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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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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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Ovejero-Pérez A, Rigual V, Domínguez JC, Alonso MV, Oliet M, Rodriguez F. Effect of autohydrolysis and ionosolv treatments on eucalyptus fractionation and recovered lignin properties †. RSC Adv 2023; 13:10338-10348. [PMID: 37020891 PMCID: PMC10068429 DOI: 10.1039/d2ra08013c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 03/20/2023] [Indexed: 04/05/2023] Open
Abstract
Wood fractionation is key for the integral valorization of its three main components. In this sense, recovering the hemicellulosic fraction after the ionosolv treatment of lignocellulosic materials is one of the main drawbacks of this process. Thus, the incorporation of a previous autohydrolyisis step to recover the hemicellulosic sugars before the ionosolv treatment is an interesting approach. The influence of both treatments, autohydrolysis and ionosolv, on the biomass fractions recovery yields was studied by a central composite design of experiments, varying the autohydrolysis temperature in a 175–195 °C range and ionosolv time between 1–5 h. Lignin recovery and cellulose purity were maximized at 184 °C and 3.5 h of autohydrolysis temperature and ionosolv time, respectively. In addition, lignin properties were incorporated to the statistical model, revealing lignin recondensation at severe conditions and a higher influence of the ionosolv treatment on lignin characteristics. These results remarked the importance of studying the effect of both treatments in the whole fractionation process and not each process separately and enhanced the understanding of the treatments combination in a complete fractionation biorefinery approach. This work enhances the understanding of the effect of autohydrolysis and ionosolv treatments combination on fractionation yields and lignin properties.![]()
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Affiliation(s)
- Antonio Ovejero-Pérez
- Department of Chemical Engineering and Materials, Complutense University of Madrid28040 MadridSpain
| | - Victoria Rigual
- Department of Chemical Engineering and Materials, Complutense University of Madrid28040 MadridSpain
| | - Juan C. Domínguez
- Department of Chemical Engineering and Materials, Complutense University of Madrid28040 MadridSpain
| | - M. Virginia Alonso
- Department of Chemical Engineering and Materials, Complutense University of Madrid28040 MadridSpain
| | - Mercedes Oliet
- Department of Chemical Engineering and Materials, Complutense University of Madrid28040 MadridSpain
| | - Francisco Rodriguez
- Department of Chemical Engineering and Materials, Complutense University of Madrid28040 MadridSpain
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Emulsion Stabilization by Cationic Lignin Surfactants Derived from Bioethanol Production and Kraft Pulping Processes. Polymers (Basel) 2022; 14:polym14142879. [PMID: 35890655 PMCID: PMC9317533 DOI: 10.3390/polym14142879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 07/01/2022] [Accepted: 07/12/2022] [Indexed: 02/01/2023] Open
Abstract
Oil-in-water bitumen emulsions stabilized by biobased surfactants such as lignin are in line with the current sustainable approaches of the asphalt industry involving bitumen emulsions for reduced temperature asphalt technologies. With this aim, three lignins, derived from the kraft pulping and bioethanol industries, were chemically modified via the Mannich reaction to be used as cationic emulsifiers. A comprehensive chemical characterization was conducted on raw lignin-rich products, showing that the kraft sample presents a higher lignin concentration and lower molecular weight. Instead, bioethanol-derived samples, with characteristics of non-woody lignins, present a high concentration of carbohydrate residues and ashes. Lignin amination was performed at pH = 10 and 13, using tetraethylene pentamine and formaldehyde as reagents at three different stoichiometric molar ratios. The emulsification ability of such cationic surfactants was firstly studied on prototype silicone oil-in-water emulsions, attending to their droplet size distribution and viscous behavior. Among the synthetized surfactants, cationic kraft lignin has shown the best emulsification performance, being used for the development of bitumen emulsions. In this regard, cationic kraft lignin has successfully stabilized oil-in-water emulsions containing 60% bitumen using small surfactant concentrations, between 0.25 and 0.75%, which was obtained at pH = 13 and reagent molar ratios between 1/7/7 and 1/28/28 (lignin/tetraethylene pentamine/formaldehyde).
