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Lau SH, Chang YT. Selective biodegradation of octylphenol polyethoxylates with different ethoxylate length chains by aerobic bacterial culture. CHEMOSPHERE 2024; 361:142538. [PMID: 38844102 DOI: 10.1016/j.chemosphere.2024.142538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2024] [Revised: 05/05/2024] [Accepted: 06/03/2024] [Indexed: 06/11/2024]
Abstract
Octylphenol polyethoxylates (OPEOn) are composed of a hydrophobic octylphenol (OP) group and a hydrophilic polyethylene oxide (EO) chain and are widely used in commercial products. Shorter EO chains and OPEOn biometabolites have been identified as endocrine-disrupting contaminants and can threaten biotic factors in the ecosystem. In this study, OPEOn at three EO lengths (TX-45, TX-114, and TX-165) were selected in monomer (MN) or micelle (MC) state for batch experiments under aerobic conditions, with results showing biodegradation rates of 90 % within 35-70 h. The pseudo-first-order constant (k) of OPEOn biodegradation was observed in the order TX-45 (0.1414 h-1) > TX-114 (0.0556 h-1) > TX-165 (0.0485 h-1), with biomineralisation reaching at least 80 % for all OPEOn. The selective biodegradation of EO chains was also measured, with initial accumulation of OPEO3 observed along with the depletion of longer EO chains for TX-45 and TX-114 in both the MN and MC states. A similar trend was observed for the MN state of TX-165, with OPEO3-OPEO9 observed to accumulate and reduced after 70 h. MC biodegradation was accomplished via the initial accumulation of OPEO3-OPEO9. The amounts of OPEO3 increased and others reduced; however, OPEO3 remained high at the end of biodegradation for TX-165. Bacterial community analysis indicated that the genera Sphingobium spp., Pseudomonas spp., Flavobacterium spp., Comamonas spp., and Sphingopyxis spp. dominate OPEOn biodegradation, and they have their roles during biodegradation, and the community-level physiological profile (CLPP) was also changed by biodegradation in both the MN and MC states.
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Affiliation(s)
- Sai Hung Lau
- Department of Microbiology, The Chinese University of Hong Kong, Hong Kong, China
| | - Yi-Tang Chang
- Department of Microbiology, Soochow University, Taipei, 11102, Taiwan.
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Zhang D, Liu J, Xu H, Liu H, He YC. Improving saccharification efficiency of corn stover through ferric chloride-deep eutectic solvent pretreatment. BIORESOURCE TECHNOLOGY 2024; 399:130579. [PMID: 38479628 DOI: 10.1016/j.biortech.2024.130579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 03/10/2024] [Accepted: 03/10/2024] [Indexed: 03/22/2024]
Abstract
An effective deep eutectic solvent (DES) and Iron(III) chloride (FeCl3) combination pretreatment system was developed to improve the removal efficiency of lignin and hemicellulose from corn stover (CS) and enhance its saccharification. N-(2-hydroxyethyl)ethylenediamine (NE) was selected as the hydrogen-bond-donor for preparing ChCl-based DES (ChCl:NE), and a mixture of ChCl:NE (60 wt%) and FeCl3 (0.5 wt%) was utilized for combination pretreatment of CS at 110 ℃ for 50 min. FeCl3/ChCl:NE effectively removed lignin (87.0 %) and xylan (55.9 %) and the enzymatic hydrolysis activity of FeCl3/ChCl:NE-treated CS was 5.5 times that of CS. The reducing sugar yield of pretreated CS was 98.6 %. FeCl3/ChCl:NE significantly disrupted the crystal structure of cellulose in CS and improved the removal of lignin and hemicellulose, enhancing the conversion of cellulose and hemicellulose into monomeric sugars. Overall, this combination of FeCl3 and DES pretreatment methods has high application potential for the biological refining of lignocellulose.
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Affiliation(s)
- Danping Zhang
- College of Food Engineering, Xuzhou University of Technology, Xuzhou 221018, PR China
| | - Jia Liu
- College of Food Engineering, Xuzhou University of Technology, Xuzhou 221018, PR China
| | - Haixu Xu
- College of Food Engineering, Xuzhou University of Technology, Xuzhou 221018, PR China
| | - Hanxiao Liu
- College of Food Engineering, Xuzhou University of Technology, Xuzhou 221018, PR China
| | - Yu-Cai He
- School of Pharmacy, National-Local Joint Engineering Research Center of Biomass Refining and High-Quality Utilization, Changzhou University, Changzhou 213164, PR China; State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan 430062, PR China.
