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Laccase-Catalyzed Derivatization of Aminoglycoside Antibiotics and Glucosamine. Microorganisms 2022; 10:microorganisms10030626. [PMID: 35336201 PMCID: PMC8955303 DOI: 10.3390/microorganisms10030626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 03/08/2022] [Accepted: 03/11/2022] [Indexed: 12/04/2022] Open
Abstract
The increasing demand for new and effective antibiotics requires intelligent strategies to obtain a wide range of potential candidates. Laccase-catalyzed reactions have been successfully applied to synthesize new β-lactam antibiotics and other antibiotics. In this work, laccases from three different origins were used to produce new aminoglycoside antibiotics. Kanamycin, tobramycin and gentamicin were coupled with the laccase substrate 2,5-dihydroxy-N-(2-hydroxyethyl)-benzamide. The products were isolated, structurally characterized and tested in vitro for antibacterial activity against various strains of Staphylococci, including multidrug-resistant strains. The cytotoxicity of these products was tested using FL cells. The coupling products showed comparable and, in some cases, better antibacterial activity than the parent antibiotics in the agar diffusion assay, and they were not cytotoxic. The products protected mice against infection with Staphylococcus aureus, which was lethal to the control animals. The results underline the great potential of laccases in obtaining new biologically active compounds, in this case new antibiotic candidates from the class of aminoglycosides.
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2
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Chen X, Ouyang X, Li J, Zhao YL. Natural Syringyl Mediators Accelerate Laccase-Catalyzed β-O-4 Cleavage and Cα-Oxidation of a Guaiacyl Model Substrate via an Aggregation Mechanism. ACS OMEGA 2021; 6:22578-22588. [PMID: 34514230 PMCID: PMC8427646 DOI: 10.1021/acsomega.1c02501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 07/15/2021] [Indexed: 05/30/2023]
Abstract
Laccase-mediator systems (LMSs) have been intensively investigated in lignin degradation. Although only natural metabolites are available for fungal lignin degradation, mediator molecules from metabolites have received substantially less attention than artificial organic-synthetic compounds. It remains unclear which metabolites can accelerate laccase-catalyzed reactions and how those natural mediators influence lignin degradation. In this work, we evaluated Trametes versicolor laccase-catalyzed reaction kinetics on a lignin guaiacyl subunit model (guaiacylglycerol-β-guaiacyl ether, G-β-GE) in the presence of a group of lignin syringyl subunit molecules: syringaldehyde, acetosyringone, and methyl syringate. We then compare their performance to a well-known synthetic mediator ABTS, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid). Time-resolved UPLC-TOF-MS revealed that the syringyl mediators were more effective in accelerating the β-O-4 cleavage and Cα-oxidation of G-β-GE than ABTS under laccase-catalysis, despite the syringyl compounds possessing slower individual oxidation rates. In addition, the product profile of polymerization was also promoted dramatically, compared to that of the ABTS/laccase system. The LMS kinetic modeling suggested that mediator-substrate aggregation played a critical role in the laccase-mediator system; in which, the lignin syringyl and guaiacyl subunits likely form a π-π stacking van der Waals complex that can be oxidized faster than the syringyl or guaiacyl monomers by themselves. This syringyl-guaiacyl aggregation hypothesis postulates that the weak interactions in lignin biopolymers are able to accelerate the laccase-catalyzed biodegradation.
