title: Production and characterization of ethanol- and protease-tolerant and xylooligosaccharides-producing endoxylanase from Humicola sp. Ly01.
abstract: This paper reports the production and characterization of crude xylanase from the newly isolated Humicola sp. Ly01. The highest (41.8 U/ml) production of the crude xylanase was obtained under the optimized conditions (w/v): 0.5% wheat bran, 0.2% KH2PO4, and 0.5% peptone; initial pH 7.0; incubation time 72 h; 30°C; and 150 rpm. A considerable amount of the crude xylanase was induced using hulless barley bran or soybean meal as the carbon source, but a small amount of the enzyme was produced when supplementary urea was used as the nitrogen source to wheat bran. The crude xylanase showed apparent optimal cellulase-free xylanase activity at 60°C and pH 6.0, more than 71.8% of the maximum xylanase activity in 3.0-30.0% (v/v) ethanol and more than 82.3% of the initial xylanase activity after incubation in 3.0-30.0% (v/v) ethanol at 30°C for 2 h. The crude xylanase was moderately resistant to both acid and neutral protease digestion, and released 7.9 and 10.9 μmol/ml reducing sugar from xylan in the simulated gastric and intestinal fluids, respectively. The xylooligosaccharides were the main products of the hydrolysis of xylan by the crude xylanase. These properties suggested the potential of the crude enzyme for being applied in the animal feed industry, xylooligosaccharides production, and high-alcohol conditions such as ethanol production and brewing.
authors.affiliation: Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Yunnan Normal University, Kunming 650500, PR China.
authors.forename: Junpei
authors.initials: J
authors.lastname: Zhou
authors.forename: Qian
authors.initials: Q
authors.lastname: Wu
authors.forename: Rui
authors.initials: R
authors.lastname: Zhang
authors.forename: Yuying
authors.initials: Y
authors.lastname: Yang
authors.forename: Xianghua
authors.initials: X
authors.lastname: Tang
authors.forename: Junjun
authors.initials: J
authors.lastname: Li
authors.forename: Junmei
authors.initials: J
authors.lastname: Ding
authors.forename: Yanyan
authors.initials: Y
authors.lastname: Dong
authors.forename: Zunxi
authors.initials: Z
authors.lastname: Huang
mesh_terms: D003470:Culture Media / Q000737:chemistry; D043364:Endo-1,4-beta Xylanases / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000378:metabolism*; D004795:Enzyme Stability; D000431:Ethanol / Q000378:metabolism*; D005965:Glucuronates / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D009844:Oligosaccharides / Q000378:metabolism*; D010447:Peptide Hydrolases / Q000378:metabolism*; D020037:Sordariales / Q000201:enzymology*; D013696:Temperature; D013997:Time Factors; D014990:Xylans / Q000378:metabolism
chemical_list: D003470:Culture Media; D004791:Enzyme Inhibitors; D005965:Glucuronates; D009844:Oligosaccharides; D014990:Xylans; C570991:xylooligosaccharide; D000431:Ethanol; D043364:Endo-1,4-beta Xylanases; D010447:Peptide Hydrolases