Polyol Structure and Ionic Moieties Influence the Hydrolytic Stability and Enzymatic Hydrolysis of Bio-Based 2,5-Furandicarboxylic Acid (FDCA) Copolyesters

Abstract

A series of copolyesters based on furanic acid and sulfonated isophthalic acid with various polyols were synthetized and their susceptibility to enzymatic hydrolysis by cutinase 1 from Thermobifida cellulosilytica (Thc_Cut1) investigated. All copolyesters consisted of 30 mol % 5-sulfoisophthalate units (NaSIP) and 70 mol % 2,5-furandicarboxylic acid (FDCA), while the polyol component was varied, including 1,2-ethanediol, 1,4-butanediol, 1,8-octanediol, diethylene glycol, triethylene glycol, or tetraethylene glycol. The composition of the copolyesters was confirmed by 1 H-NMR and the number average molecular weight (M n ) was determined by GPC to range from 2630 to 8030 g/mol. A DSC analysis revealed glass-transition temperatures (T g ) from 84 to 6 • C, which were decreasing with increasing diol chain length. The crystallinity was below 1% for all polyesters. The hydrolytic stability increased with the chain length of the alkyl diol unit, while it was generally higher for the ether diol units. Thc_Cut1 was able to hydrolyze all of the copolyesters containing alkyl diols ranging from two to eight carbon chain lengths, while the highest activities were detected for the shorter chain lengths with an amount of 13.6 ± 0.7 mM FDCA released after 72 h of incubation at 50 • C. Faster hydrolysis was observed when replacing an alkyl diol by ether diols, as indicated, e.g., by a fivefold higher release of FDCA for triethylene glycol when compared to 1,8-octanediol. A positive influence of introducing ionic phthalic acid was observed while the enzyme preferentially cleaved ester bonds associated to the non-charged building blocks.

Biobased Poly(ethylene 2,5-furancoate): No Longer an Alternative, but an Irreplaceable Polyester in the Polymer Industry

“…This result was consistent with the higher crystallinity of PEF and PLA, which made their ester bonds inaccessible to hydrolysis. Haernvall 135 synthesized a series of furan-based copolyesters with different polyols. Very interestingly, they found that when they replaced the linear diols with branched ones or incorporated ethoxy units into the polymer chain, the enzyme activity was doubled.…”

Structure–Activity Relationship of Polyester-Based Cationic Polyrotaxane Vector-Mediated In Vitro siRNA Delivery: Effect on Gene Silencing Efficiency

“…Another reason for this large difference in the MW determined by the two techniques was the aggregation characteristics of the polyols. The formation of aggregates resulted in a larger average size of the polyol molecule and was thus detected by GPC as a higher-MW polyol …”

“…The formation of aggregates resulted in a larger average size of the polyol molecule and was thus detected by GPC as a higher-MW polyol. 55 3.2. Amination of the Polyester Polyols.…”

Back-to-monomer recycling of polycondensation polymers: opportunities for chemicals and enzymes

“…The enzyme Thc_Cut1 is capable of hydrolysing polyesters with a preferred cleavage of ester bonds in the vicinity of the non-charged building blocks. 201 The effect of molecular mass, particle size and crystallinity of the PEF polyester (powders and amorphous lms) on enzymatic hydrolysis was investigated using different cutinases from Thermobida cellulosilytica (Thc_Cut1) and Humicola insolens (HiC). The enzyme Thc_Cut1 efficiently hydrolysed PEF powders with low molecular masses (M n 18 kg mol À1 ) and low crystallinity compared to higher MWs (M n 55 kg mol À1 ) and higher crystallinity.…”

“…The enzyme Thc_Cut1 is capable of hydrolysing polyesters with a preferred cleavage of ester bonds in the vicinity of the non-charged building blocks. 201 …”