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Wu F, Wang S, Zhou D, Gao S, Song G, Liang Y, Wang Q. Metabolic engineering of Escherichia coli for high-level production of the biodegradable polyester monomer 2-pyrone-4,6-dicarboxylic acid. Metab Eng 2024; 83:52-60. [PMID: 38521489 DOI: 10.1016/j.ymben.2024.03.003] [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: 11/14/2023] [Revised: 03/15/2024] [Accepted: 03/15/2024] [Indexed: 03/25/2024]
Abstract
2-Pyrone-4,6-dicarboxylic acid (PDC), a chemically stable pseudo-aromatic dicarboxylic acid, is a promising building block compound for manufacturing biodegradable polyesters. This study aimed to construct high-performance cell factories enabling the efficient production of PDC from glucose. Firstly, the effective enzymes of the PDC biosynthetic pathway were overexpressed on the chromosome of the 3-dehydroshikimate overproducing strain. Consequently, the one-step biosynthesis of PDC from glucose was achieved. Further, the PDC production was enhanced by multi-copy integration of the key gene PsligC encoding 4-carboxy-2-hydroxymuconate-6-semialdehyde dehydrogenase and co-expression of Vitreoscilla hemoglobin. Subsequently, the PDC production was substantially improved by redistributing the metabolic flux for cell growth and PDC biosynthesis based on dynamically downregulating the expression of pyruvate kinase. The resultant strain PDC50 produced 129.37 g/L PDC from glucose within 78 h under fed-batch fermentation conditions, with a yield of 0.528 mol/mol and an average productivity of 1.65 g/L/h. The findings of this study lay the foundation for the potential industrial production of PDC.
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Affiliation(s)
- Fengli Wu
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China; National Center of Technology Innovation for Synthetic Biology, Tianjin, 300308, China.
| | - Shucai Wang
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China; National Center of Technology Innovation for Synthetic Biology, Tianjin, 300308, China; College of Biotechnology, Tianjin University of Science & Technology, Tianjin, 300457, China
| | - Dan Zhou
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China; National Center of Technology Innovation for Synthetic Biology, Tianjin, 300308, China; College of Bioengineering, Chongqing University, Chongqing, 400030, China
| | - Shukai Gao
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China; National Center of Technology Innovation for Synthetic Biology, Tianjin, 300308, China
| | - Guotian Song
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China; National Center of Technology Innovation for Synthetic Biology, Tianjin, 300308, China
| | - Yanxia Liang
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China; National Center of Technology Innovation for Synthetic Biology, Tianjin, 300308, China
| | - Qinhong Wang
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China; National Center of Technology Innovation for Synthetic Biology, Tianjin, 300308, China.
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Kawazoe M, Takahashi K, Tokue Y, Hishiyama S, Seki H, Higuchi Y, Kamimura N, Masai E. Catabolic System of 5-Formylferulic Acid, a Downstream Metabolite of a β-5-Type Lignin-Derived Dimer, in Sphingobium lignivorans SYK-6. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:19663-19671. [PMID: 38038961 DOI: 10.1021/acs.jafc.3c06128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/02/2023]
Abstract
Sphingobium lignivorans SYK-6 can assimilate various lignin-derived aromatic compounds, including a β-5-type (phenylcoumaran-type) dimer, dehydrodiconiferyl alcohol (DCA). SYK-6 converts DCA to a stilbene-type intermediate via multiple reaction steps and then to vanillin and 5-formylferulic acid (FFA). Here, we first elucidated the catabolic pathway of FFA, which is the only unknown pathway in DCA catabolism. Then, we identified and characterized the enzyme-encoding genes responsible for this pathway. Analysis of the metabolites revealed that FFA was converted to 5-carboxyferulic acid (CFA) through oxidation of the formyl group, followed by conversion to ferulic acid by decarboxylation. A comprehensive analysis of the aldehyde dehydrogenase genes in SYK-6 indicated that NAD+-dependent FerD (SLG_12800) is crucial for the conversion of FFA to CFA. LigW and LigW2, which are 5-carboxyvanillic acid decarboxylases involved in the catabolism of a 5,5-type dimer, were found to be involved in the conversion of CFA to ferulic acid, and LigW2 played a significant role. The ligW2 gene forms an operon with ferD, and their transcription was induced during growth in DCA.
