Biocatalytic surface modification of knitted fabrics made of poly (ethylene terephthalate) with hydrolytic enzymes from Thermobifida fusca KW3b

Knitted fabrics made from poly(ethylene terephthalate) fibres were treated with an enzyme preparation from Thermobifida fusca KW3b showing hydrolytic activity on p-nitrophenyl butyrate. The fabrics were also treated with NaOH and the results were compared. Both enzyme- and alkaline-treated fabrics showed an increase in reactive dye uptake, vertical wicking height and water absorption capacity of the fabrics indicating an increased surface hydrophilicity. However, X-ray photoelectron (XPS) and energy-dispersive spectroscopy (EDS) did not give conclusive results on the presence of newly introduced hydrophilic groups on the surface of the fibres. Analysis of the enzyme-treated poly(ethylene terephthalate) fibres by scanning electron microscopy (SEM) and by atomic force microscopy (AFM) indicated an increase in surface roughness of the fibres, which may contribute to the observed increased hydrophilicity of the PET fabrics. However, much longer treatment times (24 h) were required to obtain these effects with the enzymes compared to the chemical treatment (1 h).