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Alkylphenol polyethoxylates (APEO n ) are the second-largest category of commercial nonionic surfactants, which are difficult to degrade naturally in the environment. This study examined the degradation of octylphenol polyethoxylate (OPEO n ) by laccase and its laccase-mediated systems. The results showed that OPEO n was poorly degraded by laccase alone. 2, 2'-azino-bis [3-ethylbenzothiazoline-6-sulphonic acid] (ABTS), 1-hydroxybenzotriazole (HBT), and 2, 2, 6, 6-tetramethylpiperidine-1-oxyl (TEMPO) were selected as the redox mediators. Experimental results also indicated that 52.4% of the initial OPEO n amount was degraded by laccase in the presence of TEMPO. The degradation efficiency was analyzed using high-performance liquid chromatography. Furthermore, the structural characteristics of the degradation products were measured using matrix-assisted laser desorption/ionization-time of flight mass spectrometry and nuclear magnetic resonance spectroscopy, and it could be found that the laccase-TEMPO system could gradually shorten the ethoxylate chain by oxidizing the primary hydroxyl group of OPEO n , thereby degrading the OPEO n of the macromolecule into small molecules. The maximum of the ion peak distributions of OPEO n decreased from n = 8 finally down to 3. The novel enzymatic system introduced by this study will become a promising alternative method for high-efficiency APEO n conversion and had great potential value in wastewater treatment., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Silk fibroin (SF) is a promising biomaterial with attractive properties, however, the practical applications of pure regenerated SF materials were severely restricted by their poor water retention and low elasticity. In this study, a tyramine-modified hyaluronic acid (mHA) was introduced to SF chains, followed by constructing double-network hydrogels via laccase-mediated crosslinking of SF and mHA. Mechanism of the enzymatic coupling reaction between SF and mHA was investigated using the model compounds. The morphology, mechanical property, and swelling behavior of SF-g-mHA hydrogel were evaluated. The results reveal that combination use of SF and mHA endowed the obtained hydrogels with high structural stability, improved mechanical properties and drug release behavior, which overcame the intrinsically poor formability of the pure fibroin hydrogels. This work provides a novel method to construct a double-network hydrogel with high flexibility and toughness, and expands the application range of the SF-based materials in biomedical fields., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Chitosan oligosaccharide (COS), a water-soluble carbohydrate obtained from chemical or enzymatic hydrolysis of chitosan, has similar structure and properties to non-toxic, biocompatible, and biodegradable chitosan. However, COS has many advantages over chitosan due to its low molecular weight and high water solubility. In the current work, COS was incorporated in the laccase-catalyzed polymerization of hydroquinone. The laccase-catalyzed polymerization of hydroquinone with or without COS was investigated by using simple structure of glucosamine hydrochloride as an alternative to COS to understand the mechanism of COS-incorporated polymerization of hydroquinone. Although polyhydroquinone can be regarded as the polymeric colorant with dark brown color, there is no affinity or chemical bonding between polyhydroquinone and cotton fibers. Cotton fabrics were successfully in-situ dyed into brown color through the laccase-catalyzed polymerization of hydroquinone by incorporating with COS as a template. The presence of COS enhanced the dye uptake of polyhydroquinone on cotton fibers due to high affinity of COS to cotton and covalent bonding between COS and polyhydroquinone during laccase catalysis. This novel approach not only provides a simple route for the biological coloration of cotton fabrics but also presents a significant way to prepare functional textiles with antibacterial property.

Polydopamine (PDA) films are generally produced by spontaneous oxidation of dopamine in basic medium, which is a highly convenient method for surface modification. This method is, however, not suitable for alkaline sensitive materials, which have poor stability in alkali medium and need over-long reaction time. Herein, we compared two dopamine polymerization methods: conventional method (induced by O 2 at pH 8.5) and laccase-catalyzed method (at pH 5.5). The comparison showed that the polymerization of dopamine was greatly improved when catalyzed by laccase. The PDA film obtained from laccase-catalyzed method was more uniform and more stable compared with that obtained from the conventional method; the film was able to further react with amine-terminated molecules. As a result of laccase, ether bonds were found between dopamine units of PDA; while such bonds were not observed in film obtained from the conventional method. This work can be a basis for a better understanding of structure and property relationships of PDA coating., (Copyright © 2018 Elsevier Inc. All rights reserved.)