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Affiliation(s)
- Xu Chen
- State Key Laboratory of Microbial
Metabolism, Joint International Research Laboratory of Metabolic and
Developmental Sciences, Department of Bioinformatics and Biostatistics,
School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, People’s Republic of China
| | - Xingyu Ouyang
- State Key Laboratory of Microbial
Metabolism, Joint International Research Laboratory of Metabolic and
Developmental Sciences, Department of Bioinformatics and Biostatistics,
School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, People’s Republic of China
| | - Jiayi Li
- State Key Laboratory of Microbial
Metabolism, Joint International Research Laboratory of Metabolic and
Developmental Sciences, Department of Bioinformatics and Biostatistics,
School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, People’s Republic of China
| | - Yi-Lei Zhao
- State Key Laboratory of Microbial
Metabolism, Joint International Research Laboratory of Metabolic and
Developmental Sciences, Department of Bioinformatics and Biostatistics,
School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, People’s Republic of China
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3
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Liu J, Liu A, Hu Y. Enzymatic dimerization in the biosynthetic pathway of microbial natural products. Nat Prod Rep 2021; 38:1469-1505. [PMID: 33404031 DOI: 10.1039/d0np00063a] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Covering: up to August 2020The dramatic increase in the identification of dimeric natural products generated by microorganisms and plants has played a significant role in drug discovery. The biosynthetic pathways of these products feature inherent dimerization reactions, which are valuable for biosynthetic applications and chemical transformations. The extraordinary mechanisms of the dimerization of secondary metabolites should advance our understanding of the uncommon chemical rules for natural product biosynthesis, which will, in turn, accelerate the discovery of dimeric reactions and molecules in nature and provide promising strategies for the total synthesis of natural products through dimerization. This review focuses on the enzymes involved in the dimerization in the biosynthetic pathway of microbial natural products, with an emphasis on cytochrome P450s, laccases, and intermolecular [4 + 2] cyclases, along with other atypical enzymes. The identification, characterization, and catalytic landscapes of these enzymes are also introduced.
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Affiliation(s)
- Jiawang Liu
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China.
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4
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Choolaei Z, Flick R, Khusnutdinova AN, Edwards EA, Yakunin AF. Lignin-oxidizing activity of bacterial laccases characterized using soluble substrates and polymeric lignin. J Biotechnol 2020; 325:128-137. [PMID: 33186661 DOI: 10.1016/j.jbiotec.2020.11.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 10/21/2020] [Accepted: 11/03/2020] [Indexed: 12/11/2022]
Abstract
Efficient biotransformation of lignin requires the activity of different oxidative enzymes. In this work, 19 bacterial multi-copper oxidases were screened for oxidase activity against 19 soluble substrates and revealed the highest activity in the laccase CotABsu (BSU0630) from Bacillus subtilis. Structure-based site-directed mutagenesis of CotABsu identified four conserved residues (His419, Cys492, His497, and Met502) as critical for activity against 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonate) (ABTS). Greatly reduced oxidase activity was found in the CotABsu mutant proteins E213A, N214A, C229A, N264A, E298A, T415A, R416A, Q468A, and T480A. We also designed a lignin-agarose plate screen for detecting oxidase activity of purified proteins against polymeric lignin, which confirmed the results obtained with ABTS and identified three mutant variants with increased activity toward kraft lignin (E213A, T415A, and T260A). X-ray photoelectron spectroscopy analysis of low sulfonate kraft lignin after incubation with CotABsu revealed a reduction in the content of CC/CC bonds and increase in CO/CO bonds. Product analyses using mass spectrometry, liquid chromatography, and bright-field microscopy revealed an increased polymerization state of reaction products suggesting that formation of radical intermediates was followed by radical coupling. Our results provide further insights into the mechanisms of lignin oxidation by laccases.
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Affiliation(s)
- Zahra Choolaei
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E5, Canada
| | - Robert Flick
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E5, Canada
| | - Anna N Khusnutdinova
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E5, Canada
| | - Elizabeth A Edwards
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E5, Canada
| | - Alexander F Yakunin
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E5, Canada; Centre for Environmental Biotechnology, School of Natural Sciences, Bangor University, Bangor, LL57 2UW, UK.
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5
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Shi Y, Zhu K, Dai Y, Zhang C, Jia H. Evolution and stabilization of environmental persistent free radicals during the decomposition of lignin by laccase. CHEMOSPHERE 2020; 248:125931. [PMID: 32000035 DOI: 10.1016/j.chemosphere.2020.125931] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 01/09/2020] [Accepted: 01/14/2020] [Indexed: 05/28/2023]
Abstract
Soil microbial enzymes may induce lignin decomposition, accompanied by generation of free radicals. The evolution of environmentally persistent free radicals (EPFRs) and reactive oxygen species (ROS) during laccase-catalyzed lignin decomposition remains unclear. Characterization by electron paramagnetic resonance spectroscopy revealed gradually increased concentration of EPFRs, with maximum levels within 6 h that remained constant, accompanied by the increase in g-factor from 2.0037 to 2.0041. The results suggested the generation of oxygen-centered radicals on lignin. The EPFRs produced on solid samples slowly decreased by 17.2% over 17 d. ROS were also detected to have a similar trend as that of the evolution of EPFRs. Scanning electron microscopy, attenuated total reflectance-Fourier transform infrared spectroscopy, gel permeation chromatography and nuclear magnetic resonance analyses suggested the demethylation and oxidation of lignin. We clarify the biogeochemical transformation of lignin and potential contributions to the generation of EPFRs and ROS in soil.
