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Li K, Wang Y, Guo X, Wang B. Effects of Lignin-Diverted Reductant with Polyphenol Oxidases on Cellulose Degradation by Wild and Mutant Types of Lytic Polysaccharide Monooxygenase. Curr Issues Mol Biol 2024; 46:3694-3712. [PMID: 38666960 PMCID: PMC11049000 DOI: 10.3390/cimb46040230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Revised: 04/12/2024] [Accepted: 04/19/2024] [Indexed: 04/28/2024] Open
Abstract
Establishing a multi-enzyme synergistic lignocellulosic biodegradation system using lytic polysaccharide monooxygenase (LPMO) and polyphenol oxidases is vital for efficiently utilizing plant biomass waste, ultimately benefiting the carbon cycle and promoting environmental protection. Single-residue mutations of LPMO can improve the efficiency of lignocellulosic biomass degradation. However, the activity of mutant-type LPMO in relation to lignin-diverted reducing agents has not been sufficiently explored. In this study, laccase and tyrosinase were initially investigated and their optimal conditions and impressive thermal stability were revealed, indicating their potential synergistic abilities with LPMO in lignocellulose biodegradation. When utilizing gallic acid as a reducing agent, the activities of LPMOs were increased by over 10%, which was particularly evident in mutant-type LPMOs after the addition of polyphenol oxidases. In particular, the combination of tyrosinase with either 4-hydroxy-3-methoxyphenylacetone or p-coumaric acid was shown to enhance the efficacy of LPMOs. Furthermore, the highest activity levels of wild-type LPMOs were observed with the addition of laccase and 3-methylcatechol. The similarities between wild and mutant LPMOs regarding their activities in lignin-diverted phenolic compounds and reducing agents are almost identical, suggesting that the single-residue mutation of LPMO does not have a detrimental effect on its performance. Above all, this study indicates that understanding the performance of both wild and mutant types of LPMOs in the presence of polyphenol oxidases and various reducing agents constitutes a key link in the industrialization of the multi-enzyme degradation of lignocellulose.
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Affiliation(s)
| | | | | | - Bo Wang
- College of Chemical and Biological Engineering, Shandong University of Science and Technology, Qingdao 266590, China; (K.L.); (Y.W.); (X.G.)
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Hultberg M, Golovko O. Use of sawdust for production of ligninolytic enzymes by white-rot fungi and pharmaceutical removal. Bioprocess Biosyst Eng 2024; 47:475-482. [PMID: 38480583 PMCID: PMC11003897 DOI: 10.1007/s00449-024-02976-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 01/23/2024] [Indexed: 04/10/2024]
Abstract
Use of white-rot fungi for enzyme-based bioremediation of wastewater is of high interest. These fungi produce considerable amounts of extracellular ligninolytic enzymes during solid-state fermentation on lignocellulosic materials such as straw and sawdust. We used pure sawdust colonized by Pleurotus ostreatus, Trametes versicolor, and Ganoderma lucidum for extraction of ligninolytic enzymes in aqueous suspension. Crude enzyme suspensions of the three fungi, with laccase activity range 12-43 U/L and manganese peroxidase activity range 5-55 U/L, were evaluated for degradation of 11 selected pharmaceuticals spiked at environmentally relevant concentrations. Sulfamethoxazole was removed significantly in all treatments. The crude enzyme suspension from P. ostreatus achieved degradation of wider range of pharmaceuticals when the enzyme activity was increased. Brief homogenization of the colonized sawdust was also observed to be favorable, resulting in significant reductions after a short exposure of 5 min. The highest reduction was observed for sulfamethoxazole which was reduced by 84% compared to an autoclaved control without enzyme activity and for trimethoprim which was reduced by 60%. The compounds metoprolol, lidocaine, and venlafaxine were reduced by approximately 30% compared to the control. Overall, this study confirmed the potential of low-cost lignocellulosic material as a substrate for production of enzymes from white-rot fungi. However, monitoring over time in bioreactors revealed a rapid decrease in enzymatic ligninolytic activity.