This study demonstrated a new enzymatic methodology to graft β-cyclodextrin onto wool. The primary hydroxyl groups in β-cyclodextrin were oxidized to aldehyde groups using laccase/2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO), which reacted with the amino groups of wool to form Schiff bases. The effects of treatment conditions (treatment temperature, laccase dosage, TEMPO dosage, treatment time) on the aldehyde and carboxyl contents in β-cyclodextrin were studied. FTIR spectrum of oxidized β-cyclodextrin showed the presence of aldehyde and carboxyl groups. Results of MALDI-TOF mass spectroscopy confirmed the coupling of β-cyclodextrin to tyrosine, which was used as a model compound for wool. ATR-FTIR spectroscopy of the grafted wool confirmed the presence of β-cyclodextrin in grafted wool and the formation of a Schiff base between β-cyclodextrin and wool., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Hydrophobic cotton fabrics were prepared by grafting octadecylamine (ODA) onto cotton fiber surfaces via the laccase/2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) treatment. The cotton fibers were oxidized by laccase/TEMPO to introduce aldehyde groups, which reacted with the amino groups of ODA to form Schiff base. First, ODA was coupled to glucan, used as a model compound of cellulose. The results of FT-IR and MALDI-TOF mass spectroscopy prove the formation of a Schiff base between ODA and glucan. Moreover, the existence of ODA in the grafted cotton fibers was verified by ATR-FTIR, elemental analysis, X-ray photoelectron spectroscopy. Finally, the hydrophobicity of the ODA-grafted cotton fabrics was estimated. The surface hydrophobicity of the cotton fabrics increased after the enzymatic grafting reaction., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Enzymatic polymerization of phenolic compounds (catechol, resorcinol, and hydroquinone) was carried out using laccase. The mechanism of polymerization and the structures of the polymers were evaluated in terms of UV-Vis and Fourier transform infrared spectroscopy. The molecular weights of the produced polyphenols were determined with GPC. The results showed that the phenolic monomers firstly turned into quinone intermediates by laccase catalysis. Through further oxidation, the intermediates formed covalent bonds. Finally, catechol units were linked together with ether bonds, and both resorcinol and hydroquinone units were linked together with C-C bonds. The number-average molecular weights of the polyphenols ranged from 1,000 to 1,400 Da (corresponding to the degree of polymerization that varied from 10 to 12) with a lower polydispersity value of about 1.10, showing selective polymerization of phenolic compounds catalyzed by laccase.

There is an increasing interest in the development of enzymatic coloration of textile fabrics as an alternative to conventional textile dyeing processes, which is successful for dyeing protein fibers. However, unmodified cotton fabrics are difficult to be dyed through enzyme catalysis due to the lack of affinity of biosynthesized dyes to cotton fibers. In order to improve the enzyme‐catalyzed dyeability of cotton fibers, chitosan was used to coat cotton fabrics as template. A novel and facile bio‐coloration technique using laccase catalysis of hydroquinone was developed to dye chitosan‐templated cotton fabrics. The polymerization of hydroquinone with the template of chitosan under the laccase catalysis was monitored by ultraviolet‐vis spectrophotometer on the absorbance of reaction solution. A significant peak of UV‐vis spectrum at 246 nm corresponding to large conjugated structures appeared and increased with increasing the duration of enzymatic catalysis. The effect of different treatment conditions on the laccase‐catalyzed dyeing of cotton fabric was investigated to determine their optimal parameters of laccase‐catalyzed coloration. Fourier‐transform infrared spectroscopy spectra demonstrated the formation of H‐bond and Schiff base reaction between chitosan and polymerized hydroquinone. Scanning electron microscopy indicated that the surface of dyed cotton fiber was much rougher than that of the control sample. Moreover, X‐ray photoelectron spectroscopy also revealed the existence of the chitosan/polymerized hydroquinone complex and polymerized hydroquinone on the dyed cotton fibers. This chitosan‐templated approach offers possibility for biological dyeing coloration of cotton fabrics and other cellulosic materials. [ABSTRACT FROM AUTHOR]

In recent years, there has been extensive interest in the research of smart fabrics and functional textiles. The present work has successfully developed the enzymatic approach for dyed wool fabrics in possession of special pH-responsive color-changing and conductive properties, via in-situ polymerization of 2,5-diaminobenzenesulfonic acid (DABSA) by laccase from Trametes versicolor. The enzymatically synthesized product, poly(2,5-diaminobenzenesulfonic acid) (PDABSA), was characterized by Fourier transform infrared spectroscopy, ultraviolet-visible (UV-Vis) spectrophotometry and matrix-assisted laser desorption ionization time-of-flight mass spectrometry. The redox property and thermal stability of the polymer products were studied by cyclic voltammetry and thermogravimetric analysis, respectively. The results proved that the resulting polymer reached 2 KDa and showed strong pH-dependence of UV-Vis absorption, electrochemical activity and high thermal stability. Utilizing the doping/dedoping process of PDABSA, the dyed wool fabrics were endowed with a pH-dependent redox potential. Furthermore, the dyed wool fabrics exhibited reversible color change from dark purple at pH 1.8 to yellowish-brown at pH 10.0, indicating that the PDABSA showed unusual pH-dependent color-changing properties on dyed wool fabrics. [ABSTRACT FROM AUTHOR]

