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Insomphun C, Chuah JA, Kobayashi S, Fujiki T, Numata K. Influence of Hydroxyl Groups on the Cell Viability of Polyhydroxyalkanoate (PHA) Scaffolds for Tissue Engineering. ACS Biomater Sci Eng 2016; 3:3064-3075. [DOI: 10.1021/acsbiomaterials.6b00279] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Chayatip Insomphun
- Enzyme
Research Team, RIKEN Center for Sustainable Resource Science, 2-1
Hirosawa, Wako-shi, Saitama 351-0198, Japan
| | - Jo-Ann Chuah
- Enzyme
Research Team, RIKEN Center for Sustainable Resource Science, 2-1
Hirosawa, Wako-shi, Saitama 351-0198, Japan
| | - Shingo Kobayashi
- Kaneka Corporation, 1-8 Miyamae-cho,
Takasago-cho, Takasago, Hyogo 676-8688, Japan
| | - Tetsuya Fujiki
- Kaneka Corporation, 1-8 Miyamae-cho,
Takasago-cho, Takasago, Hyogo 676-8688, Japan
| | - Keiji Numata
- Enzyme
Research Team, RIKEN Center for Sustainable Resource Science, 2-1
Hirosawa, Wako-shi, Saitama 351-0198, Japan
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Aerobic Toluene Degraders in the Rhizosphere of a Constructed Wetland Model Show Diurnal Polyhydroxyalkanoate Metabolism. Appl Environ Microbiol 2016; 82:4126-4132. [PMID: 27129963 DOI: 10.1128/aem.00493-16] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 04/26/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Constructed wetlands (CWs) are successfully applied for the treatment of waters contaminated with aromatic compounds. In these systems, plants provide oxygen and root exudates to the rhizosphere and thereby stimulate microbial degradation processes. Root exudation of oxygen and organic compounds depends on photosynthetic activity and thus may show day-night fluctuations. While diurnal changes in CW effluent composition have been observed, information on respective fluctuations of bacterial activity are scarce. We investigated microbial processes in a CW model system treating toluene-contaminated water which showed diurnal oscillations of oxygen concentrations using metaproteomics. Quantitative real-time PCR was applied to assess diurnal expression patterns of genes involved in aerobic and anaerobic toluene degradation. We observed stable aerobic toluene turnover by Burkholderiales during the day and night. Polyhydroxyalkanoate synthesis was upregulated in these bacteria during the day, suggesting that they additionally feed on organic root exudates while reutilizing the stored carbon compounds during the night via the glyoxylate cycle. Although mRNA copies encoding the anaerobic enzyme benzylsuccinate synthase (bssA) were relatively abundant and increased slightly at night, the corresponding protein could not be detected in the CW model system. Our study provides insights into diurnal patterns of microbial processes occurring in the rhizosphere of an aquatic ecosystem. IMPORTANCE Constructed wetlands are a well-established and cost-efficient option for the bioremediation of contaminated waters. While it is commonly accepted knowledge that the function of CWs is determined by the interplay of plants and microorganisms, the detailed molecular processes are considered a black box. Here, we used a well-characterized CW model system treating toluene-contaminated water to investigate the microbial processes influenced by diurnal plant root exudation. Our results indicated stable aerobic toluene degradation by members of the Burkholderiales during the day and night. Polyhydroxyalkanoate synthesis in these bacteria was higher during the day, suggesting that they additionally fed on organic root exudates and reutilized the stored carbon compounds during the night. Our study illuminates microbial processes occurring in the rhizosphere of an aquatic ecosystem.
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53
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Choi JE, Na HY, Yang TH, Rhee SK, Song JK. A lipophilic fluorescent LipidGreen1-based quantification method for high-throughput screening analysis of intracellular poly-3-hydroxybutyrate. AMB Express 2015; 5:131. [PMID: 26253390 PMCID: PMC4529427 DOI: 10.1186/s13568-015-0131-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 07/17/2015] [Indexed: 11/13/2022] Open
Abstract
Poly-3-hydroxybutyrate (PHB), the most abundant type of polyhydroxyalkanoates (PHA) is synthesized inside a variety of microorganisms as a primary candidate for industrial PHB production. Lipophilic dyes such as Nile red and BODIPY have been used to quantify intracellular PHB, but their uses have often been limited in terms of sensitivity and accuracy. In this study, a newly developed lipophilic fluorescent dye LipidGreen1 was used to quantify intracellular PHB. LipidGreen1 stained viable colonies by adding the dye into the medium which enabled the effective selection of PHB-positive cells. Furthermore, the fluorescence intensity of LipidGreen1 maintained its fluorescence intensity much longer than that of Nile red. The fluorescence intensities of intracellular PHB stained by LipidGreen1 accurately agreed with PHB contents measured by gas chromatography. In addition, internalization of LipidGreen1 in Escherichia coli cell was not necessary to obtain quantitative measurements. PHB-synthase mutants were differentiated by fluorescence intensities with a good correlation to increased levels of PHB production. These results show that LipidGreen1 is sensitive and accurate in high-throughput screening of newly isolated and genetically modified bacteria with enhanced PHB production.
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Riedel SL, Jahns S, Koenig S, Bock MC, Brigham CJ, Bader J, Stahl U. Polyhydroxyalkanoates production with Ralstonia eutropha from low quality waste animal fats. J Biotechnol 2015; 214:119-27. [DOI: 10.1016/j.jbiotec.2015.09.002] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 08/25/2015] [Accepted: 09/03/2015] [Indexed: 10/23/2022]
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Volodina E, Raberg M, Steinbüchel A. Engineering the heterotrophic carbon sources utilization range of Ralstonia eutropha H16 for applications in biotechnology. Crit Rev Biotechnol 2015; 36:978-991. [PMID: 26329669 DOI: 10.3109/07388551.2015.1079698] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Ralstonia eutropha H16 is an interesting candidate for the biotechnological production of polyesters consisting of hydroxy- and mercaptoalkanoates, and other compounds. It provides all the necessary characteristics, which are required for a biotechnological production strain. Due to its metabolic versatility, it can convert a broad range of renewable heterotrophic resources into diverse valuable compounds. High cell density fermentations of the non-pathogenic R. eutropha can be easily performed. Furthermore, this bacterium is accessible to engineering of its metabolism by genetic approaches having available a large repertoire of genetic tools. Since the complete genome sequence of R. eutropha H16 has become available, a variety of transcriptome, proteome and metabolome studies provided valuable data elucidating its complex metabolism and allowing a systematic biology approach. However, high production costs for bacterial large-scale production of biomass and biotechnologically valuable products are still an economic challenge. The application of inexpensive raw materials could significantly reduce the expenses. Therefore, the conversion of diverse substrates to polyhydroxyalkanoates by R. eutropha was steadily improved by optimization of cultivation conditions, mutagenesis and metabolic engineering. Industrial by-products and residual compounds like glycerol, and substrates containing high carbon content per weight like palm, soybean, corn oils as well as raw sugar-rich materials like molasses, starch and lignocellulose, are the most promising renewable substrates and were intensively studied.