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Affiliation(s)
- M Hultberg
- Department of Biosystems and Technology, Swedish University of Agricultural Sciences, Växtskyddsvägen 3, 234 56, Alnarp, Sweden.
| | - O Golovko
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences (SLU), 750 07, Uppsala, Sweden
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3
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Hao M, Huang A, Li B, Xin Y, Zhang L, Gu Z, Sun H, Li Y, Shi G. Preparation and characterization of a laccase-like enzyme from Thermomicrobium roseum. Int J Biol Macromol 2023; 242:124992. [PMID: 37211077 DOI: 10.1016/j.ijbiomac.2023.124992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 05/07/2023] [Accepted: 05/19/2023] [Indexed: 05/23/2023]
Abstract
In this study, a laccase-like gene from Thermomicrobium roseum DSM 5159 (TrLac-like) (NCBI: WP_012642205.1) was recombinantly expressed in Bacillus subtilis WB600. The optimum temperature and pH for TrLac-like were 50 °C and 6.0, respectively. TrLac-like showed high tolerance to mixed systems of water and organic solvents, indicating its potential for large-scale application in various industries. It showed 36.81 % similarity with YlmD from Geobacillus stearothermophilus (PDB:6T1B) in sequence alignment; therefore, 6T1B was employed as the template for homology modeling. To improve catalytic efficiency, amino acid substitutions within 5 Å of the inosine ligand were simulated to reduce the binding energy and promote substrate affinity. Single and double substitutions (44 and 18, respectively) were prepared, and the catalytic efficiency of the mutant A248D was increased to approximately 110-fold that of the wild type, while the thermal stability was maintained. Bioinformatics analysis revealed that the significant improvement in catalytic efficiency could be attributed to the formation of new hydrogen bonds between the enzyme and substrate. With a further decrease in the binding energy, the catalytic efficiency of the multiple mutant H129N/A248D was approximately 14-fold higher than that of the wild type but lower than that of the single mutant A248D. This is possibly because kcat also decreased with the decrease of Km; consequently, the substrate could not be released in time owing to the enzyme with the combination mutation not being able to release the substrate at a high rate.
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Affiliation(s)
- Mengyao Hao
- Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, Wuxi 214122, China; Jiangsu Provincial Engineering Research Center for Bioactive Product Processing, Jiangnan University, Wuxi 214122, China
| | - Aimin Huang
- Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, Wuxi 214122, China; Jiangsu Provincial Engineering Research Center for Bioactive Product Processing, Jiangnan University, Wuxi 214122, China
| | - Bingjie Li
- Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, Wuxi 214122, China; Jiangsu Provincial Engineering Research Center for Bioactive Product Processing, Jiangnan University, Wuxi 214122, China
| | - Yu Xin
- Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, Wuxi 214122, China; Jiangsu Provincial Engineering Research Center for Bioactive Product Processing, Jiangnan University, Wuxi 214122, China.
| | - Liang Zhang
- Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, Wuxi 214122, China; Jiangsu Provincial Engineering Research Center for Bioactive Product Processing, Jiangnan University, Wuxi 214122, China.
| | - ZhengHua Gu
- Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, Wuxi 214122, China; Jiangsu Provincial Engineering Research Center for Bioactive Product Processing, Jiangnan University, Wuxi 214122, China
| | - Haiyan Sun
- Hainan Key Laboratory of Tropical Microbe Resources, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China
| | - Youran Li
- Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, Wuxi 214122, China; Jiangsu Provincial Engineering Research Center for Bioactive Product Processing, Jiangnan University, Wuxi 214122, China
| | - Guiyang Shi
- Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, Wuxi 214122, China; Jiangsu Provincial Engineering Research Center for Bioactive Product Processing, Jiangnan University, Wuxi 214122, China
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Jafari-Nodoushan H, Fazeli MR, Faramarzi MA, Samadi N. Hierarchically-structured laccase@Ni 3(PO 4) 2 hybrid nanoflowers for antibiotic degradation: Application in real wastewater effluent and toxicity evaluation. Int J Biol Macromol 2023; 234:123574. [PMID: 36764346 DOI: 10.1016/j.ijbiomac.2023.123574] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Revised: 01/26/2023] [Accepted: 02/03/2023] [Indexed: 02/11/2023]
Abstract
Laccase@Ni3(PO4)2 hybrid nanoflowers (HNFs) were prepared by the anisotropic growth of biomineralized nickel phosphate. The immobilization yield was 77.5 ± 3.6 %, and the immobilized enzyme retained 50 % of its initial activity after 18 reusability cycles. The immobilized and free enzymes lost 80 % of their activity after 18 and 6 h incubation in municipal wastewater effluent (MWWE), respectively. The increase in α-helix content (8 %) following immobilization led to a more rigid enzyme structure, potentially contributing to its improved stability. The removal of ciprofloxacin from MWWE by laccase@Ni3(PO4)2·HNFs/p-coumaric acid oxidation system was optimized using a Box-Behnken design. Under the optimized conditions [initial laccase activity (0.05 U mL-1), the concentration of p-coumaric acid (2.9 mM), and treatment time (4.9 h)], the biocatalyst removed 90 % of ciprofloxacin (10 mg L-1) from MWWE. The toxicity of ciprofloxacin against some G+ and G- bacteria was reduced by 35-70 %, depending on their strain. The EC50 of ciprofloxacin for the alga Raphidocelis subcapitata reduced from 3.08 to 1.07 mg L-1 (p-value <0.05) after the bioremoval. Also, the acute and chronic toxicity of identified biodegradation products was lower than ciprofloxacin at three trophic levels, as predicted by ECOSAR software.
