title: Step enzymatic hydrolysis of sodium hydroxide-pretreated Chinese liquor distillers' grains for ethanol production.
abstract: Distillers' grains are a co-product of ethanol production. In China, only a small portion of distillers' grains have been used to feed the livestock because the amount was so huge. Nowadays, it has been reported that the distillers' grains have the potential for fuel ethanol production because they are composed of lignocelluloses and residual starch. In order to effectively convert distillers' grains to fuel ethanol and other valuable production, sodium hydroxide pretreatment, step-by-step enzymatic hydrolysis, and simultaneous saccharification and fermentation (SSF) were investigated. The residual starch was first recycled from wet distillers' grains (WDG) with glucoamylase to obtain glucose-rich liquid. The total sugar concentration was 21.3 g/L, and 111.9% theoretical starch was hydrolyzed. Then the removed-starch dry distillers' grains (RDDG) were pretreated with NaOH under optimal conditions and the pretreated dry distillers' grains (PDDG) were used for xylanase hydrolysis. The xylose concentration was 19.4 g/L and 68.6% theoretical xylose was hydrolyzed. The cellulose-enriched dry distillers' grains (CDDG) obtained from xylanase hydrolysis were used in SSF for ethanol production. The ethanol concentration was 42.1 g/L and the ethanol productivity was 28.7 g/100 g CDDG. After the experiment, approximately 80.6% of the fermentable sugars in WDG was converted to ethanol.
authors.affiliation: a College of Light Industry, Textile and Food Engineering, Sichuan University , Chengdu , Sichuan , China.
authors.forename: Yue-Hong
authors.initials: YH
authors.lastname: Liu
authors.forename: Zheng-Yun
authors.initials: ZY
authors.lastname: Wu
authors.forename: Jian
authors.initials: J
authors.lastname: Yang
authors.forename: Yu-Ju
authors.initials: YJ
authors.lastname: Yuan
authors.forename: Wen-Xue
authors.initials: WX
authors.lastname: Zhang
mesh_terms: D056804:Biofuels / Q000032:analysis; D001709:Biotechnology; D002523:Edible Grain / Q000378:metabolism*; D043364:Endo-1,4-beta Xylanases / Q000378:metabolism; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D005947:Glucose / Q000378:metabolism; D006868:Hydrolysis; D008031:Lignin / Q000378:metabolism; D012972:Sodium Hydroxide / Q000378:metabolism*; D013213:Starch / Q000378:metabolism; D014994:Xylose / Q000378:metabolism
chemical_list: D056804:Biofuels; C036909:lignocellulose; D000431:Ethanol; D012972:Sodium Hydroxide; D013213:Starch; D008031:Lignin; D014994:Xylose; D043364:Endo-1,4-beta Xylanases; D005947:Glucose