301
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Chen CT, Liao JC. Frontiers in microbial 1-butanol and isobutanol production. FEMS Microbiol Lett 2016; 363:fnw020. [PMID: 26832641 DOI: 10.1093/femsle/fnw020] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/27/2016] [Indexed: 12/14/2022] Open
Abstract
The heavy dependence on petroleum-derived fuel has raised concerns about energy sustainability and climate change, which have prompted researchers to explore fuel production from renewable sources. 1-Butanol and isobutanol are promising biofuels that have favorable properties and can also serve as solvents or chemical feedstocks. Microbial production of these alcohols provides great opportunities to access a wide spectrum of renewable resources. In recent years, research has improved the native 1-butanol production and has engineered isobutanol production in various organisms to explore metabolic diversity and a broad range of substrates. This review focuses on progress in metabolic engineering for the production of these two compounds using various resources.
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Affiliation(s)
- Chang-Ting Chen
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, 420 Westwood Plaza, Los Angeles, CA 90095, USA
| | - James C Liao
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, 420 Westwood Plaza, Los Angeles, CA 90095, USA UCLA-DOE Institute of Genomics and Proteomics, University of California, Los Angeles, 420 Westwood Plaza, Los Angeles, CA 90095, USA
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302
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Taheri A, Berben LA. Making C–H bonds with CO2: production of formate by molecular electrocatalysts. Chem Commun (Camb) 2016; 52:1768-77. [DOI: 10.1039/c5cc09041e] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This article reviews the progress in the reduction of CO2 to formate using molecular inorganic electrocatalysts, with an emphasis on recent insights and successes in selective C–H bond formation with CO2 to favor formate production in aqueous solutions.
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Affiliation(s)
- Atefeh Taheri
- Department of Chemistry
- University of California
- Davis
- USA
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303
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Biobutanol—“A Renewable Green Alternative of Liquid Fuel” from Algae. GREEN FUELS TECHNOLOGY 2016. [DOI: 10.1007/978-3-319-30205-8_18] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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304
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Yuan Z, Eden MR, Gani R. Toward the Development and Deployment of Large-Scale Carbon Dioxide Capture and Conversion Processes. Ind Eng Chem Res 2015. [DOI: 10.1021/acs.iecr.5b03277] [Citation(s) in RCA: 157] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Zhihong Yuan
- Department
of Chemical Engineering, Auburn University, Auburn, Alabama 36849, United States
| | - Mario R. Eden
- Department
of Chemical Engineering, Auburn University, Auburn, Alabama 36849, United States
| | - Rafiqul Gani
- Department of Chemical and
Biochemical Engineering, Technical University of Denmark, DK-2800 Kgs Lyngby, Denmark
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305
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Chen JS, Colón B, Dusel B, Ziesack M, Way JC, Torella JP. Production of fatty acids in Ralstonia eutropha H16 by engineering β-oxidation and carbon storage. PeerJ 2015; 3:e1468. [PMID: 26664804 PMCID: PMC4675107 DOI: 10.7717/peerj.1468] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 11/12/2015] [Indexed: 12/23/2022] Open
Abstract
Ralstonia eutropha H16 is a facultatively autotrophic hydrogen-oxidizing bacterium capable of producing polyhydroxybutyrate (PHB)-based bioplastics. As PHB's physical properties may be improved by incorporation of medium-chain-length fatty acids (MCFAs), and MCFAs are valuable on their own as fuel and chemical intermediates, we engineered R. eutropha for MCFA production. Expression of UcFatB2, a medium-chain-length-specific acyl-ACP thioesterase, resulted in production of 14 mg/L laurate in wild-type R. eutropha. Total fatty acid production (22 mg/L) could be increased up to 2.5-fold by knocking out PHB synthesis, a major sink for acetyl-CoA, or by knocking out the acyl-CoA ligase fadD3, an entry point for fatty acids into β-oxidation. As ΔfadD3 mutants still consumed laurate, and because the R. eutropha genome is predicted to encode over 50 acyl-CoA ligases, we employed RNA-Seq to identify acyl-CoA ligases upregulated during growth on laurate. Knockouts of the three most highly upregulated acyl-CoA ligases increased fatty acid yield significantly, with one strain (ΔA2794) producing up to 62 mg/L free fatty acid. This study demonstrates that homologous β-oxidation systems can be rationally engineered to enhance fatty acid production, a strategy that may be employed to increase yield for a range of fuels, chemicals, and PHB derivatives in R. eutropha.
