Biobased and Biodegradable Furandicarboxylate Polyesters: Linking Molecular Structure to Enzymatic Hydrolyzability

Area of Science:

• Polymer Chemistry
• Biotechnology
• Materials Science

Background:

• Enzymatic hydrolysis is the rate-limiting step in polyester biodegradation.
• Biobased and biodegradable polyesters are essential for a circular polymer economy.
• Understanding esterase activity on diverse copolyesters is key to designing effective materials.

Purpose of the Study:

• To investigate the enzymatic hydrolysis of 30 aliphatic-aromatic copolyesters using Humicola insolens cutinase (HiC) and Rhizopus oryzae lipase (RoL).
• To determine how monomer composition, specifically the type and content of aromatic diacids (biobased F vs. fossil-derived T), affects hydrolytic activity.
• To identify structural features that enhance or hinder polyester biodegradability.

Main Methods:

• Synthesized 30 aliphatic-aromatic copolyesters with varying monomer compositions, including biobased 2,5-furandicarboxylic acid (F) and terephthalic acid (T).
• Assessed the hydrolytic activity of two esterases, Humicola insolens cutinase (HiC) and Rhizopus oryzae lipase (RoL), on the synthesized copolyesters.
• Correlated copolyester chemical structure (aromatic content, diacid/diol chain lengths) with enzymatic hydrolysis rates.

Main Results:

• Increasing aromatic diacid content significantly decreased enzymatic hydrolysis rates for all tested copolyesters.
• F-containing copolyesters demonstrated higher hydrolyzability compared to T-analogues at equivalent aromatic diacid content.
• Hydrolytic susceptibility was influenced by aliphatic chain lengths, with shorter diols and longer diacids favoring hydrolysis.
• HiC exhibited broad enzymatic activity, while RoL showed activity primarily on low-aromatic content polyesters.

Conclusions:

• The chemical structure of biobased polyesters, particularly the type and proportion of aromatic diacids, critically impacts their enzymatic biodegradability.
• Biobased 2,5-furandicarboxylic acid offers a more readily hydrolyzable alternative to fossil-derived terephthalic acid in copolyester design.
• These findings provide valuable insights for designing novel biobased polyesters with tailored biodegradability for circular economy applications.