title: Effects of Impurities in Alkali-Extracted Xylan on Its Enzymatic Hydrolysis to Produce Xylo-Oligosaccharides.
abstract: As the second abundant natural carbohydrate, xylan is normally prepared through alkaline extraction and then used for xylo-oligosaccharides (XOS) production. However, the extracted xylan inevitably contains salt, ethanol, and pigment. In order to investigate the effects of these impurities on XOS production, the alkaline-extracted xylan with different kinds and concentrations of impurities was made and then hydrolyzed using alkaline xylanase (EC 3.2.1.8) to produce XOS. The results showed that a certain concentration of salt (NaCl) promoted the XOS production, while ethanol and pigment inhibited the enzymatic hydrolysis process significantly. The color value mainly ascribed to the phenolic compounds binding to xylan was a key restriction factor in the enzymatic hydrolysis later stage. Using optimal xylan sample (with 10 mg/mL NaCl, color value of 4.6 × 10(5), without ethanol) as substrate, the highest XOS yield of 58.58 % was obtained. As the substrate of XOS production, prepared xylan should contain colored materials and ethanol as less as possible, however, retains appropriate salt.
authors.affiliation: National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China.|Beijing University of Chemical Technology, Beijing, 100029, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Shen
authors.affiliation: National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China.
authors.forename: Hong-Qiang
authors.identifier: http://orcid.org/0000-0002-3858-8685
authors.initials: HQ
authors.lastname: Li
authors.affiliation: Beijing University of Chemical Technology, Beijing, 100029, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Zhang
authors.affiliation: National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China. super_xujian@yahoo.com.
authors.forename: Jian
authors.initials: J
authors.lastname: Xu
mesh_terms: D043364:Endo-1,4-beta Xylanases / Q000737:chemistry*; D000431:Ethanol / Q000737:chemistry; D006868:Hydrolysis; D009844:Oligosaccharides / Q000096:biosynthesis* / Q000737:chemistry; D010860:Pigments, Biological / Q000737:chemistry*; D012965:Sodium Chloride / Q000737:chemistry; D013696:Temperature; D014990:Xylans / Q000737:chemistry / Q000302:isolation & purification*; D014994:Xylose / Q000737:chemistry; D003313:Zea mays / Q000737:chemistry
chemical_list: D009844:Oligosaccharides; D010860:Pigments, Biological; D014990:Xylans; D000431:Ethanol; D012965:Sodium Chloride; D014994:Xylose; D043364:Endo-1,4-beta Xylanases
keywords: Enzymatic hydrolysis; Ethanol; Pigment; Sodium chloride; Xylan; Xylo-oligosaccharides