Effect of surfactants on enzymatic hydrolysis of PET

Enzyme is difficult to adsorb on the surface of high-crystallinity poly(ethylene terephthalate) fibers (PET,crystallinity of 48.56 %) due to the high hydrophobicity of PET fibers. Surfactants can effectively reduce the PET/water interface tension and improve the adsorption of enzyme on PET fibers, increasing the degradation of PET fibers promoted by enzyme. In this paper, different nonionic surfactants (Triton X-100, Triton X-114, Triton X-405, PEG 200, PEG 400, PEG 600, Tween 20, Tween 80) were selected to investigate the effect of surfactant on the degradation of PET fibers by enzyme. It was found that the addition of Triton X-405 can improve the concentration of degradation products. However, other surfactants selected in this paper, such as Tween-80 caused the decrease of the degradation yields. The results indicated that the structure of surfactant plays a very important roll on the degradation of PET catalyzed by enzyme. This is probably due to the transformation of enzyme conformation induced by surfactant, and affects on the activity of enzyme. The hydrophilic surface is beneficial to the adsorption of enzyme onto the surface of PET fibers, and further improve the degradation of PET fibers.