1
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Kaur D, Singh RP, Gupta S. Screening and Characterization of Next-Generation Biofuels Producing Bacterial Strains. Curr Microbiol 2022; 79:85. [PMID: 35129690 DOI: 10.1007/s00284-022-02781-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 01/20/2022] [Indexed: 11/28/2022]
Abstract
Production of fuels from renewable resources is of utmost importance due to fast depletion of fossil resources and related environmental issues. The present study explored the intrinsic capability of microbial strains to produce alka(e)nes, the next-generation biofuel, thus to reduce the dependence upon current petroleum fuels. Eight bacterial strains, namely, SDK-1, SDK-2, SDK-6, SDK-7, SDK-8, SDK-9, SDK-10, and SDK-11 were isolated from sludge and soil samples collected from different sources using lauric acid as a substrate with a potential to produce alka(e)nes. Production of different medium- and long-chain alka(e)nes by these isolates was confirmed via gas chromatography-mass spectrometer (GC-MS) analysis. SDK-1 (7.2%), SDK-2 (3.72%), and SDK-6 (3.52%) produced significant proportion of medium-chain hydrocarbons as compared to SDK-10 and control with no production. These isolates may be further investigated for production of these alternative sources of energy. In contrary, maximum fraction of long-chain hydrocarbons is produced in SDK-8 (75.28%) followed by SDK-9 (61.51%). Similarly more than 50% of the total hydrocarbons produced in SDK-8 constitute fossil mimic hydrocarbons while only 10.78% fractions were found in SDK-10. Since these fractions resemble different hydrocarbons obtained from crude oil, hence may be explored for their wide applications in different fields. Biochemical characterization and sequencing of the 16S rRNA gene revealed the homology of SDK-1, SDK-2 and SDK-6 with Pseudomonas aeruginosa, SDK-7 and SDK-9 with Enterobacter cloacae, SDK-8 with Klebsiella pnuemoniae, SDK-10 with Enterobacter hormaechei and SDK-11 with Pseudomonas nitroreducens, respectively.
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Affiliation(s)
- Damanjeet Kaur
- Department of Microbiology, Mata Gujri College, Fatehgarh Sahib, Punjab, 140406, India.,Department of Biotechnology, Punjabi University, Patiala, Punjab, India
| | - Rupinder Pal Singh
- Department of Food Processing Technology, Sri Guru Granth Sahib World University, Fatehgarh Sahib, Punjab, India
| | - Saurabh Gupta
- Department of Microbiology, Mata Gujri College, Fatehgarh Sahib, Punjab, 140406, India.
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2
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Passarini MRZ, E Silva TR, Bernal SPF, Cecchet NL, Sartoratto A, Boroski M, Duarte AWF, Ottoni JR, Rosa LH, de Oliveira VM. Undecane production by cold-adapted bacteria from Antarctica. Extremophiles 2020; 24:863-873. [PMID: 32944821 DOI: 10.1007/s00792-020-01200-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 09/03/2020] [Indexed: 11/27/2022]
Abstract
In the last decades, efforts to reduce the use of fossil fuels have increased the search for alternative sustainable sources of renewable energy. In this scenario, hydrocarbons derived from fatty acids are among the compounds that have been drawing attention. The intracellular production of hydrocarbons by bacteria derived from cold environments such as the Antarctic continent is currently poorly investigated, as extremophilic microorganisms provide a great range of metabolic capabilities and may represent a key tool in the production of biofuels. The aim of this study was to explore the ability of bacterial cells derived from extreme environments to produce hydrocarbons with potential for further use as biofuels. Seven bacteria isolated from Antarctic samples were evaluated for hydrocarbon production using GC-MS approaches. Two isolates, identified as Arthrobacter livingstonensis 593 and Pseudoalteromonas arctica 628, were able to produce the hydrocarbon undecane (CH3-(CH2)9-CH3) in concentrations of 1.39 mg L-1 and 1.81 mg L-1, respectively. Results from the present work encourage further research focusing on the optimization of hydrocarbon production by the isolates identified as producers, which may be used in further aircraft biofuel production. This is the first report on the production of the undecane compound by bacteria isolated from waterlogged soil and sponge from Antarctica.