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Affiliation(s)
- Janice S. Chen
- Wyss Institute for Biologically Inspired Engineering, Harvard Medical School, Boston, MA, United States
- Current affiliation: Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, United States
| | - Brendan Colón
- Department of Systems Biology, Harvard Medical School, Boston, MA, United States
| | - Brendon Dusel
- Wyss Institute for Biologically Inspired Engineering, Harvard Medical School, Boston, MA, United States
| | - Marika Ziesack
- Department of Systems Biology, Harvard Medical School, Boston, MA, United States
| | - Jeffrey C. Way
- Wyss Institute for Biologically Inspired Engineering, Harvard Medical School, Boston, MA, United States
| | - Joseph P. Torella
- Department of Systems Biology, Harvard Medical School, Boston, MA, United States
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306
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Felpeto-Santero C, Rojas A, Tortajada M, Galán B, Ramón D, García JL. Engineering alternative isobutanol production platforms. AMB Express 2015; 5:119. [PMID: 26054735 PMCID: PMC4456594 DOI: 10.1186/s13568-015-0119-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 05/18/2015] [Indexed: 01/22/2023] Open
Abstract
A synthetic inducible operon (IbPSO) expressing alsS, ilvC, ilvD and kivD genes encoding a pathway capable to transform pyruvate into 2-isobutyraldehyde has been designed and two recombinant plasmids named pIZIbPSO and p424IbPSO were constructed. The IbPSO containing plasmids can generate in a single transformation event new recombinant isobutanol producer strains and are useful for testing as suitable hosts wild type bacteria in different culture media. In this way we found that Shimwellia blattae (p424IbPSO) was able to produce in flasks up to 6 g l(-1) of isobutanol using glucose as carbon source. Moreover, for the first time, we have demonstrated that isobutanol can be produced from sucrose using Escherichia coli W (ATCC9367) transformed with pIZIbPSO. These robust recombinant strains were also able to produce isobutanol from a raw carbon source like hydrolysed lignocellulosic biomass.
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Affiliation(s)
- Carmen Felpeto-Santero
- />Department of Environmental Biology, Centro de Investigaciones Biológicas, CSIC, Madrid, Spain
| | - Antonia Rojas
- />Biopolis S.L., Parc Científic Universitat de Valencia, Paterna, Spain
| | - Marta Tortajada
- />Biopolis S.L., Parc Científic Universitat de Valencia, Paterna, Spain
| | - Beatriz Galán
- />Department of Environmental Biology, Centro de Investigaciones Biológicas, CSIC, Madrid, Spain
| | - Daniel Ramón
- />Biopolis S.L., Parc Científic Universitat de Valencia, Paterna, Spain
| | - José L García
- />Department of Environmental Biology, Centro de Investigaciones Biológicas, CSIC, Madrid, Spain
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307
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Dürre P, Eikmanns BJ. C1-carbon sources for chemical and fuel production by microbial gas fermentation. Curr Opin Biotechnol 2015; 35:63-72. [DOI: 10.1016/j.copbio.2015.03.008] [Citation(s) in RCA: 164] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Revised: 03/06/2015] [Accepted: 03/12/2015] [Indexed: 12/25/2022]
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308
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Affiliation(s)
- Tian Zhang
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2970 Hørsholm, Denmark
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309
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Chai GL, Guo ZX. Highly effective sites and selectivity of nitrogen-doped graphene/CNT catalysts for CO 2 electrochemical reduction. Chem Sci 2015; 7:1268-1275. [PMID: 29910883 PMCID: PMC5975832 DOI: 10.1039/c5sc03695j] [Citation(s) in RCA: 169] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 11/11/2015] [Indexed: 12/22/2022] Open
Abstract
The selectivity of CO2 electrochemical reduction can be tuned for N-doped graphene/CNT catalysts after active sites are determined.
