曲拉通表面活性剂/角质酶对涤纶的水解研究OA

Polyester(polyethylene terephthalate,PET)is one of the most widely produced and extensively used synthetic fibers owing to its excellent mechanical properties,making it indispensable in the textile industry.However,the lack of hydrophilic groups in its molecular chains results in poor moisture absorption and dyeing difficulties.Conventional modification and dyeing-finishing processes for PET are typically carried out under high temperature and high pressure or with the aid of chemical auxiliaries,leading to high energy consumption and serious wastewater pollution.Meanwhile,large quantities of discarded PET products are treated by incineration or landfilling,further exacerbating environmental pressure.Enzymatic approaches,characterized by mild reaction conditions,environmental friendliness,and high specificity,show significant potential for PET surface hydrophilic modification and the degradation and recycling of waste PET.Nevertheless,the inherently low hydrolytic efficiency of native cutinases toward PET severely limits their practical application. To address these challenges,this study first established a cutinase-catalyzed PET hydrolysis system through single-factor experiments.Subsequently,a series of nonionic surfactants(Triton series)were introduced to systematically investigate the effects of Triton surfactants with different ethylene oxide(EO)chain lengths and concentrations on the release of enzymatic hydrolysis products.Finally,the underlying mechanism by which Triton enhances cutinase-catalyzed PET hydrolysis was elucidated.The results showed that the optimal conditions for cutinase hydrolysis of PET fabric were pH value of 9.0,temperature of 65℃,enzyme dosage of 500 U/mL,and reaction time of 48 h.Upon the addition of Triton surfactants,all chain lengths significantly increased product release.Among them,Triton X-45,with a shorter EO chain length and stronger hydrophobicity,exhibited the most pronounced effect,increasing product release by 229.3%after 72 h at a concentration of 0.4 g/L.High-performance liquid chromatography and infrared spectroscopy confirmed that Triton did not alter the hydrolysis pathway or product types.Further investigation revealed that the promoting effect of Triton was mainly attributed to the following factors:(i)significant stabilization of enzyme activity,with the residual activity after 72 h increasing from 65.4%to 80.7%upon addition of Triton X-45;(ii)a marked reduction in solution surface tension(from 71.53 mN/m to 27.55 mN/m),thereby decreasing enzyme aggregation at the gas-liquid interface;(iii)enhanced wettability of PET by the solution(contact angle reduced from 93.9° to 18.6°,and sedimentation time shortened from>72 h to 5 min),facilitating enzyme penetration into the fabric;and(iv)modulation of the zeta potential of the enzyme system(from-11.5 mV to-6.7 mV),weakening electrostatic repulsion between the enzyme and the negatively charged PET surface and promoting adsorption.In addition,the presence of Triton enabled cutinase to act on the crystalline regions of PET,overcoming the reaction stagnation caused by depletion of amorphous regions during enzymatic hydrolysis alone. Overall,this study proposes a surfactant-assisted enzymatic hydrolysis strategy that provides an efficient and feasible approach for the green surface modification and biocatalytic degradation-recycling of PET,offering a promising solution to the challenges associated with enzymatic PET treatment and demonstrating considerable application potential.