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Affiliation(s)
- Hossein Jafari-Nodoushan
- Department of Drug and Food Control, Faculty of Pharmacy, Tehran University of Medical Sciences, P.O. Box 14155-6451, Tehran 1417614411, Iran; Department of Pharmaceutical Biotechnology, Faculty of Pharmacy & Biotechnology Research Center, Tehran University of Medical Sciences, P.O. Box 14155-6451, Tehran 1417614411, Iran
| | - Mohammad Reza Fazeli
- Department of Drug and Food Control, Faculty of Pharmacy, Tehran University of Medical Sciences, P.O. Box 14155-6451, Tehran 1417614411, Iran
| | - Mohammad Ali Faramarzi
- Department of Pharmaceutical Biotechnology, Faculty of Pharmacy & Biotechnology Research Center, Tehran University of Medical Sciences, P.O. Box 14155-6451, Tehran 1417614411, Iran.
| | - Nasrin Samadi
- Department of Drug and Food Control, Faculty of Pharmacy, Tehran University of Medical Sciences, P.O. Box 14155-6451, Tehran 1417614411, Iran; Pharmaceutical Quality Assurance Research Center, The Institute of Pharmaceutical Sciences (TIPS), Tehran University of Medical Sciences, Tehran, Iran.
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Dong CD, Tiwari A, Anisha GS, Chen CW, Singh A, Haldar D, Patel AK, Singhania RR. Laccase: A potential biocatalyst for pollutant degradation. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 319:120999. [PMID: 36608728 DOI: 10.1016/j.envpol.2023.120999] [Citation(s) in RCA: 22] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 12/13/2022] [Accepted: 12/31/2022] [Indexed: 06/17/2023]
Abstract
In the continual march to a predominantly urbanized civilization, anthropogenic activities have increased scrupulously, industrialization have occurred, economic growth has increased, and natural resources are being exploited, causing huge waste management problems, disposal issues, and the evolution of several pollutants. In order to have a sustainable environment, these pollutants need to be removed and degraded. Bioremediation employing microorganisms or enzymes can be used to treat the pollutants by degrading and/or transforming the pollutants into different form which is less or non-toxic to the environment. Laccase is a diverse enzyme/biocatalyst belonging to the oxidoreductase group of enzymes produced by microorganisms. Due to its low substrate specificity and monoelectronic oxidation of substrates in a wide range of complexes, it is most commonly used to degrade chemical pollutants. For degradation of emerging pollutants, laccase can be efficiently employed; however, large-scale application needs reusability, thermostability, and operational stability which necessitated strategies like immobilization and engineering of robust laccase possessing desirable properties. Immobilization of laccase for bioremediation, and treatment of wastewater for degrading emerging pollutants have been focussed for sustainable development. Challenges of employing biocatalysts for these applications as well as engineering robust laccase have been highlighted in this study.
