1
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Bugg TDH. The chemical logic of enzymatic lignin degradation. Chem Commun (Camb) 2024; 60:804-814. [PMID: 38165282 PMCID: PMC10795516 DOI: 10.1039/d3cc05298b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 12/19/2023] [Indexed: 01/03/2024]
Abstract
Lignin is an aromatic heteropolymer, found in plant cell walls as 20-30% of lignocellulose. It represents the most abundant source of renewable aromatic carbon in the biosphere, hence, if it could be depolymerised efficiently, then it would be a highly valuable source of renewable aromatic chemicals. However, lignin presents a number of difficulties for biocatalytic or chemocatalytic breakdown. Research over the last 10 years has led to the identification of new bacterial enzymes for lignin degradation, and the use of metabolic engineering to generate useful bioproducts from microbial lignin degradation. The aim of this article is to discuss the chemical mechanisms used by lignin-degrading enzymes and microbes to break down lignin, and to describe current methods for generating aromatic bioproducts from lignin using enzymes and engineered microbes.
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Affiliation(s)
- Timothy D H Bugg
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, UK.
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2
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Kato R, Maekawa K, Kobayashi S, Hishiyama S, Katahira R, Nambo M, Higuchi Y, Kuatsjah E, Beckham GT, Kamimura N, Masai E. Stereoinversion via Alcohol Dehydrogenases Enables Complete Catabolism of β-1-Type Lignin-Derived Aromatic Isomers. Appl Environ Microbiol 2023; 89:e0017123. [PMID: 37184397 PMCID: PMC10304671 DOI: 10.1128/aem.00171-23] [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: 02/06/2023] [Accepted: 04/24/2023] [Indexed: 05/16/2023] Open
Abstract
Sphingobium sp. strain SYK-6 is an efficient aromatic catabolic bacterium that can consume all four stereoisomers of 1,2-diguaiacylpropane-1,3-diol (DGPD), which is a ring-opened β-1-type dimer. Recently, LdpA-mediated catabolism of erythro-DGPD was reported in SYK-6, but the catabolic pathway for threo-DGPD was as yet unknown. Here, we elucidated the catabolism of threo-DGPD, which proceeds through conversion to erythro-DGPD. When threo-DGPD was incubated with SYK-6, the Cα hydroxy groups of threo-DGPD (DGPD I and II) were initially oxidized to produce the Cα carbonyl form (DGPD-keto I and II). This initial oxidation step is catalyzed by Cα-dehydrogenases, which belong to the short-chain dehydrogenase/reductase (SDR) family and are involved in the catabolism of β-O-4-type dimers. Analysis of seven candidate genes revealed that NAD+-dependent LigD and LigL are mainly involved in the conversion of DGPD I and II, respectively. Next, we found that DGPD-keto I and II were reduced to erythro-DGPD (DGPD III and IV) in the presence of NADPH. Genes involved in this reduction were sought from Cα-dehydrogenase and ldpA-neighboring SDR genes. The gene products of SLG_12690 (ldpC) and SLG_12640 (ldpB) catalyzed the NADPH-dependent conversion of DGPD-keto I to DGPD III and DGPD-keto II to DGPD IV, respectively. Mutational analysis further indicated that ldpC and ldpB are predominantly involved in the reduction of DGPD-keto. Together, these results demonstrate that SYK-6 harbors a comprehensive catabolic enzyme system to utilize all four β-1-type stereoisomers through successive oxidation and reduction reactions of the Cα hydroxy group of threo-DGPD with a net stereoinversion using multiple dehydrogenases. IMPORTANCE In many catalytic depolymerization processes of lignin polymers, aryl-ether bonds are selectively cleaved, leaving carbon-carbon bonds between aromatic units intact, including dimers and oligomers with β-1 linkages. Therefore, elucidating the catabolic system of β-1-type lignin-derived compounds will aid in the establishment of biological funneling of heterologous lignin-derived aromatic compounds to value-added products. Here, we found that threo-DGPD was converted by successive stereoselective oxidation and reduction at the Cα position by multiple alcohol dehydrogenases to erythro-DGPD, which is further catabolized. This system is very similar to that developed to obtain enantiopure alcohols from racemic alcohols by artificially combining two enantiocomplementary alcohol dehydrogenases. The results presented here demonstrate that SYK-6 has evolved to catabolize all four stereoisomers of DGPD by incorporating this stereoinversion system into its native β-1-type dimer catabolic system.
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Affiliation(s)
- Ryo Kato
- Department of Materials Science and Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, Japan
| | - Kodai Maekawa
- Department of Materials Science and Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, Japan
| | - Shota Kobayashi
- Department of Materials Science and Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, Japan
| | - Shojiro Hishiyama
- Department of Forest Resource Chemistry, Forestry and Forest Products Research Institute, Tsukuba, Ibaraki, Japan
| | - Rui Katahira
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Miki Nambo
- Department of Materials Science and Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, Japan
| | - Yudai Higuchi
- Department of Materials Science and Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, Japan
| | - Eugene Kuatsjah
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Gregg T. Beckham
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Naofumi Kamimura
- Department of Materials Science and Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, Japan
| | - Eiji Masai
- Department of Materials Science and Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, Japan
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3
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Allemann MN, Presley GN, Elkins JG, Michener JK. Sphingobium lignivorans sp. nov., isolated from river sediment downstream of a paper mill. Int J Syst Evol Microbiol 2023; 73. [PMID: 36790427 DOI: 10.1099/ijsem.0.005704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023] Open
Abstract
A bacterial isolate, B1D3AT, was isolated from river sediment collected from the Hiwassee River near Calhoun, TN, by enrichment culturing with a model 5-5' lignin dimer, dehydrodivanillate, as its sole carbon source. B1D3AT was also shown to utilize several model lignin-derived monomers and dimers as sole carbon sources in a variety of minimal media. Cells were Gram-stain-negative, aerobic, motile, rod-shaped and formed yellow/cream-coloured colonies on rich agar. Optimal growth occurred at 30 °C, pH 7-8, and in the absence of NaCl. The major fatty acids of B1D3AT were C18 : 1 ω7c and C17 : 1 ω6c. The predominant hydroxy fatty acids were C14 : 0 2-OH and C15 : 0 2-OH. The polar lipid profile consisted of a mixture of phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidyldimethylethanolamine and sphingoglycolipid. B1D3AT contained spermidine as the only major polyamine. The major isoprenoid quinone was Q-10 with minor amounts of Q-9 and Q-11. The genomic DNA G+C content of B1D3AT was 65.6 mol%. Phylogenetic analyses based on 16S rRNA gene sequences and coding sequences of 49 core, universal genes defined by Clusters of Orthologous Groups gene families indicated that B1D3AT was a member of the genus Sphingobium. B1D3AT was most closely related to Sphingobium sp. SYK-6, with a 100 % 16S rRNA gene sequence similarity. B1D3AT showed 78.1-89.9 % average nucleotide identity and 19.5-22.2% digital DNA-DNA hybridization identity with other type strains from the genus Sphingobium. On the basis of phenotypic and genotypic properties and phylogenetic inference, strain B1D3AT should be classified as representing a novel species of the genus Sphingobium, for which the name Sphingobium lignivorans sp. nov. is proposed. The type strain is strain B1D3AT (ATCC TSD-279T=DSM 111877T).
