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Lim J, Sana B, Krishnan R, Seayad J, Ghadessy FJ, Jana S, Ramalingam B. Laccase-Catalyzed Synthesis of Low-Molecular-Weight Lignin-Like Oligomers and their Application as UV-Blocking Materials. Chem Asian J 2018; 13:284-291. [PMID: 29214741 DOI: 10.1002/asia.201701573] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 12/05/2017] [Indexed: 11/11/2022]
Abstract
The laccase-catalyzed oxidative polymerization of monomeric and dimeric lignin model compounds was carried out with oxygen as the oxidant in aqueous medium. The oligomers were characterized by using gel permeation chromatography (GPC) and matrix-assisted laser desorption ionization time-of-flight mass spectroscopy (MALDI-TOF MS) analysis. Oxidative polymerization led to the formation of oligomeric species with a number-average molecular weight (Mn ) that ranged from 700 to 2300 Da with a low polydispersity index. Spectroscopic analysis provided insight into the possible modes of linkages present in the oligomers, and the oligomerization is likely to proceed through the formation of C-C linkages between phenolic aromatic rings. The oligomers were found to show good UV light absorption characteristics with high molar extinction coefficient (5000-38 000 m-1 cm-1 ) in the UV spectral region. The oligomers were blended independently with polyvinyl chloride (PVC) by using solution blending to evaluate the compatibility and UV protection ability of the oligomers. The UV/Vis transmittance spectra of the oligomer-embedded PVC films indicated that these lignin-like oligomers possessed a notable ability to block UV light. In particular, oligomers obtained from vanillyl alcohol and the dimeric lignin model were found to show good photostability in accelerated UV weathering experiments. The UV-blocking characteristics and photostability were finally compared with the commercial low-molecular-weight UV stabilizer 2,4-dihydroxybenzophenone.
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Affiliation(s)
- Jieyan Lim
- Organic Chemistry, Institute of Chemical and Engineering Sciences, #07-01/02 Neuros, 8 Biomedical Grove, Singapore, 138665, Singapore
| | - Barindra Sana
- P53 Laboratory, #06-04/05 Neuros/Immunos, 8A Biomedical Grove, Singapore, 138648, Singapore
| | - Ranganathan Krishnan
- Polymer Engineering & Characterization, Institute of Chemical and Engineering Sciences, 1, Pesek road, Jurong Island, Singapore, 627833, Singapore
| | - Jayasree Seayad
- Organic Chemistry, Institute of Chemical and Engineering Sciences, #07-01/02 Neuros, 8 Biomedical Grove, Singapore, 138665, Singapore
| | - Farid J Ghadessy
- P53 Laboratory, #06-04/05 Neuros/Immunos, 8A Biomedical Grove, Singapore, 138648, Singapore
| | - Satyasankar Jana
- Polymer Engineering & Characterization, Institute of Chemical and Engineering Sciences, 1, Pesek road, Jurong Island, Singapore, 627833, Singapore
| | - Balamurugan Ramalingam
- Organic Chemistry, Institute of Chemical and Engineering Sciences, #07-01/02 Neuros, 8 Biomedical Grove, Singapore, 138665, Singapore
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2
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Rahman MM, Balkhoyor HB, Asiri AM. Phenolic sensor development based on chromium oxide-decorated carbon nanotubes for environmental safety. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2017; 188:228-237. [PMID: 27984795 DOI: 10.1016/j.jenvman.2016.12.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Revised: 12/02/2016] [Accepted: 12/05/2016] [Indexed: 05/13/2023]
Abstract
A nanocomposite (NC) composed of chromium(III)oxide nanomaterials decorated carbon nanotubes (Cr2O3-CNT NC) was prepared via a simple solution method with reducing agents in an alkaline medium. The Cr2O3-CNT NC was characterized using ultraviolet-visible (UV/Vs.) spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, energy-dispersive X-ray spectroscopy (XEDS), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and field-emission scanning electron microscopy (FESEM). The Cr2O3-CNT composite was deposited on a flat glassy carbon electrode (GCE) with conducting nafion (5%) binders to produce a sensor that exhibited fast response and high selectivity toward 4-methoxyphenol (4MP) in phosphate buffer phase at pH 7. Furthermore, the sensor performance parameters, including the sensitivity, lower detection range, reliability, and reproducibility, ease of integration, long-term stability, and selectivity were investigated in detail. The calibration plot was found to be linear in the concentration range of 0.01 nM-0.1 μM. The sensitivity and detection limit were calculated as 1.4768 μA cm-2 μM-1 and 0.06428 ± 0.0002 nM (at a signal-to-noise ratio of 3), respectively. Thus, it was concluded that the proposed selective and efficient sensor represents a promising approach to effectively detect toxic phenolic compounds in the environment with acceptable and reliable results.