Effect of laccase treatment on the content, structure, and surface distribution of lignin in jute fibers were fundamentally investigated. Four percent lignin was removed from jute fibers via the laccase treatment. The residual lignin in the laccase-treated jute fibers showed increased molecular weights, which indicated polymerization between lignins on jute fibers. Meanwhile, the phenolic hydroxyl content in lignin decreased during the laccase oxidation accompanied by demethylation of methoxyl groups and generation of carbonyl groups. Due to the degradation and subsequent polymerization of lignin by laccase, the bulgy lignins on jute fiber surfaces were redistributed, which made the surface neat and glossy. [ABSTRACT FROM AUTHOR]

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 –C–O–H component and the increase in the –C–O–C 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. [ABSTRACT FROM AUTHOR]

Polypyrrole catalyzed by laccase appears as a black color in solution. Conductive fabric coated with polypyrrole could present a dark green color, but the colorimetric and dyeing properties have not been discussed. In this study, pyrrole was used for the dyeing of wool fabric through in situ polymerization using laccase. The absorbance of reaction solution increases as time goes on and a significant peak appears at 460 nm on the ultraviolet-visible spectrum. Scanning electron microscopy indicated polypyrrole catalyzed by laccase does fix onto the wool fiber comparing to the control sample. The structure and electrochemical activity of dyed wool fabric were characterized by Fourier transform infrared spectroscopy and cyclic voltammetry, respectively. The dyeing depth of the dyed wool fabrics increased gradually with the extension of time and increasing of concentration of laccase and pyrrole. The dyed wool fabric prepared presents good electrochemical activity in terms of in situ polymerization using laccase in solution. [ABSTRACT FROM AUTHOR]

Enzymatic coloration of fabrics has received worldwide attention in recent years. In order to improve the dyeing properties of enzymatically coloured fabrics, a novel strategy using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC), a biological coupling agent, to pretreat wool fabric was employed in this paper. Enzymatic coloration of wool fabrics with syringic acid was carried out in the presence of laccase from Trametes versicolor. The effect of different periods on laccase-catalysed polymerisation of syringic acid was examined by UV-vis spectroscopy. Enzymatic coloration results of dyed wool fabrics were evaluated by means of K/ S value and colour difference ( ∆E*). Process parameters, including the dosages of syringic acid and incubation time, that influenced the colour depth were studied. Meanwhile, the colour fastness and levelness of dyed wool fabrics were tested. The results showed that the UV-vis absorbance of reaction solution increased as oxidation time elapsed, and a new peak appeared at 360 nm. After pretreatment, the K/ S values and colour difference values of wool fabrics dyed with poly(syringic acid) improved appreciably compared with the control samples without any pretreatment. Moreover, pretreated wool fabrics showed better dyeing fastness and levelness than control samples. [ABSTRACT FROM AUTHOR]

Compared to the traditional dyeing processes using synthetic dyes, biological dyeing method has a bright future in the textile industry due to their advantages of environmentally-friendly and milder processing conditions. Biological dyeing involves the catalysis of phenolic monomers by oxidoreductases, such as laccase, to form the colorful polymers used for dyeing. In this study, wool fabrics were treated with laccase/phenol via a one- or two-step treatment, and polymers synthesized in-situ were used to dye wool fabrics. The K/S values of the wool fabrics were evaluated under different treatment conditions, including the dosages of laccase and dye precursor, temperature, pH, mediator type, and mechanical agitation. The surface of wool fibers was examined using a scanning electron microscope (SEM). The results showed that the dyeing effect of the wool fabric samples using the single step processing method of in-situ color synthesis and fabric dyeing was better than those dyed using the two-step methods of color synthesis and fabric dyeing under the same conditions. The color depth of the dyed wool fabrics increased gradually with increasing concentration of laccase, and also depended on other process parameters, such as dosage of catechol, temperature, and pH. Moreover, addition of mediators and adjustment of mechanical agitation also improved the color depth of the wool fabrics which were dyed in-situ. [ABSTRACT FROM AUTHOR]

