- Characterization of Two New Endo-β-1,4-xylanases from Eupenicillium parvum 4–14 and Their Applications for Production of Feruloylated Oligosaccharides
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Two new endo-1,4-beta-xylanases encoding genes EpXyn1 and EpXyn3 were isolated from mesophilic fungus Eupenicillium parvum 4–14. Based on analysis of catalytic domain and phylogenetic trees, the xylanases EpXYN1 (404 aa) and EpXYN3 (220 aa) belong to glycoside hydrolase (GH) family 10 and 11, respectively. Both EpXYN1 and EpXYN3 were successfully expressed in Pichia pastoris and the recombinant enzymes were characterized using beechwood xylan, birchwood xylan, or oat spelt xylan as substrates, respectively. The optimum temperatures and pH values were 75?°C and 5.5 for EpXYN1, and 55?°C and 5.0 for EpXYN3. EpXYN1 exhibited a high stability at high temperature (65?°C) or at pH values from 8 to 10. EpXYN3 kept over 80% enzymatic activity after treatment at pH values from 3 to 10. The specific activities of EpXYN1 and EpXYN3 were 384.42 and 214.20?U/mg?using beechwood xylan as substrate, respectively. EpXYN1 showed lower Km values and higher specific activities toward different xylans compared to EpXYN3. Thin-layer chromatography analysis indicated that the hydrolysis profiles of xylans or xylo-oligosacharides were different by EpXYN1and EpXYN3. EpXYN3 had a higher efficiency than EpXYN1 in production of feruloylated oligosaccharides (FOs) from de-starched wheat bran. The maximum levels of FOs released by EpXYN1 and EpXYN3 were 11.1 and 14.4?μmol/g, respectively. In conclusion, the two xylanases are potential candidates for various industrial applications.
- Long, Liangkun,Xu, Meijuan,Shi, Yuexin,Lin, Qunying,Wang, Jing,Ding, Shaojun
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p. 816 - 833
(2018/05/15)
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- Xylanase XYN IV from Trichoderma reesei showing exo- and endo-xylanase activity
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A minor xylanase, named XYN IV, was purified from the cellulolytic system of the fungus Trichoderma reesei Rut C30. The enzyme was discovered on the basis of its ability to attack aldotetraohexenuronic acid (HexA-2Xyl-4Xyl-4Xyl, HexA3Xyl3), releasing the reducing-end xylose residue. XYN IV exhibited catalytic properties incompatible with previously described endo-β-1,4-xylanases of this fungus, XYN I, XYN II and XYN III, and the xylan-hydrolyzing endo-β-1,4-glucanase EG I. XYN IV was able to degrade several different β-1,4-xylans, but was inactive on β-1,4-mannans and β-1,4-glucans. It showed both exo-and endo-xylanase activity. Rhodymenan, a linear soluble β-1,3-β-1,4-xylan, was as the best substrate. Linear xylooligosaccharides were attacked exclusively at the first glycosidic linkage from the reducing end. The gene xyn4, encoding XYN IV, was also isolated. It showed clear homology with xylanases classified in glycoside hydrolase family 30, which also includes glucanases and mannanases. The xyn4 gene was expressed slightly when grown on xylose and xylitol, clearly on arabinose, arabitol, sophorose, xylobiose, xylan and cellulose, but not on glucose or sorbitol, resembling induction of other xylanolytic enzymes from T. reesei. A recombinant enzyme prepared in a Pichia pastoris expression system exhibited identical catalytic properties to the enzyme isolated from the T. reesei culture medium. The physiological role of this unique enzyme remains unknown, but it may involve liberation of xylose from the reducing end of branched oligosaccharides that are resistant toward β-xylosidase and other types of endoxylanases. In terms of its catalytic properties, XYN IV differs from bacterial GH family 30 glucuronoxylanases that recognize 4-O-methyl-d-glucuronic acid (MeGlcA) substituents as substrate specificity determinants. 2012 The Authors Journal compilation
- Tenkanen, Maija,Vrsanska, Maria,Siika-Aho, Matti,Wong, Dominic W.,Puchart, Vladimir,Penttilae, Merja,Saloheimo, Markku,Biely, Peter
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p. 285 - 301
(2013/03/28)
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- Purification, characterization and mass spectrometric identification of two thermophilic xylanases from Sporotrichum thermophile
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Two xylanases were purified to electrophoretic homogeneity from the thermophilic fungus Sporotrichum thermophile grown in a submerged liquid culture using wheat straw as carbon source. The enzymes, StXyn1 and StXyn2, have molecular masses of 24 kDa and 48 kDa, respectively, and are optimally active at pH 5 and at 60 °C. Both enzymes displayed remarkable stability up to 50 °C for 1 h, exhibiting a half-life of 60 min (StXyn1) and 115 min (StXyn2) at 60 °C. Biochemical characterization of the two xylanases against poly- and oligosaccharides indicated that StXyn1 and StXyn2 hydrolytic profiles match those of xylanase family 11 and family 10, respectively. LC-MS/MS analysis provided peptide mass and sequence information that assisted the identification of the corresponding xylanase genes from the S. thermophile genome and the classification of the two purified StXyn1 and StXyn2 as a family GH11 and GH10 endo-1,4-β-xylanases, respectively.
