Enzymatic treatments to improve mechanical properties and surface hydrophobicity of jute fiber membranes

Fiber membranes prepared from jute fragments can be valuable, low cost, and renewable. They have broad application prospects in packing bags, geotextiles, filters, and composite reinforcements. Traditionally, chemical adhesives have been used to improve the properties of jute fiber membranes. A series of new laccase, laccase/mediator systems, and multi-enzyme synergisms were attempted. After the laccase treatment of jute fragments, the mechanical properties and surface hydrophobicity of the produced fiber membranes increased because of the cross-coupling of lignins with ether bonds mediated by laccase. The optimum conditions were a buffer pH of 4.5 and an incubation temperature of 60 °C with 0.92 U/mL laccase for 3 h. Laccase/guaiacol and laccase/alkali lignin treatments resulted in remarkable increases in the mechanical properties; in contrast, the laccase/2,2-azino-bis-(3-ethylthiazoline-6-sulfonate) (ABTS) and laccase/2,6-dimethoxyphenol treatments led to a decrease. The laccase/ guaiacol system was favorable to the surface hydrophobicity of jute fiber membranes. However, the laccase/alkali lignin system had the opposite effect. Xylanase/laccase and cellulase/laccase combined treatments were able to enhance both the mechanical properties and the surface hydrophobicity of jute fiber membranes. Among these, cellulase/laccase treatment performed better; compared to mechanical properties, the surface hydrophobicity of the jute fiber membranes showed only a slight increase after the enzymatic multi-step processes.Financially supported by the National Natural Science Foundation of China (51173071, 21274055), Program for New Century Excellent Talents in University (NCET-12-0883), Program for Changjiang Scholars, Innovative Research Team in University (IRT _15R26), and Fundamental Research Funds for the Central Universities (JUSRP51312B, JUSRP51505

Enzymatic coating of jute fabrics for enhancing anti-ultraviolent properties via in-situ polymerization of polyhydric phenols

To enhance the anti-ultraviolent properties of technical jute fabrics, the enzymatic surface coating with the in-situ produced phenolic polymers of polyhydric phenols was investigated in this study. Firstly, the laccase-mediated polymerization of the five polyhydric phenols (catechol, resorcinol, hydroquinone, pyrogallol and phloroglucinol) was analyzed by FT-IR. Catechol and pyrogallol were polymerized together by laccase with ether bonds linked. On the contrary, the units of resorcinol, hydroquinone and phloroglucinol in their enzymatically formed polymers concatenated to each other by C-C bonds. Then, the coated jute fabrics were characterized in terms of X-ray photoelectron spectroscopy and scanning electron microscopy. The increasing of the C/O ratio on the jute fabric surface after the coating treatments supported the achievement of the enzymatic coating on jute fabrics via the in-situ polymerization of phenolic compounds and the grafting reaction of polyphenols with lignins on the surface. The sequence of the coating extent by using various polyhydric phenols was proved to be catechol, pyrogallol, resorcinol, phloroglucinol and hydroquinone in order from rich to poor according to the O-C-O component of cellulose in the C1s spectra of jute fabrics and the scanning electron microscopy photographs of jute surfaces. Lastly, the ultraviolent protection factor and the ultraviolent resistance of the coated jute fabrics were measured. The ultraviolent protective performance of jute fabrics after the coating treatments depended both on the coating amount and the chemical structure of the coated polymers. Among the tested polyhydric phenols, the polymerization of catechol obtained the best coating for ultraviolent protection. Different polyhydric phenols employed for the enzymatic coating showed different trends in ultraviolent protection factor of jute fabrics with the increasing of incubation time. The jute fabrics coated with in-situ-generated polycatechols or polyresorcinols had excellent ultraviolent resistances.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was Enancially supported by National Natural Science Foundation of China (51173071), Program for New Century Excellent Talents in University (NCET-12-0883), Program for Changjiang Scholars and Innovative Research Team in University (IRT1135), Fundamental Research Funds for the Central Universities (JUSRP51312B), the Graduate Student Innovation Plan of Jiangsu Province of China (CXZZ13_0752) and the Doctor Candidate Foundation of Jiangnan University of China (JUDCF13023)