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Affiliation(s)
- Mohammed M Rahman
- Chemistry Department, King Abdulaziz University, Jeddah 21589, P.O. Box 80203, Saudi Arabia; Center of Excellence for Advanced Materials Research (CEAMR), King Abdulaziz University, Jeddah 21589, P.O. Box 80203, Saudi Arabia.
| | - Hasan B Balkhoyor
- Chemistry Department, King Abdulaziz University, Jeddah 21589, P.O. Box 80203, Saudi Arabia
| | - Abdullah M Asiri
- Chemistry Department, King Abdulaziz University, Jeddah 21589, P.O. Box 80203, Saudi Arabia; Center of Excellence for Advanced Materials Research (CEAMR), King Abdulaziz University, Jeddah 21589, P.O. Box 80203, Saudi Arabia
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3
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Ramalingam B, Sana B, Seayad J, Ghadessy FJ, Sullivan MB. Towards understanding of laccase-catalysed oxidative oligomerisation of dimeric lignin model compounds. RSC Adv 2017. [DOI: 10.1039/c6ra26975c] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The isolation of early intermediates in the laccase-catalysed oligomerisation of lignin model compounds indicated the preferential formation of C5–C5′ over C5–O–C4′ linkages.
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Affiliation(s)
- B. Ramalingam
- Organic Chemistry
- Institute of Chemical and Engineering Sciences
- Singapore 138 665
| | - B. Sana
- p53 Laboratory
- Singapore 138 648
| | - J. Seayad
- Organic Chemistry
- Institute of Chemical and Engineering Sciences
- Singapore 138 665
| | | | - M. B. Sullivan
- Institute of High Performance Computing
- Singapore 138 632
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4
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Zerva A, Manos N, Vouyiouka S, Christakopoulos P, Topakas E. Bioconversion of Biomass-Derived Phenols Catalyzed by Myceliophthora thermophila Laccase. Molecules 2016; 21:molecules21050550. [PMID: 27128897 PMCID: PMC6273956 DOI: 10.3390/molecules21050550] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 04/19/2016] [Accepted: 04/22/2016] [Indexed: 11/24/2022] Open
Abstract
Biomass-derived phenols have recently arisen as an attractive alternative for building blocks to be used in synthetic applications, due to their widespread availability as an abundant renewable resource. In the present paper, commercial laccase from the thermophilic fungus Myceliophthora thermophila was used to bioconvert phenol monomers, namely catechol, pyrogallol and gallic acid in water. The resulting products from catechol and gallic acid were polymers that were partially characterized in respect to their optical and thermal properties, and their average molecular weight was estimated via solution viscosity measurements and GPC. FT-IR and 1H-NMR data suggest that phenol monomers are connected with ether or C–C bonds depending on the starting monomer, while the achieved molecular weight of polycatechol is found higher than the corresponding poly(gallic acid). On the other hand, under the same condition, pyrogallol was dimerized in a pure red crystalline compound and its structure was confirmed by 1H-NMR as purpurogallin. The herein studied green synthesis of enzymatically synthesized phenol polymers or biological active compounds could be exploited as an alternative synthetic route targeting a variety of applications.
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Affiliation(s)
- Anastasia Zerva
- Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, 5 Iroon Polytechniou Str., Zografou Campus, Athens 15780, Greece.
| | - Nikolaos Manos
- Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, 5 Iroon Polytechniou Str., Zografou Campus, Athens 15780, Greece.
| | - Stamatina Vouyiouka
- Laboratory of Polymer Technology, School of Chemical Engineering, National Technical University of Athens, 5 Iroon Polytechniou Str., Zografou Campus, Athens 15780, Greece.
| | - Paul Christakopoulos
- Biochemical and Chemical Process Engineering, Division of Sustainable Process Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, Luleå SE-97187, Sweden.
| | - Evangelos Topakas
- Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, 5 Iroon Polytechniou Str., Zografou Campus, Athens 15780, Greece.
