Synthesis of Cellulose Hexanoate, Benzoate, and Mixed Esters: Exploring Their Potential as Enzyme Immobilization Platforms

TL;DR

This paper explores using cellulose esters to immobilize enzymes for biocatalysis, finding that spherical structures perform better than mats.

Contribution

The first study to explore cellulose esters for immobilizing Pseudomonas fluorescens lipase to resolve racemic mixtures.

Findings

PFL-incorporated spheres achieved 40% conversion with 94% enantiomeric purity.

Mat-layered structures without voltage nearly doubled conversion rates compared to mats alone.

Electrospun mats showed poor catalytic activity due to enzyme deactivation.

Abstract

This study utilizes cellulose sourced from cotton linters to synthesize cellulose esters—hexanoate, benzoate, and mixed hexanoate‐benzoate—with varying degrees of substitution (DS). These esters create electrospun mats that immobilize Pseudomonas fluorescens lipase (PFL), also in a configuration where an intermediate layer is added to a mat using an airbrush filled with PFL, covered by a third layer of electrospun mat. PFL‐incorporated spheres are produced from cellulose ester solutions. DS, acyl chain length, and electrospinning parameters influence the morphology of the electrospun mat, which consists of nanofibers and ultrafine fibers. The PFL‐incorporated mats show poor catalytic activity in resolving racemic (R,S)‐2‐chloro‐1‐phenylethanol, likely due to enzyme deactivation from high‐voltage electrospinning. In contrast, mat‐layered structures with PFL immobilized without voltage nearly doubled the conversion rate, although it was still lower than that of free enzymes. Spheres enhanced biocatalysis, achieving a 40% conversion rate with 94% enantiomeric purity while retaining 76% of their initial conversion rate in a subsequent reaction cycle. This research is the first to explore cellulose esters for the enzymatic immobilization of PFL to resolve a racemic mixture. The findings may enable PFL‐incorporated structures in broader biocatalysis applications; the materials created may be tested to support the immobilization of other enzymes.

Cellulose sourced from cotton linters was utilized to synthesize cellulose esters, specifically hexanoate, benzoate, and a mixed hexanoate‐benzoate variant, which were evaluated as platforms for enzyme immobilization. These esters were shaped into various architectural forms, including electrospun mats, layered sandwich structures, and spherical shapes. This research underscores the potential of cellulose esters in developing advanced, recyclable platforms for enzyme immobilization.

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