ABSTRACT Enzymatic processes provide new perspectives for the modification of lignocellulose materials. Lignin is an excellent substrate for laccase, and the modification of lignin-rich jute fabric via graft polymerization with acrylamide (AAm) mediated by laccase and tert-butyl hydroperoxide ( t-BHP) was investigated in this study. The products obtained were characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. The grafting rate was determined in terms of elemental analysis. The hydrophilicity and thermal and dyeing properties of the modified jute fabric were studied. The results supported the conclusion that the polyacrylamide was grafted on the lignin of the jute fiber by laccase in coordination with t-BHP, representing a grafting rate of 2.87%. The hydrophilicity, thermostability, dye uptake, and dyeing depth of the jute fiber were increased after the enzymatic graft modification with AAm. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40387. [ABSTRACT FROM AUTHOR]

An amino-functionalized magnetic core-shell structure metal-organic framework (MOF) , Fe 3 O 4 -NH 2 @MIL-100 (Fe), has been successfully constructed by a step-by-step method. The composite microspheres exhibited excellent magnetic characteristics, large surface area, and pore size, which were employed for the Trametes versicolor laccase immobilization. The immobilized laccase exhibited high activity recovery (72.05%) and significantly improved stability. The reactive activity remained 75% of its initial activity after storage for 4 weeks. Additionally, when the ambient reached 80 °C, the good stability enabled the immobilization laccase to keep 33% residual activity even after 6 h storage. Application of the immobilized laccase for environmental pollutant alkylphenol polyethoxylate (APEO) removal was also investigated. The results showed the immobilized laccase can remove 100% octylphenol polyethoxylate (OPEO) and 98.16% nonylphenol polyethoxylate (NPEO) in 200 min, and can still achieve 63.42% and 46.17% removal efficiency for OPEO and NPEO after reusing four cycles, respectively. The novel MOF based core-shell magnetic composite microspheres introduced by this study showed promising applications as laccase immobilization support, and both the immobilized laccase and its support had great potential in wastewater treatment. The endocrine pollutant alkylphenol polyethoxylate (APEO) has a wide range of potential sources and poses a serious health threat to human beings. Here, we immobilized laccase on the metal organic framework material to effectively remove APEO in the aqueous solution. ga1 • A magnetic core-shell MOF was applied for laccase immobilization. • The immobilized laccase showed excellent properties. • The removal of alkylphenol ethoxylates was efficient by the immobilized laccase. [ABSTRACT FROM AUTHOR]

Highlights: [•] The feasibility of laccase-mediated grafting dodecyl gallate (DG) on the jute fiber was investigated. [•] The grafting products were characterized by FT-IR, XPS, SEM and AFM, which revealed the covalently coupling of DG to the jute substrates mediated by laccase. [•] The grafting percentage and the DG content of the modified jute were determined in terms of weighting and saponification, respectively. [•] The surface hydrophobicity of the jute fiber was increased after the graft modification and the jute obtained excellent water repellency. [•] The breaking strength of the modified jute fiber/PP composite was also increased and the fracture section became neat and regular as the result of laccase-assisted grafting of the jute with DG. [ABSTRACT FROM AUTHOR]

A cleaner approach for functionalization of wool fabrics via laccase-catalyzed polymerization of caffeic acid was developed. Caffeic acid was first polymerized to poly(caffeic acid) in the system where poly(ethylene glycol) was used as a template under the catalysis of laccase/O 2 . Ultraviolet–Visible spectroscopic measurements verified that poly(ethylene glycol) formed a complex with caffeic acid though hydrogen bonds based on the ‘zip’ mechanism. During the catalysis of caffeic acid by laccase, poly(ethylene glycol) template promoted the enzymatic polymerization in term of the quantity of poly(caffeic acid) and the degree of polymerization. The data obtained from Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry and High Performance Liquid Chromatography-Electro Spray Ionization confirmed that poly(ethylene glycol) template aided the arrangement of the caffeic acid monomer, resulting in the increased degree of polymerization of caffeic acid in the laccase-catalyzed reaction. The poly(caffeic acid)/poly(ethylene glycol)-treated wool fabrics were prepared by laccase-catalyzed in-situ polymerization of caffeic acid under the same conditions. The treated wool fabrics showed good wettability and electroactivity. The results from fibre conductivity test and cyclic voltammetry showed that the wool fabric treated with poly(caffeic acid)/poly(ethylene glycol) complex was found to have better electrical conductivity. These data showed that the presence of poly(ethylene glycol) as a template in the laccase-catalyzed polymerization reaction greatly improved the characteristic of poly(caffeic acid). Moreover, higher color depth of poly(caffeic acid)/poly(ethylene glycol)-treated wool fabrics further validated the important role of the poly(ethylene glycol) as a template. [ABSTRACT FROM AUTHOR]

Highlights: [•] The lignins in jute fiber were degraded during LMS treatment. [•] The content of phenolic hydroxyl and methoxy of residual lignins decreased after LMS treatment. [•] The content of carboxyl of residual lignins increased after LMS treatment. [ABSTRACT FROM AUTHOR]