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Affiliation(s)
- Michel Rodrigo Zambrano Passarini
- UNILA-Universidade Federal da Integração Latino-Americana. Laboratório de Biotecnologia Ambiental, Av. Tarquínio Joslin dos Santos, 1000-Jd Universitário, Foz do Iguaçu, PR, 85870-650, Brazil.
| | - Tiago Rodrigues E Silva
- CPQBA/UNICAMP-Divisão de Recursos Microbianos, Rua Alexandre Caselatto 999, Vila Betel, CP 6171, Campinas, SP, 13083-970, Brazil
| | - Suzan Prado Fernandes Bernal
- UNILA-Universidade Federal da Integração Latino-Americana. Laboratório de Biotecnologia Ambiental, Av. Tarquínio Joslin dos Santos, 1000-Jd Universitário, Foz do Iguaçu, PR, 85870-650, Brazil
| | - Nathália Luana Cecchet
- UNILA-Universidade Federal da Integração Latino-Americana. Laboratório de Biotecnologia Ambiental, Av. Tarquínio Joslin dos Santos, 1000-Jd Universitário, Foz do Iguaçu, PR, 85870-650, Brazil
| | - Adilson Sartoratto
- CPQBA/UNICAMP-Divisão de Química Orgânica e Farmacêutica, Rua Alexandre Caselatto 999, Vila Betel, CP 6171, Campinas, SP, 13083-970, Brazil
| | - Marcela Boroski
- UNILA-Universidade Federal da Integração Latino-Americana. Laboratório de Química, Av. Tancredo Neves 6731- Conjunto B, Foz do Iguaçu, PR, 85867-970, Brazil
| | - Alysson Wagner Fernandes Duarte
- UFAL-Universidade Federal de Alagoas, Av. Manoel Severino Barbosa-Rodovia AL-115, Bom Sucesso, Arapiraca, AL, 57309-005, Brazil
| | - Júlia Ronzella Ottoni
- UDC-Centro Universitário Dinâmica das Cataratas, Rua Castelo Branco, 349, Centro, Foz do Iguaçu, PR, Brazil
| | - Luiz Henrique Rosa
- UFMG-Departamento de Microbiologia, Universidade Federal de Minas Gerais, Instituto de Ciências Biológicas, Av. Antônio Carlos, 6627, Pampulha, Belo Horizonte, MG, 31270-901, Brazil
| | - Valéria Maia de Oliveira
- CPQBA/UNICAMP-Divisão de Recursos Microbianos, Rua Alexandre Caselatto 999, Vila Betel, CP 6171, Campinas, SP, 13083-970, Brazil
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3
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Surger M, Angelov A, Liebl W. Distribution and diversity of olefins and olefin-biosynthesis genes in Gram-positive bacteria. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:70. [PMID: 32313552 PMCID: PMC7158056 DOI: 10.1186/s13068-020-01706-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 04/02/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND The natural production of olefins (unsaturated aliphatic hydrocarbons) by certain bacterial genera represents an alternative and sustainable source of biofuels and lubricant components. The biochemical steps of olefin biosynthesis via the ole pathway encoded by oleABCD have been unraveled recently, and the occurrence of olefins has been reported for several Gram-negative and Gram-positive bacteria. However, the distribution and diversity of olefins among the Gram-positive bacteria has not been studied in detail. RESULTS We report the distribution of olefin synthesis gene clusters in the bacterial domain and focus on the olefin composition and the determinants of olefin production within the phylum of Actinobacteria. The olefin profiles of numerous genera of the Micrococcales order were analyzed by GC/MS. We describe for the first time olefin synthesis in representatives of the genera Pseudarthrobacter, Paenarthrobacter, Glutamicibacter, Clavibacter, Rothia, Dermacoccus, Kytococcus, Curtobacterium, and Microbacterium. By exchange of the native ole genes of Micrococcus luteus with the corresponding genes of actinobacteria producing different olefins, we demonstrate that the olefin composition can be manipulated with respect to chain length and isomer composition. CONCLUSIONS This study provides a catalogue of the diversity of olefin structures found in the Actinobacteria. Our ole gene swapping data indicate that the olefin structures are fundamentally determined by the substrate specificity of OleA, and at the same time by the availability of a sufficient supply of suitable fatty acyl-CoA substrates from cellular fatty acid metabolism. This makes OleA of Gram-positive bacteria a promising target for structural analysis and protein engineering aiming to generate olefin chain lengths and isomer profiles which are designed to match the requirements of various industrial applications.