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Affiliation(s)
- Cheng-Di Dong
- Institute of Aquatic Science and Technology, College of Hydrosphere, National Kaohsiung University of Science and Technology, Kaohsiung City, 81157, Taiwan; Department of Marine Environmental Engineering, College of Hydrosphere, National Kaohsiung University of Science and Technology, Kaohsiung City, 81157, Taiwan
| | - Ashutosh Tiwari
- Institute of Aquatic Science and Technology, College of Hydrosphere, National Kaohsiung University of Science and Technology, Kaohsiung City, 81157, Taiwan
| | - Grace Sathyanesan Anisha
- Post-graduate and Research Department of Zoology, Government College for Women, Thiruvananthapuram, 695014, Kerala, India
| | - Chiu-Wen Chen
- Institute of Aquatic Science and Technology, College of Hydrosphere, National Kaohsiung University of Science and Technology, Kaohsiung City, 81157, Taiwan; Department of Marine Environmental Engineering, College of Hydrosphere, National Kaohsiung University of Science and Technology, Kaohsiung City, 81157, Taiwan
| | - Anusuiya Singh
- Department of Marine Environmental Engineering, College of Hydrosphere, National Kaohsiung University of Science and Technology, Kaohsiung City, 81157, Taiwan
| | - Dibyajyoti Haldar
- Department of Biotechnology, Karunya Institute of Technology and Sciences, Coimbatore, Tamil Nadu, 641114, India
| | - Anil Kumar Patel
- Institute of Aquatic Science and Technology, College of Hydrosphere, National Kaohsiung University of Science and Technology, Kaohsiung City, 81157, Taiwan; Centre for Energy and Environmental Sustainability, Lucknow, 226 029, Uttar Pradesh, India
| | - Reeta Rani Singhania
- Department of Marine Environmental Engineering, College of Hydrosphere, National Kaohsiung University of Science and Technology, Kaohsiung City, 81157, Taiwan; Sustainable Environment Research Center, National Kaohsiung University of Science and Technology, Kaohsiung City, 81157, Taiwan; Centre for Energy and Environmental Sustainability, Lucknow, 226 029, Uttar Pradesh, India.
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6
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NMR Study on Laccase Polymerization of Kraft Lignin Using Different Enzymes Source. Int J Mol Sci 2023; 24:ijms24032359. [PMID: 36768678 PMCID: PMC9917248 DOI: 10.3390/ijms24032359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 01/19/2023] [Accepted: 01/21/2023] [Indexed: 01/27/2023] Open
Abstract
The usage of laccases is a sustainable and environmentally friendly approach to modifying the Kraft lignin structure for use in certain applications. However, the inherent structure of Kraft lignin, as well as that resulting from laccase modification, still presents challenges for fundamental comprehension and successful lignin valorization. In this study, bacterial and fungal laccases were employed to modify eucalypt Kraft lignin. To evaluate the type and range of the chemical and structural changes of laccase-treated lignins, different NMR techniques, including solution 1H and 2D NMR (heteronuclear single quantum correlation (HSQC)), and solid-state 13C NMR, were applied. Size exclusion chromatography and infrared spectroscopy were also used. Interestingly, HSQC analysis showed substantial changes in the oxygenated aliphatic region of lignins, showing an almost complete absence of signals corresponding to side-chains due to laccase depolymerization. Simultaneously, a significant loss of aromatic signals was observed by HSQC and 1H NMR, which was attributed to a deprotonation of the lignin benzenic rings due to polymerization/condensation by laccase reactions. Then, condensed structures, such as α-5', 5-5', and 4-O-5', were detected by HSQC and 13C NMR, supporting the increment in molecular weight, as well as the phenolic content reduction determined in lignins.
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7
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Enzyme-Catalyzed Polymerization of Kraft Lignin from Eucalyptus globulus: Comparison of Bacterial and Fungal Laccases Efficacy. Polymers (Basel) 2023; 15:polym15030513. [PMID: 36771814 PMCID: PMC9920240 DOI: 10.3390/polym15030513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 01/11/2023] [Accepted: 01/13/2023] [Indexed: 01/21/2023] Open
Abstract
Kraft lignin, a side-stream from the pulp and paper industry, can be modified by laccases for the synthesis of high added-value products. This work aims to study different laccase sources, including a bacterial laccase from Streptomyces ipomoeae (SiLA) and a fungal laccase from Myceliophthora thermophila (MtL), for kraft lignin polymerization. To study the influence of some variables in these processes, a central composite design (CCD) with two continuous variables (enzyme concentration and reaction time) and three levels for each variable was used. The prediction of the behavior of the output variables (phenolic content and molecular weight of lignins) were modelled by means of response surface methodology (RSM). Moreover, characterization of lignins was performed by Fourier-transform infrared (FTIR) spectroscopy and different nuclear magnetic resonance (NMR) spectroscopy techniques. In addition, antioxidant activity was also analyzed. Results showed that lignin polymerization (referring to polymerization as lower phenolic content and higher molecular weight) occurred by the action of both laccases. The enzyme concentration was the most influential variable in the lignin polymerization reaction within the range studied for SiLA laccase, while the most influential variable for MtL laccase was the reaction time. FTIR and NMR characterization analysis corroborated lignin polymerization results obtained from the RSM.