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Affiliation(s)
- Yafang Shi
- College of Natural Resources and Environment, Northwest A & F University, Yangling, 712100, China
| | - Kecheng Zhu
- College of Natural Resources and Environment, Northwest A & F University, Yangling, 712100, China
| | - Yunchao Dai
- College of Natural Resources and Environment, Northwest A & F University, Yangling, 712100, China
| | - Chi Zhang
- College of Natural Resources and Environment, Northwest A & F University, Yangling, 712100, China
| | - Hanzhong Jia
- College of Natural Resources and Environment, Northwest A & F University, Yangling, 712100, China; State Key Laboratory of Soil Erosion and Dryland Farming on Loess Plateau, Institute of Soil and Water Conservation, Northwest A & F University, Yangling, 712100, China.
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6
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Ilyasov IR, Beloborodov VL, Selivanova IA, Terekhov RP. ABTS/PP Decolorization Assay of Antioxidant Capacity Reaction Pathways. Int J Mol Sci 2020; 21:ijms21031131. [PMID: 32046308 PMCID: PMC7037303 DOI: 10.3390/ijms21031131] [Citation(s) in RCA: 176] [Impact Index Per Article: 44.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 02/04/2020] [Accepted: 02/05/2020] [Indexed: 01/12/2023] Open
Abstract
The 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS•+) radical cation-based assays are among the most abundant antioxidant capacity assays, together with the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-based assays according to the Scopus citation rates. The main objective of this review was to elucidate the reaction pathways that underlie the ABTS/potassium persulfate decolorization assay of antioxidant capacity. Comparative analysis of the literature data showed that there are two principal reaction pathways. Some antioxidants, at least of phenolic nature, can form coupling adducts with ABTS•+, whereas others can undergo oxidation without coupling, thus the coupling is a specific reaction for certain antioxidants. These coupling adducts can undergo further oxidative degradation, leading to hydrazindyilidene-like and/or imine-like adducts with 3-ethyl-2-oxo-1,3-benzothiazoline-6-sulfonate and 3-ethyl-2-imino-1,3-benzothiazoline-6-sulfonate as marker compounds, respectively. The extent to which the coupling reaction contributes to the total antioxidant capacity, as well as the specificity and relevance of oxidation products, requires further in-depth elucidation. Undoubtedly, there are questions as to the overall application of this assay and this review adds to them, as specific reactions such as coupling might bias a comparison between antioxidants. Nevertheless, ABTS-based assays can still be recommended with certain reservations, particularly for tracking changes in the same antioxidant system during storage and processing.
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Mnich E, Bjarnholt N, Eudes A, Harholt J, Holland C, Jørgensen B, Larsen FH, Liu M, Manat R, Meyer AS, Mikkelsen JD, Motawia MS, Muschiol J, Møller BL, Møller SR, Perzon A, Petersen BL, Ravn JL, Ulvskov P. Phenolic cross-links: building and de-constructing the plant cell wall. Nat Prod Rep 2020; 37:919-961. [PMID: 31971193 DOI: 10.1039/c9np00028c] [Citation(s) in RCA: 78] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Covering: Up to 2019Phenolic cross-links and phenolic inter-unit linkages result from the oxidative coupling of two hydroxycinnamates or two molecules of tyrosine. Free dimers of hydroxycinnamates, lignans, play important roles in plant defence. Cross-linking of bound phenolics in the plant cell wall affects cell expansion, wall strength, digestibility, degradability, and pathogen resistance. Cross-links mediated by phenolic substituents are particularly important as they confer strength to the wall via the formation of new covalent bonds, and by excluding water from it. Four biopolymer classes are known to be involved in the formation of phenolic cross-links: lignins, extensins, glucuronoarabinoxylans, and side-chains of rhamnogalacturonan-I. Lignins and extensins are ubiquitous in streptophytes whereas aromatic substituents on xylan and pectic side-chains are commonly assumed to be particular features of Poales sensu lato and core Caryophyllales, respectively. Cross-linking of phenolic moieties proceeds via radical formation, is catalyzed by peroxidases and laccases, and involves monolignols, tyrosine in extensins, and ferulate esters on xylan and pectin. Ferulate substituents, on xylan in particular, are thought to be nucleation points for lignin polymerization and are, therefore, of paramount importance to wall architecture in grasses and for the development of technology for wall disassembly, e.g. for the use of grass biomass for production of 2nd generation biofuels. This review summarizes current knowledge on the intra- and extracellular acylation of polysaccharides, and inter- and intra-molecular cross-linking of different constituents. Enzyme mediated lignan in vitro synthesis for pharmaceutical uses are covered as are industrial exploitation of mutant and transgenic approaches to control cell wall cross-linking.
