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Issue 69, 2016, Issue in Progress
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Vinyl sulfone-activated silica for efficient covalent immobilization of alkaline unstable enzymes: application to levansucrase for fructooligosaccharide synthesis

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Abstract

Most methodologies for covalent immobilization of enzymes usually take place at high pH values to enhance the nucleophilicity of protein reactive residues; however, many enzymes inactivate during the immobilization process due to their intrinsic instability at alkaline pH values. Vinyl sulfone (VS)-activated carriers may react with several protein side-chains at neutral pHs. In this work, levansucrase-an alkaline unstable enzyme of technological interest because it forms fructooligosaccharides (FOS) and levan from sucrose-was covalently attached to VS-activated silica at pH 7.0 in a short time (5 h). Theoretical immobilization yields were close to 95% but the apparent activity did not surpass 25%, probably due to random attachment with unproductive orientations and rigidification of the enzyme structure. Due to diffusional hindrance and/or local microenvironmental effects caused by the silica surface, the immobilized levansucrase was unable to produce levan but synthesized a similar amount of FOS than the free enzyme [95 g L−1 in 28 h, with a major contribution of FOS of the β(2 → 1) type]. The VS-activated biocatalysts showed a notable operational stability in batch reactors.

Graphical abstract: Vinyl sulfone-activated silica for efficient covalent immobilization of alkaline unstable enzymes: application to levansucrase for fructooligosaccharide synthesis

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Publication details

The article was received on 31 May 2016, accepted on 28 Jun 2016 and first published on 29 Jun 2016


Article type: Paper
DOI: 10.1039/C6RA14046G
RSC Adv., 2016,6, 64175-64181

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    Vinyl sulfone-activated silica for efficient covalent immobilization of alkaline unstable enzymes: application to levansucrase for fructooligosaccharide synthesis

    P. Santos-Moriano, L. Monsalve-Ledesma, M. Ortega-Muñoz, L. Fernandez-Arrojo, A. O. Ballesteros, F. Santoyo-Gonzalez and F. J. Plou, RSC Adv., 2016, 6, 64175
    DOI: 10.1039/C6RA14046G

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