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Affiliation(s)
- Elena Volodina
- a Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster , Münster , Germany and
| | - Matthias Raberg
- a Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster , Münster , Germany and
| | - Alexander Steinbüchel
- a Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster , Münster , Germany and.,b Environmental Science Department, King Abdulaziz University , Jeddah , Saudi Arabia
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Application of a non-halogenated solvent, methyl ethyl ketone (MEK) for recovery of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(HB-co-HV)] from bacterial cells. BIOTECHNOL BIOPROC E 2015. [DOI: 10.1007/s12257-014-0546-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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57
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Tveit AT, Urich T, Frenzel P, Svenning MM. Metabolic and trophic interactions modulate methane production by Arctic peat microbiota in response to warming. Proc Natl Acad Sci U S A 2015; 112:E2507-16. [PMID: 25918393 PMCID: PMC4434766 DOI: 10.1073/pnas.1420797112] [Citation(s) in RCA: 101] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Arctic permafrost soils store large amounts of soil organic carbon (SOC) that could be released into the atmosphere as methane (CH4) in a future warmer climate. How warming affects the complex microbial network decomposing SOC is not understood. We studied CH4 production of Arctic peat soil microbiota in anoxic microcosms over a temperature gradient from 1 to 30 °C, combining metatranscriptomic, metagenomic, and targeted metabolic profiling. The CH4 production rate at 4 °C was 25% of that at 25 °C and increased rapidly with temperature, driven by fast adaptations of microbial community structure, metabolic network of SOC decomposition, and trophic interactions. Below 7 °C, syntrophic propionate oxidation was the rate-limiting step for CH4 production; above this threshold temperature, polysaccharide hydrolysis became rate limiting. This change was associated with a shift within the functional guild for syntrophic propionate oxidation, with Firmicutes being replaced by Bacteroidetes. Correspondingly, there was a shift from the formate- and H2-using Methanobacteriales to Methanomicrobiales and from the acetotrophic Methanosarcinaceae to Methanosaetaceae. Methanogenesis from methylamines, probably stemming from degradation of bacterial cells, became more important with increasing temperature and corresponded with an increased relative abundance of predatory protists of the phylum Cercozoa. We concluded that Arctic peat microbiota responds rapidly to increased temperatures by modulating metabolic and trophic interactions so that CH4 is always highly produced: The microbial community adapts through taxonomic shifts, and cascade effects of substrate availability cause replacement of functional guilds and functional changes within taxa.
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Affiliation(s)
- Alexander Tøsdal Tveit
- Department of Arctic and Marine Biology, University of Tromsø The Arctic University of Norway, 9037 Tromsø, Norway;
| | - Tim Urich
- Department of Ecogenomics and Systems Biology, University of Vienna, 1090 Vienna, Austria; Austrian Polar Research Institute, 1090, Vienna, Austria; and
| | - Peter Frenzel
- Department of Biochemistry, Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
| | - Mette Marianne Svenning
- Department of Arctic and Marine Biology, University of Tromsø The Arctic University of Norway, 9037 Tromsø, Norway;
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58
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Sato S, Andreeßen B, Steinbüchel A. Strain and process development for poly(3HB-co-3HP) fermentation by engineered Shimwellia blattae from glycerol. AMB Express 2015; 5:18. [PMID: 25852995 PMCID: PMC4385116 DOI: 10.1186/s13568-015-0105-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 02/17/2015] [Indexed: 12/11/2022] Open
Abstract
Poly(3-hydroxybytyrate-co-3-hydroxypropionate), poly(3HB-co-3HP), is a possible alternative to synthetic polymers such as polypropylene, polystyrene and polyethylene due to its low crystallinity and fragility. We already reported that recombinant strains of Shimwellia blattae expressing 1,3-propanediol dehydrogenase DhaT as well as aldehyde dehydrogenase AldD of Pseudomonas putida KT2442, propionate-CoA transferase Pct of Clostridium propionicum X2 and PHA synthase PhaC1 of Ralstonia eutropha H16 are able to accumulate up to 14.5% (wtPHA/wtCDW) of poly(3-hydroxypropionate), poly(3HP), homopolymer from glycerol as a sole carbon source (Appl Microbiol Biotechnol 98:7409-7422, 2014a). However, the cell density was rather low. In this study, we optimized the medium aiming at a more efficient PHA synthesis, and we engineered a S. blattae strain accumulating poly(3HB-co-3HP) with varying contents of the constituent 3-hydroxypropionate (3HP) depending on the cultivation conditions. Consequently, 7.12, 0.77 and 0.32 gPHA/L of poly(3HB-co-3HP) containing 2.1, 8.3 and 18.1 mol% 3HP under anaerobic/aerobic (the first 24 hours under anaerobic condition, thereafter, aerobic condition), low aeration/agitation (the minimum stirring rate required in medium mixing and small amount of aeration) and anaerobic conditions (the minimum stirring rate required in medium mixing without aeration), respectively, were synthesized from glycerol by the genetically modified S. blattae ATCC33430 strains in optimized culture medium.
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Prieto A, Escapa IF, Martínez V, Dinjaski N, Herencias C, de la Peña F, Tarazona N, Revelles O. A holistic view of polyhydroxyalkanoate metabolism inPseudomonas putida. Environ Microbiol 2015; 18:341-57. [DOI: 10.1111/1462-2920.12760] [Citation(s) in RCA: 129] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Revised: 12/12/2014] [Accepted: 12/20/2014] [Indexed: 11/29/2022]
Affiliation(s)
- Auxiliadora Prieto
- Department of Environmental Biology; Centro de Investigaciones Biológicas; CSIC; Madrid 28040 Spain
| | - Isabel F. Escapa
- Department of Environmental Biology; Centro de Investigaciones Biológicas; CSIC; Madrid 28040 Spain
| | - Virginia Martínez
- Department of Environmental Biology; Centro de Investigaciones Biológicas; CSIC; Madrid 28040 Spain
| | - Nina Dinjaski
- Department of Environmental Biology; Centro de Investigaciones Biológicas; CSIC; Madrid 28040 Spain
| | - Cristina Herencias
- Department of Environmental Biology; Centro de Investigaciones Biológicas; CSIC; Madrid 28040 Spain
| | - Fernando de la Peña
- Department of Environmental Biology; Centro de Investigaciones Biológicas; CSIC; Madrid 28040 Spain
| | - Natalia Tarazona
- Department of Environmental Biology; Centro de Investigaciones Biológicas; CSIC; Madrid 28040 Spain
| | - Olga Revelles
- Department of Environmental Biology; Centro de Investigaciones Biológicas; CSIC; Madrid 28040 Spain
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60
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Huschner F, Grousseau E, Brigham CJ, Plassmeier J, Popovic M, Rha C, Sinskey AJ. Development of a feeding strategy for high cell and PHA density fed-batch fermentation of Ralstonia eutropha H16 from organic acids and their salts. Process Biochem 2015. [DOI: 10.1016/j.procbio.2014.12.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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61
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Comparative proteome analysis reveals four novel polyhydroxybutyrate (PHB) granule-associated proteins in Ralstonia eutropha H16. Appl Environ Microbiol 2014; 81:1847-58. [PMID: 25548058 DOI: 10.1128/aem.03791-14] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Identification of proteins that were present in a polyhydroxybutyrate (PHB) granule fraction isolated from Ralstonia eutropha but absent in the soluble, membrane, and membrane-associated fractions revealed the presence of only 12 polypeptides with PHB-specific locations plus 4 previously known PHB-associated proteins with multiple locations. None of the previously postulated PHB depolymerase isoenzymes (PhaZa2 to PhaZa5, PhaZd1, and PhaZd2) and none of the two known 3-hydroxybutyrate oligomer hydrolases (PhaZb and PhaZc) were significantly present in isolated PHB granules. Four polypeptides were found that had not yet been identified in PHB granules. Three of the novel proteins are putative α/β-hydrolases, and two of those (A0671 and B1632) have a PHB synthase/depolymerase signature. The third novel protein (A0225) is a patatin-like phospholipase, a type of enzyme that has not been described for PHB granules of any PHB-accumulating species. No function has been ascribed to the fourth protein (A2001), but its encoding gene forms an operon with phaB2 (acetoacetyl-coenzyme A [CoA] reductase) and phaC2 (PHB synthase), and this is in line with a putative function in PHB metabolism. The localization of the four new proteins at the PHB granule surface was confirmed in vivo by fluorescence microscopy of constructed fusion proteins with enhanced yellow fluorescent protein (eYFP). Deletion of A0671 and B1632 had a minor but detectable effect on the PHB mobilization ability in the stationary growth phase of nutrient broth (NB)-gluconate cells, confirming the functional involvement of both proteins in PHB metabolism.