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Affiliation(s)
- Ewelina Mnich
- Department of Plant and Environmental Sciences, University of Copenhagen, Denmark.
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He F, Machemer-Noonan K, Golfier P, Unda F, Dechert J, Zhang W, Hoffmann N, Samuels L, Mansfield SD, Rausch T, Wolf S. The in vivo impact of MsLAC1, a Miscanthus laccase isoform, on lignification and lignin composition contrasts with its in vitro substrate preference. BMC PLANT BIOLOGY 2019; 19:552. [PMID: 31830911 PMCID: PMC6909574 DOI: 10.1186/s12870-019-2174-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 11/28/2019] [Indexed: 05/18/2023]
Abstract
BACKGROUND Understanding lignin biosynthesis and composition is of central importance for sustainable bioenergy and biomaterials production. Species of the genus Miscanthus have emerged as promising bioenergy crop due to their rapid growth and modest nutrient requirements. However, lignin polymerization in Miscanthus is poorly understood. It was previously shown that plant laccases are phenol oxidases that have multiple functions in plant, one of which is the polymerization of monolignols. Herein, we link a newly discovered Miscanthus laccase, MsLAC1, to cell wall lignification. Characterization of recombinant MsLAC1 and Arabidopsis transgenic plants expressing MsLAC1 were carried out to understand the function of MsLAC1 both in vitro and in vivo. RESULTS Using a comprehensive suite of molecular, biochemical and histochemical analyses, we show that MsLAC1 localizes to cell walls and identify Miscanthus transcription factors capable of regulating MsLAC1 expression. In addition, MsLAC1 complements the Arabidopsis lac4-2 lac17 mutant and recombinant MsLAC1 is able to oxidize monolignol in vitro. Transgenic Arabidopsis plants over-expressing MsLAC1 show higher G-lignin content, although recombinant MsLAC1 seemed to prefer sinapyl alcohol as substrate. CONCLUSIONS In summary, our results suggest that MsLAC1 is regulated by secondary cell wall MYB transcription factors and is involved in lignification of xylem fibers. This report identifies MsLAC1 as a promising breeding target in Miscanthus for biofuel and biomaterial applications.
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Affiliation(s)
- Feng He
- Centre for Organismal Studies (COS) Heidelberg, Heidelberg University, Heidelberg, Germany
| | - Katja Machemer-Noonan
- Centre for Organismal Studies (COS) Heidelberg, Heidelberg University, Heidelberg, Germany
| | - Philippe Golfier
- Centre for Organismal Studies (COS) Heidelberg, Heidelberg University, Heidelberg, Germany
| | - Faride Unda
- Department of Wood Science, University of British Columbia, Vancouver, Canada
| | - Johanna Dechert
- Centre for Organismal Studies (COS) Heidelberg, Heidelberg University, Heidelberg, Germany
| | - Wan Zhang
- Centre for Organismal Studies (COS) Heidelberg, Heidelberg University, Heidelberg, Germany
| | - Natalie Hoffmann
- Department of Botany, University of British Columbia, Vancouver, Canada
| | - Lacey Samuels
- Department of Botany, University of British Columbia, Vancouver, Canada
| | - Shawn D Mansfield
- Department of Wood Science, University of British Columbia, Vancouver, Canada
| | - Thomas Rausch
- Centre for Organismal Studies (COS) Heidelberg, Heidelberg University, Heidelberg, Germany.
| | - Sebastian Wolf
- Centre for Organismal Studies (COS) Heidelberg, Heidelberg University, Heidelberg, Germany.