New strategy for grafting hydrophobization of lignocellulosic fiber materials with octadecylamine using a laccase/TEMPO system

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Enzyme-mediated surface modification of jute and its influence on the properties of jute/epoxy composites

Surface modification of jute fibers is necessary to improve the adhesion and interfacial compatibility between fibers and resin matrix before using fibers in polymer composites. In this study, dodecyl gallate (DG) was enzymatically grafted onto the jute fiber by laccase to endow the fiber with hydrophobicity. A hand lay-up technique was then adopted to prepare jute/epoxy composites. Contact angle and wetting time measurements showed that the surface hydrophobicity of the jute fabric was increased after the enzymatic graft modification. The water absorption and thickness swelling of the DG-grafted jute fabric/epoxy composite were lower than those of the other composites. The tensile and dynamic mechanical properties of the jute/epoxy composites were enhanced by the surface modification. Scanning electron microscopy images revealed stronger fibermatrix adhesion in composites with modified fibers. Therefore, the enzymatic graft modification increased the fibermatrix interface area. The fibermatrix adhesion was enhanced, and the mechanical properties of the composites were improved.Contract grant sponsor: National Natural Science Foundation of China; contract grant number: 51173071; contract grant sponsor: Program for New Century Excellent Talents in University; contract grant number: NCET-12-0883; contract grant sponsor: Fundamental Research Funds for the Central Universities; contract grant sponsor: JUSRP51312B.info:eu-repo/semantics/publishedVersio

Laccase-mediated dye-free coloration of wool fabric

In this study, an investigation on a novel coloring technique, based on laccase-mediated radical coupling of amino acidmolecules of wool fibres, has been carried out. Firstly, the influence of temperature, incubation time, and pH on the K/Svalue and hue angle (h) of the colored wool fabrics is studied. Analysis of levelness of coloration, wash fastness, rubfastness, and UV-protection factor of the colored wool fabrics has been done. Then, the surface morphology and structure ofthe wool fibres are analyzed by scanning electron microscopy (SEM) and Fourier transform Infrared spectroscopy (FTIR).The enzymatic coloration processes are carried out in an acetate-sodium acetate buffer medium (pH 5) at 50 C for 24 h andthe colored wool fabrics show good color fastness and uniformity. The results obtained are as per the requirements of textilecolor fastness. SEM study shows that no particles are adhered to the surface of the wool fibres. The results of FTIR andultraviolet-visible spectroscopy show that the obvious oxidation coupling reactions take place between the molecules in thepolypeptide chains of the wool

The role of mesenchymal stem cells derived exosomes as a novel nanobiotechnology target in the diagnosis and treatment of cancer

Mesenchymal stem cells (MSCs), one of the most common types of stem cells, are involved in the modulation of the tumor microenvironment (TME). With the advancement of nanotechnology, exosomes, especially exosomes secreted by MSCs, have been found to play an important role in the initiation and development of tumors. In recent years, nanobiotechnology and bioengineering technology have been gradually developed to detect and identify exosomes for diagnosis and modify exosomes for tumor treatment. Several novel therapeutic strategies bioengineer exosomes to carry drugs, proteins, and RNAs, and further deliver their encapsulated cargoes to cancer cells through the properties of exosomes. The unique properties of exosomes in cancer treatment include targeting, low immunogenicity, flexibility in modification, and high biological barrier permeability. Nevertheless, the current comprehensive understanding of the roles of MSCs and their secreted exosomes in cancer development remain inadequate. It is necessary to better understand/update the mechanism of action of MSCs-secreted exosomes in cancer development, providing insights for better modification of exosomes through bioengineering technology and nanobiotechnology. Therefore, this review focuses on the role of MSCs-secreted exosomes and bioengineered exosomes in the development, progression, diagnosis, and treatment of cancer

Hydrophobic functionalization of jute fabrics by enzymatic-assisted grafting of vinyl copolymers