- Vafiadi, Christina,Christakopoulos, Paul,Topakas, Evangelos
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experimental part
p. 419 - 424
(2011/10/31)
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- Biochemical and catalytic properties of an endoxylanase purified from the culture filtrate of Sporotrichum thermophile
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An endo-β-1,4-xylanase (1,4-β-D-xylan xylanoxydrolase, EC 3.2.1.8) present in culture filtrates of Sporotrichum thermophile ATCC 34628 was purified to homogeneity by Q-Sepharose and Sephacryl S-200 column chromatographies. The enzyme has a molecular mass of 25,000 Da, an isoelectric point of 6.7, and is optimally active at pH 5 and at 70°C. Thin-layer chromatography (TLC) analysis showed that endo-xylanase liberates mainly xylose (Xyl) and xylobiose (Xyl2) from beechwood 4-O-methyl-D-glucuronoxylan, O-acetyl-4-O-methylglucuronoxylan and rhodymenan (a β-(1→4)-β(1→3)-xylan). Also, the enzyme releases an acidic xylo-oligosaccharide from 4-O-methyl-D-glucuronoxylan, and an isomeric xylotetraose and an isomeric xylopentaose from rhodymenan. Analysis of reaction mixtures by high performance liquid chromatography (HPLC) revealed that the enzyme cleaves preferentially the internal glycosidic bonds of xylooligosaccharides, [1-3H]-xylooligosaccharides and xylan. The enzyme also hydrolyses the 4-methylumbelliferyl glycosides of β-xylobiose and β-xylotriose at the second glycosidic bond adjacent to the aglycon. The endoxylanase is not active on pNPX and pNPC. The enzyme mediates a decrease in the viscosity of xylan associated with a release of only small amounts of reducing sugar. The enzyme is irreversibly inhibited by series of ω-epoxyalkyl glycosides of D-xylopyranose. The results suggest that the endoxylanase from S. thermophile has catalytic properties similar to the enzymes belonging to family 11.
- Katapodis, Petros,Vrsanska, Maria,Kekos, Dimitris,Nerinckx, Wim,Biely, Peter,Claeyssens, Marc,Macris, Basil J.,Christakopoulos, Paul
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p. 1881 - 1890
(2007/10/03)
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- Hydrolysis of (1->3)- and (1->2)-β-D-xylosidic linkages by an endo-(1->4)-β-D-xylanase of Cryptococcus albidus
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The substrate specificity of an endo-(1->4)-β-D-xylanase of the yeast Cryptococcus albidus was investigated using a series of methyl β-D-xylotriosides.In addition to (1->4) linkages, the enzyme could cleave (1->3) and (1->2) linkages adjacent to a (1->4) linkage and further from the non-reducing end of the substrate.The enzyme could hydrolyse a (1->3) linkage that attached a terminal xylopyranosyl group to a (1->4)-linked xylobiosyl moiety.The enzyme did not attack α-D-xylosidic linkages.The rate of cleavage of (1->4) linkages was much higher than those of other linkages at 0.5 mM substrate, but the rates were comparable at 20 mM substrate when transglycosylation reactions also occurred that facilitated degradation of the substrates.
- Vrsanska, Maria,Hirsch, Jan,Kovac, Pavol,Biely, Peter
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p. 251 - 256
(2007/10/02)
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