Hydrolysis rate and mechanism of water-dispersed polyesters with different sulfonate group contents in the cutinase-catalyzed system

Water-dispersed polyester (WPET) has irreplaceable and wide application prospects in the textile field, but it is easy to form printing and dyeing wastewater during traditional fabric treatment. In this paper, cutinase-catalyzed green hydrolysis of WPET was achieved. The main purpose of this paper is to study the difference between two PEG-free WPETs with different -SO₃^- content in the cutinase-catalyzed hydrolysis process. Differences in solution properties, enzyme activity, SSIPA, and TPA release as well as functional groups and thermal properties of the hydrolysis products of the systems during cutinase hydrolysis were analyzed in detail for 14.1 % S-0 % PEG and 9.5 % S-0 % PEG. Results show that the structure of WPET has an influential effect on its hydrolysis rate in cutinase-catalyzed systems, which mainly originates from the -SO₃^- content. SSIPA released by WPET during hydrolysis has an inhibitory effect on cutinase enzyme activity. The hydrolysis process of WPET with higher -SO₃^- content releases more SSIPA, which in turn inhibits the enzyme activity of cutinase in the reaction system, ultimately leading to a slower hydrolysis rate of WPET. These findings provide new ideas for cutinase to target WPETs with different structures and are important for the green development of the textile industry.