1. Characterization of an acetyl esterase from Myceliophthora thermophila C1 able to deacetylate xanthan
- Author
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Harry Gruppen, Bruno M. Moerschbacher, Marijn M. Kool, Henk A. Schols, Sandra W.A. Hinz, and Martin Wagenknecht
- Subjects
carbohydrate esterases ,CAZy ,Polymers and Plastics ,Stereochemistry ,Mannose ,Esterase ,chemistry.chemical_compound ,Hydrolysis ,Ascomycota ,Enzymatic hydrolysis ,Levensmiddelenchemie ,Materials Chemistry ,plant polysaccharides ,VLAG ,Food Chemistry ,biology ,Polysaccharides, Bacterial ,Organic Chemistry ,transition ,Acetylation ,families ,Carbohydrate ,biology.organism_classification ,xanthomonas-campestris ,xylan esterases ,Xanthomonas campestris ,rheological properties ,gum ,Biochemistry ,chemistry ,enzymatic-hydrolysis ,Acetylesterase ,bacterial polysaccharide xanthan ,Myceliophthora thermophila - Abstract
Screening of eight carbohydrate acetyl esterases for their activity towards xanthan resulted in the recognition of one active esterase. AXE3, a CAZy family CE1 acetyl xylan esterase originating from Myceliophthora thermophila C1, removed 31% of all acetyl groups present in xanthan after a 48 h incubation. AXE3 activity towards xanthan was only observed when xanthan molecules were in the disordered conformation. Optimal performance towards xanthan was observed at 53 °C in the complete absence of salt, a condition favouring the disordered conformation. AXE3-deacetylated xanthan was hydrolyzed using cellulases and analyzed for its repeating units using UPLC–HILIC–ELSD/ESI–MS. This showed that AXE3 specifically removes the acetyl groups positioned on the inner mannose and that acetyl groups positioned on the outer mannose are not removed at all. After a prolonged incubation at optimal conditions, 57% of all acetyl groups, representing 70% of all acetyl groups on the inner mannose units, were hydrolyzed.
- Published
- 2014
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