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Affiliation(s)
- Maximilian Surger
- Chair of Microbiology, Technical University of Munich, Emil-Ramann-Str. 4, 85354 Freising-Weihenstephan, Germany
| | - Angel Angelov
- Chair of Microbiology, Technical University of Munich, Emil-Ramann-Str. 4, 85354 Freising-Weihenstephan, Germany
| | - Wolfgang Liebl
- Chair of Microbiology, Technical University of Munich, Emil-Ramann-Str. 4, 85354 Freising-Weihenstephan, Germany
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4
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Smith MD, Robinson SL, Molomjamts M, Wackett LP. In Vivo Assay Reveals Microbial OleA Thiolases Initiating Hydrocarbon and β-Lactone Biosynthesis. mBio 2020; 11:e00111-20. [PMID: 32156808 PMCID: PMC7064751 DOI: 10.1128/mbio.00111-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 01/22/2020] [Indexed: 12/29/2022] Open
Abstract
OleA, a member of the thiolase superfamily, is known to catalyze the Claisen condensation of long-chain acyl coenzyme A (acyl-CoA) substrates, initiating metabolic pathways in bacteria for the production of membrane lipids and β-lactone natural products. OleA homologs are found in diverse bacterial phyla, but to date, only one homodimeric OleA has been successfully purified to homogeneity and characterized in vitro A major impediment for the identification of new OleA enzymes has been protein instability and time-consuming in vitro assays. Here, we developed a bioinformatic pipeline to identify OleA homologs and a new rapid assay to screen OleA enzyme activity in vivo and map their taxonomic diversity. The screen is based on the discovery that OleA displayed surprisingly high rates of p-nitrophenyl ester hydrolysis, an activity not shared by other thiolases, including FabH. The high rates allowed activity to be determined in vitro and with heterologously expressed OleA in vivo via the release of the yellow p-nitrophenol product. Seventy-four putative oleA genes identified in the genomes of diverse bacteria were heterologously expressed in Escherichia coli, and 25 showed activity with p-nitrophenyl esters. The OleA proteins tested were encoded in variable genomic contexts from seven different phyla and are predicted to function in distinct membrane lipid and β-lactone natural product metabolic pathways. This study highlights the diversity of unstudied OleA proteins and presents a rapid method for their identification and characterization.IMPORTANCE Microbially produced β-lactones are found in antibiotic, antitumor, and antiobesity drugs. Long-chain olefinic membrane hydrocarbons have potential utility as fuels and specialty chemicals. The metabolic pathway to both end products share bacterial enzymes denoted as OleA, OleC, and OleD that transform acyl-CoA cellular intermediates into β-lactones. Bacteria producing membrane hydrocarbons via the Ole pathway additionally express a β-lactone decarboxylase, OleB. Both β-lactone and olefin biosynthesis pathways are initiated by OleA enzymes that define the overall structure of the final product. There is currently very limited information on OleA enzymes apart from the single representative from Xanthomonas campestris In this study, bioinformatic analysis identified hundreds of new, putative OleA proteins, 74 proteins were screened via a rapid whole-cell method, leading to the identification of 25 stably expressed OleA proteins representing seven bacteria phyla.
