Publications (2)0 Total impact
Article: Ring-opening polymerization of ɛ-caprolactone catalyzed by a novel thermophilic lipase from Fervidobacterium nodosum[show abstract] [hide abstract]
ABSTRACT: The paper explored the catalytic activity of a novel thermophilic lipase from Fervidobacterium nodosum for polyester synthesis, using the ring-opening polymerization of ɛ-caprolactone as the model. Effects of enzyme concentration, reaction medium, temperature and reaction time on monomer conversion, product molecular weight and distribution were systematically investigated. Remarkably, the enzyme could be effectively performed at high temperatures, and showed the highest activity towards the polymerization of ɛ-caprolactone at 90 °C. Through the optimization of reaction conditions, poly(ɛ-caprolactone) was obtained in almost 100% monomer conversion, with a number-average molecular weight of 2340 g/mol and a polydispersity index of 1.34 in toluene at 90 °C for 72 h. Michaelis–Menten kinetic analysis indicated that compared with Candida antarctica lipase B, the enzyme had higher affinity for ɛ-caprolactone with a Km value of 0.35 mol/L. Furthermore, the possible structural and energetic basis of the interaction of enzyme and the monomer ɛ-caprolactone was elucidated using molecular docking.Process Biochemistry. 46(1):253-257.
Article: Highly efficient ring-opening polymerization of ɛ-caprolactone catalyzed by a recombinant Escherichia coli whole-cell biocatalyst[show abstract] [hide abstract]
ABSTRACT: This paper discussed the use of a recombinant Escherichia coli whole-cell biocatalyst harboring a thermophilic lipase gene from Fervidobacterium nodosum in the catalytic synthesis of polyesters. The ring-opening polymerization of ɛ-caprolactone was used as a model reaction to study the effects of temperature and reaction medium on monomer conversion and the molecular weight of the product. The whole-cell biocatalyst displayed high catalytic activity at high temperatures (70–90 °C), with almost 100% monomer conversion. Meanwhile, high monomer conversion values (>97%) were achieved in both hydrophobic and hydrophilic solvents, with the exception of dichloromethane (85%). Poly(ɛ-caprolactone) was obtained in 100% monomer conversion, with a number-average molecular weight of 2000 g/mol and a polydispersity index of 1.47 in cyclohexane at 70 °C for 72 h. Furthermore, the whole-cell biocatalyst exhibited excellent operational stability, with monomer conversion values exceeding 90% over the course of 10 batch reactions. To verify the practicality of the procedure, scale-up reaction was also performed with isolated yield and number-average molecular weight of ca. 70% and 2140 g/mol, respectively.Process Biochemistry.