- Biochemical and Chemical Process Engineering, Division of Sustainable Process Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, Luleå SE-97187, Sweden.
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Synthesis, characterization, thermal stability and electrochemical properties of ortho-imine-functionalized oligophenol via enzymatic oxidative polycondensation. JOURNAL OF POLYMER RESEARCH 2016. [DOI: 10.1007/s10965-016-0953-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Shoda SI, Uyama H, Kadokawa JI, Kimura S, Kobayashi S. Enzymes as Green Catalysts for Precision Macromolecular Synthesis. Chem Rev 2016; 116:2307-413. [PMID: 26791937 DOI: 10.1021/acs.chemrev.5b00472] [Citation(s) in RCA: 303] [Impact Index Per Article: 37.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The present article comprehensively reviews the macromolecular synthesis using enzymes as catalysts. Among the six main classes of enzymes, the three classes, oxidoreductases, transferases, and hydrolases, have been employed as catalysts for the in vitro macromolecular synthesis and modification reactions. Appropriate design of reaction including monomer and enzyme catalyst produces macromolecules with precisely controlled structure, similarly as in vivo enzymatic reactions. The reaction controls the product structure with respect to substrate selectivity, chemo-selectivity, regio-selectivity, stereoselectivity, and choro-selectivity. Oxidoreductases catalyze various oxidation polymerizations of aromatic compounds as well as vinyl polymerizations. Transferases are effective catalysts for producing polysaccharide having a variety of structure and polyesters. Hydrolases catalyzing the bond-cleaving of macromolecules in vivo, catalyze the reverse reaction for bond forming in vitro to give various polysaccharides and functionalized polyesters. The enzymatic polymerizations allowed the first in vitro synthesis of natural polysaccharides having complicated structures like cellulose, amylose, xylan, chitin, hyaluronan, and chondroitin. These polymerizations are "green" with several respects; nontoxicity of enzyme, high catalyst efficiency, selective reactions under mild conditions using green solvents and renewable starting materials, and producing minimal byproducts. Thus, the enzymatic polymerization is desirable for the environment and contributes to "green polymer chemistry" for maintaining sustainable society.
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Affiliation(s)
- Shin-ichiro Shoda
- Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University , Aoba-ku, Sendai 980-8579, Japan
| | - Hiroshi Uyama
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University , Yamadaoka, Suita 565-0871, Japan
| | - Jun-ichi Kadokawa
- Department of Chemistry, Biotechnology, and Chemical Engineering, Graduate School of Science and Engineering, Kagoshima University , Korimoto, Kagoshima 890-0065, Japan
| | - Shunsaku Kimura
- Department of Material Chemistry, Graduate School of Engineering, Kyoto University , Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Shiro Kobayashi
- Center for Fiber & Textile Science, Kyoto Institute of Technology , Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
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Antenucci S, Panzella L, Farina H, Ortenzi MA, Caneva E, Martinotti S, Ranzato E, Burlando B, d'Ischia M, Napolitano A, Verotta L. Powering tyrosol antioxidant capacity and osteogenic activity by biocatalytic polymerization. RSC Adv 2016. [DOI: 10.1039/c5ra23004g] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Oxidative polymerization of tyrosol afforded a mixture of oligomers (OligoTyr) which proved to be more active than tyrosol as antioxidant and as stimulator of alkaline phosphatase (ALP) activity when loaded into polylactic acid (PLA) scaffolds.