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Affiliation(s)
- Marco N Allemann
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
| | - Gerald N Presley
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA.,Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA.,Present address: Wood Science and Engineering, Oregon State University, Corvallis, OR 97331, USA
| | - James G Elkins
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA.,Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
| | - Joshua K Michener
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA.,Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
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4
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Molecular Mechanism of Chloramphenicol and Thiamphenicol Resistance Mediated by a Novel Oxidase, CmO, in Sphingomonadaceae. Appl Environ Microbiol 2023; 89:e0154722. [PMID: 36519886 PMCID: PMC9888274 DOI: 10.1128/aem.01547-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Antibiotic resistance mediated by bacterial enzyme inactivation plays a crucial role in the degradation of antibiotics in the environment. Chloramphenicol (CAP) resistance by enzymatic inactivation comprises nitro reduction, amide bond hydrolysis, and acetylation modification. However, the molecular mechanism of enzymatic oxidation of CAP remains unknown. Here, a novel oxidase gene, cmO, was identified and confirmed biochemically. The encoded CmO oxidase could catalyze the oxidation at the C-1' and C-3' positions of CAP and thiamphenicol (TAP) in Sphingobium sp. strain CAP-1. CmO is highly conserved in members of the family Sphingomonadaceae and shares the highest amino acid similarity of 41.05% with the biochemically identified glucose methanol choline (GMC) oxidoreductases. Molecular docking and site-directed mutagenesis analyses demonstrated that CAP was anchored inside the protein pocket of CmO with the hydrogen bonding of key residues glycine (G) 99, asparagine (N) 518, methionine (M) 474, and tyrosine (Y) 380. CAP sensitivity tests demonstrated that the acetyltransferase and CmO could enable a higher level of resistance to CAP than the amide bond-hydrolyzing esterase and nitroreductase. This study provides a better theoretical basis and a novel diagnostic gene for understanding and assessing the fate and resistance risk of CAP and TAP in the environment. IMPORTANCE Rising levels of antibiotic resistance are undermining ecological and human health as a result of the indiscriminate usage of antibiotics. Various resistance mechanisms have been characterized-for example, genes encoding proteins that degrade antibiotics-and yet, this requires further exploration. In this study, we report a novel gene encoding an oxidase involved in the inactivation of typical amphenicol antibiotics (chloramphenicol and thiamphenicol), and the molecular mechanism is elucidated. The findings provide novel data with which to understand the capabilities of bacteria to tackle antibiotic stress, as well as the complex function of enzymes in the contexts of antibiotic resistance development and antibiotic removal. The reported gene can be further employed as an indicator to monitor amphenicol's fate in the environment, thus benefiting risk assessment in this era of antibiotic resistance.
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5
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Alruwaili A, Rashid GMM, Sodré V, Mason J, Rehman Z, Menakath AK, Cheung D, Brown SP, Bugg TDH. Elucidation of microbial lignin degradation pathways using synthetic isotope-labelled lignin. RSC Chem Biol 2023; 4:47-55. [PMID: 36685258 PMCID: PMC9811514 DOI: 10.1039/d2cb00173j] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 11/20/2022] [Indexed: 11/25/2022] Open
Abstract
Pathways by which the biopolymer lignin is broken down by soil microbes could be used to engineer new biocatalytic routes from lignin to renewable chemicals, but are currently not fully understood. In order to probe these pathways, we have prepared synthetic lignins containing 13C at the sidechain β-carbon. Feeding of [β-13C]-labelled DHP lignin to Rhodococcus jostii RHA1 has led to the incorporation of 13C label into metabolites oxalic acid, 4-hydroxyphenylacetic acid, and 4-hydroxy-3-methoxyphenylacetic acid, confirming that they are derived from lignin breakdown. We have identified a glycolate oxidase enzyme in Rhodococcus jostii RHA1 which is able to oxidise glycolaldehyde via glycolic acid to oxalic acid, thereby identifying a pathway for the formation of oxalic acid. R. jostii glycolate oxidase also catalyses the conversion of 4-hydroxyphenylacetic acid to 4-hydroxybenzoylformic acid, identifying another possible pathway to 4-hydroxybenzoylformic acid. Formation of labelled oxalic acid was also observed from [β-13C]-polyferulic acid, which provides experimental evidence in favour of a radical mechanism for α,β-bond cleavage of β-aryl ether units.
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Affiliation(s)
- Awatif Alruwaili
- Department of Chemistry, University of WarwickCoventryCV4 7ALUK+44(0)-2476-573018
| | - Goran M. M. Rashid
- Department of Chemistry, University of WarwickCoventryCV4 7ALUK+44(0)-2476-573018
| | - Victoria Sodré
- Department of Chemistry, University of WarwickCoventryCV4 7ALUK+44(0)-2476-573018
| | - James Mason
- Department of Chemistry, University of WarwickCoventryCV4 7ALUK+44(0)-2476-573018
| | - Zainab Rehman
- Department of Physics, University of WarwickCoventryCV4 7ALUK
| | | | - David Cheung
- Department of Physics, University of WarwickCoventryCV4 7ALUK
| | - Steven P. Brown
- Department of Physics, University of WarwickCoventryCV4 7ALUK
| | - Timothy D. H. Bugg
- Department of Chemistry, University of WarwickCoventryCV4 7ALUK+44(0)-2476-573018
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6
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Cai C, Xu Z, Li J, Zhou H, Jin M. Developing
Rhodococcus opacus
and
Sphingobium
sp. co‐culture systems for valorization of lignin‐derived dimers. Biotechnol Bioeng 2022; 119:3162-3177. [DOI: 10.1002/bit.28215] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 08/17/2022] [Accepted: 08/21/2022] [Indexed: 11/09/2022]
Affiliation(s)
- Chenggu Cai
- School of Environmental and Biological EngineeringNanjing University of Science and TechnologyNanjing210094China
| | - Zhaoxian Xu
- School of Environmental and Biological EngineeringNanjing University of Science and TechnologyNanjing210094China
| | - Jie Li
- School of Environmental and Biological EngineeringNanjing University of Science and TechnologyNanjing210094China
| | - Huarong Zhou
- School of Environmental and Biological EngineeringNanjing University of Science and TechnologyNanjing210094China
| | - Mingjie Jin
- School of Environmental and Biological EngineeringNanjing University of Science and TechnologyNanjing210094China
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7
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Fujita M, Yano S, Shibata K, Kondo M, Hishiyama S, Kamimura N, Masai E. Functional roles of multiple Ton complex genes in a Sphingobium degrader of lignin-derived aromatic compounds. Sci Rep 2021; 11:22444. [PMID: 34789769 PMCID: PMC8599685 DOI: 10.1038/s41598-021-01756-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 10/27/2021] [Indexed: 01/04/2023] Open
Abstract
TonB-dependent transporters (TBDTs) mediate outer membrane transport of nutrients using the energy derived from proton motive force transmitted from the TonB–ExbB–ExbD complex localized in the inner membrane. Recently, we discovered ddvT encoding a TBDT responsible for the uptake of a 5,5-type lignin-derived dimer in Sphingobium sp. strain SYK-6. Furthermore, overexpression of ddvT in an SYK-6-derivative strain enhanced its uptake capacity, improving the rate of platform chemical production. Thus, understanding the uptake system of lignin-derived aromatics is fundamental for microbial conversion-based lignin valorization. Here we examined whether multiple tonB-, exbB-, and exbD-like genes in SYK-6 contribute to the outer membrane transport of lignin-derived aromatics. The disruption of tonB2–6 and exbB3 did not reduce the capacity of SYK-6 to convert or grow on lignin-derived aromatics. In contrast, the introduction of the tonB1–exbB1–exbD1–exbD2 operon genes into SYK-6, which could not be disrupted, promoted the conversion of β-O-4-, β-5-, β-1-, β-β-, and 5,5-type dimers and monomers, such as ferulate, vanillate, syringate, and protocatechuate. These results suggest that TonB-dependent uptake involving the tonB1 operon genes is responsible for the outer membrane transport of the above aromatics. Additionally, exbB2/tolQ and exbD3/tolR were suggested to constitute the Tol-Pal system that maintains the outer membrane integrity.