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Liu E, Mercado MIV, Segato F, Wilkins MR. A green pathway for lignin valorization: Enzymatic lignin depolymerization in biocompatible ionic liquids and deep eutectic solvents. Enzyme Microb Technol 2024; 174:110392. [PMID: 38171172 DOI: 10.1016/j.enzmictec.2023.110392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 12/20/2023] [Accepted: 12/22/2023] [Indexed: 01/05/2024]
Abstract
Lignin depolymerization, which enables the breakdown of a complex and heterogeneous aromatic polymer into relatively uniform derivatives, serves as a critical process in valorization of lignin. Enzymatic lignin depolymerization has become a promising biological strategy to overcome the heterogeneity of lignin, due to its mild reaction conditions and high specificity. However, the low solubility of lignin compounds in aqueous environments prevents efficient lignin depolymerization by lignin-degrading enzymes. The employment of biocompatible ionic liquids (ILs) and deep eutectic solvents (DESs) in lignin fractionation has created a promising pathway to enzymatically depolymerize lignin within these green solvents to increase lignin solubility. In this review, recent research progress on enzymatic lignin depolymerization, particularly in a consolidated process involving ILs/DESs is summarized. In addition, the interactions between lignin-degrading enzymes and solvent systems are explored, and potential protein engineering methodology to improve the performance of lignin-degrading enzymes is discussed. Consolidation of enzymatic lignin depolymerization and biocompatible ILs/DESs paves a sustainable, efficient, and synergistic way to convert lignin into value-added products.
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Affiliation(s)
- Enshi Liu
- Department of Biological Systems Engineering, University of Nebraska-Lincoln, Lincoln, NE, USA
| | | | - Fernando Segato
- Department of Biotechnology, University of São Paulo, Lorena, SP, Brazil
| | - Mark R Wilkins
- Carl and Melinda Helwig Department of Biological and Agricultural Engineering, Kansas State University, Manhattan, KS, USA.
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Bossa M, Alaniz-Zanon MS, Monesterolo NE, Monge MDP, Coria YM, Chulze SN, Chiotta ML. Aflatoxin Decontamination in Maize Steep Liquor Obtained from Bioethanol Production Using Laccases from Species within the Basidiomycota Phylum. Toxins (Basel) 2024; 16:27. [PMID: 38251243 PMCID: PMC10819231 DOI: 10.3390/toxins16010027] [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: 11/30/2023] [Revised: 12/22/2023] [Accepted: 12/28/2023] [Indexed: 01/23/2024] Open
Abstract
Maize (Zea mays L.) is an important crop in Argentina. Aspergillus section Flavi can infect this crop at the pre-harvest stage, and the harvested grains can be contaminated with aflatoxins (AFs). During the production of bioethanol from maize, AF levels can increase up to three times in the final co-products, known as, dry and wet distiller's grain with solubles (DDGS and WDGS), intended for animal feed. Fungal enzymes like laccases can be a useful tool for reducing AF contamination in the co-products obtained from this process. The aim of the present study was to evaluate the ability of laccase enzymes included in enzymatic extracts (EE) produced by different species in the Basidiomycota phylum to reduce AF (AFB1 and AFB2) accumulation under the conditions of in vitro assays. Four laccase activities (5, 10, 15, and 20 U/mL) exerted by nine isolates were evaluated in the absence and presence of vanillic acid (VA), serving as a laccase redox mediator for the degradation of total AFs. The enzymatic stability in maize steep liquor (MSL) was confirmed after a 60 h incubation period. The most effective EE in terms of reducing AF content in the buffer was selected for an additional assay carried out under the same conditions using maize steep liquor obtained after the saccharification stage during the bioethanol production process. The highest degradation percentages were observed at 20 U/mL of laccase enzymatic activity and 1 mM of VA, corresponding to 26% for AFB1 and 26.6% for AFB2. The present study provides valuable data for the development of an efficient tool based on fungal laccases for preventing AF accumulation in the co-products of bioethanol produced from maize used for animal feed.