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Affiliation(s)
- Megan D Smith
- Biotechnology Institute, University of Minnesota, St. Paul, Minnesota, USA
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Serina L Robinson
- Biotechnology Institute, University of Minnesota, St. Paul, Minnesota, USA
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Mandkhai Molomjamts
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota, USA
| | - Lawrence P Wackett
- Biotechnology Institute, University of Minnesota, St. Paul, Minnesota, USA
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota, USA
- Microbial and Plant Genomics Institute, University of Minnesota, St. Paul, Minnesota, USA
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5
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Christenson JK, Robinson SL, Engel TA, Richman JE, Kim AN, Wackett LP. OleB from Bacterial Hydrocarbon Biosynthesis Is a β-Lactone Decarboxylase That Shares Key Features with Haloalkane Dehalogenases. Biochemistry 2017; 56:5278-5287. [PMID: 28872321 DOI: 10.1021/acs.biochem.7b00667] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
OleB is an α/β-hydrolase found in bacteria that biosynthesize long-chain olefinic hydrocarbons, but its function has remained obscure. We report that OleB from the Gram-negative bacterium Xanthomonas campestris performs an unprecedented β-lactone decarboxylation reaction, to complete cis-olefin biosynthesis. OleB reactions monitored by 1H nuclear magnetic resonance spectroscopy revealed a selectivity for decarboxylating cis-β-lactones and no discernible activity with trans-β-lactones, consistent with the known configuration of pathway intermediates. Protein sequence analyses showed OleB proteins were most related to haloalkane dehalogenases (HLDs) and retained the canonical Asp-His-Asp catalytic triad of HLDs. Unexpectedly, it was determined that an understudied subfamily, denoted as HLD-III, is comprised mostly of OleB proteins encoded within oleABCD gene clusters, suggesting a misannotation. OleB from X. campestris showed very low dehalogenase activity only against haloalkane substrates with long alkyl chains. A haloalkane substrate mimic alkylated wild-type X. campestris OleB but not OleBD114A, implicating this residue as the active site nucleophile as in HLDs. A sequence-divergent OleB, found as part of a natural OleBC fusion and classified as an HLD-III, from the Gram-positive bacterium Micrococcus luteus was demonstrated to have the same activity, stereochemical preference, and dependence on the proposed Asp nucleophile. H218O studies with M. luteus OleBC suggested that the canonical alkyl-enzyme intermediate of HLDs is hydrolyzed differently by OleB enzymes, as 18O is not incorporated into the nucleophilic aspartic acid. This work defines a previously unrecognized reaction in nature, functionally identifies some HLD-III enzymes as β-lactone decarboxylases, and posits an enzymatic mechanism of β-lactone decarboxylation.
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Affiliation(s)
- James K Christenson
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota , Minneapolis, Minnesota 55455, United States.,Biotechnology Institute, University of Minnesota , St. Paul, Minnesota 55108, United States
| | - Serina L Robinson
- Biotechnology Institute, University of Minnesota , St. Paul, Minnesota 55108, United States.,Department of Microbiology and Immunology, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Tiffany A Engel
- Biotechnology Institute, University of Minnesota , St. Paul, Minnesota 55108, United States
| | - Jack E Richman
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota , Minneapolis, Minnesota 55455, United States.,Biotechnology Institute, University of Minnesota , St. Paul, Minnesota 55108, United States
| | - An N Kim
- Biotechnology Institute, University of Minnesota , St. Paul, Minnesota 55108, United States
| | - Larry P Wackett
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota , Minneapolis, Minnesota 55455, United States.,Biotechnology Institute, University of Minnesota , St. Paul, Minnesota 55108, United States.,Microbial and Plant Genomics Institute, University of Minnesota , St. Paul, Minnesota 55108, United States
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6
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Christenson JK, Richman JE, Jensen MR, Neufeld JY, Wilmot CM, Wackett LP. β-Lactone Synthetase Found in the Olefin Biosynthesis Pathway. Biochemistry 2017; 56:348-351. [PMID: 28029240 PMCID: PMC5499249 DOI: 10.1021/acs.biochem.6b01199] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The first β-lactone synthetase enzyme is reported, creating an unexpected link between the biosynthesis of olefinic hydrocarbons and highly functionalized natural products. The enzyme OleC, involved in the microbial biosynthesis of long-chain olefinic hydrocarbons, reacts with syn- and anti-β-hydroxy acid substrates to yield cis- and trans-β-lactones, respectively. Protein sequence comparisons reveal that enzymes homologous to OleC are encoded in natural product gene clusters that generate β-lactone rings, suggesting a common mechanism of biosynthesis.