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Affiliation(s)
- Mitsuru Kawazoe
- Department of Materials Science and Bioengineering, Nagaoka University of Technology, Nagaoka 940-2188, Niigata, Japan
| | - Kenji Takahashi
- Department of Materials Science and Bioengineering, Nagaoka University of Technology, Nagaoka 940-2188, Niigata, Japan
| | - Yosuke Tokue
- Department of Materials Science and Bioengineering, Nagaoka University of Technology, Nagaoka 940-2188, Niigata, Japan
| | - Shojiro Hishiyama
- Department of Forest Resource Chemistry, Forestry and Forest Products Research Institute, Tsukuba 305-8687, Ibaraki, Japan
| | - Hayato Seki
- Department of Materials Science and Bioengineering, Nagaoka University of Technology, Nagaoka 940-2188, Niigata, Japan
| | - Yudai Higuchi
- Department of Materials Science and Bioengineering, Nagaoka University of Technology, Nagaoka 940-2188, Niigata, Japan
| | - Naofumi Kamimura
- Department of Materials Science and Bioengineering, Nagaoka University of Technology, Nagaoka 940-2188, Niigata, Japan
| | - Eiji Masai
- Department of Materials Science and Bioengineering, Nagaoka University of Technology, Nagaoka 940-2188, Niigata, Japan
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3
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Delmulle T, Bovijn S, Deketelaere S, Castelein M, Erauw T, D'hooghe M, Soetaert WK. Engineering Comamonas testosteroni for the production of 2-pyrone-4,6-dicarboxylic acid as a promising building block. Microb Cell Fact 2023; 22:188. [PMID: 37726725 PMCID: PMC10510227 DOI: 10.1186/s12934-023-02202-2] [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: 08/08/2023] [Accepted: 09/06/2023] [Indexed: 09/21/2023] Open
Abstract
BACKGROUND Plastics are an indispensable part of our daily life. However, mismanagement at their end-of-life results in severe environmental consequences. The microbial conversion of these polymers into new value-added products offers a promising alternative. In this study, we engineered the soil-bacterium Comamonas testosteroni KF-1, a natural degrader of terephthalic acid, for the conversion of the latter to the high-value product 2-pyrone-4,6-dicarboxylic acid. RESULTS In order to convert terephthalic acid to 2-pyrone-4,6-dicarboxylic acid, we deleted the native PDC hydrolase and observed only a limited amount of product formation. To test whether this was the result of an inhibition of terephthalic acid uptake by the carbon source for growth (i.e. glycolic acid), the consumption of both carbon sources was monitored in the wild-type strain. Both carbon sources were consumed at the same time, indicating that catabolite repression was not the case. Next, we investigated if the activity of pathway enzymes remained the same in the wild-type and mutant strain. Here again, no statistical differences could be observed. Finally, we hypothesized that the presence of a pmdK variant in the degradation operon could be responsible for the observed phenotype and created a double deletion mutant strain. This newly created strain accumulated PDC to a larger extent and again consumed both carbon sources. The double deletion strain was then used in a bioreactor experiment, leading to the accumulation of 6.5 g/L of product in 24 h with an overall productivity of 0.27 g/L/h. CONCLUSIONS This study shows the production of the chemical building block 2-pyrone-4,6-dicarboxylic acid from terephthalic acid through an engineered C. testosteroni KF-1 strain. It was observed that both a deletion of the native PDC hydrolase as well as a pmdK variant is needed to achieve high conversion yields. A product titer of 6.5 g/L in 24 h with an overall productivity of 0.27 g/L/h was achieved.
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Affiliation(s)
- Tom Delmulle
- Centre for Industrial Biotechnology and Biocatalysis (InBio.be), Department of Biotechnology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, Ghent, 9000, Belgium.
| | - Stijn Bovijn
- Centre for Industrial Biotechnology and Biocatalysis (InBio.be), Department of Biotechnology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, Ghent, 9000, Belgium
| | - Sari Deketelaere
- SynBioC Research group, Department of Green Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, Ghent, 9000, Belgium
| | - Martijn Castelein
- Centre for Industrial Biotechnology and Biocatalysis (InBio.be), Department of Biotechnology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, Ghent, 9000, Belgium
| | - Tom Erauw
- Centre for Industrial Biotechnology and Biocatalysis (InBio.be), Department of Biotechnology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, Ghent, 9000, Belgium
| | - Matthias D'hooghe
- SynBioC Research group, Department of Green Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, Ghent, 9000, Belgium
| | - Wim K Soetaert
- Centre for Industrial Biotechnology and Biocatalysis (InBio.be), Department of Biotechnology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, Ghent, 9000, Belgium
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Wu X, De Bruyn M, Barta K. Deriving high value products from depolymerized lignin oil, aided by (bio)catalytic funneling strategies. Chem Commun (Camb) 2023; 59:9929-9951. [PMID: 37526604 DOI: 10.1039/d3cc01555f] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/02/2023]
Abstract
Lignin holds tremendous and versatile possibilities to produce value-added chemicals and high performing polymeric materials. Over the years, different cutting-edge lignin depolymerization methodologies have been developed, mainly focusing on achieving excellent yields of mono-phenolic products, some even approaching the theoretical maximum. However, due to lignin's inherent heterogeneity and recalcitrance, its depolymerization leads to relatively complex product streams, also containing dimers, and higher molecular weight fragments in substantial quantities. The subsequent chemo-catalytic valorization of these higher molecular weight streams, containing difficult-to-break, mainly C-C covalent bonds, is tremendously challenging, and has consequently received much less attention. In this minireview, we present an overview of recent advances on the development of sustainable biorefinery strategies aimed at the production of well-defined chemicals and polymeric materials, the prime focus being on depolymerized lignin oils, containing high molecular weight fractions. The key central unit operation to achieve this is (bio)catalytic funneling, which holds great potential to overcome separation and purification challenges.
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Affiliation(s)
- Xianyuan Wu
- University of Groningen, Stratingh Institute for Chemistry, Nijenborgh 4, Groningen, The Netherlands
| | - Mario De Bruyn
- University of Graz, Department of Chemistry, Organic and Bioorganic Chemistry, Heinrichstrasse 28/II, 8010 Graz, Austria.
| | - Katalin Barta
- University of Groningen, Stratingh Institute for Chemistry, Nijenborgh 4, Groningen, The Netherlands
- University of Graz, Department of Chemistry, Organic and Bioorganic Chemistry, Heinrichstrasse 28/II, 8010 Graz, Austria.