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Affiliation(s)
- Marianela Bossa
- Instituto de Investigación en Micología y Micotoxicología (IMICO), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)—Universidad Nacional de Río Cuarto (UNRC), Ruta Nacional 36 Km 601, Río Cuarto 5800, Córdoba, Argentina; (M.B.); (M.S.A.-Z.); (M.d.P.M.); (Y.M.C.); (S.N.C.)
| | - María Silvina Alaniz-Zanon
- Instituto de Investigación en Micología y Micotoxicología (IMICO), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)—Universidad Nacional de Río Cuarto (UNRC), Ruta Nacional 36 Km 601, Río Cuarto 5800, Córdoba, Argentina; (M.B.); (M.S.A.-Z.); (M.d.P.M.); (Y.M.C.); (S.N.C.)
| | - Noelia Edith Monesterolo
- Instituto de Biotecnología Ambiental y de la Salud (INBIAS), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)—Universidad Nacional de Río Cuarto (UNRC), Ruta Nacional 36 Km 601, Río Cuarto 5800, Córdoba, Argentina;
| | - María del Pilar Monge
- Instituto de Investigación en Micología y Micotoxicología (IMICO), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)—Universidad Nacional de Río Cuarto (UNRC), Ruta Nacional 36 Km 601, Río Cuarto 5800, Córdoba, Argentina; (M.B.); (M.S.A.-Z.); (M.d.P.M.); (Y.M.C.); (S.N.C.)
| | - Yamila Milagros Coria
- Instituto de Investigación en Micología y Micotoxicología (IMICO), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)—Universidad Nacional de Río Cuarto (UNRC), Ruta Nacional 36 Km 601, Río Cuarto 5800, Córdoba, Argentina; (M.B.); (M.S.A.-Z.); (M.d.P.M.); (Y.M.C.); (S.N.C.)
| | - Sofía Noemí Chulze
- Instituto de Investigación en Micología y Micotoxicología (IMICO), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)—Universidad Nacional de Río Cuarto (UNRC), Ruta Nacional 36 Km 601, Río Cuarto 5800, Córdoba, Argentina; (M.B.); (M.S.A.-Z.); (M.d.P.M.); (Y.M.C.); (S.N.C.)
| | - María Laura Chiotta
- Instituto de Investigación en Micología y Micotoxicología (IMICO), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)—Universidad Nacional de Río Cuarto (UNRC), Ruta Nacional 36 Km 601, Río Cuarto 5800, Córdoba, Argentina; (M.B.); (M.S.A.-Z.); (M.d.P.M.); (Y.M.C.); (S.N.C.)
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Mu X, Sun S, Li Z, Han L, Lv K, Liu T. Molecular mechanism of the transformation of oxidized lignin to N-substituted aromatics. Org Biomol Chem 2023; 21:9356-9361. [PMID: 37927135 DOI: 10.1039/d3ob01398g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2023]
Abstract
The cleavage of C-C bonds in oxidized lignin model compounds is a highly effective methodology for achieving lignin depolymerization, as well the generation of N-substituted aromatics. Here, density functional theory calculations were performed to understand the mechanism of the transformation of an oxidized lignin model compound (ligninox) and hydroxylamine hydrochloride to N-substituted aromatics. The reaction was proposed to proceed via an energetically viable mechanism featuring the initial production of HOAc acting as proton bridge. According to our calculations, Z-type oxime is the major intermediate of the reaction, with an energy barrier of 22.9 kcal mol-1, owing to the weak interactions between methoxy and oximino groups being stronger than that of E-type oxime. Additionally, the hydroxy addition is the rate-determining step, with an energy barrier of 27.0 kcal mol-1. Moreover, the huge net energy change of Beckmann and abnormal Beckmann rearrangements is the main overall thermodynamic driving force for producing N-substituted aromatics from oximes. The theoretical results have provided a clear picture of how ligninox transforms into N-substituted aromatics and are expected to provide valuable theoretical guidance for lignin depolymerization.