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Affiliation(s)
- James K. Christenson
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Min-nesota, 55455, United States
- BioTechnology Institute, University of Minnesota, St. Paul, Minnesota, 55108, United States
| | - Jack E. Richman
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Min-nesota, 55455, United States
- BioTechnology Institute, University of Minnesota, St. Paul, Minnesota, 55108, United States
| | - Matthew R. Jensen
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Min-nesota, 55455, United States
- BioTechnology Institute, University of Minnesota, St. Paul, Minnesota, 55108, United States
| | - Jennifer Y. Neufeld
- BioTechnology Institute, University of Minnesota, St. Paul, Minnesota, 55108, United States
| | - Carrie M. Wilmot
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Min-nesota, 55455, United States
- BioTechnology Institute, University of Minnesota, St. Paul, Minnesota, 55108, United States
| | - Lawrence P. Wackett
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Min-nesota, 55455, United States
- BioTechnology Institute, University of Minnesota, St. Paul, Minnesota, 55108, United States
- Microbial and Plant Genomic Institute, University of Minnesota, St. Paul, Minnesota, 55108, United States
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7
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Sun H, Gao T, Chen X, Hitchings MD, Li S, Chen T, Zhang H, An L, Dyson P. Complete genome sequence of a psychotrophic Arthrobacter strain A3 (CGMCC 1.8987), a novel long-chain hydrocarbons producer. J Biotechnol 2016; 222:23-4. [PMID: 26854946 DOI: 10.1016/j.jbiotec.2016.02.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 02/03/2016] [Indexed: 11/16/2022]
Abstract
Arthrobacter strain A3, a psychotrophic bacterium isolated from the Tian Shan Mountain of China, can degrade the cellulose and synthesis the long-chain hydrocarbons efficiently in low temperature. Here we report the complete genome sequence of this bacterium. The complete genome sequence of Arthrobacter strain A3, consisting of a cycle chromosome with a size of 4.26 Mbp and a cycle plasmid with a size of 194kbp. In this genome, a hydrocarbon biosynthesis gene cluster (oleA, oleB/oleC and oleD) was identified. To resistant the extreme environment, this strain contains a unique mycothiol-biosynthetic pathway (mshA-D), which has not been found in other Arthrobacter species before. The availability of this genome sequence allows us to investigate the genetic basis of adaptation to growth in a nutrient-poor permafrost environment and to evaluate of the biofuel-synthetic potential of this species.
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Affiliation(s)
- Haili Sun
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China; Lanzhou University; Centre of Urban Ecology and Environmental Biotechnology; Lanzhou City University, Lanzhou 730000, China
| | - Tianpeng Gao
- Lanzhou University; Centre of Urban Ecology and Environmental Biotechnology; Lanzhou City University, Lanzhou 730000, China
| | - Ximing Chen
- Key Laboratory of Extreme Environmental Microbial Resources and Engineering of Gansu Province, Lanzhou 730000, China; Key Laboratory of Desert and Desertification, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Matthew D Hitchings
- Institute of Life Science; College of Medicine, Swansea University, Singleton Park, Swansea SA2 8PP, UK
| | - Shuyan Li
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry & Chemical Engineering, Lanzhou Univerisity, Lanzhou 730000, China
| | - Tao Chen
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Hua Zhang
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Lizhe An
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China.