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62
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Insomphun C, Xie H, Mifune J, Kawashima Y, Orita I, Nakamura S, Fukui T. Improved artificial pathway for biosynthesis of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) with high C6-monomer composition from fructose in Ralstonia eutropha. Metab Eng 2014; 27:38-45. [PMID: 25446974 DOI: 10.1016/j.ymben.2014.10.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Revised: 09/25/2014] [Accepted: 10/06/2014] [Indexed: 02/06/2023]
Abstract
Poly((R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoate) [P(3HB-co-3HHx)], a flexible and practical kind of polyhydroxyalkanoates, is generally produced from plant oils and fatty acids by several wild and recombinant bacteria. This study established an improved artificial pathway for the biosynthesis of P(3HB-co-3HHx) with high 3HHx composition from structurally unrelated fructose in Ralstonia eutropha. Depression of (R)-specific reduction of acetoacetyl-CoA by the deletion of phaB1 was an effective modification for formation of the C6-monomer unit from fructose driven by crotonyl-CoA carboxylase/reductase (Ccr). Co-overexpression of phaJ4a, which encodes medium-chain-length (R)-enoyl-CoA hydratase, with ccr promoted the incorporation of both 3HB and 3HHx units. Further introduction of emdMm, a synthetic gene encoding ethylmalonyl-CoA decarboxylase derived from mouse, was remarkably effective for P(3HB-co-3HHx) biosynthesis, probably by converting ethylmalonyl-CoA generated by the reductive carboxylase activity of Ccr back into butyryl-CoA. A high cellular content of P(3HB-co-3HHx) composed of 22mol% 3HHx could be produced from fructose by the engineered strain of R. eutropha with ΔphaB1 genotype expressing ccr, phaJ4a, and emd.
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Affiliation(s)
- Chayatip Insomphun
- Department of Bioengineering, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan
| | - Huan Xie
- Department of Bioengineering, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan
| | - Jun Mifune
- Department of Bioengineering, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan
| | - Yui Kawashima
- Department of Bioengineering, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan
| | - Izumi Orita
- Department of Bioengineering, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan
| | - Satoshi Nakamura
- Department of Bioengineering, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan
| | - Toshiaki Fukui
- Department of Bioengineering, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan.
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63
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(S)-3-hydroxyacyl-CoA dehydrogenase/enoyl-CoA hydratase (FadB') from fatty acid degradation operon of Ralstonia eutropha H16. AMB Express 2014; 4:69. [PMID: 25401070 PMCID: PMC4230905 DOI: 10.1186/s13568-014-0069-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 08/13/2014] [Indexed: 11/12/2022] Open
Abstract
In this study (S)-3-hydroxyacyl-CoA dehydrogenase/enoyl-CoA hydratase (H16_A0461/FadB’, gene ID: 4247876) from one of two active fatty acid degradation operons of Ralstonia eutropha H16 has been heterologously expressed in Escherichia coli, purified as protein possessing a His-Tag and initially characterized. FadB’ is an enzyme with two catalytic domains exhibiting a single monomeric structure and possessing a molecular weight of 86 kDa. The C-terminal part of the enzyme harbors enoyl-CoA hydratase activity and is able to convert trans-crotonyl-CoA to 3-hydroxybutyryl-CoA. The N-terminal part of FadB’ comprises an NAD+ binding site and is responsible for 3-hydroxyacyl-CoA dehydrogenase activity converting (S)-3-hydroxybutyryl-CoA to acetoacetyl-CoA. Enoyl-CoA hydratase activity was detected spectrophotometrically with trans-crotonyl-CoA. (S)-3-Hydroxyacyl-CoA dehydrogenase activity was measured in both directions with acetoacetyl-CoA and 3-hydroxybutyryl-CoA. FadB’ was found to be strictly stereospecific to (S)-3-hydroxybutyryl-CoA and to prefer NAD+. The Km value for acetoacetyl-CoA was 48 μM and Vmax 149 μmol mg−1 min−1. NADP(H) was utilized at a rate of less than 10% in comparison to activity with NAD(H). FadB’ exhibited optimal activity at pH 6–7 and the activity decreased at alkaline and acidic pH values. Acetyl-CoA, propionyl-CoA and CoA were found to have an inhibitory effect on FadB’. This study is a first report on biochemical properties of purified (S)-stereospecific 3-hydroxyacyl-CoA dehydrogenase/enoyl-CoA hydratase with the inverted domain order from R. eutropha H16. In addition to fundamental information about FadB’ and fatty acid metabolism, FadB’ might be also interesting for biotechnological applications.
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64
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Grunwald S, Mottet A, Grousseau E, Plassmeier JK, Popović MK, Uribelarrea JL, Gorret N, Guillouet SE, Sinskey A. Kinetic and stoichiometric characterization of organoautotrophic growth of Ralstonia eutropha on formic acid in fed-batch and continuous cultures. Microb Biotechnol 2014; 8:155-63. [PMID: 25123319 PMCID: PMC4321381 DOI: 10.1111/1751-7915.12149] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Revised: 04/28/2014] [Accepted: 07/06/2014] [Indexed: 11/29/2022] Open
Abstract
Formic acid, acting as both carbon and energy source, is a safe alternative to a carbon dioxide, hydrogen and dioxygen mix for studying the conversion of carbon through the Calvin–Benson–Bassham (CBB) cycle into value-added chemical compounds by non-photosynthetic microorganisms. In this work, organoautotrophic growth of Ralstonia eutropha on formic acid was studied using an approach combining stoichiometric modeling and controlled cultures in bioreactors. A strain deleted of its polyhydroxyalkanoate production pathway was used in order to carry out a physiological characterization. The maximal growth yield was determined at 0.16 Cmole Cmole−1 in a formate-limited continuous culture. The measured yield corresponded to 76% to 85% of the theoretical yield (later confirmed in pH-controlled fed-batch cultures). The stoichiometric study highlighted the imbalance between carbon and energy provided by formic acid and explained the low growth yields measured. Fed-batch cultures were also used to determine the maximum specific growth rate (μmax = 0.18 h−1) and to study the impact of increasing formic acid concentrations on growth yields. High formic acid sensitivity was found in R eutropha since a linear decrease in the biomass yield with increasing residual formic acid concentrations was observed between 0 and 1.5 g l−1.
