Journal article
Bioconversion of xylose to xylonic acid via co-immobilized dehydrogenases for conjunct cofactor regeneration
Poznań University of Technology1
Polish Academy of Sciences2
PROSYS - Process and Systems Engineering Centre, Department of Chemical and Biochemical Engineering, Technical University of Denmark3
Department of Chemical and Biochemical Engineering, Technical University of Denmark4
Enzyme Technology, Section for Protein Chemistry and Enzyme Technology, Department of Biotechnology and Biomedicine, Technical University of Denmark5
Section for Protein Chemistry and Enzyme Technology, Department of Biotechnology and Biomedicine, Technical University of Denmark6
Department of Biotechnology and Biomedicine, Technical University of Denmark7
Enzymatic cofactor-dependent conversion of monosaccharides can be used in the bioproduction of value-added compounds. In this study, we demonstrate co-immobilization of xylose dehydrogenase (XDH, EC 1.1.1.175) and alcohol dehydrogenase (ADH, EC 1.1.1.1) using magnetite-silica core-shell particles for simultaneous conversion of xylose into xylonic acid (XA) and in situ cofactor regeneration.
The reaction conditions were optimized by factorial design, and were found to be: XDH:ADH ratio 2:1, temperature 25 °C, pH 7, and process duration 60 min. Under these conditions enzymatic production of xylonic acid exceeded 4.1 mM and was more than 25% higher than in the case of a free enzymes system.
Moreover, the pH and temperature tolerance as well as the thermo- and storage stability of the co-immobilized enzymes were significantly enhanced. Co-immobilized XDH and ADH make it possible to obtain higher xylonic acid concentration over broad ranges of pH (6-8) and temperature (15-35 °C) as compared to free enzymes, and retained over 60% of their initial activity after 20 days of storage.
In addition, the half-life of the co-immobilized system was 4.5 times longer, and the inactivation constant (kD = 0.0141 1/min) four times smaller, than those of the free biocatalysts (kD = 0.0046 1/min). Furthermore, after five reaction cycles, immobilized XDH and ADH retained over 65% of their initial properties, with a final biocatalytic productivity of 1.65 mM of xylonic acid per 1 U of co-immobilized XDH.
The results demonstrate the advantages of the use of co-immobilized enzymes over a free enzyme system in terms of enhanced activity and stability.
Language: | English |
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Year: | 2019 |
Pages: | 102747 |
ISSN: | 10902120 and 00452068 |
Types: | Journal article |
DOI: | 10.1016/j.bioorg.2019.01.043 |
ORCIDs: | Pinelo, Manuel , Meyer, Anne S. and 0000-0002-7602-7803 |