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Affiliation(s)
- Stefano Antenucci
- Department of Chemistry
- University of Milan
- I-20133 Milan
- Italy
- CRC Materiali Polimerici “LaMPo”
| | - Lucia Panzella
- Department of Chemical Sciences
- University of Naples “Federico II”
- Naples
- Italy
| | - Hermes Farina
- Department of Chemistry
- University of Milan
- I-20133 Milan
- Italy
| | - Marco Aldo Ortenzi
- Department of Chemistry
- University of Milan
- I-20133 Milan
- Italy
- CRC Materiali Polimerici “LaMPo”
| | - Enrico Caneva
- Interdepartmental Center for Large Instrumentation (CIGA)
- University of Milan
- I-20133 Milan
- Italy
| | - Simona Martinotti
- Department of Science and Technological Innovation
- University of Piemonte Orientale “Amedeo Avogadro”
- I-15121 Alessandria
- Italy
| | - Elia Ranzato
- Department of Science and Technological Innovation
- University of Piemonte Orientale “Amedeo Avogadro”
- I-15121 Alessandria
- Italy
| | - Bruno Burlando
- Department of Science and Technological Innovation
- University of Piemonte Orientale “Amedeo Avogadro”
- I-15121 Alessandria
- Italy
- Biophysics Institute
| | - Marco d'Ischia
- Department of Chemical Sciences
- University of Naples “Federico II”
- Naples
- Italy
| | | | - Luisella Verotta
- Department of Chemistry
- University of Milan
- I-20133 Milan
- Italy
- CRC Materiali Polimerici “LaMPo”
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8
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Synthesis and characterization of imine-functionalized polyphenol via enzymatic oxidative polycondensation of a bisphenol derivative. Polym Bull (Berl) 2015. [DOI: 10.1007/s00289-015-1478-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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9
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Oliva-Taravilla A, Tomás-Pejó E, Demuez M, González-Fernández C, Ballesteros M. Inhibition of cellulose enzymatic hydrolysis by laccase-derived compounds from phenols. Biotechnol Prog 2015; 31:700-6. [DOI: 10.1002/btpr.2068] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Revised: 02/05/2015] [Indexed: 11/07/2022]
Affiliation(s)
- Alfredo Oliva-Taravilla
- IMDEA Energy Inst; Biotechnology Processes for Energy Production Unit; Avenida Ramón de la Sagra, 3 28935 Móstoles Spain
| | - Elia Tomás-Pejó
- IMDEA Energy Inst; Biotechnology Processes for Energy Production Unit; Avenida Ramón de la Sagra, 3 28935 Móstoles Spain
| | - Marie Demuez
- IMDEA Energy Inst; Biotechnology Processes for Energy Production Unit; Avenida Ramón de la Sagra, 3 28935 Móstoles Spain
| | - Cristina González-Fernández
- IMDEA Energy Inst; Biotechnology Processes for Energy Production Unit; Avenida Ramón de la Sagra, 3 28935 Móstoles Spain
| | - Mercedes Ballesteros
- IMDEA Energy Inst; Biotechnology Processes for Energy Production Unit; Avenida Ramón de la Sagra, 3 28935 Móstoles Spain
- CIEMAT, Renewable Energy Div; Biofuels Unit; Av. Complutense, 40 28040 Madrid Spain
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10
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Mogharabi M, Faramarzi MA. Laccase and Laccase-Mediated Systems in the Synthesis of Organic Compounds. Adv Synth Catal 2014. [DOI: 10.1002/adsc.201300960] [Citation(s) in RCA: 183] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
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11
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Bernini R, Crisante F, Gentili P, Menta S, Morana F, Pierini M. Unexpected different chemoselectivity in the aerobic oxidation of methylated planar catechin and bent epicatechin derivatives catalysed by the Trametes villosa laccase/1-hydroxybenzotriazole system. RSC Adv 2014. [DOI: 10.1039/c3ra47753c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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12
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Andreu G, Vidal T. Laccase from Pycnoporus cinnabarinus and phenolic compounds: can the efficiency of an enzyme mediator for delignifying kenaf pulp be predicted? BIORESOURCE TECHNOLOGY 2013; 131:536-540. [PMID: 23403063 DOI: 10.1016/j.biortech.2013.01.033] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2012] [Revised: 01/04/2013] [Accepted: 01/06/2013] [Indexed: 06/01/2023]
Abstract
In this work, kenaf pulp was delignified by using laccase in combination with various redox mediators and the efficiency of the different laccase–mediator systems assessed in terms of the changes in pulp properties after bleaching. The oxidative ability of the individual mediators used (acetosyringone, syringaldehyde, p-coumaric acid, vanillin and actovanillone) and the laccase–mediator systems was determined by monitoring the oxidation–reduction potential (ORP) during process. The results confirmed the production of phenoxy radicals of variable reactivity and stressed the significant role of lignin structure in the enzymatic process. Although changes in ORP were correlated with the oxidative ability of the mediators, pulp properties as determined after the bleaching stage were also influenced by condensation and grafting reactions. As shown here, ORP measurements provide a first estimation of the delignification efficiency of a laccase–mediator system.
