Highly efficient ring-opening polymerization of ɛ-caprolactone catalyzed by a recombinant Escherichia coli whole-cell biocatalyst

Thermophilic esterase from the archaeon Archaeoglobus fulgidus physically immobilized on hydrophobic macroporous resin: A novel biocatalyst for polyester synthesis

“…The filtrate was collected and roto-evaporated to remove dichloromethane, and the remaining viscous sample was precipitated in methanol at −20 o C. The cloudy solution was then centrifuged (8,000 rpm, 15 min), and the white precipitate was dried in a vacuum oven. The structure of PCL was identified by 1 H NMR, and the result was coincident with previous reports from our laboratory [16,22,23].…”

Biocatalytic Synthesis of Poly(δ-Valerolactone) Using a Thermophilic Esterase from Archaeoglobus fulgidus as Catalyst

“…Using ionic liquids as reaction medium, the ring-opening polymerization of δ-valerolactone with Candida antarctica lipase B (CALB) could also be realized, producing a product with a degree of polymerization of only 25 [ 11 ]. Similar to these results, previous work in our laboratory showed that a recombinant Escherichia coli whole-cell biocatalyst harboring the thermophilic lipase gene FN1333 could efficiently catalyze the ring-opening polymerization of δ-valerolactone, with monomer conversion of 97% and product M n value of 1020 g/mol at 70 °C in toluene [ 12 ]. Michaelis-Menten kinetic analysis elucidated that due to the cis conformation of the ester bond of δ-valerolactone, CALB exhibited a similar affinity ( K m = 0.73 mol/L) to ɛ-caprolactone ( K m = 0.72 mol/L); nevertheless, the k cat value for the CALB-catalyzed ring-opening polymerization of δ-valerolactone ( k cat = 35.2 s −1 ) was obviously lower than that of ɛ-caprolactone ( k cat = 72.9 s −1 ) [ 13 – 15 ].…”

Effect of ionic liquids on the structural, thermal, and in vitro degradation properties of poly(ε‐caprolactone) synthesized in the presence of Candida antarctica lipase B

“…Another feature is the chemical shift for proton from methylene groups next to the end‐functional hydroxyl groups, which appears as triplet at 3.66 ppm (q). Chemical shift, which appears as triplets at 4.16 ppm (y) was attributed to the CH 2 O of the cyclic lactone which was likely to be presented as a result of intramolecular transesterification. The triplets at 2.31 (a) and 2.38 ppm (y′) also suggested the presence of a diverse mixture of linear polymers and cyclic lactone.…”