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Affiliation(s)
- Xueli Mu
- School of Chemistry, Chemical Engineering and Materials, Jining University, Qufu 273155, Shandong, China.
| | - Shijie Sun
- School of Chemistry, Chemical Engineering and Materials, Jining University, Qufu 273155, Shandong, China.
| | - Zhihao Li
- School of Chemistry, Chemical Engineering and Materials, Jining University, Qufu 273155, Shandong, China.
| | - Lingli Han
- School of Chemistry, Chemical Engineering and Materials, Jining University, Qufu 273155, Shandong, China.
| | - Kang Lv
- School of Chemistry, Chemical Engineering and Materials, Jining University, Qufu 273155, Shandong, China.
| | - Tao Liu
- School of Chemistry, Chemical Engineering and Materials, Jining University, Qufu 273155, Shandong, China.
- School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu 273165, Shandong, China
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Rodríguez-Escribano D, de Salas F, Pliego R, Marques G, Levée T, Suonpää A, Gutiérrez A, Martínez ÁT, Ihalainen P, Rencoret J, Camarero S. Depolymerisation of Kraft Lignin by Tailor-Made Alkaliphilic Fungal Laccases. Polymers (Basel) 2023; 15:4433. [PMID: 38006155 PMCID: PMC10675753 DOI: 10.3390/polym15224433] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 10/30/2023] [Accepted: 11/12/2023] [Indexed: 11/26/2023] Open
Abstract
Lignins released in the black liquors of kraft pulp mills are an underutilised source of aromatics. Due to their phenol oxidase activity, laccases from ligninolytic fungi are suitable biocatalysts to depolymerise kraft lignins, which are characterised by their elevated phenolic content. However, the alkaline conditions necessary to solubilise kraft lignins make it difficult to use fungal laccases whose activity is inherently acidic. We recently developed through enzyme-directed evolution high-redox potential laccases active and stable at pH 10. Here, the ability of these tailor-made alkaliphilic fungal laccases to oxidise, demethylate, and depolymerise eucalyptus kraft lignin at pH 10 is evidenced by the increment in the content of phenolic hydroxyl and carbonyl groups, the methanol released, and the appearance of lower molecular weight moieties after laccase treatment. Nonetheless, in a second assay carried out with higher enzyme and lignin concentrations, these changes were accompanied by a strong increase in the molecular weight and content of β-O-4 and β-5 linkages of the main lignin fraction, indicating that repolymerisation of the oxidised products prevails in one-pot reactions. To prevent it, we finally conducted the enzymatic reaction in a bench-scale reactor coupled to a membrane separation system and were able to prove the depolymerisation of kraft lignin by high-redox alkaliphilic laccase.
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Affiliation(s)
- David Rodríguez-Escribano
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas (CSIC), 28040 Madrid, Spain; (D.R.-E.); (Á.T.M.)
| | - Felipe de Salas
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas (CSIC), 28040 Madrid, Spain; (D.R.-E.); (Á.T.M.)
| | - Rocío Pliego
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas (CSIC), 28040 Madrid, Spain; (D.R.-E.); (Á.T.M.)
| | - Gisela Marques
- Instituto de Recursos Naturales y Agrobiología de Sevilla, Consejo Superior de Investigaciones Científicas (CSIC), 41012 Sevilla, Spain; (G.M.); (A.G.)
| | - Thomas Levée
- MetGen Oy, 20780 Kaarina, Finland (A.S.); (P.I.)
| | - Anu Suonpää
- MetGen Oy, 20780 Kaarina, Finland (A.S.); (P.I.)
| | - Ana Gutiérrez
- Instituto de Recursos Naturales y Agrobiología de Sevilla, Consejo Superior de Investigaciones Científicas (CSIC), 41012 Sevilla, Spain; (G.M.); (A.G.)
| | - Ángel T. Martínez
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas (CSIC), 28040 Madrid, Spain; (D.R.-E.); (Á.T.M.)
| | | | - Jorge Rencoret
- Instituto de Recursos Naturales y Agrobiología de Sevilla, Consejo Superior de Investigaciones Científicas (CSIC), 41012 Sevilla, Spain; (G.M.); (A.G.)
| | - Susana Camarero
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas (CSIC), 28040 Madrid, Spain; (D.R.-E.); (Á.T.M.)
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