| | - Paul Dyson
- Institute of Life Science; College of Medicine, Swansea University, Singleton Park, Swansea SA2 8PP, UK
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8
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Revellame ED, Hernandez R, French W, Holmes WE, Benson TJ, Pham PJ, Forks A, Callahan II R. Lipid storage compounds in raw activated sludge microorganisms for biofuels and oleochemicals production. RSC Adv 2012. [DOI: 10.1039/c2ra01078j] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
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9
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Chen XM, Jiang Y, Li YT, Zhang HH, Li J, Chen X, Zhao Q, Zhao J, Si J, Lin ZW, Zhang H, Dyson P, An LZ. Regulation of expression of trehalose-6-phosphate synthase during cold shock in Arthrobacter strain A3. Extremophiles 2011; 15:499-508. [DOI: 10.1007/s00792-011-0380-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2010] [Accepted: 05/20/2011] [Indexed: 10/18/2022]
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10
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Frias JA, Richman JE, Erickson JS, Wackett LP. Purification and characterization of OleA from Xanthomonas campestris and demonstration of a non-decarboxylative Claisen condensation reaction. J Biol Chem 2011; 286:10930-8. [PMID: 21266575 PMCID: PMC3064148 DOI: 10.1074/jbc.m110.216127] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Revised: 01/24/2011] [Indexed: 11/06/2022] Open
Abstract
OleA catalyzes the condensation of fatty acyl groups in the first step of bacterial long-chain olefin biosynthesis, but the mechanism of the condensation reaction is controversial. In this study, OleA from Xanthomonas campestris was expressed in Escherichia coli and purified to homogeneity. The purified protein was shown to be active with fatty acyl-CoA substrates that ranged from C(8) to C(16) in length. With limiting myristoyl-CoA (C(14)), 1 mol of the free coenzyme A was released/mol of myristoyl-CoA consumed. Using [(14)C]myristoyl-CoA, the other products were identified as myristic acid, 2-myristoylmyristic acid, and 14-heptacosanone. 2-Myristoylmyristic acid was indicated to be the physiologically relevant product of OleA in several ways. First, 2-myristoylmyristic acid was the major condensed product in short incubations, but over time, it decreased with the concomitant increase of 14-heptacosanone. Second, synthetic 2-myristoylmyristic acid showed similar decarboxylation kinetics in the absence of OleA. Third, 2-myristoylmyristic acid was shown to be reactive with purified OleC and OleD to generate the olefin 14-heptacosene, a product seen in previous in vivo studies. The decarboxylation product, 14-heptacosanone, did not react with OleC and OleD to produce any demonstrable product. Substantial hydrolysis of fatty acyl-CoA substrates to the corresponding fatty acids was observed, but it is currently unclear if this occurs in vivo. In total, these data are consistent with OleA catalyzing a non-decarboxylative Claisen condensation reaction in the first step of the olefin biosynthetic pathway previously found to be present in at least 70 different bacterial strains.
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Affiliation(s)
- Janice A. Frias
- From the Department of Biochemistry, Molecular Biology, and Biophysics and BioTechnology Institute, University of Minnesota, St. Paul, Minnesota 55108
| | - Jack E. Richman
- From the Department of Biochemistry, Molecular Biology, and Biophysics and BioTechnology Institute, University of Minnesota, St. Paul, Minnesota 55108
| | - Jasmine S. Erickson
- From the Department of Biochemistry, Molecular Biology, and Biophysics and BioTechnology Institute, University of Minnesota, St. Paul, Minnesota 55108
| | - Lawrence P. Wackett
- From the Department of Biochemistry, Molecular Biology, and Biophysics and BioTechnology Institute, University of Minnesota, St. Paul, Minnesota 55108
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11
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Sukovich DJ, Seffernick JL, Richman JE, Gralnick JA, Wackett LP. Widespread head-to-head hydrocarbon biosynthesis in bacteria and role of OleA. Appl Environ Microbiol 2010; 76:3850-62. [PMID: 20418421 PMCID: PMC2893475 DOI: 10.1128/aem.00436-10] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2010] [Accepted: 04/13/2010] [Indexed: 11/20/2022] Open
Abstract
Previous studies identified the oleABCD genes involved in head-to-head olefinic hydrocarbon biosynthesis. The present study more fully defined the OleABCD protein families within the thiolase, alpha/beta-hydrolase, AMP-dependent ligase/synthase, and short-chain dehydrogenase superfamilies, respectively. Only 0.1 to 1% of each superfamily represents likely Ole proteins. Sequence analysis based on structural alignments and gene context was used to identify highly likely ole genes. Selected microorganisms from the phyla Verucomicrobia, Planctomyces, Chloroflexi, Proteobacteria, and Actinobacteria were tested experimentally and shown to produce long-chain olefinic hydrocarbons. However, different species from the same genera sometimes lack the ole genes and fail to produce olefinic hydrocarbons. Overall, only 1.9% of 3,558 genomes analyzed showed clear evidence for containing ole genes. The type of olefins produced by different bacteria differed greatly with respect to the number of carbon-carbon double bonds. The greatest number of organisms surveyed biosynthesized a single long-chain olefin, 3,6,9,12,15,19,22,25,28-hentriacontanonaene, that contains nine double bonds. Xanthomonas campestris produced the greatest number of distinct olefin products, 15 compounds ranging in length from C(28) to C(31) and containing one to three double bonds. The type of long-chain product formed was shown to be dependent on the oleA gene in experiments with Shewanella oneidensis MR-1 ole gene deletion mutants containing native or heterologous oleA genes expressed in trans. A strain deleted in oleABCD and containing oleA in trans produced only ketones. Based on these observations, it was proposed that OleA catalyzes a nondecarboxylative thiolytic condensation of fatty acyl chains to generate a beta-ketoacyl intermediate that can decarboxylate spontaneously to generate ketones.