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9
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Navas LE, Martínez FD, Taverna ME, Fetherolf MM, Eltis LD, Nicolau V, Estenoz D, Campos E, Benintende GB, Berretta MF. A thermostable laccase from Thermus sp. 2.9 and its potential for delignification of Eucalyptus biomass. AMB Express 2019; 9:24. [PMID: 30756202 PMCID: PMC6372703 DOI: 10.1186/s13568-019-0748-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 02/04/2019] [Indexed: 11/25/2022] Open
Abstract
Laccases are multicopper oxidases that are being studied for their potential application in pretreatment strategies of lignocellulosic feedstocks for bioethanol production. Here, we report the expression and characterization of a predicted laccase (LAC_2.9) from the thermophilic bacterial strain Thermus sp. 2.9 and investigate its capacity to delignify lignocellulosic biomass. The purified enzyme displayed a blue color typical of laccases, showed strict copper dependence and retained 80% of its activity after 16 h at 70 °C. At 60 °C, the enzyme oxidized 2,2′-azino-di-(3-ethylbenzthiazoline sulfonate) (ABTS) and 2,6-dimethoxyphenol (DMP) at optimal pH of 5 and 6, respectively. LAC_2.9 had higher substrate specificity (kcat/KM) for DMP with a calculated value that accounts for one of the highest reported for laccases. Further, the enzyme oxidized a phenolic lignin model dimer. The incubation of steam-exploded eucalyptus biomass with LAC_2.9 and 1-hydroxybenzotriazole (HBT) as mediator changed the structural properties of the lignocellulose as evidenced by Fourier transform infrared (FTIR) spectroscopy and thermo-gravimetric analysis (TGA). However, this did not increase the yield of sugars released by enzymatic saccharification. In conclusion, LAC_2.9 is a thermostable laccase with potential application in the delignification of lignocellulosic biomass.
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Hilgers R, Twentyman-Jones M, van Dam A, Gruppen H, Zuilhof H, Kabel MA, Vincken JP. The impact of lignin sulfonation on its reactivity with laccase and laccase/HBT. Catal Sci Technol 2019. [DOI: 10.1039/c9cy00249a] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This study shows and explains how sulfonation of lignin influences its reactivity with laccase and LMS (with mediator HBT), and what consequences this has for the overall outcome of laccase and LMS treatments.
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Affiliation(s)
- Roelant Hilgers
- Laboratory of Food Chemistry
- Wageningen University and Research
- 6708 WG Wageningen
- The Netherlands
| | - Megan Twentyman-Jones
- Laboratory of Food Chemistry
- Wageningen University and Research
- 6708 WG Wageningen
- The Netherlands
| | - Annemieke van Dam
- Laboratory of Organic Chemistry
- Wageningen University and Research
- The Netherlands
| | - Harry Gruppen
- Laboratory of Food Chemistry
- Wageningen University and Research
- 6708 WG Wageningen
- The Netherlands
| | - Han Zuilhof
- Laboratory of Organic Chemistry
- Wageningen University and Research
- The Netherlands
- School of Pharmaceutical Sciences and Technology
- Tianjin University
| | - Mirjam A. Kabel
- Laboratory of Food Chemistry
- Wageningen University and Research
- 6708 WG Wageningen
- The Netherlands
| | - Jean-Paul Vincken
- Laboratory of Food Chemistry
- Wageningen University and Research
- 6708 WG Wageningen
- The Netherlands
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11
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A novel laccase from thermoalkaliphilic bacterium Caldalkalibacillus thermarum strain TA2.A1 able to catalyze dimerization of a lignin model compound. Appl Microbiol Biotechnol 2018; 102:4075-4086. [DOI: 10.1007/s00253-018-8898-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 02/20/2018] [Accepted: 02/23/2018] [Indexed: 10/17/2022]
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12
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Hilgers R, Vincken JP, Gruppen H, Kabel MA. Laccase/Mediator Systems: Their Reactivity toward Phenolic Lignin Structures. ACS SUSTAINABLE CHEMISTRY & ENGINEERING 2018; 6:2037-2046. [PMID: 29430340 PMCID: PMC5805406 DOI: 10.1021/acssuschemeng.7b03451] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 11/30/2017] [Indexed: 05/03/2023]
Abstract