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5
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Chen M, Li Y, Lu F, Luterbacher JS, Ralph J. Lignin Hydrogenolysis: Phenolic Monomers from Lignin and Associated Phenolates across Plant Clades. ACS SUSTAINABLE CHEMISTRY & ENGINEERING 2023; 11:10001-10017. [PMID: 37448721 PMCID: PMC10337261 DOI: 10.1021/acssuschemeng.3c01320] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Revised: 06/13/2023] [Indexed: 07/15/2023]
Abstract
The chemical complexity of lignin remains a major challenge for lignin valorization into commodity and fine chemicals. A knowledge of the lignin features that favor its valorization and which plants produce such lignins can be used in plant selection or to engineer them to produce lignins that are more ideally suited for conversion. Sixteen biomass samples were compositionally surveyed by NMR and analytical degradative methods, and the yields of phenolic monomers following hydrogenolytic depolymerization were assessed to elucidate the key determinants controlling the depolymerization. Hardwoods, including those incorporating monolignol p-hydroxybenzoates into their syringyl/guaiacyl copolymeric lignins, produced high monomer yields by hydrogenolysis, whereas grasses incorporating monolignol p-coumarates and ferulates gave lower yields, on a lignin basis. Softwoods, with their more condensed guaiacyl lignins, gave the lowest yields. Lignins with a high syringyl unit content released elevated monomer levels, with a high-syringyl polar transgenic being particularly striking. Herein, we distinguish phenolic monomers resulting from the core lignin vs those from pendent phenolate esters associated with the biomass cell wall, acylating either polysaccharides or lignins. The basis for these observations is rationalized as a means to select or engineer biomass for optimal conversion to worthy phenolic monomers.
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Affiliation(s)
- Mingjie Chen
- Department
of Energy, Great Lakes Bioenergy Research Center, Wisconsin Energy Institute, Madison, Wisconsin 53726, United States
| | - Yanding Li
- Department
of Energy, Great Lakes Bioenergy Research Center, Wisconsin Energy Institute, Madison, Wisconsin 53726, United States
| | - Fachuang Lu
- Department
of Energy, Great Lakes Bioenergy Research Center, Wisconsin Energy Institute, Madison, Wisconsin 53726, United States
| | - Jeremy S. Luterbacher
- Institute
of Chemical Sciences and Engineering, École
Polytechnique Fédérale de Lausanne, Lausanne 1015, Switzerland
| | - John Ralph
- Department
of Energy, Great Lakes Bioenergy Research Center, Wisconsin Energy Institute, Madison, Wisconsin 53726, United States
- Department
of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
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6
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Higuchi Y, Ishimaru H, Yoshikawa T, Masuda T, Sakamoto C, Kamimura N, Masai E, Takeuchi D, Sonoki T. Successful selective production of vanillic acid from depolymerized sulfite lignin and its application to poly(ethylene vanillate) synthesis. BIORESOURCE TECHNOLOGY 2023:129450. [PMID: 37406831 DOI: 10.1016/j.biortech.2023.129450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 06/30/2023] [Accepted: 07/01/2023] [Indexed: 07/07/2023]
Abstract
Towards lignin upgrading, vanillic acid (VA), a lignin-derived guaiacyl compound, was produced from sulfite lignin for successfully synthesizing poly(ethylene vanillate), an aromatic polymer. The engineered Sphingobium sp. SYK-6-based strain in which the genes responsible for VA/3-O-methyl gallic acid O-demethylase and syringic acid O-demethylase were disrupted was able to produce vanillic acid (VA) from the mixture consisting of acetovanillone, vanillin, VA, and other low-molecular-weight aromatics obtained by Cu(OH)2-catalyzed alkaline depolymerization of sulfite lignin and membrane fractionation. From the bio-based VA, methyl-4-(2-hydroxyethoxy)-3-methoxybenzoate was synthesized via methylesterification, hydroxyethylation, and distillation, and then it was subjected to polymerization catalyzed by titanium tetraisopropoxide. The molecular weight of the obtained poly(ethylene vanillate) was evaluated to be Mw = 13,000 (Mw/Mn = 1.99) and its melting point was 261°C. The present work proved that poly(ethylene vanillate) is able to be synthesized using VA produced from lignin for the first time.
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Affiliation(s)
- Yudai Higuchi
- Faculty of Agriculture and Life Science, Hirosaki University, Hirosaki, Aomori 036-8561, Japan
| | - Hiroya Ishimaru
- Faculty of Engineering, Hokkaido University, Sapporo, Hokkaido 060-8628, Japan
| | - Takuya Yoshikawa
- Faculty of Engineering, Hokkaido University, Sapporo, Hokkaido 060-8628, Japan; Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan
| | - Takao Masuda
- Faculty of Engineering, Hokkaido University, Sapporo, Hokkaido 060-8628, Japan
| | - Chiho Sakamoto
- Faculty of Agriculture and Life Science, Hirosaki University, Hirosaki, Aomori 036-8561, Japan
| | - Naofumi Kamimura
- Department of Materials Science and Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata 940-2188, Japan
| | - Eiji Masai
- Department of Materials Science and Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata 940-2188, Japan
| | - Daisuke Takeuchi
- Graduate School of Science and Technology, Hirosaki University, Hirosaki, Aomori 036-8561, Japan
| | - Tomonori Sonoki
- Faculty of Agriculture and Life Science, Hirosaki University, Hirosaki, Aomori 036-8561, Japan.
