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Highly efficient enzymatic synthesis of an ascorbyl unstaturated fatty acid ester with ecofriendly biomass-derived 2-methyltetrahydrofuran as cosolvent

Authors

  • Ying-Dan Hu,

    1. State Key Laboratory of Pulp and Paper Engineering, College of Light Industry and Food Sciences, South China University of Technology, Guangzhou, China
    2. College of Biosciences and Bioengineering, South China University of Technology, Guangzhou, China
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  • Ye-Zhi Qin,

    1. State Key Laboratory of Pulp and Paper Engineering, College of Light Industry and Food Sciences, South China University of Technology, Guangzhou, China
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  • Ning Li,

    Corresponding author
    1. State Key Laboratory of Pulp and Paper Engineering, College of Light Industry and Food Sciences, South China University of Technology, Guangzhou, China
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  • Min-Hua Zong

    Corresponding author
    1. State Key Laboratory of Pulp and Paper Engineering, College of Light Industry and Food Sciences, South China University of Technology, Guangzhou, China
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  • Conflict of Interest: The authors have no conflict of interest to declare.

Abstract

Enzymatic synthesis of ascorbyl undecylenate, an unsaturated fatty acid ester of ascorbic acid, was reported with biomass-derived 2-methyltetrahydrofuran (MeTHF) as the cosolvent. Of the immobilized lipases tested, Candida antarctica lipase B (CAL-B) showed the highest activity for enzymatic synthesis of ascorbyl undecylenate. Effect of reaction media on the enzymatic reaction was studied. The cosolvent mixture, t-butanol-MeTHF (1:4, v/v) proved to be the optimal medium, in which not only ascorbic acid had moderate solubility, but also CAL-B showed a high activity, thus addressing the major problem of the solvent conflict for dissolving substrate and keeping satisfactory enzyme activity. In addition, the enzyme was much more stable in MeTHF and t-butanol-MeTHF (1:4) than in previously widely used organic solvents, t-butanol, 2-methyl-2-butanol, and acetone. The much higher initial reaction rate in this cosolvent mixture may be rationalized by the much lower apparent activation energy of this enzymatic reaction (26.6 vs. 38.1–39.1 kJ/mol) and higher enzyme catalytic efficiency (Vmax/Km, 8.4 vs. 1.3–1.4 h−1). Ascorbyl undecylenate was obtained with the yields of 84–89% and 6-regioselectivity of >99% in t-butanol-MeTHF (1:4) at supersaturated substrate concentrations (60 and 100 mM) after 5–8 h. © 2014 American Institute of Chemical Engineers Biotechnol. Prog., 30:1005–1011, 2014

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