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Affiliation(s)
- Masaya Fujita
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, 940-2188, Japan.,Structural Biology Research Center, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki, Japan
| | - Shodai Yano
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, 940-2188, Japan
| | - Koki Shibata
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, 940-2188, Japan
| | - Mizuki Kondo
- Center for Integrated Technology Support, Nagaoka University of Technology, Nagaoka, Niigata, Japan
| | - Shojiro Hishiyama
- Forestry and Forest Products Research Institute, Tsukuba, Ibaraki, Japan
| | - Naofumi Kamimura
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, 940-2188, Japan
| | - Eiji Masai
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, 940-2188, Japan.
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8
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Azubuike CC, Allemann MN, Michener JK. Microbial assimilation of lignin-derived aromatic compounds and conversion to value-added products. Curr Opin Microbiol 2021; 65:64-72. [PMID: 34775172 DOI: 10.1016/j.mib.2021.10.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 10/19/2021] [Accepted: 10/21/2021] [Indexed: 11/03/2022]
Abstract
Lignin is an abundant and sustainable source of aromatic compounds that can be converted to value-added products. However, lignin is underutilized, since depolymerization produces a complex mixture of aromatic compounds that is difficult to convert to a single product. Microbial conversion of mixed aromatic substrates provides a potential solution to this conversion challenge. Recent advances have expanded the range of lignin-derived aromatic substrates that can be assimilated and demonstrated efficient conversion via central metabolism to new potential products. The development of additional non-model microbial hosts and genetic tools for these hosts have accelerated engineering efforts. However, yields with real depolymerized lignin are still low, and additional work will be required to achieve viable conversion processes.
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Affiliation(s)
| | - Marco N Allemann
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
| | - Joshua K Michener
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA.
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9
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Wang L, Maranas CD. Computationally Prospecting Potential Pathways from Lignin Monomers and Dimers toward Aromatic Compounds. ACS Synth Biol 2021; 10:1064-1076. [PMID: 33877818 DOI: 10.1021/acssynbio.0c00598] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The heterogeneity of the aromatic products originating from lignin catalytic depolymerization remains one of the major challenges associated with lignin valorization. Microbes have evolved catabolic pathways that can funnel heterogeneous intermediates to a few central aromatic products. These aromatic compounds can subsequently undergo intra- or extradiol ring opening to produce value-added chemicals. However, such funneling pathways are only partially characterized for a few organisms such as Sphingobium sp. SYK-6 and Pseudomonas putida KT2440. Herein, we apply the de novo pathway design tool (novoStoic) to computationally prospect possible ways of funneling lignin-derived mono- and biaryls. novoStoic employs reaction rules between molecular moieties to hypothesize de novo conversions by flagging known enzymes that carry out the same biotransformation on the most similar substrate. Both reaction rules and known reactions are then deployed by novoStoic to identify a mass-balanced biochemical network that converts a source to a target metabolite while minimizing the number of de novo steps. We demonstrate the application of novoStoic for (i) designing alternative pathways of funneling S, G, and H lignin monomers, and (ii) exploring cleavage pathways of β-1 and β-β dimers. By exploring the uncharted chemical space afforded by enzyme promiscuity, novoStoic can help predict previously unknown native pathways leveraging enzyme promiscuity and propose new carbon/energy efficient lignin funneling pathways with few heterologous enzymes.
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Affiliation(s)
- Lin Wang
- Department of Chemical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Costas D. Maranas
- Department of Chemical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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10
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Oxidative Catabolism of (+)-Pinoresinol Is Initiated by an Unusual Flavocytochrome Encoded by Translationally Coupled Genes within a Cluster of (+)-Pinoresinol-Coinduced Genes in Pseudomonas sp. Strain SG-MS2. Appl Environ Microbiol 2020; 86:AEM.00375-20. [PMID: 32198167 DOI: 10.1128/aem.00375-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 03/12/2020] [Indexed: 12/19/2022] Open
Abstract
Burkholderia sp. strain SG-MS1 and Pseudomonas sp. strain SG-MS2 have previously been found to mineralize (+)-pinoresinol through a common catabolic pathway. Here, we used comparative genomics, proteomics, protein semipurification, and heterologous expression to identify a flavoprotein from the vanillyl alcohol oxidase/p-cresol methyl hydroxylase (VAO/PCMH) enzyme family in SG-MS2 that carries out the initial hydroxylation of (+)-pinoresinol at the benzylic carbon. The cognate gene is translationally coupled with a downstream cytochrome gene, and the cytochrome is required for activity. The flavoprotein has a unique combination of cofactor binding and cytochrome requirements for the VAO/PCMH family. The heterologously expressed enzyme has a Km of 1.17 μM for (+)-pinoresinol. The enzyme is overexpressed in strain SG-MS2 upon exposure to (+)-pinoresinol, along with 45 other proteins, 22 of which were found to be encoded by genes in an approximately 35.1-kb cluster also containing the flavoprotein and cytochrome genes. Homologs of 18 of these 22 genes, plus the flavoprotein and cytochrome genes, were also found in a 38.7-kb cluster in SG-MS1. The amino acid identities of four of the other proteins within the SG-MS2 cluster suggest they catalyze conversion of hydroxylated pinoresinol to protocatechuate and 2-methoxyhydroquinone. Nine other proteins upregulated in SG-MS2 on exposure to (+)-pinoresinol appear to be homologs of proteins known to comprise the protocatechuate and 2-methoxyhydroquinone catabolic pathways, but only three of the cognate genes lie within the cluster containing the flavoprotein and cytochrome genes.IMPORTANCE (+)-Pinoresinol is an important plant defense compound, a major food lignan for humans and some other animals, and the model compound used to study degradation of the β-β' linkages in lignin. We report a gene cluster, in one strain each of Pseudomonas and Burkholderia, that is involved in the oxidative catabolism of (+)-pinoresinol. The flavoprotein component of the α-hydroxylase which heads the pathway belongs to the 4-phenol oxidizing (4PO) subgroup of the vanillyl alcohol oxidase/p-cresol methyl hydroxylase (VAO/PCMH) enzyme family but constitutes a novel combination of cofactor and electron acceptor properties for the family. It is translationally coupled with a cytochrome gene whose product is also required for activity. The work casts new light on the biology of (+)-pinoresinol and its transformation to other bioactive molecules. Potential applications of the findings include new options for deconstructing lignin into useful chemicals and the generation of new phytoestrogenic enterolactones from lignans.
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11
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Fujita M, Mori K, Hara H, Hishiyama S, Kamimura N, Masai E. A TonB-dependent receptor constitutes the outer membrane transport system for a lignin-derived aromatic compound. Commun Biol 2019; 2:432. [PMID: 31799434 PMCID: PMC6874591 DOI: 10.1038/s42003-019-0676-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Accepted: 11/04/2019] [Indexed: 12/23/2022] Open
Abstract
TonB-dependent receptors (TBDRs) mediate substrate-specific transport across the outer membrane, utilizing energy derived from the proton motive force transmitted from the TonB-ExbB-ExbD complex located in the inner membrane (TonB system). Although a number of TonB systems involved in the uptake of siderophores, vitamin B12 and saccharides have been identified, their involvement in the uptake and catabolism of aromatic compounds was previously unknown. Here, we show that the outer membrane transport of a biphenyl compound derived from lignin is mediated by the TonB system in a Gram-negative bacterium capable of degrading lignin-derived aromatic compounds, Sphingobium sp. strain SYK-6. Furthermore, we found that overexpression of the corresponding TBDR gene enhanced the uptake of this biphenyl compound, contributing to the improved rate of platform chemical production. Our results will provide an important basis for establishing engineered strains optimized for use in lignin valorisation.