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Otsuka Y, Araki T, Suzuki Y, Nakamura M, Kamimura N, Masai E. High-level production of 2-pyrone-4,6-dicarboxylic acid from vanillic acid as a lignin-related aromatic compound by metabolically engineered fermentation to realize industrial valorization processes of lignin. BIORESOURCE TECHNOLOGY 2023; 377:128956. [PMID: 36965585 DOI: 10.1016/j.biortech.2023.128956] [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: 02/05/2023] [Revised: 03/20/2023] [Accepted: 03/21/2023] [Indexed: 06/18/2023]
Abstract
2-Pyrone-4,6-dicarboxylic acid (PDC) is a valuable building block molecule produced from lignin-derived aromatic compounds by biological funneling. This study aimed to design a fermentation process for producing PDC from vanillic acid, which could be applied at an industrial production. Metabolomic analysis revealed that a high primary metabolic activity within cells was required to improve the production efficiency. Moreover, a medium with ammonium salts and no alkali metals was advantageous because it suppressed the formation of PDC-metal complexes. Resulting optimized process yielded the highest PDC titer and productivity ever reported: 99.9 g/L and 1.69 g/L/h, respectively. Per batch, 190 g of PDC was produced per liter of initial culture media, and the final liquid volume was 1.9 L. This study demonstrates the design of fermentation processes for the advanced industrial utilization of lignin by biological funneling.
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Affiliation(s)
- Yuichiro Otsuka
- Department of Forest Resource Chemistry, Forestry and Forest Products Research Institute, Tsukuba, Ibaraki 305-8687, Japan.
| | - Takuma Araki
- Department of Forest Resource Chemistry, Forestry and Forest Products Research Institute, Tsukuba, Ibaraki 305-8687, Japan
| | - Yuzo Suzuki
- Department of Forest Resource Chemistry, Forestry and Forest Products Research Institute, Tsukuba, Ibaraki 305-8687, Japan
| | - Masaya Nakamura
- Department of Forest Resource Chemistry, Forestry and Forest Products Research Institute, Tsukuba, Ibaraki 305-8687, Japan
| | - Naofumi Kamimura
- Department of Materials Science and Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata 940-2188, Japan
| | - Eiji Masai
- Department of Materials Science and Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata 940-2188, Japan
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8
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Zhou D, Wu F, Peng Y, Qazi MA, Li R, Wang Y, Wang Q. Multi-step biosynthesis of the biodegradable polyester monomer 2-pyrone-4,6-dicarboxylic acid from glucose. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:92. [PMID: 37264438 DOI: 10.1186/s13068-023-02350-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Accepted: 05/26/2023] [Indexed: 06/03/2023]
Abstract
BACKGROUND 2-Pyrone-4,6-dicarboxylic acid (PDC), a chemically stable pseudoaromatic dicarboxylic acid, represents a promising building block for the manufacture of biodegradable polyesters. Microbial production of PDC has been extensively investigated, but low titers and yields have limited industrial applications. RESULTS In this study, a multi-step biosynthesis strategy for the microbial production of PDC was demonstrated using engineered Escherichia coli whole-cell biocatalysts. The PDC biosynthetic pathway was first divided into three synthetic modules, namely the 3-dehydroshikimic acid (DHS) module, the protocatechuic acid (PCA) module and the PDC module. Several effective enzymes, including 3-dehydroshikimate dehydratase for the PCA module as well as protocatechuate 4,5-dioxygenase and 4-carboxy-2-hydroxymuconate-6-semialdehyde dehydrogenase for the PDC module were isolated and characterized. Then, the highly efficient whole-cell bioconversion systems for producing PCA and PDC were constructed and optimized, respectively. Finally, the efficient multi-step biosynthesis of PDC from glucose was achieved by smoothly integrating the above three biosynthetic modules, resulting in a final titer of 49.18 g/L with an overall 27.2% molar yield, which represented the highest titer for PDC production from glucose reported to date. CONCLUSIONS This study lays the foundation for the microbial production of PDC, including one-step de novo biosynthesis from glucose as well as the microbial transformation of monoaromatics.
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Affiliation(s)
- Dan Zhou
- Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, College of Bioengineering, Chongqing University, Chongqing, 400030, China
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
- National Center of Technology Innovation for Synthetic Biology, Tianjin, 300308, China
| | - Fengli Wu
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.
- National Center of Technology Innovation for Synthetic Biology, Tianjin, 300308, China.
| | - Yanfeng Peng
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
- National Center of Technology Innovation for Synthetic Biology, Tianjin, 300308, China
| | - Muneer Ahmed Qazi
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
- National Center of Technology Innovation for Synthetic Biology, Tianjin, 300308, China
- Institute of Microbiology, Faculty of Natural Science, Shah Abdul Latif University, Khairpur, 66020, Sindh, Pakistan
| | - Ruosong Li
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
- National Center of Technology Innovation for Synthetic Biology, Tianjin, 300308, China
- College of Biotechnology, Tianjin University of Science & Technology, Tianjin, 300457, China
| | - Yongzhong Wang
- Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, College of Bioengineering, Chongqing University, Chongqing, 400030, China.
