Post-Synthetic Enzymatic and Chemical Modifications for Novel Sustainable Polyesters

Fady Abd El-Malek,Alexander Steinbüchel

doi:10.3389/fbioe.2021.817023

Fady Abd El-Malek, Alexander Steinbüchel

Open Access

https://doi.org/10.3389/fbioe.2021.817023

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Abstract

Because of their biodegradability, compostability, compatibility and flexible structures, biodegradable polymers such as polyhydroxyalkanoates (PHA) are an important class of biopolymers with various industrial and biological uses. PHAs are thermoplastic polyesters with a limited processability due to their low heat resistance. Furthermore, due to their high crystallinity, some PHAs are stiff and brittle. These features result sometimes in very poor mechanical characteristics with low extension at break values which limit the application range of some natural PHAs. Several in vivo approaches for PHA copolymer modifications range from polymer production to enhance PHA-based material performance after synthesis. The methods for enzymatic and chemical polymer modifications are aiming at modifying the structures of the polyesters and thereby their characteristics while retaining the biodegradability. This survey illustrates the efficient use of enzymes and chemicals in post-synthetic PHA modifications, offering insights on these green techniques for modifying and improving polymer performance. Important studies in this sector will be reviewed, as well as chances and obstacles for their stability and hyper-production.

Highlights

PHAs are biodegradable polyesters with a wide range of building blocks
We focused our efforts for alternate methods on the generation of new PHAs by polymer modification to extend the spectrum of PHAs applications
The crystallinity, porosity, molecular weight, roughness and monomer composition of the polymer surface are among the factors that contribute to the enzymatic degradation of PHA films (Ansari and Amirul, 2013)

Summary

Introduction

PHAs are biodegradable polyesters with a wide range of building blocks. PHAs became quite attractive, as they have similar thermal and material properties like conventional thermoplastics (Abd El-malek et al, 2020; Abd El-malek et al, 2021). The excellent connection between the hydrophobic surface of the PHB nanoparticle and the PHB chain produced by the enzyme fused with a particular ligand, offered a straight forward method of functionalizing nanoparticles with active protein layers in an aqueous environment. The crystallinity, porosity, molecular weight, roughness and monomer composition of the polymer surface are among the factors that contribute to the enzymatic degradation of PHA films (Ansari and Amirul, 2013).

Results

Conclusion