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Affiliation(s)
- Masaya Fujita
- 1Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata Japan
| | - Kosuke Mori
- 1Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata Japan
| | - Hirofumi Hara
- 2Department of Chemical Process Engineering, Malaysia-Japan International Institute of Technology, Universiti Teknologi Malaysia, Kuala Lumpur, Malaysia
| | - Shojiro Hishiyama
- 3Forestry and Forest Products Research Institute, Tsukuba, Ibaraki Japan
| | - Naofumi Kamimura
- 1Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata Japan
| | - Eiji Masai
- 1Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata Japan
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12
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Genetic basis for the cooperative bioactivation of plant lignans by Eggerthella lenta and other human gut bacteria. Nat Microbiol 2019; 5:56-66. [PMID: 31686027 PMCID: PMC6941677 DOI: 10.1038/s41564-019-0596-1] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 09/18/2019] [Indexed: 12/14/2022]
Abstract
Plant-derived lignans, consumed daily by most individuals, are thought to protect against cancer and other diseases1; however, their bioactivity requires gut bacterial conversion to enterolignans2. Here, we dissect a four-species bacterial consortium sufficient for all five reactions in this pathway. A single enzyme (benzyl ether reductase; ber), was sufficient for the first two biotransformations, variable between strains of Eggerthella lenta, critical for enterolignan production in gnotobiotic mice, and unique to Coriobacteriia. Transcriptional profiling (RNAseq) independently identified ber and genomic loci upregulated by each of the remaining substrates. Despite their low abundance in gut microbiomes and restricted phylogenetic range, all of the identified genes were detectable in the distal gut microbiomes of most individuals living in Northern California. Together, these results emphasize the importance of considering strain-level variations and bacterial co-occurrence to gain a mechanistic understanding of the bioactivation of plant secondary metabolites by the human gut microbiome.
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Braune A, Gütschow M, Blaut M. An NADH-Dependent Reductase from Eubacterium ramulus Catalyzes the Stereospecific Heteroring Cleavage of Flavanones and Flavanonols. Appl Environ Microbiol 2019; 85:e01233-19. [PMID: 31375488 PMCID: PMC6752008 DOI: 10.1128/aem.01233-19] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2019] [Accepted: 07/29/2019] [Indexed: 11/20/2022] Open
Abstract
The human intestinal anaerobe Eubacterium ramulus is known for its ability to degrade various dietary flavonoids. In the present study, we demonstrate the cleavage of the heterocyclic C-ring of flavanones and flavanonols by an oxygen-sensitive NADH-dependent reductase, previously described as enoate reductase, from E. ramulus This flavanone- and flavanonol-cleaving reductase (Fcr) was purified following its heterologous expression in Escherichia coli and further characterized. Fcr cleaved the flavanones naringenin, eriodictyol, liquiritigenin, and homoeriodictyol. Moreover, the flavanonols taxifolin and dihydrokaempferol served as substrates. The catalyzed reactions were stereospecific for the (2R)-enantiomers of the flavanone substrates and for the (2S,3S)-configured flavanonols. The enantioenrichment of the nonconverted stereoisomers allowed for the determination of hitherto unknown flavanone racemization rates. Fcr formed the corresponding dihydrochalcones and hydroxydihydrochalcones in the course of an unusual reductive cleavage of cyclic ether bonds. Fcr did not convert members of other flavonoid subclasses, including flavones, flavonols, and chalcones, the latter indicating that the reaction does not involve a chalcone intermediate. This view is strongly supported by the observed enantiospecificity of Fcr. Cinnamic acids, which are typical substrates of bacterial enoate reductases, were also not reduced by Fcr. Based on the presence of binding motifs for dinucleotide cofactors and a 4Fe-4S cluster in the amino acid sequence of Fcr, a cofactor-mediated hydride transfer from NADH onto C-2 of the respective substrate is proposed.IMPORTANCE Gut bacteria play a crucial role in the metabolism of dietary flavonoids, thereby contributing to their activation or inactivation after ingestion by the human host. Thus, bacterial activities in the intestine may influence the beneficial health effects of these polyphenolic plant compounds. While an increasing number of flavonoid-converting gut bacterial species have been identified, knowledge of the responsible enzymes is still limited. Here, we characterized Fcr as a key enzyme involved in the conversion of flavonoids of several subclasses by Eubacterium ramulus, a prevalent human gut bacterium. Sequence similarity of this enzyme to hypothetical proteins from other flavonoid-degrading intestinal bacteria in databases suggests a more widespread occurrence of this enzyme. Functional characterization of gene products of human intestinal microbiota enables the assignment of metagenomic sequences to specific bacteria and, more importantly, to certain activities, which is a prerequisite for targeted modulation of gut microbial functionality.
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Affiliation(s)
- Annett Braune
- Department of Gastrointestinal Microbiology, German Institute of Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany
| | - Michael Gütschow
- Pharmaceutical Institute, Pharmaceutical Chemistry I, University of Bonn, Bonn, Germany
| | - Michael Blaut
- Department of Gastrointestinal Microbiology, German Institute of Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany
- Institute of Nutritional Sciences, University of Potsdam, Nuthetal, Germany
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Markulin L, Corbin C, Renouard S, Drouet S, Gutierrez L, Mateljak I, Auguin D, Hano C, Fuss E, Lainé E. Pinoresinol-lariciresinol reductases, key to the lignan synthesis in plants. PLANTA 2019; 249:1695-1714. [PMID: 30895445 DOI: 10.1007/s00425-019-03137-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 03/12/2019] [Indexed: 05/20/2023]
Abstract
This paper provides an overview on activity, stereospecificity, expression and regulation of pinoresinol-lariciresinol reductases in plants. These enzymes are shared by the pathways to all 8-8' lignans derived from pinoresinol. Pinoresinol-lariciresinol reductases (PLR) are enzymes involved in the lignan biosynthesis after the initial dimerization of two monolignols. They catalyze two successive reduction steps leading to the production of lariciresinol or secoisolariciresinol from pinoresinol. Two secoisolariciresinol enantiomers can be synthetized with different fates. Depending on the plant species, these enantiomers are either final products (e.g., in the flaxseed where it is stored after glycosylation) or are the starting point for the synthesis of a wide range of lignans, among which the aryltetralin type lignans are used to semisynthesize anticancer drugs such as Etoposide®. Thus, the regulation of the gene expression of PLRs as well as the possible specificities of these reductases for one reduction step or one enantiomer are key factors to fine-tune the lignan synthesis. Results published in the last decade have shed light on the presence of more than one PLR in each plant and revealed various modes of action. Nevertheless, there are not many results published on the PLRs and most of them were obtained in a limited range of species. Indeed, a number of them deal with wild and cultivated flax belonging to the genus Linum. Despite the occurrence of lignans in bryophytes, pteridophytes and monocots, data on PLRs in these taxa are still missing and indeed the whole diversity of PLRs is still unknown. This review summarizes the data, published mainly in the last decade, on the PLR gene expression, enzymatic activity and biological function.