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García-Fuentevilla L, Rubio-Valle JF, Martín-Sampedro R, Valencia C, Eugenio ME, Ibarra D. Different Kraft lignin sources for electrospun nanostructures production: Influence of chemical structure and composition. Int J Biol Macromol 2022; 214:554-567. [PMID: 35752340 DOI: 10.1016/j.ijbiomac.2022.06.121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 06/13/2022] [Accepted: 06/17/2022] [Indexed: 11/05/2022]
Abstract
This work focuses on the structural features and physicochemical properties of different Kraft lignins and how they can influence the electrospinning process to obtain nanostructures. Structural features of Kraft lignins were characterized by Nuclear Magnetic Resonance, Size Exclusion Chromatography, Fourier-transform Infrared Spectroscopy, and thermal analysis, whereas chemical composition was analyzed by standard method. The addition of cellulose acetate (CA) improves the electrospinning process of Kraft lignins (KL). Thus, solutions of KL/CA at 30 wt% with a KL:CA weight ratio of 70:30 were prepared and then physicochemical and rheologically characterized. The morphology of electrospun nanostructures depends on the intrinsic properties of the solutions and the chemical structure and composition of Kraft lignins. Then, surface tension, electrical conductivity and viscosity of eucalypt/CA and poplar/CA solutions were suitable to obtain electrospun nanostructures based on uniform cross-linked nanofibers with a few beaded fibers. It could be related with the higher purity and higher linear structure, phenolic content and S/G ratios of lignin samples. However, the higher values of electrical conductivity and viscosity of OTP/CA solutions resulted in electrospun nanostructure with micro-sized particles connected by thin fibers, due to a lower purity, S/G ratio and phenolic content and higher branched structure in OTP lignin.
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Affiliation(s)
| | - José F Rubio-Valle
- Pro2TecS-Chemical Process and Product Technology Research Centre, Departamento de Ingeniería Química, ETSI, Campus de "El Carmen", Universidad de Huelva, 21071 Huelva, Spain
| | | | - Concepción Valencia
- Pro2TecS-Chemical Process and Product Technology Research Centre, Departamento de Ingeniería Química, ETSI, Campus de "El Carmen", Universidad de Huelva, 21071 Huelva, Spain
| | - María E Eugenio
- Forest Research Center, INIA-CSIC, Ctra. de la Coruña, km 7.5., 28040 Madrid, Spain.
| | - David Ibarra
- Forest Research Center, INIA-CSIC, Ctra. de la Coruña, km 7.5., 28040 Madrid, Spain
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Ovejero-Pérez A, Rigual V, Domínguez JC, Alonso MV, Oliet M, Rodriguez F. Organosolv and ionosolv processes for autohydrolyzed poplar fractionation: Lignin recovery and characterization. Int J Biol Macromol 2021; 197:131-140. [PMID: 34971638 DOI: 10.1016/j.ijbiomac.2021.12.079] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 11/29/2021] [Accepted: 12/12/2021] [Indexed: 11/05/2022]
Abstract
Biomass fractionation plays a major role in the search for competitive biorefineries, where the isolation and recovery of the three woody fractions is key. In this sense, we have used autohydrolyzed hemicellulose-free poplar as feedstock to compare two fractionation processes, organosolv and ionosolv, oriented to lignin recovery. The recovered lignins were then characterize by different techniques (NMR, GPC, TGA). Both treatments were tested at different temperatures to analyze temperature influence on lignin recovery and properties. The highest lignin recovery was obtained with the ionosolv process at 135 °C, reaching a solid yield of ~70%. Lignin characterization showed differences between both treatments. Lignins enriched in C-O linkages and G units were recovered with the organosolv process, where increasing temperature led to highly depolymerized lignins. However, lignins with higher C-C linkages and S units contents were obtained with the ionosolv process, producing more thermically stable lignins. In addition, increasing temperature caused lignin repolymerization when employing ionic liquids as solvents. Therefore, this work outlines the most important differences between ionosolv and organosolv processes for biomass fractionation, focusing on lignin recovery and its properties, which is the first step in order to valorize all biomass fractions.