We report an eco-friendly approach to improve the hydrophobicity of jute fabrics via horseradish peroxidase (HRP)-catalyzed covalent grafting of butyl acrylate (BA) and 2,2,3,4,4,4-hexafluorobutyl methacrylate (HFBMA). Hydrophobic vinyl monomers were grafted onto the exposed lignin molecules of the jute surface by free-radical polymerization in the presence of a HRP/H2O2/acetylacetone (ACAC) system. Coupling onto the lignin-jute surface was demonstrated by attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), solid-state nuclear magnetic resonance (solid-state 19F NMR), elemental analyses, X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDS), matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS) and scanning electron microscopy (SEM). The hydrophobicity and oleophobicity of modified jute fabrics was estimated in terms of contact angle and wetting time. The results indicated that it was essential to attain vinyl monomers grafting polymerization onto jute surfaces in a HRP/H2O2/ACAC system. Moreover, the grafting of vinyl monomers led to hydrophobicity increases of 53.86% and 61.03% in the contact angle of grafted jute fabrics with BA and HFBMA when compared with unmodified jute fabrics, respectively. Both vinyl monomers demonstrated high propensity to be polymerized by HRP in the presence of H2O2, and acquired the ability to act as high-performance composites with hydrophobic resins.This work was financially supported by the National Natural Science Foundation of China (51673087, 51603087), Fundamental Research Funds for the Central Universities (JUSRP51717A), the Programme for Changjiang Scholars and Innovative Research Teams at University (IRT_15R26), the Portuguese Foundation for Science and Technology (UID/BIO/04469/2013 unit) and COMPETE 2020 (POCI-01-0145-FEDER-006684).info:eu-repo/semantics/publishedVersio

Laccase-catalyzed synthesis of conducting polyaniline-lignosulfonate composite

ABSTRACT: Enzymatic polymerization of aniline was first performed in lignosulfonate (LGS) template system. High-redox-potential catalyst laccase, isolated from Aspergillus, was used as a biocatalyst in the synthesis of conducting polyaniline/lignosulfonate (PANI-ES-LGS) complex using atmospheric oxygen as the oxidizing agent. The linear templates (LGS), also serving as the dopants, could facilitate the directional alignment of the monomer and improve the solubility of the conducting polymer. The process of the polymerization was monitored using UV-Vis spectroscopy, by which the conditions for laccase-catalyzed synthesis of PANI-ES-LGS complex were also optimized. The structure characterizations and solubility of the complex were carried out using corresponding characterization techniques respectively. The PANI-ES-LGS suspensions obtained was used as coating for cotton with a conventional padder to explore the applications of the complex. The variable optoelectronic properties of the coated cotton were confirmed by cyclic voltammetry and color strength test. The molecular weight changes of LGS treated by laccase were also studied to discuss the mechanism of laccase catalyzed aniline polymerization in LGS template system

Changes on content, structure and surface distribution of lignin in jute fibers after laccase treatment

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.This work was financially supported by the National Natural Science Foundations of China (51603087, 51673087), Program for Changjiang Scholars and Innovative Research Team in University (IRT_15R26), Fundamental Research Funds for the Central Universities (JUSRP51717A), Key R&D Program of Jiangsu Province (BE2016208), Portuguese Foundation for Science and Technology (UID/BIO/04469/2013 unit), and COMPETE 2020 (POCI-01-0145-FEDER006684).info:eu-repo/semantics/publishedVersio

Conductive cotton prepared by polyaniline in situ polymerization using laccase

The high-redox-potential catalyst laccase, isolated from Aspergillus, was first used as a biocatalyst in the oxidative polymerization of water-soluble conductive polyaniline, and then conductive cotton was prepared by in situ polymerization under the same conditions. The polymerization of aniline was performed in a water dispersion of sodium dodecylbenzenesulfonate (SDBS) micellar solution with atmospheric oxygen serving as the oxidizing agent. This method is ecologically clean and permits a greater degree of control over the kinetics of the reaction. The conditions for polyaniline synthesis were optimized. Characterizations of the conducting polyaniline and cotton were carried out using Fourier transform infrared spectroscopy, UV–vis spectroscopy, cyclic voltammetry, the fabric induction electrostatic tester, and the far-field EMC shielding effectiveness test fixture.This work was financially supported by the National Natural Science Foundation of China (21274055, 51173071), the Program for New Century Excellent Talents in University (NCET-12-0883), the Natural Science Foundation of Jiangsu Province (BK2011157), the Fundamental Research Funds for the Central Universities (JUSRP51312B), and the Program for Changjiang Scholars and Innovative Research Team in University (IRT1135)