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Affiliation(s)
| | | | | | - Samantha Drouet
- Centre Régional de Ressources en Biologie Moléculaire (CRRBM), Université Picardie Jules Verne, 33 rue Saint-Leu, 80039, Amiens, France
| | - Laurent Gutierrez
- Centre Régional de Ressources en Biologie Moléculaire (CRRBM), Université Picardie Jules Verne, 33 rue Saint-Leu, 80039, Amiens, France
| | - Ivan Mateljak
- LBLGC, INRA USC 1328 Université d'Orléans, Orléans, France
| | - Daniel Auguin
- LBLGC, INRA USC 1328 Université d'Orléans, Orléans, France
| | | | - Elisabeth Fuss
- Interfaculty Institute of Biochemistry, Hoppe-Seyler-St. 4, 72076, Tübingen, Germany
| | - Eric Lainé
- LBLGC, INRA USC 1328 Université d'Orléans, Orléans, France.
- LBLGC, INRA USC 1328 Antenne Scientifique Universitaire de Chartres, 21 rue de Loigny, 28000, Chartres, France.
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15
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Advances in microbial lignin degradation and its applications. Curr Opin Biotechnol 2019; 56:179-186. [DOI: 10.1016/j.copbio.2018.11.011] [Citation(s) in RCA: 87] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 11/14/2018] [Accepted: 11/14/2018] [Indexed: 12/29/2022]
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16
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Takahashi K, Miyake K, Hishiyama S, Kamimura N, Masai E. Two novel decarboxylase genes play a key role in the stereospecific catabolism of dehydrodiconiferyl alcohol in Sphingobium sp. strain SYK-6. Environ Microbiol 2018. [PMID: 29528542 DOI: 10.1111/1462-2920.14099] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Sphingobium sp. strain SYK-6 is able to use a phenylcoumaran-type biaryl, dehydrodiconiferyl alcohol (DCA), as a sole source of carbon and energy. In SYK-6 cells, the alcohol group of the B-ring side chain of DCA was first oxidized to the carboxyl group, and then the alcohol group of the A-ring side chain was oxidized to generate 5-(2-carboxyvinyl)-2-(4-hydroxy-3-methoxyphenyl)-7-methoxy-2,3-dihydrobenzofuran-3-carboxylate (DCA-CC). We identified phcF, phcG and phcH, which conferred the ability to convert DCA-CC into 3-(4-hydroxy-3-(4-hydroxy-3-methoxystyryl)-5-methoxyphenyl)acrylate (DCA-S) in a host strain. These genes exhibited no significant sequence similarity with known enzyme genes, whereas phcF and phcG, which contain a DUF3237 domain of unknown function, showed 32% amino acid sequence identity with each other. The DCA-CC conversion activities were markedly decreased by disruption of phcF and phcG, indicating that phcF and phcG play dominant roles in the conversion of DCA-CC. Purified PhcF and PhcG catalysed the decarboxylation of the A-ring side chain of DCA-CC, producing DCA-S, and showed enantiospecificity towards (+)- and (-)-DCA-CC respectively. PhcF and PhcG formed homotrimers, and their Km for DCA-CC were determined to be 84 μM and 103 μM, and Vmax were 307 μmol⋅min-1 ⋅mg-1 and 137 μmol⋅min-1 ⋅mg-1 respectively. In conclusion, PhcF and PhcG are enantiospecific decarboxylases involved in phenylcoumaran catabolism.
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Affiliation(s)
- Kenji Takahashi
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, Japan
| | - Kyohei Miyake
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, Japan
| | - Shojiro Hishiyama
- Forestry and Forest Products Research Institute, Tsukuba, Ibaraki, Japan
| | - Naofumi Kamimura
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, Japan
| | - Eiji Masai
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, Japan
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Bacterial Catabolism of β-Hydroxypropiovanillone and β-Hydroxypropiosyringone Produced in the Reductive Cleavage of Arylglycerol-β-Aryl Ether in Lignin. Appl Environ Microbiol 2018; 84:AEM.02670-17. [PMID: 29374031 DOI: 10.1128/aem.02670-17] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 01/19/2018] [Indexed: 12/11/2022] Open
Abstract
Sphingobium sp. strain SYK-6 converts four stereoisomers of arylglycerol-β-guaiacyl ether into achiral β-hydroxypropiovanillone (HPV) via three stereospecific reaction steps. Here, we determined the HPV catabolic pathway and characterized the HPV catabolic genes involved in the first two steps of the pathway. In SYK-6 cells, HPV was oxidized to vanilloyl acetic acid (VAA) via vanilloyl acetaldehyde (VAL). The resulting VAA was further converted into vanillate through the activation of VAA by coenzyme A. A syringyl-type HPV analog, β-hydroxypropiosyringone (HPS), was also catabolized via the same pathway. SLG_12830 (hpvZ), which belongs to the glucose-methanol-choline oxidoreductase family, was isolated as the HPV-converting enzyme gene. An hpvZ mutant completely lost the ability to convert HPV and HPS, indicating that hpvZ is essential for the conversion of both the substrates. HpvZ produced in Escherichia coli oxidized both HPV and HPS and other 3-phenyl-1-propanol derivatives. HpvZ localized to both the cytoplasm and membrane of SYK-6 and used ubiquinone derivatives as electron acceptors. Thirteen gene products of the 23 aldehyde dehydrogenase (ALDH) genes in SYK-6 were able to oxidize VAL into VAA. Mutant analyses suggested that multiple ALDH genes, including SLG_20400, contribute to the conversion of VAL. We examined whether the genes encoding feruloyl-CoA synthetase (ferA) and feruloyl-CoA hydratase/lyase (ferB and ferB2) are involved in the conversion of VAA. Only FerA exhibited activity toward VAA; however, disruption of ferA did not affect VAA conversion. These results indicate that another enzyme system is involved in VAA conversion.IMPORTANCE Cleavage of the β-aryl ether linkage is the most essential process in lignin biodegradation. Although the bacterial β-aryl ether cleavage pathway and catabolic genes have been well documented, there have been no reports regarding the catabolism of HPV or HPS, the products of cleavage of β-aryl ether compounds. HPV and HPS have also been found to be obtained from lignin by chemoselective catalytic oxidation by 2,3-dichloro-5,6-dicyano-1,4-benzoquinone/tert-butyl nitrite/O2, followed by cleavage of the β-aryl ether with zinc. Therefore, value-added chemicals are expected to be produced from these compounds. In this study, we determined the SYK-6 catabolic pathways for HPV and HPS and identified the catabolic genes involved in the first two steps of the pathways. Since SYK-6 catabolizes HPV through 2-pyrone-4,6-dicarboxylate, which is a building block for functional polymers, characterization of HPV catabolism is important not only for understanding the bacterial lignin catabolic system but also for lignin utilization.