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Marino I, Pignataro E, Danzi D, Cellini F, Cardellicchio C, Biundo A, Pisano I, Capozzi MAM. A comparative screening of laccase-mediator systems by white-rot fungi laccases for biocatalytic benzyl alcohol oxidation. Sci Rep 2022; 12:21602. [PMID: 36517502 PMCID: PMC9751274 DOI: 10.1038/s41598-022-24839-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 11/21/2022] [Indexed: 12/15/2022] Open
Abstract
Production of value-added compounds from waste materials is of utmost importance for the development of a sustainable society especially regarding their use as catalysts in industrially relevant synthetic reactions. Herein, we show the production of laccases from four white-rot fungi, which were grown on agricultural residues, specifically Trametes versicolor 11269, Pleurotus ostreatus 1020, Panus tigrinus 707 and Lentinula edodes SC-495. The produced laccases were tested on a laccase-mediator system (LMS) for the biocatalytic oxidation of the model substrate benzyl alcohol into benzaldehyde. The LMS was carried out in the presence both of tetrahydrofuran as co-solvent and of the mediator 2,2,6,6-tetramethyl-1-piperidinyloxyl (TEMPO) due to its high redox potential and its ability to perform the oxidation. Tolerance studies showed that the dialyzed solutions were able to tolerate 1% (99:1 v/v) of co-solvent, whereas a concentration of 10% v/v had a detrimental activity. Performances in the biocatalytic oxidation of laccase solutions from different purification steps were compared. Similar conversion was observed for laccase in dialysis (raw) and gel filtration (GF) product versus commercial T. versicolor laccase. The latter oxidized almost 99% of substrate while the other laccase solutions were able to reach a conversion from 91% for the laccase solution from P. tigrinus 707 after dialysis, to 50% for the laccase solution from P. ostreatus 1020 after gel filtration. This work highlights the potential of unpurified laccase solutions to be used as catalysts in synthetic reactions.
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Affiliation(s)
- Ivana Marino
- Agenzia Lucana di Sviluppo e Innovazione in Agricoltura (ALSIA), Centro Ricerche Metapontum Agrobios, SS. Jonica 106, Km 448, 2, 75012 Bernalda, Italy
| | - Eugenia Pignataro
- Agenzia Lucana di Sviluppo e Innovazione in Agricoltura (ALSIA), Centro Ricerche Metapontum Agrobios, SS. Jonica 106, Km 448, 2, 75012 Bernalda, Italy ,grid.7644.10000 0001 0120 3326Department of Chemistry, University of Bari Aldo Moro, Via Edoardo Orabona 4, 70125 Bari, Italy
| | - Donatella Danzi
- grid.5326.20000 0001 1940 4177Institute of Biosciences and Bioresources, National Research Council, 70126 Bari, Italy
| | - Francesco Cellini
- Agenzia Lucana di Sviluppo e Innovazione in Agricoltura (ALSIA), Centro Ricerche Metapontum Agrobios, SS. Jonica 106, Km 448, 2, 75012 Bernalda, Italy
| | - Cosimo Cardellicchio
- grid.7644.10000 0001 0120 3326CNR ICCOM, Department of Chemistry, University of Bari Aldo Moro, Via Edoardo Orabona 4, 70125 Bari, Italy
| | - Antonino Biundo
- grid.7644.10000 0001 0120 3326Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari Aldo Moro, Via Edoardo Orabona 4, 70125 Bari, Italy
| | - Isabella Pisano
- grid.7644.10000 0001 0120 3326Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari Aldo Moro, Via Edoardo Orabona 4, 70125 Bari, Italy
| | - Maria Annunziata M. Capozzi
- grid.7644.10000 0001 0120 3326Department of Chemistry, University of Bari Aldo Moro, Via Edoardo Orabona 4, 70125 Bari, Italy
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Abstract
Lignin, a rigid polymer composed of phenolic subunits with high molecular weight and complex structure, ranks behind only cellulose in the contribution to the biomass of plants. Therefore, lignin can be used as a new environmentally friendly resource for the industrial production of a variety of polymers, dyes and adhesives. Since laccase was found to be able to degrade lignin, increasing attention had been paid to the valorization of lignin. Research has mainly focused on the identification of lignin-degrading enzymes, which play a key role in lignin biodegradation, and the potential application of lignin degradation products. In this review, we describe the source, catalytic specificity and enzyme reaction mechanism of the four classes of the lignin-degrading enzymes so far discovered. In addition, the major pathways of lignin biodegradation and the applications of the degradative products are also discussed. Lignin-degrading bacteria or enzymes can be used in combination with chemical pretreatment for the production of value-added chemicals from lignin, providing a promising strategy for lignin valorization.
