title: Enhanced enzymatic hydrolysis of pretreated almond-tree prunings for sugar production.
abstract: Almond-tree prunings (ATP), an agricultural residue largely available in Mediterranean countries, were pretreated with either hot water or dilute sulphuric acid at 180-230 °C. Solids derived from hot water pretreatments were further submitted to alkaline peroxide delignification. In addition, all solids obtained from the three mentioned processes were hydrolysed by cellulases and β-glucosidases to investigate their enzymatic digestibilities. Hot water pretreatment led to high oligosaccharide yields (18.2 g/100 g ATP at 190 °C) while dilute acid pretreatment provided the highest monosaccharide yields (24.0 g/100 g ATP at 190 °C) along with low concentrations of fermentation inhibitors. Glucose yields from enzymatic hydrolysis were strongly affected by both pretreatment type and pretreatment temperature. The highest temperature assayed for both hydrothermal and dilute sulphuric acid pretreatment maximized the glucose recovery (49.2% and 72.8%, respectively) while solids derived from alkaline peroxide treatment achieved maximal glucose concentrations (41.9 g/L, 58.4% of potential yield).
authors.affiliation: Department of Chemical, Environmental and Materials Engineering, University of Jaén, Campus 'Las Lagunillas', 23071 Jaén, Spain. Electronic address: mcuevas@ujaen.es.
authors.forename: Manuel
authors.initials: M
authors.lastname: Cuevas
authors.forename: Juan Francisco
authors.initials: JF
authors.lastname: García
authors.forename: Sebastián
authors.initials: S
authors.lastname: Sánchez
mesh_terms: D044602:Cellulases / Q000737:chemistry*; D002482:Cellulose / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D005947:Glucose / Q000302:isolation & purification*; D006358:Hot Temperature; D006861:Hydrogen Peroxide / Q000737:chemistry; D006868:Hydrolysis; D009005:Monosaccharides / Q000737:chemistry / Q000302:isolation & purification; D009844:Oligosaccharides / Q000737:chemistry / Q000302:isolation & purification; D027861:Prunus / Q000737:chemistry*; D012972:Sodium Hydroxide / Q000737:chemistry; D012995:Solubility; D013464:Sulfuric Acids / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D009005:Monosaccharides; D009844:Oligosaccharides; D013464:Sulfuric Acids; D014867:Water; D012972:Sodium Hydroxide; D002482:Cellulose; D006861:Hydrogen Peroxide; D044602:Cellulases; D005947:Glucose; C033158:sulfuric acid
keywords: Almond-tree prunings; Delignification; Dilute acid pretreatment; Enzymatic hydrolysis; Hydrothermal pretreatment