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18
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Isolation of the (+)-Pinoresinol-Mineralizing Pseudomonas sp. Strain SG-MS2 and Elucidation of Its Catabolic Pathway. Appl Environ Microbiol 2018; 84:AEM.02531-17. [PMID: 29222099 DOI: 10.1128/aem.02531-17] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 11/28/2017] [Indexed: 11/20/2022] Open
Abstract
Pinoresinol is a dimer of two β-β'-linked coniferyl alcohol molecules. It is both a plant defense molecule synthesized through the shikimic acid pathway and a representative of several β-β-linked dimers produced during the microbial degradation of lignin in dead plant material. Until now, little has been known about the bacterial catabolism of such dimers. Here we report the isolation of the efficient (+)-pinoresinol-mineralizing Pseudomonas sp. strain SG-MS2 and its catabolic pathway. Degradation of pinoresinol in this strain is inducible and proceeds via a novel oxidative route, which is in contrast to the previously reported reductive transformation by other bacteria. Based on enzyme assays and bacterial growth, cell suspension, and resting cell studies, we provide conclusive evidence that pinoresinol degradation in strain SG-MS2 is initiated by benzylic hydroxylation, generating a hemiketal via a quinone methide intermediate, which is then hydrated at the benzylic carbon by water. The hemiketal, which stays in equilibrium with the corresponding keto alcohol, undergoes an aryl-alkyl cleavage to generate a lactone and 2-methoxyhydroquinone. While the fate of 2-methoxyhydroquinone is not investigated further, it is assumed to be assimilated by ring cleavage. The lactone is further metabolized via two routes, namely, lactone ring cleavage and benzylic hydroxylation via a quinone methide intermediate, as described above. The resulting hemiketal again exists in equilibrium with a keto alcohol. Our evidence suggests that both routes of lactone metabolism lead to vanillin and vanillic acid, which we show can then be mineralized by strain SG-MS2.IMPORTANCE The oxidative catabolism of (+)-pinoresinol degradation elucidated here is fundamentally different from the reductive cometabolism reported for two previously characterized bacteria. Our findings open up new opportunities to use lignin for the biosynthesis of vanillin, a key flavoring agent in foods, beverages, and pharmaceuticals, as well as various new lactones. Our work also has implications for the study of new pinoresinol metabolites in human health. The enterodiol and enterolactone produced through reductive transformation of pinoresinol by gut microbes have already been associated with decreased risks of cancer and cardiovascular diseases. The metabolites from oxidative metabolism we find here also deserve attention in this respect.
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19
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Kamimura N, Takahashi K, Mori K, Araki T, Fujita M, Higuchi Y, Masai E. Bacterial catabolism of lignin-derived aromatics: New findings in a recent decade: Update on bacterial lignin catabolism. ENVIRONMENTAL MICROBIOLOGY REPORTS 2017; 9:679-705. [PMID: 29052962 DOI: 10.1111/1758-2229.12597] [Citation(s) in RCA: 160] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 09/26/2017] [Accepted: 10/03/2017] [Indexed: 05/21/2023]
Abstract
Lignin is the most abundant phenolic polymer; thus, its decomposition by microorganisms is fundamental to carbon cycling on earth. Lignin breakdown is initiated by depolymerization catalysed by extracellular oxidoreductases secreted by white-rot basidiomycetous fungi. On the other hand, bacteria play a predominant role in the mineralization of lignin-derived heterogeneous low-molecular-weight aromatic compounds. The outline of bacterial catabolic pathways for lignin-derived bi- and monoaryls are typically composed of the following sequential steps: (i) funnelling of a wide variety of lignin-derived aromatics into vanillate and syringate, (ii) O demethylation of vanillate and syringate to form catecholic derivatives and (iii) aromatic ring-cleavage of the catecholic derivatives to produce tricarboxylic acid cycle intermediates. Knowledge regarding bacterial catabolic systems for lignin-derived aromatic compounds is not only important for understanding the terrestrial carbon cycle but also valuable for promoting the shift to a low-carbon economy via biological lignin valorisation. This review summarizes recent progress in bacterial catabolic systems for lignin-derived aromatic compounds, including newly identified catabolic pathways and genes for decomposition of lignin-derived biaryls, transcriptional regulation and substrate uptake systems. Recent omics approaches on catabolism of lignin-derived aromatic compounds are also described.
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Affiliation(s)
- Naofumi Kamimura
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata 940-2188, Japan
| | - Kenji Takahashi
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata 940-2188, Japan
| | - Kosuke Mori
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata 940-2188, Japan
| | - Takuma Araki
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata 940-2188, Japan
| | - Masaya Fujita
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata 940-2188, Japan
| | - Yudai Higuchi
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata 940-2188, Japan
| | - Eiji Masai
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata 940-2188, Japan
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20
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Gall DL, Ralph J, Donohue TJ, Noguera DR. Biochemical transformation of lignin for deriving valued commodities from lignocellulose. Curr Opin Biotechnol 2017; 45:120-126. [DOI: 10.1016/j.copbio.2017.02.015] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 02/06/2017] [Accepted: 02/24/2017] [Indexed: 11/30/2022]
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21
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A bacterial aromatic aldehyde dehydrogenase critical for the efficient catabolism of syringaldehyde. Sci Rep 2017; 7:44422. [PMID: 28294121 PMCID: PMC5353671 DOI: 10.1038/srep44422] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 02/07/2017] [Indexed: 01/18/2023] Open
Abstract
Vanillin and syringaldehyde obtained from lignin are essential intermediates for the production of basic chemicals using microbial cell factories. However, in contrast to vanillin, the microbial conversion of syringaldehyde is poorly understood. Here, we identified an aromatic aldehyde dehydrogenase (ALDH) gene responsible for syringaldehyde catabolism from 20 putative ALDH genes of Sphingobium sp. strain SYK-6. All these genes were expressed in Escherichia coli, and nine gene products, including previously characterized BzaA, BzaB, and vanillin dehydrogenase (LigV), exhibited oxidation activities for syringaldehyde to produce syringate. Among these genes, SLG_28320 (desV) and ligV were most highly and constitutively transcribed in the SYK-6 cells. Disruption of desV in SYK-6 resulted in a significant reduction in growth on syringaldehyde and in syringaldehyde oxidation activity. Furthermore, a desV ligV double mutant almost completely lost its ability to grow on syringaldehyde. Purified DesV showed similar kcat/Km values for syringaldehyde (2100 s−1·mM−1) and vanillin (1700 s−1·mM−1), whereas LigV substantially preferred vanillin (8800 s−1·mM−1) over syringaldehyde (1.4 s−1·mM−1). These results clearly demonstrate that desV plays a major role in syringaldehyde catabolism. Phylogenetic analyses showed that DesV-like ALDHs formed a distinct phylogenetic cluster separated from the vanillin dehydrogenase cluster.
