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One‐pot lipase‐catalyzed esterification of ε‐caprolactone with methyl‐ d ‐glucopyranoside and its elongation with free 6‐hydroxyhexanoate monomer units
Author(s) -
Saat Muhammad Naziz,
Mohamad Annuar Mohamad Suffian
Publication year - 2020
Publication title -
biotechnology and applied biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.468
H-Index - 70
eISSN - 1470-8744
pISSN - 0885-4513
DOI - 10.1002/bab.1859
Subject(s) - monomer , lipase , elongation , chemistry , triacylglycerol lipase , catalysis , caprolactone , enzyme , organic chemistry , polymer , polymerization , materials science , metallurgy , ultimate tensile strength
One‐pot synthesis of sugar‐functionalized oligomeric caprolactone was carried out by lipase‐catalyzed esterification of ε‐caprolactone (ECL) with methyl‐ d ‐glucopyranoside (MGP) followed by the elongation of functionalized oligomer chain. Functionalization was performed in a custom‐fabricated glass reactor equipped with Rushton turbine impeller and controlled temperature at 60 °C using tert ‐butanol as reaction medium. The overall reaction steps include MGP esterification of ECL monomer and its subsequent elongation by free 6‐hydroxyhexanoate monomer units. A ping‐pong bi‐bi mechanism without ternary complex was proposed for esterification of ECL and MGP with apparent values of kinetic constant, namely maximal velocity ( V max ), Michaelis constant for MGP ( K mMGP ), and Michaelis constant for ECL ( K mECL ) at 3.848 × 10 −3 M H −1 , 8.189 × 10 −2 M, and 6.050 M, respectively. Chain propagation step of MGP‐functionalized ECL oligomer exhibits the properties of living polymerization mechanism. Linear relationship between conversion (%) and number average molecular weight, M n (g mol −1 ), of functionalized oligomer was observed. Synthesized functionalized oligomer showed narrow range of molecular weight from 1,400 to 1,600 g mol −1 with more than 90% conversion achieved. Structural analysis confirmed the presence of covalent bond between the hydroxyl group in MGP with carboxyl end group of ECL oligomer.