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Affiliation(s)
- Stephan Grunwald
- Department of Biology, Massachusetts Institute of Technology, Bldg. 68-370, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA; Department of Biotechnology, Beuth Hochschule für Technik Berlin, 13353, Berlin, Germany
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65
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Characterization and modification of enzymes in the 2-ketoisovalerate biosynthesis pathway of Ralstonia eutropha H16. Appl Microbiol Biotechnol 2014; 99:761-74. [DOI: 10.1007/s00253-014-5965-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Revised: 07/15/2014] [Accepted: 07/16/2014] [Indexed: 11/27/2022]
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66
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Jeon JM, Brigham CJ, Kim YH, Kim HJ, Yi DH, Kim H, Rha C, Sinskey AJ, Yang YH. Biosynthesis of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (P(HB-co-HHx)) from butyrate using engineered Ralstonia eutropha. Appl Microbiol Biotechnol 2014; 98:5461-9. [DOI: 10.1007/s00253-014-5617-7] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 02/11/2014] [Accepted: 02/11/2014] [Indexed: 12/23/2022]
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67
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Isopropanol production with engineered Cupriavidus necator as bioproduction platform. Appl Microbiol Biotechnol 2014; 98:4277-90. [DOI: 10.1007/s00253-014-5591-0] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Revised: 02/04/2014] [Accepted: 02/04/2014] [Indexed: 10/25/2022]
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68
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Chen YJ, Tsai PC, Hsu CH, Lee CY. Critical residues of class II PHA synthase for expanding the substrate specificity and enhancing the biosynthesis of polyhydroxyalkanoate. Enzyme Microb Technol 2014; 56:60-6. [DOI: 10.1016/j.enzmictec.2014.01.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Revised: 01/02/2014] [Accepted: 01/07/2014] [Indexed: 10/25/2022]
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69
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Identification of Genes Required for Soil Survival in Burkholderia thailandensis by Transposon-Directed Insertion Site Sequencing. Curr Microbiol 2014; 68:693-701. [DOI: 10.1007/s00284-014-0526-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2013] [Accepted: 11/23/2013] [Indexed: 01/19/2023]
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70
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Yang JE, Choi SY, Shin JH, Park SJ, Lee SY. Microbial production of lactate-containing polyesters. Microb Biotechnol 2013; 6:621-36. [PMID: 23718266 PMCID: PMC3815930 DOI: 10.1111/1751-7915.12066] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 04/19/2013] [Accepted: 04/22/2013] [Indexed: 12/31/2022] Open
Abstract
Due to our increasing concerns on environmental problems and limited fossil resources, biobased production of chemicals and materials through biorefinery has been attracting much attention. Optimization of the metabolic performance of microorganisms, the key biocatalysts for the efficient production of the desired target bioproducts, has been achieved by metabolic engineering. Metabolic engineering allowed more efficient production of polyhydroxyalkanoates, a family of microbial polyesters. More recently, non-natural polyesters containing lactate as a monomer have also been produced by one-step fermentation of engineered bacteria. Systems metabolic engineering integrating traditional metabolic engineering with systems biology, synthetic biology, protein/enzyme engineering through directed evolution and structural design, and evolutionary engineering, enabled microorganisms to efficiently produce natural and non-natural products. Here, we review the strategies for the metabolic engineering of microorganisms for the in vivo biosynthesis of lactate-containing polyesters and for the optimization of whole cell metabolism to efficiently produce lactate-containing polyesters. Also, major problems to be solved to further enhance the production of lactate-containing polyesters are discussed.
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Affiliation(s)
- Jung Eun Yang
- Metabolic and Biomolecular Engineering National Research Laboratory, Department of Chemical and Biomolecular Engineering (BK21 Program), Center for Systems and Synthetic Biotechnology, KAIST291 Daehak-ro, Yuseong-gu, Daejeon, 305-701, Korea
- Institute for the BioCentury, KAIST291 Daehak-ro, Yuseong-gu, Daejeon, 305-701, Korea
| | - So Young Choi
- Metabolic and Biomolecular Engineering National Research Laboratory, Department of Chemical and Biomolecular Engineering (BK21 Program), Center for Systems and Synthetic Biotechnology, KAIST291 Daehak-ro, Yuseong-gu, Daejeon, 305-701, Korea
- Institute for the BioCentury, KAIST291 Daehak-ro, Yuseong-gu, Daejeon, 305-701, Korea
| | - Jae Ho Shin
- Metabolic and Biomolecular Engineering National Research Laboratory, Department of Chemical and Biomolecular Engineering (BK21 Program), Center for Systems and Synthetic Biotechnology, KAIST291 Daehak-ro, Yuseong-gu, Daejeon, 305-701, Korea
- Institute for the BioCentury, KAIST291 Daehak-ro, Yuseong-gu, Daejeon, 305-701, Korea
| | - Si Jae Park
- Department of Environmental Engineering and Energy (Undergraduate program), Myongji UniversitySan 38-2, Nam-dong, Cheoin-gu, Yongin-si, Gyeonggido, 449-728, Korea
- Department of Energy Science and Technology (Graduate program), Myongji UniversitySan 38-2, Nam-dong, Cheoin-gu, Yongin-si, Gyeonggido, 449-728, Korea
| | - Sang Yup Lee
- Metabolic and Biomolecular Engineering National Research Laboratory, Department of Chemical and Biomolecular Engineering (BK21 Program), Center for Systems and Synthetic Biotechnology, KAIST291 Daehak-ro, Yuseong-gu, Daejeon, 305-701, Korea
- Institute for the BioCentury, KAIST291 Daehak-ro, Yuseong-gu, Daejeon, 305-701, Korea
- Department of Bio and Brain Engineering, Department of Biological Sciences, BioProcess Engineering Research Center, KAIST291 Daehak-ro, Yuseong-gu, Daejeon, 305-701, Korea
- Bioinformatics Research Center, KAIST291 Daehak-ro, Yuseong-gu, Daejeon, 305-701, Korea
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71
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Metabolic engineering of Ralstonia eutropha for the biosynthesis of 2-hydroxyacid-containing polyhydroxyalkanoates. Metab Eng 2013; 20:20-8. [DOI: 10.1016/j.ymben.2013.08.002] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2013] [Revised: 07/20/2013] [Accepted: 08/14/2013] [Indexed: 01/22/2023]
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72
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Calcium homeostasis in Pseudomonas aeruginosa requires multiple transporters and modulates swarming motility. Cell Calcium 2013; 54:350-61. [PMID: 24074964 DOI: 10.1016/j.ceca.2013.08.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Revised: 08/21/2013] [Accepted: 08/30/2013] [Indexed: 11/21/2022]
Abstract
Pseudomonas aeruginosa is an opportunistic human pathogen causing severe acute and chronic infections. Earlier we have shown that calcium (Ca(2+)) induces P. aeruginosa biofilm formation and production of virulence factors. To enable further studies of the regulatory role of Ca(2+), we characterized Ca(2+) homeostasis in P. aeruginosa PAO1 cells. By using Ca(2+)-binding photoprotein aequorin, we determined that the concentration of free intracellular Ca(2+) ([Ca(2+)]in) is 0.14±0.05μM. In response to external Ca(2+), the [Ca(2+)]in quickly increased at least 13-fold followed by a multi-phase decline by up to 73%. Growth at elevated Ca(2+) modulated this response. Treatment with inhibitors known to affect Ca(2+) channels, monovalent cations gradient, or P-type and F-type ATPases impaired [Ca(2+)]in response, suggesting the importance of the corresponding mechanisms in Ca(2+) homeostasis. To identify Ca(2+) transporters maintaining this homeostasis, bioinformatic and LC-MS/MS-based membrane proteomic analyses were used. [Ca(2+)]in homeostasis was monitored for seven Ca(2+)-affected and eleven bioinformatically predicted transporters by using transposon insertion mutants. Disruption of P-type ATPases PA2435, PA3920, and ion exchanger PA2092 significantly impaired Ca(2+) homeostasis. The lack of PA3920 and vanadate treatment abolished Ca(2+)-induced swarming, suggesting the role of the P-type ATPase in regulating P. aeruginosa response to Ca(2+).