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22
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Jaufurally AS, Teixeira A, Hollande L, Allais F, Ducrot PH. Optimization of the Laccase-Catalyzed Synthesis of (±)-Syringaresinol and Study of its Thermal and Antiradical Activities. ChemistrySelect 2016. [DOI: 10.1002/slct.201600543] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Abdus S. Jaufurally
- Chaire Agro-Biotechnologies Industrielles (ABI); AgroParisTech; CEBB - 3 rue des Rouges Terres F-51110 Pomacle France
- Institut Jean-Pierre Bourgin, INRA; AgroParisTech, CNRS; Université Paris-Saclay; RD10 F-78026 Versailles Cedex France
| | - Andreia R. S. Teixeira
- Chaire Agro-Biotechnologies Industrielles (ABI); AgroParisTech; CEBB - 3 rue des Rouges Terres F-51110 Pomacle France
- UMR 1145 GENIAL, INRA; AgroParisTech, CNRS; Université Paris-Saclay; 1 avenue des Olympiades F-91744 Massy France
| | - Louis Hollande
- Chaire Agro-Biotechnologies Industrielles (ABI); AgroParisTech; CEBB - 3 rue des Rouges Terres F-51110 Pomacle France
- Institut Jean-Pierre Bourgin, INRA; AgroParisTech, CNRS; Université Paris-Saclay; RD10 F-78026 Versailles Cedex France
| | - Florent Allais
- Chaire Agro-Biotechnologies Industrielles (ABI); AgroParisTech; CEBB - 3 rue des Rouges Terres F-51110 Pomacle France
- UMR 782 GMPA, INRA; AgroParisTech, CNRS; Université Paris-Saclay; Avenue Lucien Brétignières F-78850 Thiverval-Grignon France
| | - Paul-Henri Ducrot
- Institut Jean-Pierre Bourgin, INRA; AgroParisTech, CNRS; Université Paris-Saclay; RD10 F-78026 Versailles Cedex France
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Ricklefs E, Girhard M, Urlacher VB. Three-steps in one-pot: whole-cell biocatalytic synthesis of enantiopure (+)- and (-)-pinoresinol via kinetic resolution. Microb Cell Fact 2016; 15:78. [PMID: 27160378 PMCID: PMC4862135 DOI: 10.1186/s12934-016-0472-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 04/24/2016] [Indexed: 11/22/2022] Open
Abstract
Background Pinoresinol is a high-value plant-derived lignan with multiple health supporting effects. Enantiomerically pure pinoresinol can be isolated from natural sources, but with low efficiency. Most chemical and biocatalytic approaches that have been described for the synthesis of pinoresinol furnish the racemic mixture. In this study we devised a three-step biocatalytic cascade for the production of enantiomerically pure pinoresinol from the cheap compound eugenol. Two consecutive oxidations of eugenol through vanillyl-alcohol oxidase and laccase are followed by kinetic resolution of racemic pinoresinol by enantiospecific pinoresinol reductases. Results The addition of the enantiospecific pinoresinol reductase from Arabidopsis thaliana for kinetic resolution of (±)-pinoresinol to an in vitro cascade involving the vanillyl-alcohol oxidase from Penicillium simplicissimum and the bacterial laccase CgL1 from Corynebacterium glutamicum resulted in increasing ee values for (+)-pinoresinol; however, an ee value of 34 % was achieved in the best case. The ee value could be increased up to ≥99 % by applying Escherichia coli-based whole-cell biocatalysts. The optimized process operated in a one-pot “two-cell” sequential mode and yielded 876 µM (+)-pinoresinol with an ee value of 98 %. Switching the reductase to the enantiospecific pinoresinol lariciresinol reductase from Forsythia intermedia enabled the production of 610 µM (−)-pinoresinol with an ee value of 97 %. Conclusion A new approach for the synthesis of enantiomerically pure (+)- and (−)-pinoresinol is described that combines three biotransformation steps in one pot. By switching the reductase in the last step, the whole-cell biocatalysts can be directed to produce either (+)- or (−)-pinoresinol. The products of the reductases’ activity, (−)-lariciresinol and (−)-secoisolariciresinol, are valuable precursors that can also be applied for the synthesis of further lignans. Electronic supplementary material The online version of this article (doi:10.1186/s12934-016-0472-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Esther Ricklefs
- Institute of Biochemistry, Heinrich-Heine University, Universitätsstraße 1, 40225, Düsseldorf, Germany
| | - Marco Girhard
- Institute of Biochemistry, Heinrich-Heine University, Universitätsstraße 1, 40225, Düsseldorf, Germany
| | - Vlada B Urlacher
- Institute of Biochemistry, Heinrich-Heine University, Universitätsstraße 1, 40225, Düsseldorf, Germany.
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24
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Xiao Y, Ji Q, Gao S, Tan H, Chen R, Li Q, Chen J, Yang Y, Zhang L, Wang Z, Chen W, Hu Z. Combined transcriptome and metabolite profiling reveals that IiPLR1 plays an important role in lariciresinol accumulation in Isatis indigotica. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:6259-71. [PMID: 26163698 PMCID: PMC7107596 DOI: 10.1093/jxb/erv333] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
A lignan, lariciresinol, is an important efficacious compound for the antiviral effect of Isatis indigotica, a widely used herb for the treatment of colds, fever, and influenza. Although some rate-limiting steps of the lariciresinol biosynthetic pathway are well known, the specific roles of gene family members in I. indigotica in regulating lariciresinol production are poorly understood. In the present study, a correlation analysis between the RNA sequencing (RNA-Seq) expression profile and lignan content by using I. indigotica hairy roots treated with methyl jamonate (0.5 μM) at different time points as a source implicated that I. indigotica pinoresinol/lariciresinol reductase 1 (IiPLR1), but not IiPLR2 or IiPLR3, contributed greatly to lariciresinol accumulation. Gene silencing by RNA interference (RNAi) demonstrated that IiPLR1 indeed influenced lariciresinol biosynthesis, whereas suppression of IiPLR2 or IiPLR3 did not change lariciresinol abundance significantly. IiPLR1 was thus further characterized; IiPLR1 was constitutively expressed in roots, stems, leaves, and flowers of I. indigotica, with the highest expression in roots, and it responds to different stress treatments to various degrees. Recombinant IiPLR1 reduces both (±)-pinoresinol and (±)-lariciresinol efficiently, with comparative K cat/K m values. Furthermore, overexpression of IiPLR1 significantly enhanced lariciresinol accumulation in I. indigotica hairy roots, and the best line (ovx-2) produced 353.9 μg g(-1) lariciresinol, which was ~6.3-fold more than the wild type. This study sheds light on how to increase desired metabolites effectively by more accurate or appropriate genetic engineering strategies, and also provides an effective approach for the large-scale commercial production of pharmaceutically valuable lariciresinol by using hairy root culture systems as bioreactors.
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Affiliation(s)
- Ying Xiao
- The MOE Key Laboratory of Standardization of Chinese Medicines, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China Department of Pharmacy, Changzheng Hospital, Second Military Medical University, Shanghai 200003, China
| | - Qian Ji
- Department of Pharmaceutical Botany, School of Pharmacy, Second Military Medical University, Shanghai 200433, China
| | - Shouhong Gao
- Department of Pharmacy, Changzheng Hospital, Second Military Medical University, Shanghai 200003, China
| | - Hexin Tan
- Department of Pharmaceutical Botany, School of Pharmacy, Second Military Medical University, Shanghai 200433, China
| | - Ruibing Chen
- Department of Pharmaceutical Botany, School of Pharmacy, Second Military Medical University, Shanghai 200433, China
| | - Qing Li
- Department of Pharmacy, Changzheng Hospital, Second Military Medical University, Shanghai 200003, China
| | - Junfeng Chen
- Department of Pharmacy, Changzheng Hospital, Second Military Medical University, Shanghai 200003, China
| | - Yingbo Yang
- The MOE Key Laboratory of Standardization of Chinese Medicines, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Lei Zhang
- Department of Pharmaceutical Botany, School of Pharmacy, Second Military Medical University, Shanghai 200433, China
| | - Zhengtao Wang
- The MOE Key Laboratory of Standardization of Chinese Medicines, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Wansheng Chen
- Department of Pharmacy, Changzheng Hospital, Second Military Medical University, Shanghai 200003, China
| | - Zhibi Hu
- The MOE Key Laboratory of Standardization of Chinese Medicines, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
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Membrane-associated glucose-methanol-choline oxidoreductase family enzymes PhcC and PhcD are essential for enantioselective catabolism of dehydrodiconiferyl alcohol. Appl Environ Microbiol 2015; 81:8022-36. [PMID: 26362985 DOI: 10.1128/aem.02391-15] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 09/09/2015] [Indexed: 01/06/2023] Open
Abstract
Sphingobium sp. strain SYK-6 is able to degrade various lignin-derived biaryls, including a phenylcoumaran-type compound, dehydrodiconiferyl alcohol (DCA). In SYK-6 cells, the alcohol group of the B-ring side chain of DCA is initially oxidized to the carboxyl group to generate 3-(2-(4-hydroxy-3-methoxyphenyl)-3-(hydroxymethyl)-7-methoxy-2,3-dihydrobenzofuran-5-yl) acrylic acid (DCA-C). Next, the alcohol group of the A-ring side chain of DCA-C is oxidized to the carboxyl group, and then the resulting metabolite is catabolized through vanillin and 5-formylferulate. In this study, the genes involved in the conversion of DCA-C were identified and characterized. The DCA-C oxidation activities in SYK-6 were enhanced in the presence of flavin adenine dinucleotide and an artificial electron acceptor and were induced ca. 1.6-fold when the cells were grown with DCA. Based on these observations, SLG_09480 (phcC) and SLG_09500 (phcD), encoding glucose-methanol-choline oxidoreductase family proteins, were presumed to encode DCA-C oxidases. Analyses of phcC and phcD mutants indicated that PhcC and PhcD are essential for the conversion of (+)-DCA-C and (-)-DCA-C, respectively. When phcC and phcD were expressed in SYK-6 and Escherichia coli, the gene products were mainly observed in their membrane fractions. The membrane fractions of E. coli that expressed phcC and phcD catalyzed the specific conversion of DCA-C into the corresponding carboxyl derivatives. In the oxidation of DCA-C, PhcC and PhcD effectively utilized ubiquinone derivatives as electron acceptors. Furthermore, the transcription of a putative cytochrome c gene was significantly induced in SYK-6 grown with DCA. The DCA-C oxidation catalyzed by membrane-associated PhcC and PhcD appears to be coupled to the respiratory chain.