| | - Qinhong Wang
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
- National Center of Technology Innovation for Synthetic Biology, Tianjin, 300308, China
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9
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Suzuki Y, Okamura-Abe Y, Otsuka Y, Araki T, Nojiri M, Kamimura N, Masai E, Nakamura M. Integrated process development for grass biomass utilization through enzymatic saccharification and upgrading hydroxycinnamic acids via microbial funneling. BIORESOURCE TECHNOLOGY 2022; 363:127836. [PMID: 36031121 DOI: 10.1016/j.biortech.2022.127836] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 08/20/2022] [Accepted: 08/22/2022] [Indexed: 06/15/2023]
Abstract
In grass biomass, hydroxycinnamic acids (HCAs) play crucial roles in the crosslinking of lignin and polysaccharides and can be easily extracted by mild alkaline pretreatment, albeit heterogeneously. Here, HCAs were extracted from bamboo and rice straw as model grass biomass with different HCAs composition, and microbial funneling was then conducted to produce 2-pyrone-4,6-dicarboxylic acid (PDC) and (4S)-3-carboxymuconolactone (4S-3CML), promising building blocks for bio-based polymers, respectively. Pseudomonas putida PpY1100 engineered for efficient microbial funneling completely converted HCAs to PDC and 4S-3CML with high titers of 3.9-9.3 g/L and molar yields of 92-99%, respectively. The enzymatic saccharification efficiencies of lignocellulose after HCAs extraction were 29.5% in bamboo and 73.8% in rice straw, which are 8.9 and 6.8 times higher than in alkaline-untreated media, respectively. These results provide a green-like process for total valorization of grass biomass through enzymatic saccharification integrated with upgrading heterogeneous HCAs to a valuable single chemical via microbial funneling.
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Affiliation(s)
- Yuzo Suzuki
- Department of Forest Resource Chemistry, Forestry and Forest Products Research Institute, Matsunosato 1, Tsukuba, Ibaraki 305-8687, Japan.
| | - Yuriko Okamura-Abe
- Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture & Technology, Koganei, Tokyo 184-8588, Japan
| | - Yuichiro Otsuka
- Department of Forest Resource Chemistry, Forestry and Forest Products Research Institute, Matsunosato 1, Tsukuba, Ibaraki 305-8687, Japan
| | - Takuma Araki
- Department of Forest Resource Chemistry, Forestry and Forest Products Research Institute, Matsunosato 1, Tsukuba, Ibaraki 305-8687, Japan
| | - Masanobu Nojiri
- Department of Forest Resource Chemistry, Forestry and Forest Products Research Institute, Matsunosato 1, Tsukuba, Ibaraki 305-8687, Japan
| | - Naofumi Kamimura
- Department of Materials Science and Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata 940-2188, Japan
| | - Eiji Masai
- Department of Materials Science and Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata 940-2188, Japan
| | - Masaya Nakamura
- Department of Forest Resource Chemistry, Forestry and Forest Products Research Institute, Matsunosato 1, Tsukuba, Ibaraki 305-8687, Japan
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10
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Li J, Maravelias CT, Van Lehn RC. Adaptive Conformer Sampling for Property Prediction Using the Conductor-like Screening Model for Real Solvents. Ind Eng Chem Res 2022. [DOI: 10.1021/acs.iecr.2c01163] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jianping Li
- Department of Chemical and Biological Engineering and DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Christos T. Maravelias
- Department of Chemical and Biological Engineering and Andlinger Center for Energy and the Environment, Princeton University, Princeton, New Jersey 08540, United States
| | - Reid C. Van Lehn
- Department of Chemical and Biological Engineering and DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
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12
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Cheng Y, Kuboyama K, Akasaka S, Araki T, Masai E, Nakamura M, Michinobu T. Polyurethanes based on lignin-derived metabolic intermediate with strong adhesion to metals. Polym Chem 2022. [DOI: 10.1039/d2py01128j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Polyurethanes based on lignin-derived 2-pyrone-4,6-dicarboxylic acid (PDC) were successfully synthesized in one-pot, and their thermal, mechanical, and adhesive properties were investigated.
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Affiliation(s)
- Ye Cheng
- Department of Materials Science and Engineering, Tokyo Institute of Technology, Tokyo 152-8552, Japan
| | - Keiichi Kuboyama
- Department of Materials Science and Engineering, Tokyo Institute of Technology, Tokyo 152-8552, Japan
| | - Shuichi Akasaka
- Department of Materials Science and Engineering, Tokyo Institute of Technology, Tokyo 152-8552, Japan
| | - Takuma Araki
- Department of Forest Resource Chemistry, Forestry and Forest Products Research Institute, Tsukuba, Ibaraki 305-8687, Japan
| | - Eiji Masai
- Department of Materials Science and Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata 940-2188, Japan
| | - Masaya Nakamura
- Department of Forest Resource Chemistry, Forestry and Forest Products Research Institute, Tsukuba, Ibaraki 305-8687, Japan
| | - Tsuyoshi Michinobu
- Department of Materials Science and Engineering, Tokyo Institute of Technology, Tokyo 152-8552, Japan
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13
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Weiland F, Kohlstedt M, Wittmann C. Guiding stars to the field of dreams: Metabolically engineered pathways and microbial platforms for a sustainable lignin-based industry. Metab Eng 2021; 71:13-41. [PMID: 34864214 DOI: 10.1016/j.ymben.2021.11.011] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 11/25/2021] [Accepted: 11/29/2021] [Indexed: 12/19/2022]
Abstract
Lignin is an important structural component of terrestrial plants and is readily generated during biomass fractionation in lignocellulose processing facilities. Due to lacking alternatives the majority of technical lignins is industrially simply burned into heat and energy. However, regarding its vast abundance and a chemically interesting richness in aromatics, lignin is presently regarded as the most under-utilized and promising feedstock for value-added applications. Notably, microbes have evolved powerful enzymes and pathways that break down lignin and metabolize its various aromatic components. This natural pathway atlas meanwhile serves as a guiding star for metabolic engineers to breed designed cell factories and efficiently upgrade this global waste stream. The metabolism of aromatic compounds, in combination with success stories from systems metabolic engineering, as reviewed here, promises a sustainable product portfolio from lignin, comprising bulk and specialty chemicals, biomaterials, and fuels.