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73
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Przybylski D, Rohwerder T, Harms H, Yaneva N, Müller RH. Synthesis of the building block 2-hydroxyisobutyrate from fructose and butyrate by Cupriavidus necator H16. Appl Microbiol Biotechnol 2013; 97:8875-85. [PMID: 23942876 DOI: 10.1007/s00253-013-5064-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Revised: 06/11/2013] [Accepted: 06/13/2013] [Indexed: 11/27/2022]
Abstract
2-Hydroxyisobutyryl-coenzyme A mutase, originally discovered in the context of methyl tert-butyl ether degradation in Aquincola tertiaricarbonis L108, catalyzes the isomerization of 3-hydroxybutyryl-coenzyme A (3-HB-CoA) to 2-hydroxyisobutyryl-CoA. It thus constitutes the basis for a biotechnological route from practically any renewable carbon to 2-hydroxyisobutyrate (2-HIB) via the common metabolite 3-hydroxybutyrate. At first sight, recombinant Cupriavidus necator H16 expressing the mutase seems to be well suited for such a synthesis process, as a strong overflow metabolism via (R)-3-HB-CoA is easily induced in this bacterium possessing the poly-3-hydroxybutyrate metabolism. However, the recently established stereospecificity of the mutase, dominantly preferring the (S)-enantiomer of 3-HB-CoA, calls for a closer investigation of C. necator as potential 2-HIB production strain and raised the question about the strain's potential to yield 2-HIB from substrates directly providing (S)-3-HB-CoA. We compared two mutase-expressing C. necator H16 strains for their capability to synthesize 2-HIB from fructose and butyrate, delivering either (R)- or (S)-3-HB-CoA. Our results indicate that due to the enantiospecificity of the mutase, fructose is a weaker substrate for 2-HIB synthesis than butyrate. Production rates achieved with the PHB-negative strain H16 PHB(-)4 on butyrate were higher than on fructose. Using the wild-type did not significantly improve the production rates as the latter showed a 34-fold and a 5-fold lower 2-HIB synthesis rate compared to H16 PHB(-)4 on fructose and butyrate, respectively. Moreover, both strains showed concomitant excretion of undesired side products, such as pyruvate and 3-hydroxybutyrate, significantly decreasing the 2-HIB yield.
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Affiliation(s)
- Denise Przybylski
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research (UFZ), Permoserstrasse 15, 04318, Leipzig, Germany
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74
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Directed evolution and structural analysis of NADPH-dependent Acetoacetyl Coenzyme A (Acetoacetyl-CoA) reductase from Ralstonia eutropha reveals two mutations responsible for enhanced kinetics. Appl Environ Microbiol 2013; 79:6134-9. [PMID: 23913421 DOI: 10.1128/aem.01768-13] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
NADPH-dependent acetoacetyl-coenzyme A (acetoacetyl-CoA) reductase (PhaB) is a key enzyme in the synthesis of poly(3-hydroxybutyrate) [P(3HB)], along with β-ketothiolase (PhaA) and polyhydroxyalkanoate synthase (PhaC). In this study, PhaB from Ralstonia eutropha was engineered by means of directed evolution consisting of an error-prone PCR-mediated mutagenesis and a P(3HB) accumulation-based in vivo screening system using Escherichia coli. From approximately 20,000 mutants, we obtained two mutant candidates bearing Gln47Leu (Q47L) and Thr173Ser (T173S) substitutions. The mutants exhibited kcat values that were 2.4-fold and 3.5-fold higher than that of the wild-type enzyme, respectively. In fact, the PhaB mutants did exhibit enhanced activity and P(3HB) accumulation when expressed in recombinant Corynebacterium glutamicum. Comparative three-dimensional structural analysis of wild-type PhaB and highly active PhaB mutants revealed that the beneficial mutations affected the flexibility around the active site, which in turn played an important role in substrate recognition. Furthermore, both the kinetic analysis and crystal structure data supported the conclusion that PhaB forms a ternary complex with NADPH and acetoacetyl-CoA. These results suggest that the mutations affected the interaction with substrates, resulting in the acquirement of enhanced activity.
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75
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Detection of phase-dependent transcriptomic changes and Rubisco-mediated CO2 fixation into poly (3-hydroxybutyrate) under heterotrophic condition in Ralstonia eutropha H16 based on RNA-seq and gene deletion analyses. BMC Microbiol 2013; 13:169. [PMID: 23879744 PMCID: PMC3734047 DOI: 10.1186/1471-2180-13-169] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Accepted: 07/12/2013] [Indexed: 11/16/2022] Open
Abstract
Background Ralstonia eutropha H16 is well known to produce polyhydroxyalkanoates (PHAs), which are potential bio-based biodegradable plastics, in an efficient manner as an energy storage material under unbalanced growth conditions. To obtain further knowledge of PHA biosynthesis, this study performed a quantitative transcriptome analysis based on deep sequencing of the complementary DNA generated from the RNA (RNA-seq) of R. eutropha H16. Results Total RNAs were extracted from R. eutropha cells in growth, PHA production, and stationary phases on fructose. rRNAs in the preparation were removed by repeated treatments with magnetic beads specific to bacterial rRNAs, and then the 36 bp sequences were determined using an Illumina high-throughput sequencer. The RNA-seq results indicated the induction of gene expression for transcription, translation, cell division, peptidoglycan biosynthesis, pilus and flagella assembly, energy conservation, and fatty acid biosynthesis in the growth phase; and the repression trends of genes involved in central metabolisms in the PHA production phase. Interestingly, the transcription of genes for Calvin-Benson-Bassham (CBB) cycle and several genes for β-oxidation were significantly induced in the PHA production phase even when the cells were grown on fructose. Moreover, incorporation of 13C was observed in poly(3-hydroxybutyrate) synthesized by R. eutropha H16 from fructose in the presence of NaH13CO3, and further gene deletion analyses revealed that both of the two ribulose 1,5-bisphosphate carboxylase (Rubiscos) in CBB cycle were actually functional in CO2 fixation under the heterotrophic condition. Conclusions The results revealed the phase-dependent transcriptomic changes and a CO2 fixation capability under heterotrophic conditions by PHA-producing R. eutropha.
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76
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Cordeiro FA, Tadra-Sfeir MZ, Huergo LF, de Oliveira Pedrosa F, Monteiro RA, de Souza EM. Proteomic analysis of Herbaspirillum seropedicae cultivated in the presence of sugar cane extract. J Proteome Res 2013; 12:1142-50. [PMID: 23331092 DOI: 10.1021/pr300746j] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Bacterial endophytes of the genus Herbaspirillum colonize sugar cane and can promote plant growth. The molecular mechanisms that mediate plant- H. seropedicae interaction are poorly understood. In this work, we used 2D-PAGE electrophoresis to identify H. seropedicae proteins differentially expressed at the log growth phase in the presence of sugar cane extract. The differentially expressed proteins were validated by RT qPCR. A total of 16 differential spots (1 exclusively expressed, 7 absent, 5 up- and 3 down-regulated) in the presence of 5% sugar cane extract were identified; thus the host extract is able to induce and repress specific genes of H. seropedicae. The differentially expressed proteins suggest that exposure to sugar cane extract induced metabolic changes and adaptations in H. seropedicae presumably in preparation to establish interaction with the plant.