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Affiliation(s)
- Glòria Andreu
- Chemical Engineering Department, ETSEIAT, Universitat Politècnica de Catalunya, Colom 11, E-08222 Terrassa, Spain
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13
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Yamaguchi I, Suyama A, Goto K, Sato M. Synthesis and chemical properties of polyphenols with oligoaniline pendant groups. HIGH PERFORM POLYM 2012. [DOI: 10.1177/0954008312439081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Horseradish peroxidaze (HRP)- or N, N′-bis(salicylidene)ethylenediamineiron(III)-catalyzed polymerizations of 4-(4-phenylaminophenylamino)phenol (monomer-1) and 4-[4-(4-phenylaminophenylamino)phenylamino]phenol (monomer-2) caused oxidative coupling at the hydroxyphenyl group to yield polyphenols (PPs) with pendant oligoaniline (OAN) groups. UV-vis measurements suggested that the OAN pendant groups of the polymers were oxidized in air, resulting in the formation of quinoid structures, which were converted into benzonoid structures by treatment with hydrazine monohydrate. The polymers were electrochemically oxidized in solution.
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Affiliation(s)
- Isao Yamaguchi
- Department of Material Science, Faculty of Science and Engineering, Shimane University, Nishikawatsu, Matsue, Japan
| | - Ami Suyama
- Department of Material Science, Faculty of Science and Engineering, Shimane University, Nishikawatsu, Matsue, Japan
| | - Kazuyuki Goto
- Department of Material Science, Faculty of Science and Engineering, Shimane University, Nishikawatsu, Matsue, Japan
| | - Moriyuki Sato
- Department of Material Science, Faculty of Science and Engineering, Shimane University, Nishikawatsu, Matsue, Japan
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Moldes D, Vidal T. Laccase for biobleaching of eucalypt kraft pulp by means of a modified industrial bleaching sequence. Biotechnol Prog 2012; 28:1225-31. [DOI: 10.1002/btpr.1594] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2012] [Revised: 06/20/2012] [Indexed: 11/07/2022]
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Barneto AG, Aracri E, Andreu G, Vidal T. Investigating the structure-effect relationships of various natural phenols used as laccase mediators in the biobleaching of kenaf and sisal pulps. BIORESOURCE TECHNOLOGY 2012; 112:327-35. [PMID: 22437048 DOI: 10.1016/j.biortech.2012.02.136] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Revised: 02/25/2012] [Accepted: 02/28/2012] [Indexed: 05/02/2023]
Abstract
Nine phenol derivatives, p-coumaric acid (PC), vanillin (V), acetovanillone (AV), acetosyringone (AS), syringaldehyde (SA), coniferaldehyde (CLD), ferulic acid (FRC), sinapic acid (SNC), and sinapyl aldehyde (SLD) were assayed as laccase redox mediators in the biobleaching of kenaf and sisal pulps. As a general behaviour, the phenolic mediators increased the kappa number (KN) and reduced the brightness of pulps. In particular, these changes were found to depend in a linear manner on the energy of the highest occupied molecular orbital (E(HOMO)) of the mediators. The phenolic mediator with the lowest E(HOMO) (PC) led to the highest increase of KN and the lowest reduction of brightness. On the contrary, syringyl derivatives (i.e. SA) with high E(HOMO) values caused small KN increases and significant losses of brightness. This behaviour was explained on the basis of a competition between grafting and polymerisation processes. The former basically affects KN, whereas the latter affects pulp brightness.
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Affiliation(s)
- Agustín G Barneto
- Department of Chemical Engineering, Physical Chemistry, and Organic Chemistry, University of Huelva (ceiA3), Spain.