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Affiliation(s)
- Fabia Weiland
- Institute of Systems Biotechnology, Saarland University, Saarbrücken, Germany
| | - Michael Kohlstedt
- Institute of Systems Biotechnology, Saarland University, Saarbrücken, Germany
| | - Christoph Wittmann
- Institute of Systems Biotechnology, Saarland University, Saarbrücken, Germany.
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14
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Suzuki Y, Otsuka Y, Araki T, Kamimura N, Masai E, Nakamura M, Katayama Y. Lignin valorization through efficient microbial production of β-ketoadipate from industrial black liquor. BIORESOURCE TECHNOLOGY 2021; 337:125489. [PMID: 34320768 DOI: 10.1016/j.biortech.2021.125489] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Revised: 06/28/2021] [Accepted: 06/29/2021] [Indexed: 06/13/2023]
Abstract
Vanillin and vanillate are the major lignin-derived aromatic compounds produced through the alkaline oxidation of softwood lignin. Because the production of higher-value added chemicals from these compounds is essential for lignin valorization, the microbial production of β-ketoadipate, a promising raw material for the synthesis of novel nylons, from lignin was considered. Pseudomonas putida KT2440 was engineered to convert vanillin and vanillate to β-ketoadipate. By examining the culture conditions with an initial culture volume of 1 L, the engineered strain completely converted 25 g of vanillin and 25 g of vanillate and produced approximately 23 g of β-ketoadipate from each of them with a yield of 93% or higher. Furthermore, this strain showed the ability to efficiently produce β-ketoadipate from softwood lignin extracts in black liquor, a byproduct of pulp production. These results suggest that the production of β-ketoadipate from industrial black liquor is highly feasible for substantial lignin valorization.
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Affiliation(s)
- Yuzo Suzuki
- Department of Forest Resource Chemistry, Forestry and Forest Products Research Institute, Tsukuba, Ibaraki 305-8687 Japan.
| | - Yuichiro Otsuka
- Department of Forest Resource Chemistry, Forestry and Forest Products Research Institute, Tsukuba, Ibaraki 305-8687 Japan
| | - Takuma Araki
- Department of Forest Resource Chemistry, Forestry and Forest Products Research Institute, Tsukuba, Ibaraki 305-8687 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
| | - Masaya Nakamura
- Department of Forest Resource Chemistry, Forestry and Forest Products Research Institute, Tsukuba, Ibaraki 305-8687 Japan
| | - Yoshihiro Katayama
- Bio-based Solution Division, Kantechs Co. Ltd., Bunkyo, Tokyo 112-0004, Japan
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15
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Kuatsjah E, Chan ACK, Katahira R, Haugen SJ, Beckham GT, Murphy MEP, Eltis LD. Structural and functional analysis of lignostilbene dioxygenases from Sphingobium sp. SYK-6. J Biol Chem 2021; 296:100758. [PMID: 33965373 PMCID: PMC8191317 DOI: 10.1016/j.jbc.2021.100758] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 04/28/2021] [Accepted: 05/03/2021] [Indexed: 11/27/2022] Open
Abstract
Lignostilbene-α,β-dioxygenases (LSDs) are iron-dependent oxygenases involved in the catabolism of lignin-derived stilbenes. Sphingobium sp. SYK-6 contains eight LSD homologs with undetermined physiological roles. To investigate which homologs are involved in the catabolism of dehydrodiconiferyl alcohol (DCA), derived from β-5 linked lignin subunits, we heterologously produced the enzymes and screened their activities in lysates. The seven soluble enzymes all cleaved lignostilbene, but only LSD2, LSD3, and LSD4 exhibited high specific activity for 3-(4-hydroxy-3-(4-hydroxy-3-methoxystyryl)-5-methoxyphenyl) acrylate (DCA-S) relative to lignostilbene. LSD4 catalyzed the cleavage of DCA-S to 5-formylferulate and vanillin and cleaved lignostilbene and DCA-S (∼106 M−1 s−1) with tenfold greater specificity than pterostilbene and resveratrol. X-ray crystal structures of native LSD4 and the catalytically inactive cobalt-substituted Co-LSD4 at 1.45 Å resolution revealed the same fold, metal ion coordination, and edge-to-edge dimeric structure as observed in related enzymes. Key catalytic residues, Phe-59, Tyr-101, and Lys-134, were also conserved. Structures of Co-LSD4·vanillin, Co-LSD4·lignostilbene, and Co-LSD4·DCA-S complexes revealed that Ser-283 forms a hydrogen bond with the hydroxyl group of the ferulyl portion of DCA-S. This residue is conserved in LSD2 and LSD4 but is alanine in LSD3. Substitution of Ser-283 with Ala minimally affected the specificity of LSD4 for either lignostilbene or DCA-S. By contrast, substitution with phenylalanine, as occurs in LSD5 and LSD6, reduced the specificity of the enzyme for both substrates by an order of magnitude. This study expands our understanding of an LSD critical to DCA catabolism as well as the physiological roles of other LSDs and their determinants of substrate specificity.