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Affiliation(s)
- Fabio Aparecido Cordeiro
- Department of Biochemistry and Molecular Biology, Universidade Federal do Paraná, Centro Politécnico, PO Box 19071, Curitiba, PR 81531-990, Brazil
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77
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Mann MS, Lütke-Eversloh T. Thiolase engineering for enhanced butanol production in Clostridium acetobutylicum. Biotechnol Bioeng 2012; 110:887-97. [PMID: 23096577 DOI: 10.1002/bit.24758] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2012] [Revised: 10/01/2012] [Accepted: 10/12/2012] [Indexed: 12/20/2022]
Abstract
Biosynthetic thiolases catalyze the condensation of two molecules acetyl-CoA to acetoacetyl-CoA and represent key enzymes for carbon-carbon bond forming metabolic pathways. An important biotechnological example of such a pathway is the clostridial n-butanol production, comprising various natural constraints that limit titer, yield, and productivity. In this study, the thiolase of Clostridium acetobutylicum, the model organism for solventogenic clostridia, was specifically engineered for reduced sensitivity towards its physiological inhibitor coenzyme A (CoA-SH). A high-throughput screening assay in 96-well microtiter plates was developed employing Escherichia coli as host cells for expression of a mutant thiolase gene library. Screening of this library resulted in the identification of a thiolase derivative with significantly increased activity in the presence of free CoA-SH. This optimized thiolase comprised three amino acid substitutions (R133G, H156N, G222V) and its gene was expressed in C. acetobutylicum ATCC 824 to assess the effect of reduced CoA-SH sensitivity on solvent production. In addition to a clearly delayed ethanol and acetone formation, the ethanol and butanol titers were increased by 46% and 18%, respectively, while the final acetone concentrations were similar to the vector control strain. These results demonstrate that thiolase engineering constitutes a suitable methodology applicable to improve clostridial butanol production, but other biosynthetic pathways involving thiolase-mediated carbon flux limitations might also be subjected to this new metabolic engineering approach.
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Affiliation(s)
- Miriam S Mann
- Abteilung Mikrobiologie, Institut für Biowissenschaften, Universität Rostock, Rostock, Germany
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78
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Whole-genome microarray and gene deletion studies reveal regulation of the polyhydroxyalkanoate production cycle by the stringent response in Ralstonia eutropha H16. Appl Environ Microbiol 2012; 78:8033-44. [PMID: 22961894 DOI: 10.1128/aem.01693-12] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Poly(3-hydroxybutyrate) (PHB) production and mobilization in Ralstonia eutropha are well studied, but in only a few instances has PHB production been explored in relation to other cellular processes. We examined the global gene expression of wild-type R. eutropha throughout the PHB cycle: growth on fructose, PHB production using fructose following ammonium depletion, and PHB utilization in the absence of exogenous carbon after ammonium was resupplied. Our results confirm or lend support to previously reported results regarding the expression of PHB-related genes and enzymes. Additionally, genes for many different cellular processes, such as DNA replication, cell division, and translation, are selectively repressed during PHB production. In contrast, the expression levels of genes under the control of the alternative sigma factor σ(54) increase sharply during PHB production and are repressed again during PHB utilization. Global gene regulation during PHB production is strongly reminiscent of the gene expression pattern observed during the stringent response in other species. Furthermore, a ppGpp synthase deletion mutant did not show an accumulation of PHB, and the chemical induction of the stringent response with DL-norvaline caused an increased accumulation of PHB in the presence of ammonium. These results indicate that the stringent response is required for PHB accumulation in R. eutropha, helping to elucidate a thus-far-unknown physiological basis for this process.
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79
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Lu J, Brigham CJ, Gai CS, Sinskey AJ. Studies on the production of branched-chain alcohols in engineered Ralstonia eutropha. Appl Microbiol Biotechnol 2012; 96:283-97. [DOI: 10.1007/s00253-012-4320-9] [Citation(s) in RCA: 101] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Revised: 07/16/2012] [Accepted: 07/17/2012] [Indexed: 11/25/2022]
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80
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Kaddor C, Voigt B, Hecker M, Steinbüchel A. Impact of the Core Components of the Phosphoenolpyruvate-Carbohydrate Phosphotransferase System, HPr and EI, on Differential Protein Expression in Ralstonia eutropha H16. J Proteome Res 2012; 11:3624-36. [DOI: 10.1021/pr300042f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Chlud Kaddor
- Institut für
Molekulare
Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, Corrensstrasse
3, D-48149 Münster, Germany
| | - Birgit Voigt
- Institut für Mikrobiologie, Ernst-Moritz-Arndt Universität, Friedrich-Ludwig-Jahn-Straße
15, D-17489 Greifswald, Germany
| | - Michael Hecker
- Institut für Mikrobiologie, Ernst-Moritz-Arndt Universität, Friedrich-Ludwig-Jahn-Straße
15, D-17489 Greifswald, Germany
| | - Alexander Steinbüchel
- Institut für
Molekulare
Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, Corrensstrasse
3, D-48149 Münster, Germany
- King Abdul Aziz University, Jeddah 22254,
Saudi Arabia
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81
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Brigham CJ, Reimer EN, Rha C, Sinskey AJ. Examination of PHB Depolymerases in Ralstonia eutropha: Further Elucidation of the Roles of Enzymes in PHB Homeostasis. AMB Express 2012; 2:26. [PMID: 22537946 PMCID: PMC3430594 DOI: 10.1186/2191-0855-2-26] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Accepted: 04/26/2012] [Indexed: 11/29/2022] Open
Abstract
Polyhydroxyalkanoates (PHA) are biodegradable polymers that are attractive materials for use in tissue engineering and medical device manufacturing. Ralstonia eutropha is regarded as the model organism for PHA biosynthesis. We examined the effects of PHA depolymerase (PhaZ) expression on PHA homeostasis in R. eutropha strains. In order to analyze the impact of PhaZs on R. eutropha granule architecture, we performed electron microscopy on several phaZ knockout strains and the wild type strain grown under PHA production conditions. Analysis of the acquired micrographs was based on stereology: the ratio of granule area and cell area was determined, along with total granule count per full-size cell image. Cells bearing a phaZ2 knockout mutation alone or in conjunction with a phaZ1 mutation were found to have a high granule volume per cell volume and a higher granule count compared to wild type. A phaZ quadruple knockout strain appeared to have a low granule volume per cell volume and a low granule count per cell. Cells bearing a phaZ3 knockout were found to have a higher granule count than the wild type, whereas granule volume per cell volume was similar. Accordingly, we hypothesize that PhaZs have not only an impact on PHA degradation but also on the 3-dimensional granule architecture. Based on our data, PhaZ2 is postulated to affect granule density. This work increased our knowledge about PHA depolymerases in R. eutropha, including enzymes that had previously been uncharacterized.
