Polyol Structure Influences Enzymatic Hydrolysis of Bio-Based 2,5-Furandicarboxylic Acid (FDCA) Polyesters

Polyesters of 2,5-furandicarboxylic acid (FDCA) have gained attention as they can be regarded as the bio-based alternatives to the petroleum-based polyesters of terephthalic acid. However, only little is known about the biodegradation and enzymatic hydrolysis of FDCA-based polyesters. This work aims to investigate the influence of different polyols on enzymatic hydrolysis of FDCA-based polyesters. A series of polyesters containing various polyols are synthesized and analyzed regarding susceptibility to enzymatic hydrolysis by cutinase 1 from Thermobifida cellulosilytica (Thc_Cut1). FDCA-based polyesters' number average molecular weight (M_n ) ranged from 9360-35 800 g mol^-1 according to gel permeation chromatography (GPC) analysis. Differential scanning calorimetry (DSC) analyses show decreasing glass transition temperature (T_g ) with increasing diol chain length. Crystallinity of all polyesters is below 1% except for polyesters containing 1,6-hexanediol, 1,8-octanediol, and 1,12-dodecanediol for which calculated crystallinities are 27, 37, and 30%, respectively. Thc_Cut1 hydrolyzes all tested polyesters with preference for polyesters containing 1,5-pentanediol and 1,9-nonanediol (57.7 ± 7.5 and 52.8 ± 4.0% released FDCA). Enzyme activity increases when the linear diol 1,3-propanediol is replaced by the branched analog 1,2-propanediol or ethoxy units are introduced into the polyester chain. The results will contribute to expand the knowledge of microbial biodegradation of FDCA-based polyesters.