Laccase-mediator systems (LMS) have been widely studied for their capacity to oxidize the nonphenolic subunits of lignin (70-90% of the polymer). The phenolic subunits (10-30% of the polymer), which can also be oxidized without mediators, have received considerably less attention. Consequently, it remains unclear to what extent the presence of a mediator influences the reactions of the phenolic subunits of lignin. To get more insight in this, UHPLC-MS was used to study the reactions of a phenolic lignin dimer (GBG), initiated by a laccase from Trametes versicolor, alone or in combination with the mediators HBT and ABTS. The role of HBT was negligible, as its oxidation by laccase occurred slowly in comparison to that of GBG. Laccase and laccase/HBT oxidized GBG at a comparable rate, resulting in extensive polymerization of GBG. In contrast, laccase/ABTS converted GBG at a higher rate, as GBG was oxidized both directly by laccase but also by ABTS radical cations, which were rapidly formed by laccase. The laccase/ABTS system resulted in Cα oxidation of GBG and coupling of ABTS to GBG, rather than polymerization of GBG. Based on these results, we propose reaction pathways of phenolic lignin model compounds with laccase/HBT and laccase/ABTS.
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13
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Xie J, Zhang H, An S, Qian X, Cheng H, Zhang F, Li X. Role of a "surface wettability switch" in inter-fiber bonding properties. RSC Adv 2018; 8:3081-3089. [PMID: 35541166 PMCID: PMC9077703 DOI: 10.1039/c7ra12307h] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 01/08/2018] [Indexed: 11/21/2022] Open
Abstract
The fiber surface wettability is one of the most important lignocellulosic fiber characteristics affecting the inter-fiber bonding properties of final bio-products. In this study, the surface wettability (evaluated by the surface free energy, surface lignin and surface charge) of mechanically refined fibers and the bonding properties of the fiber matrix (handsheets) were measured and correlated to each other. The results showed that the fiber surface charge increased from 48.38 mmol kg-1 to 60.38 mmol kg-1 and the surface lignin decreased from 87.1% to 77.5% during the fiber mechanical treatment, leading to the improvement of the fiber surface free energy from 46.63 mJ m-2 to 54.45 mJ m-2. As a result, the bonding strength index increased from 2.60 N m g-1 to 9.73 N m g-1 without significant loss of bulk properties. In a word, the fiber surface wettability could be adjusted to facilitate the inter-fiber bonding properties of the paper or paperboard products using lignin-rich fibers as raw materials.
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Affiliation(s)
- Jinglei Xie
- Tianjin Key Lab of Pulp & Paper, Tianjin University of Science & Technology Tianjin 300457 China +86-22-6060-2510 +86-22-6060-2199
| | - Hongjie Zhang
- Tianjin Key Lab of Pulp & Paper, Tianjin University of Science & Technology Tianjin 300457 China +86-22-6060-2510 +86-22-6060-2199
- Hebei Huatai Paper Industry Co. Ltd., Huatai Group Zhaoxian 051530 China
- Shandong Huatai Paper Industry Co. Ltd., Huatai Group Dongying 257335 China
| | - Shuai An
- Tianjin Key Lab of Pulp & Paper, Tianjin University of Science & Technology Tianjin 300457 China +86-22-6060-2510 +86-22-6060-2199
| | - Xuejun Qian
- Hebei Huatai Paper Industry Co. Ltd., Huatai Group Zhaoxian 051530 China
| | - Hongshun Cheng
- Hebei Huatai Paper Industry Co. Ltd., Huatai Group Zhaoxian 051530 China
| | - Fengshan Zhang
- Shandong Huatai Paper Industry Co. Ltd., Huatai Group Dongying 257335 China
| | - Xiaoliang Li
- Shandong Huatai Paper Industry Co. Ltd., Huatai Group Dongying 257335 China
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14
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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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15
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Kong W, Fu X, Wang L, Alhujaily A, Zhang J, Ma F, Zhang X, Yu H. A novel and efficient fungal delignification strategy based on versatile peroxidase for lignocellulose bioconversion. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:218. [PMID: 28924453 PMCID: PMC5598073 DOI: 10.1186/s13068-017-0906-x] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 09/07/2017] [Indexed: 05/15/2023]
Abstract