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Affiliation(s)
- Christopher J Brigham
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | | | - ChoKyun Rha
- Biomaterials Science and Engineering Laboratory, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Anthony J Sinskey
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- Division of Health Sciences Technology, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- Engineering Systems Division, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
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82
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Cho M, Brigham CJ, Sinskey AJ, Stubbe J. Purification of polyhydroxybutyrate synthase from its native organism, Ralstonia eutropha: implications for the initiation and elongation of polymer formation in vivo. Biochemistry 2012; 51:2276-88. [PMID: 22369488 DOI: 10.1021/bi2013596] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Class I polyhydroxybutyrate (PHB) synthase (PhaC) from Ralstonia eutropha catalyzes the formation of PHB from (R)-3-hydroxybutyryl-CoA, ultimately resulting in the formation of insoluble granules. Previous mechanistic studies of R. eutropha PhaC, purified from Escherichia coli (PhaC(Ec)), demonstrated that the polymer elongation rate is much faster than the initiation rate. In an effort to identify a factor(s) from the native organism that might prime the synthase and increase the rate of polymer initiation, an N-terminally Strep2-tagged phaC (Strep2-PhaC(Re)) was constructed and integrated into the R. eutropha genome in place of wild-type phaC. Strep2-PhaC(Re) was expressed and purified by affinity chromatography from R. eutropha grown in nutrient-rich TSB medium for 4 h (peak production PHB, 15% cell dry weight) and 24 h (PHB, 2% cell dry weight). Analysis of the purified PhaC by size exclusion chromatography, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and gel permeation chromatography revealed that it unexpectedly copurified with the phasin protein, PhaP1, and with soluble PHB (M(w) = 350 kDa) in a "high-molecular weight" (HMW) complex and in monomeric/dimeric (M/D) forms with no associated PhaP1 or PHB. Assays for monitoring the formation of PHB in the HMW complex showed no lag phase in CoA release, in contrast to M/D forms of PhaC(Re) (and PhaC(Ec)), suggesting that PhaC in the HMW fraction has been isolated in a PHB-primed form. The presence of primed and nonprimed PhaC suggests that the elongation rate for PHB formation is also faster than the initiation rate in vivo. A modified micelle model for granule genesis is proposed to accommodate the reported observations.
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Affiliation(s)
- Mimi Cho
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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83
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Bassas-Galia M, Nogales B, Arias S, Rohde M, Timmis K, Molinari G. Plant original Massilia isolates producing polyhydroxybutyrate, including one exhibiting high yields from glycerol. J Appl Microbiol 2012; 112:443-54. [DOI: 10.1111/j.1365-2672.2011.05228.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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84
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Escapa IF, García JL, Bühler B, Blank LM, Prieto MA. The polyhydroxyalkanoate metabolism controls carbon and energy spillage in Pseudomonas putida. Environ Microbiol 2012; 14:1049-63. [PMID: 22225632 DOI: 10.1111/j.1462-2920.2011.02684.x] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The synthesis and degradation of polyhydroxyalkanoates (PHAs), the storage polymer of many bacteria, is linked to the operation of central carbon metabolism. To rationalize the impact of PHA accumulation on central carbon metabolism of the prototype bacterium Pseudomonas putida, we have revisited PHA production in quantitative physiology experiments in the wild-type strain vs. a PHA negative mutant growing under low nitrogen conditions. When octanoic acid was used as PHA precursor and as carbon and energy source, we have detected higher intracellular flux via acetyl-CoA in the mutant strain than in the wild type, which correlates with the stimulation of the TCA cycle and glyoxylate shunt observed on the transcriptional level. The mutant defective in carbon and energy storage spills the additional resources, releasing CO(2) instead of generating biomass. Hence, P. putida operates the metabolic network to optimally exploit available resources and channels excess carbon and energy to storage via PHA, without compromising growth. These findings demonstrate that the PHA metabolism plays a critical role in synchronizing global metabolism to availability of resources in PHA-producing microorganisms.
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Affiliation(s)
- I F Escapa
- Environmental Biology Department, Centro de Investigaciones Biológicas, CSIC, 28040 Madrid, Spain
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85
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Brigham CJ, Zhila N, Shishatskaya E, Volova TG, Sinskey AJ. Manipulation of Ralstonia eutropha carbon storage pathways to produce useful bio-based products. Subcell Biochem 2012; 64:343-366. [PMID: 23080259 DOI: 10.1007/978-94-007-5055-5_17] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Ralstonia eutrophais a Gram-negative betaproteobacterium found natively in soils that can utilize a wide array of carbon sources for growth, and can store carbon intracellularly in the form of polyhydroxyalkanoate. Many aspects of R. eutrophamake it a good candidate for use in biotechnological production of polyhydroxyalkanoate and other bio-based, value added compounds. Manipulation of the organism's carbon flux is a cornerstone to success in developing it as a biotechnologically relevant organism. Here, we examine the methods of controlling and adapting the flow of carbon in R. eutrophametabolism and the wide range of compounds that can be synthesized as a result. The presence of many different carbon utilization pathways and the custom genetic toolkit for manipulation of those pathways gives R. eutrophaa versatility that allows it to be a biotechnologically important organism.
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Affiliation(s)
- Christopher J Brigham
- Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA
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86
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Characterization and functional analyses of R-specific enoyl coenzyme A hydratases in polyhydroxyalkanoate-producing Ralstonia eutropha. Appl Environ Microbiol 2011; 78:493-502. [PMID: 22081565 DOI: 10.1128/aem.06937-11] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A genome survey of polyhydroxyalkanoate (PHA)-producing Ralstonia eutropha H16 detected the presence of 16 orthologs of R-specific enoyl coenzyme A (enoyl-CoA) hydratase, among which three proteins shared high homologies with the enzyme specific to enoyl-CoAs of medium chain length encoded by phaJ4 from Pseudomonas aeruginosa (phaJ4(Pa)). The recombinant forms of the three proteins, termed PhaJ4a(Re) to PhaJ4c(Re), actually showed enoyl-CoA hydratase activity with R specificity, and the catalytic efficiencies were elevated as the substrate chain length increased from C(4) to C(8). PhaJ4a(Re) and PhaJ4b(Re) showed >10-fold-higher catalytic efficiency than PhaJ4c(Re). The functions of the new PhaJ4 proteins were investigated using previously engineered R. eutropha strains as host strains; these strains are capable of synthesizing poly((R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoate) [P(3HB-co-3HHx)] from soybean oil. Deletion of phaJ4a(Re) from the chromosome resulted in significant decrease of 3HHx composition in the accumulated copolyester, whereas no change was observed with deletion of phaJ4b(Re) or phaJ4c(Re), indicating that only PhaJ4a(Re) was one of the major enzymes supplying the (R)-3HHx-CoA monomer through β-oxidation. Introduction of phaJ4a(Re) or phaJ4b(Re) into the R. eutropha strains using a broad-host-range vector enhanced the 3HHx composition of the copolyesters, but the introduction of phaJ4c(Re) did not. The two genes were then inserted into the pha operon on chromosome 1 of the engineered R. eutropha by homologous recombination. These modifications enabled the biosynthesis of P(3HB-co-3HHx) composed of a larger 3HHx fraction without a negative impact on cell growth and PHA production on soybean oil, especially when phaJ4a(Re) or phaJ4b(Re) was tandemly introduced with phaJ(Ac) from Aeromonas caviae.
