Specificities of a chemically modified laccase from trametes hirsuta on soluble and cellulose-bound substrates

Laccases could prevent fabrics and garments from re-deposition of dyes during washing and finishing processes by degrading the solubilized dye. However, laccase action must be restricted to solubilized dye molecules thereby avoiding decolorization of fabrics. Chemical modification of enzymes can provide a powerful tool to change the adsorption behaviour of enzymes on water insoluble polymers. Polyethylene glycol (PEG) was covalently attached onto a laccase from Trametes hirsuta. Different molecular weights of the synthetic polymer were tested in terms of adsorption behaviour and retained laccase activity. Covalent attachment of PEG onto the laccase resulted in enhanced enzyme stability while with increasing molecular weight of attached PEG the substrate affinity for the laccase conjugate decreased. The activity of the modified laccases on fibre bound dye was drastically reduced decreasing the adsorption of the enzyme on various fabrics. Compared to the 5 kDa PEG laccase conjugate (K/S value 47.60

Enzymatic modification of jute fabrics for enhancing the reinforcement in jute/PP composites

In this work, laccase was employed to improve the properties of lignocellulosic jute fabrics and then the modified jute was used as the fiber reinforcement of polypropylene (PP) matrix composites to improve its reinforcing effect on the polymer resins and obtain composite materials with better performance. The decrease in the COH component and the increase in the COC component on the surface of laccase-treated jute fabrics suggested that phenolic hydroxyl groups of lignins on the jute fiber surface were oxidized by laccase and the produced phenoxyl radicals were coupled to form ether structures. The laccase-treated jute fiber surface became smooth with lignins attached tightly. Moreover, the surface hydrophobicity and tensile properties of the jute fabrics were increased via the laccase-mediated reactions of lignins. PP composites reinforced by the laccase-treated jute fabrics showed higher breaking strength, storage modulus, and melting temperature than the control. The fracture surface of the laccase-treated jute fabric/PP composites was neat and jute fibers on the section surface were surrounded by PP resins closely, which indicated better interfacial adhesion between the modified jute reinforcement and PP matrix.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was financially supported by the National Natural Science Foundations of China (51603087 and 51673087); Program for Changjiang Scholars and Innovative Research Team in University (IRT_15R26), and Fundamental Research Funds for the Central Universities (JUSRP51717A).info:eu-repo/semantics/publishedVersio