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Yoshikata T, Suzuki K, Kamimura N, Namiki M, Hishiyama S, Araki T, Kasai D, Otsuka Y, Nakamura M, Fukuda M, Katayama Y, Masai E. Three-Component O-Demethylase System Essential for Catabolism of a Lignin-Derived Biphenyl Compound in Sphingobium sp. Strain SYK-6. Appl Environ Microbiol 2014; 80:7142-53. [PMID: 25217011 PMCID: PMC4249175 DOI: 10.1128/aem.02236-14] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Accepted: 09/05/2014] [Indexed: 11/20/2022] Open
Abstract
Sphingobium sp. strain SYK-6 is able to assimilate lignin-derived biaryls, including a biphenyl compound, 5,5'-dehydrodivanillate (DDVA). Previously, ligXa (SLG_07770), which is similar to the gene encoding oxygenase components of Rieske-type nonheme iron aromatic-ring-hydroxylating oxygenases, was identified to be essential for the conversion of DDVA; however, the genes encoding electron transfer components remained unknown. Disruption of putative electron transfer component genes scattered through the SYK-6 genome indicated that SLG_08500 and SLG_21200, which showed approximately 60% amino acid sequence identities with ferredoxin and ferredoxin reductase of dicamba O-demethylase, were essential for the normal growth of SYK-6 on DDVA. LigXa and the gene products of SLG_08500 (LigXc) and SLG_21200 (LigXd) were purified and were estimated to be a trimer, a monomer, and a monomer, respectively. LigXd contains FAD as the prosthetic group and showed much higher reductase activity toward 2,6-dichlorophenolindophenol with NADH than with NADPH. A mixture of purified LigXa, LigXc, and LigXd converted DDVA into 2,2',3-trihydroxy-3'-methoxy-5,5'-dicarboxybiphenyl in the presence of NADH, indicating that DDVA O-demethylase is a three-component monooxygenase. This enzyme requires Fe(II) for its activity and is highly specific for DDVA, with a Km value of 63.5 μM and kcat of 6.1 s(-1). Genome searches in six other sphingomonads revealed genes similar to ligXc and ligXd (>58% amino acid sequence identities) with a limited number of electron transfer component genes, yet a number of diverse oxygenase component genes were found. This fact implies that these few electron transfer components are able to interact with numerous oxygenase components and the conserved LigXc and LigXd orthologs are important in sphingomonads.
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Affiliation(s)
- Taichi Yoshikata
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, Japan
| | - Kazuya Suzuki
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, Japan
| | - Naofumi Kamimura
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, Japan
| | - Masahiro Namiki
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, Japan
| | - Shojiro Hishiyama
- Forestry and Forest Products Research Institute, Tsukuba, Ibaraki, Japan
| | - Takuma Araki
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, Japan
| | - Daisuke Kasai
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, Japan
| | - Yuichiro Otsuka
- Forestry and Forest Products Research Institute, Tsukuba, Ibaraki, Japan
| | - Masaya Nakamura
- Forestry and Forest Products Research Institute, Tsukuba, Ibaraki, Japan
| | - Masao Fukuda
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, Japan
| | - Yoshihiro Katayama
- College of Bioresource Sciences, Nihon University, Fujisawa, Kanagawa, Japan
| | - Eiji Masai
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, Japan
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Tamura M, Tsuji Y, Kusunose T, Okazawa A, Kamimura N, Mori T, Nakabayashi R, Hishiyama S, Fukuhara Y, Hara H, Sato-Izawa K, Muranaka T, Saito K, Katayama Y, Fukuda M, Masai E, Kajita S. Successful expression of a novel bacterial gene for pinoresinol reductase and its effect on lignan biosynthesis in transgenic Arabidopsis thaliana. Appl Microbiol Biotechnol 2014; 98:8165-77. [DOI: 10.1007/s00253-014-5934-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Revised: 07/02/2014] [Accepted: 07/05/2014] [Indexed: 01/22/2023]
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Takahashi K, Kamimura N, Hishiyama S, Hara H, Kasai D, Katayama Y, Fukuda M, Kajita S, Masai E. Characterization of the catabolic pathway for a phenylcoumaran-type lignin-derived biaryl in Sphingobium sp. strain SYK-6. Biodegradation 2014; 25:735-45. [PMID: 24916011 DOI: 10.1007/s10532-014-9695-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 05/24/2014] [Indexed: 11/29/2022]
Abstract
Sphingobium sp. strain SYK-6 is capable of degrading various lignin-derived biaryls. We determined the catabolic pathway of a phenylcoumaran-type compound, dehydrodiconiferyl alcohol (DCA) in SYK-6, and identified some of the DCA catabolism genes. In SYK-6 cells, the alcohol group of DCA was oxidized to the carboxyl group, first at the B-ring side chain and then at the A-ring side chain. The resultant metabolite was degraded to 5-formylferulate and vanillin through the decarboxylation and the Cα-Cβ cleavage of the A-ring side chain. Based on the DCA catabolic pathway, alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) genes are thought to be involved in the conversion of DCA into an aldehyde intermediate (DCA-L) and the conversion of DCA-L into a carboxylic acid intermediate (DCA-C), respectively. SLG_05620 and SLG_24930, which belong to quinohemoprotein ADH and aryl ADH, respectively, were isolated as the genes responsible for the oxidation of DCA. In addition to these genes, multiple genes similar to SLG_05620 and SLG_24930 were found to confer DCA oxidation activities on Escherichia coli cells. In order to identify the DCA-L dehydrogenase genes, the DCA-L oxidation activities of the SYK-6 gene products of putative twenty-one ALDH genes were examined. Significant activities were observed in the four ALDH gene products, including the SLG_27910 product, which showed the highest activity. The disruption of SLG_27910 caused a decreased conversion of DCA-L, suggesting that SLG_27910 plays an important role in the DCA-L oxidation. In conclusion, no specific gene seems to be solely responsible for the conversion of DCA and DCA-L, however, the multiple genes encoding quinohemoprotein ADH and aryl ADH genes, and four ALDH genes are probably involved in the conversion processes.
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Affiliation(s)
- Kenji Takahashi
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, 940-2188, Japan
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