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Affiliation(s)
- Antonio Ovejero-Pérez
- Department of Chemical Engineering and Materials, Complutense University of Madrid, Av Complutense s/n, 28040 Madrid, Spain.
| | - Victoria Rigual
- Department of Chemical Engineering and Materials, Complutense University of Madrid, Av Complutense s/n, 28040 Madrid, Spain
| | - Juan Carlos Domínguez
- Department of Chemical Engineering and Materials, Complutense University of Madrid, Av Complutense s/n, 28040 Madrid, Spain
| | - M Virginia Alonso
- Department of Chemical Engineering and Materials, Complutense University of Madrid, Av Complutense s/n, 28040 Madrid, Spain
| | - Mercedes Oliet
- Department of Chemical Engineering and Materials, Complutense University of Madrid, Av Complutense s/n, 28040 Madrid, Spain
| | - Francisco Rodriguez
- Department of Chemical Engineering and Materials, Complutense University of Madrid, Av Complutense s/n, 28040 Madrid, Spain
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Eugenio ME, Martín-Sampedro R, Santos JI, Wicklein B, Ibarra D. Chemical, Thermal and Antioxidant Properties of Lignins Solubilized during Soda/AQ Pulping of Orange and Olive Tree Pruning Residues. Molecules 2021; 26:3819. [PMID: 34201524 PMCID: PMC8270295 DOI: 10.3390/molecules26133819] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 06/18/2021] [Accepted: 06/18/2021] [Indexed: 11/20/2022] Open
Abstract
Some agroforestry residues such as orange and olive tree pruning have been extensively evaluated for their valorization due to its high carbohydrates content. However, lignin-enriched residues generated during carbohydrates valorization are normally incinerated to produce energy. In order to find alternative high added-value applications for these lignins, a depth characterization of them is required. In this study, lignins isolated from the black liquors produced during soda/anthraquinone (soda/AQ) pulping of orange and olive tree pruning residues were analyzed by analytical standard methods and Fourier-transform infrared spectroscopy (FTIR), nuclear magnetic resonance (solid state 13C NMR and 2D NMR) and size exclusion chromatography (SEC). Thermal analysis (thermogravimetric analysis (TGA), differential scanning calorimetry (DSC)) and antioxidant capacity (Trolox equivalent antioxidant capacity) were also evaluated. Both lignins showed a high OH phenolic content as consequence of a wide breakdown of β-aryl ether linkages. This extensive degradation yielded lignins with low molecular weights and polydispersity values. Moreover, both lignins exhibited an enrichment of syringyl units together with different native as well as soda/AQ lignin derived units. Based on these chemical properties, orange and olive lignins showed relatively high thermal stability and good antioxidant activities. These results make them potential additives to enhance the thermo-oxidation stability of synthetic polymers.
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Affiliation(s)
- María E. Eugenio
- Forest Research Center (INIA, CSIC), Ctra. de la Coruña Km 7.5, 28040 Madrid, Spain; (M.E.E.); (R.M.-S.)
| | - Raquel Martín-Sampedro
- Forest Research Center (INIA, CSIC), Ctra. de la Coruña Km 7.5, 28040 Madrid, Spain; (M.E.E.); (R.M.-S.)
| | - José I. Santos
- NMR of Facility of Research (SGIker), University of the Basque Country (UPV/EHU), Avenida Tolosa 72, 20018 Donostia-San Sebastián, Spain;
| | - Bernd Wicklein
- Materials Science Institute of Madrid (ICMM), Consejo Superior de Investigaciones Científicas (CSIC), Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain;
| | - David Ibarra
- Forest Research Center (INIA, CSIC), Ctra. de la Coruña Km 7.5, 28040 Madrid, Spain; (M.E.E.); (R.M.-S.)
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