D014990:Xylans; C036909:lignocellulose; D000431:Ethanol; D002482:Cellulose; D008031:Lignin; C027433:bagasse; D001616:beta-Galactosidase; D002480:Cellulase; C033158:sulfuric acid