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Pfeiffer D, Wahl A, Jendrossek D. Identification of a multifunctional protein, PhaM, that determines number, surface to volume ratio, subcellular localization and distribution to daughter cells of poly(3-hydroxybutyrate), PHB, granules in Ralstonia eutropha H16. Mol Microbiol 2011; 82:936-51. [DOI: 10.1111/j.1365-2958.2011.07869.x] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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88
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Pfeiffer D, Jendrossek D. Interaction between poly(3-hydroxybutyrate) granule-associated proteins as revealed by two-hybrid analysis and identification of a new phasin in Ralstonia eutropha H16. Microbiology (Reading) 2011; 157:2795-2807. [DOI: 10.1099/mic.0.051508-0] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A large number of polypeptides are attached to poly(3-hydroxybutyrate) (PHB) granules of Ralstonia eutropha, such as PHB synthase (PhaC1), several PHB depolymerases (PhaZs) and phasins (PhaPs), the regulator protein PhaR
Reu
, and possibly others. In this study we used the bacterial adenylate cyclase-based two-hybrid assay to investigate interactions between known PHB granule-associated proteins (PGAPs) and to screen for new PGAPs. The utility of the system was tested by the in vivo verification of previously postulated interactions of the PHB synthase subunits of R. eutropha (PhaC1 homo-oligomerization) and of Bacillus megaterium (PhaC
Bmeg
–PhaR
Bmeg
hetero-oligomerization). Nine proteins (PhaA, PhaB1, PhaC1, PhaP1–PhaP4, PhaZ1 and PhaR), with established functions in PHB metabolism of R. eutropha, were tested for interaction in all combinations. While no significant interaction was detected between the PHB synthase PhaC1 and any of the other eight tested Pha proteins, strong interactions were found between all phasin proteins, in particular between PhaP2 and PhaP4. When PhaP2 was used as bait in a two-hybrid screening experiment with a genomic library of R. eutropha, the B1934 gene product was identified in 24 out of 53 isolated clones. B1934 encodes a hypothetical protein (15.7 kDa) with similarity to phasins of PHB-accumulating bacteria. A fusion protein of eYfp and the B1934 gene product colocalized with PHB granules, confirming that B1934 represents a new phasin (PhaP5). PhaP5 was not essential for PHB granule formation, but overexpression of PhaP5 increased the number of cells with PHB granules at the cell poles.
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Affiliation(s)
- Daniel Pfeiffer
- Institut für Mikrobiologie, Universität Stuttgart, Allmandring 31, Stuttgart, Germany
| | - Dieter Jendrossek
- Institut für Mikrobiologie, Universität Stuttgart, Allmandring 31, Stuttgart, Germany
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Riedel SL, Bader J, Brigham CJ, Budde CF, Yusof ZAM, Rha C, Sinskey AJ. Production of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) by Ralstonia eutropha in high cell density palm oil fermentations. Biotechnol Bioeng 2011; 109:74-83. [DOI: 10.1002/bit.23283] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2011] [Revised: 07/06/2011] [Accepted: 07/22/2011] [Indexed: 11/08/2022]
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90
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Production of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) from plant oil by engineered Ralstonia eutropha strains. Appl Environ Microbiol 2011; 77:2847-54. [PMID: 21398488 DOI: 10.1128/aem.02429-10] [Citation(s) in RCA: 141] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The polyhydroxyalkanoate (PHA) copolymer poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) [P(HB-co-HHx)] has been shown to have potential to serve as a commercial bioplastic. Synthesis of P(HB-co-HHx) from plant oil has been demonstrated with recombinant Ralstonia eutropha strains expressing heterologous PHA synthases capable of incorporating HB and HHx into the polymer. With these strains, however, short-chain-length fatty acids had to be included in the medium to generate PHA with high HHx content. Our group has engineered two R. eutropha strains that accumulate high levels of P(HB-co-HHx) with significant HHx content directly from palm oil, one of the world's most abundant plant oils. The strains express a newly characterized PHA synthase gene from the bacterium Rhodococcus aetherivorans I24. Expression of an enoyl coenzyme A (enoyl-CoA) hydratase gene (phaJ) from Pseudomonas aeruginosa was shown to increase PHA accumulation. Furthermore, varying the activity of acetoacetyl-CoA reductase (encoded by phaB) altered the level of HHx in the polymer. The strains with the highest PHA titers utilized plasmids for recombinant gene expression, so an R. eutropha plasmid stability system was developed. In this system, the essential pyrroline-5-carboxylate reductase gene proC was deleted from strain genomes and expressed from a plasmid, making the plasmid necessary for growth in minimal media. This study resulted in two engineered strains for production of P(HB-co-HHx) from palm oil. In palm oil fermentations, one strain accumulated 71% of its cell dry weight as PHA with 17 mol% HHx, while the other strain accumulated 66% of its cell dry weight as PHA with 30 mol% HHx.
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91
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Versatile metabolic adaptations of Ralstonia eutropha H16 to a loss of PdhL, the E3 component of the pyruvate dehydrogenase complex. Appl Environ Microbiol 2011; 77:2254-63. [PMID: 21296938 DOI: 10.1128/aem.02360-10] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A previous study reported that the Tn5-induced poly(3-hydroxybutyric acid) (PHB)-leaky mutant Ralstonia eutropha H1482 showed a reduced PHB synthesis rate and significantly lower dihydrolipoamide dehydrogenase (DHLDH) activity than the wild-type R. eutropha H16 but similar growth behavior. Insertion of Tn5 was localized in the pdhL gene encoding the DHLDH (E3 component) of the pyruvate dehydrogenase complex (PDHC). Taking advantage of the available genome sequence of R. eutropha H16, observations were verified and further detailed analyses and experiments were done. In silico genome analysis revealed that R. eutropha possesses all five known types of 2-oxoacid multienzyme complexes and five DHLDH-coding genes. Of these DHLDHs, only PdhL harbors an amino-terminal lipoyl domain. Furthermore, insertion of Tn5 in pdhL of mutant H1482 disrupted the carboxy-terminal dimerization domain, thereby causing synthesis of a truncated PdhL lacking this essential region, obviously leading to an inactive enzyme. The defined ΔpdhL deletion mutant of R. eutropha exhibited the same phenotype as the Tn5 mutant H1482; this excludes polar effects as the cause of the phenotype of the Tn5 mutant H1482. However, insertion of Tn5 or deletion of pdhL decreases DHLDH activity, probably negatively affecting PDHC activity, causing the mutant phenotype. Moreover, complementation experiments showed that different plasmid-encoded E3 components of R. eutropha H16 or of other bacteria, like Burkholderia cepacia, were able to restore the wild-type phenotype at least partially. Interestingly, the E3 component of B. cepacia possesses an amino-terminal lipoyl domain, like the wild-type H16. A comparison of the proteomes of the wild-type H16 and of the mutant H1482 revealed striking differences and allowed us to reconstruct at least partially the impressive adaptations of R. eutropha H1482 to the loss of PdhL on the cellular level.
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Budde CF, Riedel SL, Hübner F, Risch S, Popović MK, Rha C, Sinskey AJ. Growth and polyhydroxybutyrate production by Ralstonia eutropha in emulsified plant oil medium. Appl Microbiol Biotechnol 2011; 89:1611-9. [DOI: 10.1007/s00253-011-3102-0] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2010] [Revised: 11/28/2010] [Accepted: 11/29/2010] [Indexed: 11/30/2022]
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