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Affiliation(s)
- David J. Sukovich
- Graduate Program in Microbiology, Immunology, and Cancer Biology, BioTechnology Institute, Department of Biochemistry, Molecular Biology and Biophysics, Department of Microbiology, University of Minnesota, St. Paul, Minnesota 55108
| | - Jennifer L. Seffernick
- Graduate Program in Microbiology, Immunology, and Cancer Biology, BioTechnology Institute, Department of Biochemistry, Molecular Biology and Biophysics, Department of Microbiology, University of Minnesota, St. Paul, Minnesota 55108
| | - Jack E. Richman
- Graduate Program in Microbiology, Immunology, and Cancer Biology, BioTechnology Institute, Department of Biochemistry, Molecular Biology and Biophysics, Department of Microbiology, University of Minnesota, St. Paul, Minnesota 55108
| | - Jeffrey A. Gralnick
- Graduate Program in Microbiology, Immunology, and Cancer Biology, BioTechnology Institute, Department of Biochemistry, Molecular Biology and Biophysics, Department of Microbiology, University of Minnesota, St. Paul, Minnesota 55108
| | - Lawrence P. Wackett
- Graduate Program in Microbiology, Immunology, and Cancer Biology, BioTechnology Institute, Department of Biochemistry, Molecular Biology and Biophysics, Department of Microbiology, University of Minnesota, St. Paul, Minnesota 55108
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12
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Structure, function, and insights into the biosynthesis of a head-to-head hydrocarbon in Shewanella oneidensis strain MR-1. Appl Environ Microbiol 2010; 76:3842-9. [PMID: 20418444 DOI: 10.1128/aem.00433-10] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A polyolefinic hydrocarbon was found in nonpolar extracts of Shewanella oneidensis MR-1 and identified as 3,6,9,12,15,19,22,25,28-hentriacontanonaene (compound I) by mass spectrometry, chemical modification, and nuclear magnetic resonance spectroscopy. Compound I was shown to be the product of a head-to-head fatty acid condensation biosynthetic pathway dependent on genes denoted as ole (for olefin biosynthesis). Four ole genes were present in S. oneidensis MR-1. Deletion of the entire oleABCD gene cluster led to the complete absence of nonpolar extractable products. Deletion of the oleC gene alone generated a strain that lacked compound I but produced a structurally analogous ketone. Complementation of the oleC gene eliminated formation of the ketone and restored the biosynthesis of compound I. A recombinant S. oneidensis strain containing oleA from Stenotrophomonas maltophilia strain R551-3 produced at least 17 related long-chain compounds in addition to compound I, 13 of which were identified as ketones. A potential role for OleA in head-to-head condensation was proposed. It was further proposed that long-chain polyunsaturated compounds aid in adapting cells to a rapid drop in temperature, based on three observations. In S. oneidensis wild-type cells, the cellular concentration of polyunsaturated compounds increased significantly with decreasing growth temperature. Second, the oleABCD deletion strain showed a significantly longer lag phase than the wild-type strain when shifted to a lower temperature. Lastly, compound I has been identified in a significant number of bacteria isolated from cold environments.
