title: Improvement of trans-sialylation versus hydrolysis activity of an engineered sialidase from Trypanosoma rangeli by use of co-solvents.
abstract: Biocatalytic trans-sialylation is relevant for the design of biomimetic oligosaccharides such as human milk oligosaccharides. t-Butanol and ionic liquids, EAN (ethylammonium nitrate), [MMIm][MeSO4] (1,3-dimethylimidazolium methyl sulfate), and [C2OHMIm][PF6] (1-(2-hydroxyethyl)-3-methylimidazolium hexafluorophosphate), were examined as co-solvents for the improvement of the synthesis versus hydrolysis ratio in the trans-sialylation of lactose, catalysed by an engineered sialidase from Trypanosoma rangeli. The use of 25 % (v/v) t-butanol as co-solvent significantly increased 3'-sialyllactose production by 40 % from 1.04 ± 0.09 to 1.47 ± 0.01 mM. The synthesis versus hydrolysis ratio increased correspondingly by 1.2-times. 1-2.5 % (v/v) EAN or [C2OHMIm][PF6] improved the synthesis versus hydrolysis ratio up to 2.5-times but simultaneously decreased the 3'-sialyllactose yield, probably due to enzyme inactivation caused by the ionic liquid. [MMIm][MeSO4] had a detrimental effect on the trans-sialylation yield and on the ratio between synthesis and hydrolysis.
authors.affiliation: Center for BioProcess Engineering, Department of Chemical and Biochemical Engineering, Technical University of Denmark, Building 229, 2800 Kgs., Lyngby, Denmark.
authors.forename: Birgitte
authors.initials: B
authors.lastname: Zeuner
authors.forename: Anders
authors.initials: A
authors.lastname: Riisager
authors.forename: Jørn Dalgaard
authors.initials: JD
authors.lastname: Mikkelsen
authors.forename: Anne S
authors.initials: AS
authors.lastname: Meyer
mesh_terms: D006868:Hydrolysis; D009439:Neuraminidase / Q000235:genetics / Q000378:metabolism*; D009844:Oligosaccharides / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012997:Solvents; D057509:Trypanosoma rangeli / Q000235:genetics / Q000378:metabolism*
chemical_list: C421467:3'-sialyllactose; D009844:Oligosaccharides; D011994:Recombinant Proteins; D012997:Solvents; D009439:Neuraminidase