BACKGROUND The selective lignin-degrading white-rot fungi are regarded to be the best lignin degraders and have been widely used for reducing the saccharification recalcitrance of lignocellulose. However, the biological delignification and conversion of lignocellulose in biorefinery is still limited. It is necessary to develop novel and more efficient bio-delignification systems. RESULTS Physisporinus vitreus relies on a new versatile peroxidase (VP)-based delignification strategy to remove enzymatic recalcitrance of corn stover efficiently, so that saccharification of corn stover was significantly enhanced to 349.1 mg/g biomass (yield of glucose) and 91.5% (hydrolysis yield of cellulose) at 28 days, as high as levels reached by thermochemical treatment. Analysis of the lignin structure using pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS) showed that the total abundance of lignin-derived compounds decreased by 54.0% and revealed a notable demethylation during lignin degradation by P. vitreus. Monomeric and dimeric lignin model compounds were used to confirm the ligninolytic capabilities of extracellular ligninases secreted by P. vitreus. The laccase (Lac) from P. vitreus could not oxidize nonphenolic lignin compounds and polymerized β-O-4 and 5-5' dimers to precipitate which had a negative effect on the enzymatic hydrolysis of corn stover in vitro. However, the VP from P. vitreus could oxidize both phenolic and nonphenolic lignin model compounds as well as break the β-O-4 and 5-5' dimers into monomeric compounds, which were measured by high-performance liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS). Moreover, we showed that addition of purified VP in vitro improved the enzymatic hydrolysis of corn stover by 14.1%. CONCLUSIONS From the highly efficient system of enzymatic recalcitrance removal by new white-rot fungus, we identified a new delignification strategy based on VP which could oxidize both phenolic and nonphenolic lignin units and break different linkages in lignin. In addition, this is the first evidence that VP could break 5-5' linkage efficiently in vitro. Moreover, VP improved the enzymatic hydrolysis of corn stover in vitro. The remarkable lignin-degradative potential makes VP attractive for biotechnological applications.
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Affiliation(s)
- Wen Kong
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074 People’s Republic of China
| | - Xiao Fu
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074 People’s Republic of China
| | - Lei Wang
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074 People’s Republic of China
| | - Ahmad Alhujaily
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074 People’s Republic of China
| | - Jingli Zhang
- College of Life Science and Technology, WuHan University of Technology, Wuhan, 430070 People’s Republic of China
| | - Fuying Ma
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074 People’s Republic of China
| | - Xiaoyu Zhang
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074 People’s Republic of China
| | - Hongbo Yu
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074 People’s Republic of China
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16
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Albarrán-Velo J, López-Iglesias M, Gotor V, Gotor-Fernández V, Lavandera I. Synthesis of nitrogenated lignin-derived compounds and reactivity with laccases. Study of their application in mild chemoenzymatic oxidative processes. RSC Adv 2017. [DOI: 10.1039/c7ra10497a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The chemical synthesis of a series of nitrogenated lignin-derived compounds, their reactivity with laccases and further application in mild oxidative processes are here disclosed.
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Affiliation(s)
- Jesús Albarrán-Velo
- Organic and Inorganic Chemistry Department
- Biotechnology Institute of Asturias (IUBA)
- University of Oviedo
- 33006 Oviedo
- Spain
| | - María López-Iglesias
- Organic and Inorganic Chemistry Department
- Biotechnology Institute of Asturias (IUBA)
- University of Oviedo
- 33006 Oviedo
- Spain
| | - Vicente Gotor
- Organic and Inorganic Chemistry Department
- Biotechnology Institute of Asturias (IUBA)
- University of Oviedo
- 33006 Oviedo
- Spain
| | - Vicente Gotor-Fernández
- Organic and Inorganic Chemistry Department
- Biotechnology Institute of Asturias (IUBA)
- University of Oviedo
- 33006 Oviedo
- Spain
| | - Iván Lavandera
- Organic and Inorganic Chemistry Department
- Biotechnology Institute of Asturias (IUBA)
- University of Oviedo
- 33006 Oviedo
- Spain
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