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Genes involved in long-chain alkene biosynthesis in Micrococcus luteus. Appl Environ Microbiol 2009; 76:1212-23. [PMID: 20038703 DOI: 10.1128/aem.02312-09] [Citation(s) in RCA: 124] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Aliphatic hydrocarbons are highly appealing targets for advanced cellulosic biofuels, as they are already predominant components of petroleum-based gasoline and diesel fuels. We have studied alkene biosynthesis in Micrococcus luteus ATCC 4698, a close relative of Sarcina lutea (now Kocuria rhizophila), which 4 decades ago was reported to biosynthesize iso- and anteiso-branched, long-chain alkenes. The underlying biochemistry and genetics of alkene biosynthesis were not elucidated in those studies. We show here that heterologous expression of a three-gene cluster from M. luteus (Mlut_13230-13250) in a fatty acid-overproducing Escherichia coli strain resulted in production of long-chain alkenes, predominantly 27:3 and 29:3 (no. carbon atoms: no. C=C bonds). Heterologous expression of Mlut_13230 (oleA) alone produced no long-chain alkenes but unsaturated aliphatic monoketones, predominantly 27:2, and in vitro studies with the purified Mlut_13230 protein and tetradecanoyl-coenzyme A (CoA) produced the same C(27) monoketone. Gas chromatography-time of flight mass spectrometry confirmed the elemental composition of all detected long-chain alkenes and monoketones (putative intermediates of alkene biosynthesis). Negative controls demonstrated that the M. luteus genes were responsible for production of these metabolites. Studies with wild-type M. luteus showed that the transcript copy number of Mlut_13230-13250 and the concentrations of 29:1 alkene isomers (the dominant alkenes produced by this strain) generally corresponded with bacterial population over time. We propose a metabolic pathway for alkene biosynthesis starting with acyl-CoA (or-ACP [acyl carrier protein]) thioesters and involving decarboxylative Claisen condensation as a key step, which we believe is catalyzed by OleA. Such activity is consistent with our data and with the homology (including the conserved Cys-His-Asn catalytic triad) of Mlut_13230 (OleA) to FabH (beta-ketoacyl-ACP synthase III), which catalyzes decarboxylative Claisen condensation during fatty acid biosynthesis.
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Genome sequence of the Fleming strain of Micrococcus luteus, a simple free-living actinobacterium. J Bacteriol 2009; 192:841-60. [PMID: 19948807 DOI: 10.1128/jb.01254-09] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Micrococcus luteus (NCTC2665, "Fleming strain") has one of the smallest genomes of free-living actinobacteria sequenced to date, comprising a single circular chromosome of 2,501,097 bp (G+C content, 73%) predicted to encode 2,403 proteins. The genome shows extensive synteny with that of the closely related organism, Kocuria rhizophila, from which it was taxonomically separated relatively recently. Despite its small size, the genome harbors 73 insertion sequence (IS) elements, almost all of which are closely related to elements found in other actinobacteria. An IS element is inserted into the rrs gene of one of only two rrn operons found in M. luteus. The genome encodes only four sigma factors and 14 response regulators, a finding indicative of adaptation to a rather strict ecological niche (mammalian skin). The high sensitivity of M. luteus to beta-lactam antibiotics may result from the presence of a reduced set of penicillin-binding proteins and the absence of a wblC gene, which plays an important role in the antibiotic resistance in other actinobacteria. Consistent with the restricted range of compounds it can use as a sole source of carbon for energy and growth, M. luteus has a minimal complement of genes concerned with carbohydrate transport and metabolism and its inability to utilize glucose as a sole carbon source may be due to the apparent absence of a gene encoding glucokinase. Uniquely among characterized bacteria, M. luteus appears to be able to metabolize glycogen only via trehalose and to make trehalose only via glycogen. It has very few genes associated with secondary metabolism. In contrast to most other actinobacteria, M. luteus encodes only one resuscitation-promoting factor (Rpf) required for emergence from dormancy, and its complement of other dormancy-related proteins is also much reduced. M. luteus is capable of long-chain alkene biosynthesis, which is of interest for advanced biofuel production; a three-gene cluster essential for this metabolism has been identified in the genome.
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