Probing Water-Temperature Relationships for Lipase-Catalyzed Lactone Ring-Opening Polymerizations

Abstract

Polymerizations of -CL catalyzed by Novozyme-435 (immobilized Lipase B from Candida antarctica) were studied at temperatures between 20 and 108 °C. The monomer conversion to polymer was remarkably rapid at ambient temperature. At 20 °C by 7 h, -CL conversion and product M n were >97% and 17 800, respectively. Contrary to previous reports, the number of chains formed, as well as the product molecular weight, was almost identical for polymerizations at constant enzyme water content between 60 and 108 °C. Thus, differences in reaction temperature over a 48 °C range did not "free" water from "bound" states so that it could function for chain initiation. At 60 °C, variation in the enzyme water content from 0.6 to 1.9% increased the number of chains formed but did not change the polymerization propagation kinetics. Therefore, the enzyme water content and not the reaction temperature regulated the product molecular weight. In contrast, at 108 °C, an increase in the reaction water content from 0.6 to 1.8% increased both the number of chains and the polymerization propagation kinetics. Explanations for these differences in behavior as a function of temperature and water contents are discussed.

Covalent Enzyme Immobilization onto Photopolymerized Highly Porous Monoliths

“…A specific activity of around 50-60 lmol PNPA min - . study [2] by Gross and co-workers showed that in Novozyme 435 CAL-B is agglomerated with a thickness of 100 lm on the outside of the PMMA beads (overall diameter of beads: 500 lm). The low activity observed suggests that only the CAL-B at the surface of this 100 lm layer can participate in biocatalysis.…”

“…In recent years enzymes have found widespread use in areas as diverse as chemical synthesis, [1][2][3] decontamination of waste streams, [4] and biosensors. [5,6] For ease of application and for stabilization purposes, enzymes are often immobilized on solid supports.…”

Genetically Fused T4L Acts as a Shield in Covalent Enzyme Immobilisation Enhancing the Rescued Activity

“…Such inability to retain activity upon covalent immobilisation is characteristic of many esterases [24,25]. Gross and co-workers speculated that this class of proteins tend to create a superficial layer preventing an efficient substrate diffusion [26]. As an example, the commercial catalyst NovoZyme 435 (Candida antarctica lipase-B, CAL-B) is immobilised at 82 mg enzyme /g resin but yields only 7.5% recovery activity, highlighting how this class of enzyme is particularly affected by immobilisation [27].…”

Candida antarctica Lipase B as Catalyst for Cyclic Esters Synthesis, Their Polymerization and Degradation of Aliphatic Polyesters

“…Furthermore, immobilization allows ease removal of the catalyst from reaction mixture which can be reuse even up to ten times. N-435, the most extensively studied immobilized lipase B from C. antarctica, (immobilized on acrylic resin), shows significant thermal stability, specially under elevated temperatures, even up to 100 °C [27].…”