Covalently Immobilized Lipase on a Thermoresponsive Polymer with an Upper Critical Solution Temperature as an Efficient and Recyclable Asymmetric Catalyst in Aqueous Media

Abstract

A thermoresponsive lipase catalyst with an upper critical solution temperature (UCST) of about 26 °C was exploited by covalent immobilization of an enzyme, Pseudomonas cepacia lipase (PSL), onto poly(acrylamide‐co‐acrylonitrile) by glutaraldehyde coupling. The experimental conditions for the PSL immobilization were optimized. The immobilized PSL was much more stable for wide ranges of temperature and pH than free PSL. The material was also evaluated as an asymmetric catalyst in the kinetic resolution of racemic α‐methylbenzyl butyrate at 55 °C in an aqueous medium and exhibited high catalytic performance and stability. Up to 50 % conversion and 99.5 % product enantiomeric excess were achieved, thus providing highly pure enantiomers. This biocatalyst could be easily recovered by simple decantation for reuse based on temperature‐induced precipitation. It showed good reusability and retained 80.5 % of its original activity with a well reserved enantioselectivity in the 6th cycle. This work would shed light on the future development of new UCST‐type enzyme catalysts.

Polymer supports for the removal and degradation of hazardous organic pollutants: an overview

“…and chemical characteristics (various types of functional groups, spacer groups and amino acid residues, among others) . In recent years, the most commonly used supports are those that have amino, epoxide, glutaraldehyde and carbonyl groups . These supports have been synthesized according to the applications of the processes, but they can also be commercially available as are Eupergit C or Sepabeads…”

Fluorescent Labeling Method Re-Evaluates the Intriguing Thermoresponsive Behavior of Poly(acrylamide-co-acrylonitrile)s with Upper Critical Solution Temperatures

“…Such polymers have been employed in many applications, − such as in thermal sensing, , separation analysis, , drug delivery, , tissue engineering, and cell culturing . Recently, polymers with UCSTs have attracted much attention from polymer chemists. − The thermoresponsive properties of UCST-type polymers, for example, solubility, flexibility, and isolability at higher temperatures, are more suitable for applications such as drug delivery systems combined with hyperthermia − or careers of catalysts that show maximum reactivities at higher temperatures. , …”

“…This is a great advantage for use in cosmetics because sweat cannot influence the UCST behavior of the polymer. In the recent literature (published after 2014), these advantages of poly­(AAm- co -AN) have been extensively utilized for biological applications as drug delivery system − , and other applications. ,, …”

“…26−28 The thermoresponsive properties of UCST-type polymers, for example, solubility, flexibility, and isolability at higher temperatures, are more suitable for applications such as drug delivery systems combined with hyperthermia 29−33 or careers of catalysts that show maximum reactivities at higher temperatures. 34,35 We considered a UCST-type polymer, poly(acrylamide-coacrylonitrile) (poly(AAm-co-AN) (see Figure 1)), which was first reported by Seuring and Agarwal in 2012, 36 as a good candidate for incorporation into cosmetics for the following reasons. (1) The dramatic increase in their water solubility with increasing temperature is useful for the development of novel cosmetics that offer long-lasting durability at ambient temperature and washability with hot water.…”

“…In the recent literature (published after 2014), these advantages of poly(AAm-co-AN) have been extensively utilized for biological applications 41 as drug delivery system [29][30][31][32]42 and other applications. 34,35,43 Although the use of poly(AAm-co-AN)s appears promising, with many reported applications, 29−32,34,35,41−43 the fundamental aspects of the polymers (e.g., the synthetic procedure, methods for determining unit ratios, and effects of molecular weight on thermal responses) are not fully understood, and some discrepancies have been reported. In the present study, we first established a method for synthesizing poly(AAm-co-AN)s with controllable UCSTs by precisely controlling the amount of AN units in the prepared polymer.…”