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Euring M, Ostendorf K, Rühl M, Kües U. Enzymatic Oxidation of Ca-Lignosulfonate and Kraft Lignin in Different Lignin-Laccase-Mediator-Systems and MDF Production. Front Bioeng Biotechnol 2022; 9:788622. [PMID: 35155404 PMCID: PMC8831759 DOI: 10.3389/fbioe.2021.788622] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Accepted: 12/13/2021] [Indexed: 11/13/2022] Open
Abstract
Laccase-mediator-oxidized lignin offers replacement for conventional chemical binders to produce fiberboards. Compared to the previously reported laccase–mediator system (LMS), a lignin-laccase-mediator-system (LLMS) has an advantage in that it requires much shorter fiber-enzyme incubation time due to significantly increased redox reactions. However, the cost of regularly applying laccase on an industrial scale is currently too high. We have employed CcLcc5 from cultures of the basidiomycete Coprinopsis cinerea as a novel basi-laccase (a CAZy subfamily AA1_1 laccase) in medium-density fiberboard (MDF) production, in comparison to the commercial formulation Novozym 51003 with recombinantly produced asco-laccase MtL (a CAZy subfamily AA1_3 laccase-like multicopper oxidase from the ascomycete Myceliophthora thermophila). With the best-performing natural mediator 2,6-dimethoxyphenol (DMP), unpurified CcLcc5 was almost as good as formulated Novozym 51003 in increasing the molecular weight (MW) of the technical lignins tested, the hydrophilic high-MW Ca-lignosulfonate and the hydrophobic low-MW kraft lignin (Indulin AT). Oxygen consumption rates of the two distantly related, poorly conserved enzymes (31% sequence identity) with different mediators and lignosulfonate were also comparable, but Indulin AT significantly reduced the oxidative activity of Novozym 51003 unlike CcLcc5, regardless of the mediator used, either DMP or guaiacol. Oxygen uptake by both laccases was much faster with both technical lignins with DMP than with guaiacol. In case of lignosulfonate and DMP, 20–30 min of incubation was sufficient for full oxygen consumption, which fits in well in time with the usual binder application steps in industrial MDF production processes. LLMS-bonded MDF was thus produced on a pilot-plant scale with either crude CcLcc5 or Novozym 51003 at reduced enzyme levels of 5 kU/kg absolutely dry wood fiber with lignosulfonate and mediator DMP. Boards produced with CcLcc5 were comparably good as those made with Novozym 51003. Boards reached nearly standard specifications in internal bond strength (IB) and modulus of rupture (MOR), while thickness swelling (TS) was less good based on the hydrophilic character of lignosulfonate. LLMS-bonded MDF with Indulin AT and DMP performed better in TS but showed reduced IB and MOR values.
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Affiliation(s)
- Markus Euring
- Department of Molecular Wood Biotechnology and Technical Mycology, Büsgen-Institute, Georg-August-University of Göttingen, Göttingen, Germany
- Department of Wood Technology and Wood-based Composites, Burckhardt-Institute, Georg-August-University of Göttingen, Göttingen, Germany
- *Correspondence: Markus Euring, ; Ursula Kües,
| | - Kolja Ostendorf
- Department of Molecular Wood Biotechnology and Technical Mycology, Büsgen-Institute, Georg-August-University of Göttingen, Göttingen, Germany
- Department of Wood Technology and Wood-based Composites, Burckhardt-Institute, Georg-August-University of Göttingen, Göttingen, Germany
| | - Martin Rühl
- Department of Molecular Wood Biotechnology and Technical Mycology, Büsgen-Institute, Georg-August-University of Göttingen, Göttingen, Germany
- Department of Biology and Chemistry, Institute of Food Chemistry and Food Biotechnology, Justus Liebig University Giessen, Gießen, Germany
- Current address, Department of Food and Feed Improvement Agents, Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Gießen, Germany
| | - Ursula Kües
- Department of Molecular Wood Biotechnology and Technical Mycology, Büsgen-Institute, Georg-August-University of Göttingen, Göttingen, Germany
- Center for Molecular Biosciences (GZMB), Göttingen, Germany
- Center of Sustainable Land Use, University of Göttingen, Göttingen, Germany
- *Correspondence: Markus Euring, ; Ursula Kües,
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