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Jeon JR, Baldrian P, Murugesan K, Chang YS. Laccase-catalysed oxidations of naturally occurring phenols: from in vivo biosynthetic pathways to green synthetic applications. Microb Biotechnol 2011; 5:318-32. [PMID: 21791030 PMCID: PMC3821676 DOI: 10.1111/j.1751-7915.2011.00273.x] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Laccases are oxidases that contain several copper atoms, and catalyse single-electron oxidations of phenolic compounds with concomitant reduction of oxygen to water. The enzymes are particularly widespread in ligninolytic basidiomycetes, but also occur in certain prokaryotes, insects and plants. Depending on the species, laccases are involved in various biosynthetic processes contributing to carbon recycling in land ecosystems and the morphogenesis of biomatrices, wherein low-molecular-weight naturally occurring phenols serve as key enzyme substrates. Studies of these in vivo synthetic pathways have afforded new insights into fungal laccase applicability in green synthetic chemistry. Thus, we here review fungal laccase-catalysed oxidations of naturally occurring phenols that are particularly relevant to the synthesis of fine organic chemicals, and we discuss how the discovered synthetic strategies mimic laccase-involved in vivo pathways, thus enhancing the green nature of such reactions. Laccase-catalysed in vivo processes yield several types of biopolymers, including those of cuticles, lignin, polyflavonoids, humus and the melanin pigments, using natural mono- or poly-phenols as building blocks. The in vivo synthetic pathways involve either phenoxyl radical-mediated coupling or cross-linking reactions, and can be adapted to the design of in vitro oxidative processes involving fungal laccases in organic synthesis; the laccase substrates and the synthetic mechanisms reflect in vivo processes. Notably, such in vitro synthetic pathways can also reproduce physicochemical properties (e.g. those of chromophores, and radical-scavenging, hydration and antimicrobial activities) found in natural biomaterials. Careful study of laccase-associated in vivo metabolic pathways has been rewarded by the discovery of novel green applications for fungal laccases. This review comprehensively summarizes the available data on laccase-catalysed biosynthetic pathways and associated applications in fine chemical syntheses.
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Affiliation(s)
- Jong-Rok Jeon
- Corporate R&D Group, LG Chem Research Park, Daejeon 305-380, Korea
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17
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Bernini R, Crisante F, Gentili P, Morana F, Pierini M, Piras M. Chemoselective C-4 aerobic oxidation of catechin derivatives catalyzed by the Trametes villosa laccase/1-hydroxybenzotriazole system: synthetic and mechanistic aspects. J Org Chem 2011; 76:820-32. [PMID: 21204551 DOI: 10.1021/jo101886s] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Catechin derivatives were oxidized in air in the presence of the Trametes villosa laccase/1-hydroxybenzotriazole (HBT) system in buffered water/1,4-dioxane as reaction medium. The oxidation products, flavan-3,4-diols and the corresponding C-4 ketones, are bioactive compounds and useful intermediates for the hemisynthesis of proanthocyanidins, plant polyphenols which provide beneficial health properties for humans. Determinations of oxidation potentials excluded that catechin derivatives could be directly oxidized by laccase Cu(II), while it resulted in the H-abstraction from benzylic positions being promptly promoted by the enzyme in the presence of the mediator HBT, the parent species producing in situ the reactive intermediate benzotriazole-N-oxyl (BTNO) radical. A remarkable and unexpected result for the laccase/HBT oxidative system has been the chemoselective insertion of the oxygen atom into the C-4-H bond of catechin derivatives. Mechanistic aspects of the oxidation reaction have been investigated in detail for the first time in order to corroborate these results. Since the collected experimental findings could not alone provide information useful to clarify the origin of the observed chemoselectivity, these data were expressly supplemented with information derived by suitable molecular modeling investigations. The integrated evaluation of the dissociation energies of the C-H bonds calculated both by semiempirical and DFT methods and the differential activation energies of the process estimated by a molecular modeling approach suggested that the observed selective oxidation at the C-4 carbon has a kinetic origin.
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Affiliation(s)
- Roberta Bernini
- Dipartimento di Agrobiologia e Agrochimica, Università degli Studi della Tuscia, Viterbo, Italy.
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