Action of different types of endoxylanases on eucalyptus xylan in situ
| Autor: | Vladimír Puchart, Peter Biely, Kristian B. R. M. Krogh, Tine Hoff, Lucia Fraňová |
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| Rok vydání: | 2017 |
| Předmět: |
0106 biological sciences
0301 basic medicine Magnetic Resonance Spectroscopy 01 natural sciences Applied Microbiology and Biotechnology Esterase 03 medical and health sciences Hydrolysis 010608 biotechnology Glucuronoxylan Glycoside hydrolase Acetylxylan esterase chemistry.chemical_classification Eucalyptus Endo-1 4-beta Xylanases General Medicine Xylan 030104 developmental biology chemistry Biochemistry Spectrometry Mass Matrix-Assisted Laser Desorption-Ionization Xylanase Xylans Chromatography Thin Layer Xylooligosaccharide Biotechnology |
| Zdroj: | Applied microbiology and biotechnology. 102(4) |
| ISSN: | 1432-0614 |
| Popis: | Most studies of the mode of action of industrially important endoxylanases have been done on alkali extracted-plant xylan. In just few cases, the native form of the polysaccharide, acetylated xylan, was used as a substrate. In this work action of xylanases belonging to three glycoside hydrolase families, GH10, GH11, and GH30 was investigated on acetylglucuronoxylan directly in hardwood cell walls. Powdered eucalyptus wood was used as xylanase substrate. Enzyme-generated fragments were characterized by TLC, MALDI ToF MS, and NMR spectroscopy. All three xylanases generated from eucalyptus wood powder acetylated xylooligosaccharides. Those released by GH10 enzyme were the shortest, and those released by GH30 xylanase were of the largest diversity. For GH30 xylanase the 4-O-methyl-D-glucuronic acid (MeGlcA) side residues function as substrate specificity determinants regardless the acetylation of the neighboring hydroxyl group. Much simpler xylooligosaccharide patterns were observed when xylanases were applied in combination with carbohydrate esterase family 6 acetylxylan esterase. In the presence of the esterase, all aldouronic acids remained 3-O-acetylated on the xylopyranosyl (Xylp) residue substituted with MeGlcA. The 3-O-acetyl group, in contrast to the acetyl groups of otherwise unsubstituted Xylp residues, does not affect the mode of action of endoxylanases, but contributes to recalcitrance of the acidic xylan fragments. The results confirm importance of acetylxylan esterases in microbial degradation of acetylated hardwood glucuronoxylan. They also point to still unresolved question of efficient enzymatic removal of the 3-O-acetyl group on MeGlcA-substituted Xylp residues negatively affecting the saccharification yields. |
| Databáze: | OpenAIRE |
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