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Affiliation(s)
- Eugene Kuatsjah
- Department of Microbiology and Immunology, Life Sciences Institute, The University of British Columbia, Vancouver, Canada; Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, Colorado, USA; Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge Tennessee, USA
| | - Anson C K Chan
- Department of Microbiology and Immunology, Life Sciences Institute, The University of British Columbia, Vancouver, Canada
| | - Rui Katahira
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Stefan J Haugen
- 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; Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge Tennessee, USA
| | - Michael E P Murphy
- Department of Microbiology and Immunology, Life Sciences Institute, The University of British Columbia, Vancouver, Canada; BioProducts Institute, The University of British Columbia, Vancouver, Canada
| | - Lindsay D Eltis
- Department of Microbiology and Immunology, Life Sciences Institute, The University of British Columbia, Vancouver, Canada; BioProducts Institute, The University of British Columbia, Vancouver, Canada.
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16
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Yaguchi AL, Lee SJ, Blenner MA. Synthetic Biology towards Engineering Microbial Lignin Biotransformation. Trends Biotechnol 2021; 39:1037-1064. [PMID: 33712323 DOI: 10.1016/j.tibtech.2021.02.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 02/03/2021] [Accepted: 02/03/2021] [Indexed: 01/19/2023]
Abstract
Lignin is the second most abundant biopolymer on earth and is a major source of aromatic compounds; however, it is vastly underutilized owing to its heterogeneous and recalcitrant nature. Microorganisms have evolved efficient mechanisms that overcome these challenges to depolymerize lignin and funnel complex mixtures of lignin-derived monomers to central metabolites. This review summarizes recent synthetic biology efforts to enhance lignin depolymerization and aromatic catabolism in bacterial and fungal hosts for the production of both natural and novel bioproducts. We also highlight difficulties in engineering complex phenotypes and discuss the outlook for the future of lignin biological valorization.
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Affiliation(s)
- Allison L Yaguchi
- Department of Chemical and Biomolecular Engineering, Clemson University, 206 South Palmetto Boulevard, Clemson, SC 29634, USA
| | - Stephen J Lee
- Department of Chemical and Biomolecular Engineering, Clemson University, 206 South Palmetto Boulevard, Clemson, SC 29634, USA
| | - Mark A Blenner
- Department of Chemical and Biomolecular Engineering, Clemson University, 206 South Palmetto Boulevard, Clemson, SC 29634, USA; Current address: Department of Chemical and Biomolecular Engineering, University of Delaware, 590 Avenue 1743, Newark, DE 19713, USA.
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17
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Wada A, Prates ÉT, Hirano R, Werner AZ, Kamimura N, Jacobson DA, Beckham GT, Masai E. Characterization of aromatic acid/proton symporters in Pseudomonas putida KT2440 toward efficient microbial conversion of lignin-related aromatics. Metab Eng 2021; 64:167-179. [PMID: 33549838 DOI: 10.1016/j.ymben.2021.01.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 12/10/2020] [Accepted: 01/30/2021] [Indexed: 11/18/2022]
Abstract
Pseudomonas putida KT2440 (hereafter KT2440) is a well-studied platform bacterium for the production of industrially valuable chemicals from heterogeneous mixtures of aromatic compounds obtained from lignin depolymerization. KT2440 can grow on lignin-related monomers, such as ferulate (FA), 4-coumarate (4CA), vanillate (VA), 4-hydroxybenzoate (4HBA), and protocatechuate (PCA). Genes associated with their catabolism are known, but knowledge about the uptake systems remains limited. In this work, we studied the KT2440 transporters of lignin-related monomers and their substrate selectivity. Based on the inhibition by protonophores, we focused on five genes encoding aromatic acid/H+ symporter family transporters categorized into major facilitator superfamily that uses the proton motive force. The mutants of PP_1376 (pcaK) and PP_3349 (hcnK) exhibited significantly reduced growth on PCA/4HBA and FA/4CA, respectively, while no change was observed on VA for any of the five gene mutants. At pH 9.0, the conversion of these compounds by hcnK mutant (FA/4CA) and vanK mutant (VA) was dramatically reduced, revealing that these transporters are crucial for the uptake of the anionic substrates at high pH. Uptake assays using 14C-labeled substrates in Escherichia coli and biosensor-based assays confirmed that PcaK, HcnK, and VanK have ability to take up PCA, FA/4CA, and VA/PCA, respectively. Additionally, analyses of the predicted protein structures suggest that the size and hydropathic properties of the substrate-binding sites of these transporters determine their substrate preferences. Overall, this study reveals that at physiological pH, PcaK and HcnK have a major role in the uptake of PCA/4HBA and FA/4CA, respectively, and VanK is a VA/PCA transporter. This information can contribute to the engineering of strains for the efficient conversion of lignin-related monomers to value-added chemicals.
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Affiliation(s)
- Ayumu Wada
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, Japan
| | - Érica T Prates
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA; Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Ryo Hirano
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, Japan
| | - Allison Z Werner
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA; Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Naofumi Kamimura
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, Japan
| | - Daniel A Jacobson
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA; Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Gregg T Beckham
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA; Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Eiji Masai
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, Japan.
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18
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Li J, Wang P, Salam N, Li X, Ahmad M, Tian Y, Duan L, Huang L, Xiao M, Mou X, Li W. Unraveling bacteria-mediated degradation of lignin-derived aromatic compounds in a freshwater environment. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 749:141236. [PMID: 32846344 DOI: 10.1016/j.scitotenv.2020.141236] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 07/23/2020] [Accepted: 07/23/2020] [Indexed: 06/11/2023]
Abstract
Terrestrial organic carbon-lignin plays a crucial role in the global carbon balance. However, limited studies presented the functional and ecological traits of lignin decomposers population in natural aquatic ecosystem. In this study, we performed a multi-omics analysis by deploying amplicon, metagenomic, and metatranscriptomic approaches to identify the key potential degraders and pathways involved lignin-derived aromatic compounds in the later stage of lignin degradation. By establishing microcosms with model lignin-derived aromatic compound (vanillic acid, VAN), based on the estimated absolute abundance (EAA) and the metagenome-assembled genomes (MAGs), novel potential lignin-derived aromatic compounds degraders were identified in the aquatic ecosystem. Furthermore, members of the phyla Proteobacteria and Actinobacteria were the potential major lignin-derived aromatic compounds degraders in the studied ecosystem. Our study demonstrated that genomes of the class Betaproteobacteria (Proteobacteria) possess a complete enzymatic system for the degradation of diarylpropanes, vanillate and protocatechuate, besides having the capacity to degrade other lignin-derived aromatic compounds. This study provides strong evidence for the ability of aquatic bacteria to degrade lignin-derived aromatic compounds and suggest that different microbes might occupy different niches in the later stage of lignin degradation.
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Affiliation(s)
- Jialing Li
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) and State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, Guangdong, China
| | - Pandeng Wang
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) and State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, Guangdong, China
| | - Nimaichand Salam
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) and State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, Guangdong, China
| | - Xin Li
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) and State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, Guangdong, China
| | - Manzoor Ahmad
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) and State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, Guangdong, China
| | - Ye Tian
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) and State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, Guangdong, China
| | - Li Duan
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) and State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, Guangdong, China
| | - Linan Huang
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) and State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, Guangdong, China
| | - Min Xiao
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) and State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, Guangdong, China
| | - Xiaozhen Mou
- Department of Biological Sciences, Kent State University, Kent, 44242, OH, USA.
| | - Wenjun Li
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) and State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, Guangdong, China.
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19
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The Syringate O-Demethylase Gene of Sphingobium sp. Strain SYK-6 Is Regulated by DesX, while Other Vanillate and Syringate Catabolism Genes Are Regulated by DesR. Appl Environ Microbiol 2020; 86:AEM.01712-20. [PMID: 32917754 DOI: 10.1128/aem.01712-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Accepted: 09/02/2020] [Indexed: 12/26/2022] Open
Abstract
Syringate and vanillate are the major metabolites of lignin biodegradation. In Sphingobium sp. strain SYK-6, syringate is O demethylated to gallate by consecutive reactions catalyzed by DesA and LigM, and vanillate is O demethylated to protocatechuate by a reaction catalyzed by LigM. The gallate ring is cleaved by DesB, and protocatechuate is catabolized via the protocatechuate 4,5-cleavage pathway. The transcriptions of desA, ligM, and desB are induced by syringate and vanillate, while those of ligM and desB are negatively regulated by the MarR-type transcriptional regulator DesR, which is not involved in desA regulation. Here, we clarified the regulatory system for desA transcription by analyzing the IclR-type transcriptional regulator desX, located downstream of desA Quantitative reverse transcription (RT)-PCR analyses of a desX mutant indicated that the transcription of desA was negatively regulated by DesX. In contrast, DesX was not involved in the regulation of ligM and desB The ferulate catabolism genes (ferBA), under the control of a MarR-type transcriptional regulator, FerC, are located upstream of desA RT-PCR analyses suggested that the ferB-ferA-SLG_25010-desA gene cluster consists of the ferBA operon and the SLG_25010-desA operon. Promoter assays revealed that a syringate- and vanillate-inducible promoter is located upstream of SLG_25010. Purified DesX bound to this promoter region, which overlaps an 18-bp inverted-repeat sequence that appears to be essential for the DNA binding of DesX. Syringate and vanillate inhibited the DNA binding of DesX, indicating that the compounds are effector molecules of DesX.IMPORTANCE Syringate is a major degradation product in the microbial and chemical degradation of syringyl lignin. Along with other low-molecular-weight aromatic compounds, syringate is produced by chemical lignin depolymerization. Converting this mixture into value-added chemicals using bacterial metabolism (i.e., biological funneling) is a promising option for lignin valorization. To construct an efficient microbial lignin conversion system, it is necessary to identify and characterize the genes involved in the uptake and catabolism of lignin-derived aromatic compounds and to elucidate their transcriptional regulation. In this study, we found that the transcription of desA, encoding syringate O-demethylase in SYK-6, is regulated by an IclR-type transcriptional regulator, DesX. The findings of this study, combined with our previous results on desR (encoding a MarR transcriptional regulator that controls the transcription of ligM and desB), provide an overall picture of the transcriptional-regulatory systems for syringate and vanillate catabolism in SYK-6.
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