Metal-free catalysts, such as graphene/carbon nanostructures, are highly cost-effective to replace expensive noble metals for CO2 reduction if fundamental issues, such as active sites and selectivity, are clearly understood. Using both density functional theory (DFT) and ab initio molecular dynamic calculations, we show that the interplay of N-doping and curvature can effectively tune the activity and selectivity of graphene/carbon-nanotube (CNT) catalysts. The CO2 activation barrier can be optimized to 0.58 eV for graphitic-N doped graphene edges, compared with 1.3 eV in the un-doped counterpart. The graphene catalyst without curvature shows strong selectivity for CO/HCOOH production, whereas the (6, 0) CNT with a high degree of curvature is effective for both CH3OH and HCHO production. Curvature is also very influential to tune the overpotential for a given product, e.g. from 1.5 to 0.02 V for CO production and from 1.29 to 0.49 V for CH3OH production. Hence, the graphene/CNT nanostructures offer great scope and flexibility for effective tunning of catalyst efficiency and selectivity, as shown here for CO2 reduction.
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Affiliation(s)
- Guo-Liang Chai
- Department of Chemistry , University College London , London WC1H 0AJ , UK .
| | - Zheng-Xiao Guo
- Department of Chemistry , University College London , London WC1H 0AJ , UK .
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310
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Impact of continuous and intermittent supply of electric field on the function and microbial community of wastewater treatment electro-bioreactors. Electrochim Acta 2015. [DOI: 10.1016/j.electacta.2015.04.095] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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311
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Bioconversion of methanol to value-added mevalonate by engineered Methylobacterium extorquens AM1 containing an optimized mevalonate pathway. Appl Microbiol Biotechnol 2015; 100:2171-82. [DOI: 10.1007/s00253-015-7078-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Revised: 09/20/2015] [Accepted: 10/12/2015] [Indexed: 12/21/2022]
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312
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Kernan T, Majumdar S, Li X, Guan J, West AC, Banta S. Engineering the iron‐oxidizing chemolithoautotroph
Acidithiobacillus ferrooxidans
for biochemical production. Biotechnol Bioeng 2015; 113:189-97. [DOI: 10.1002/bit.25703] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 06/22/2015] [Accepted: 07/08/2015] [Indexed: 12/28/2022]
Affiliation(s)
- Timothy Kernan
- Department of Chemical EngineeringColumbia University500 W. 120th StreetNew York CityNew York10027
| | - Sudipta Majumdar
- Department of Chemical EngineeringColumbia University500 W. 120th StreetNew York CityNew York10027
| | - Xiaozheng Li
- Department of Chemical EngineeringColumbia University500 W. 120th StreetNew York CityNew York10027
| | - Jingyang Guan
- Department of Chemical EngineeringColumbia University500 W. 120th StreetNew York CityNew York10027
| | - Alan C. West
- Department of Chemical EngineeringColumbia University500 W. 120th StreetNew York CityNew York10027
| | - Scott Banta
- Department of Chemical EngineeringColumbia University500 W. 120th StreetNew York CityNew York10027
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313
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Nichols EM, Gallagher JJ, Liu C, Su Y, Resasco J, Yu Y, Sun Y, Yang P, Chang MCY, Chang CJ. Hybrid bioinorganic approach to solar-to-chemical conversion. Proc Natl Acad Sci U S A 2015; 112:11461-6. [PMID: 26305947 PMCID: PMC4577177 DOI: 10.1073/pnas.1508075112] [Citation(s) in RCA: 143] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Natural photosynthesis harnesses solar energy to convert CO2 and water to value-added chemical products for sustaining life. We present a hybrid bioinorganic approach to solar-to-chemical conversion in which sustainable electrical and/or solar input drives production of hydrogen from water splitting using biocompatible inorganic catalysts. The hydrogen is then used by living cells as a source of reducing equivalents for conversion of CO2 to the value-added chemical product methane. Using platinum or an earth-abundant substitute, α-NiS, as biocompatible hydrogen evolution reaction (HER) electrocatalysts and Methanosarcina barkeri as a biocatalyst for CO2 fixation, we demonstrate robust and efficient electrochemical CO2 to CH4 conversion at up to 86% overall Faradaic efficiency for ≥ 7 d. Introduction of indium phosphide photocathodes and titanium dioxide photoanodes affords a fully solar-driven system for methane generation from water and CO2, establishing that compatible inorganic and biological components can synergistically couple light-harvesting and catalytic functions for solar-to-chemical conversion.
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Affiliation(s)
- Eva M Nichols
- Department of Chemistry, University of California, Berkeley, CA 94720; Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - Joseph J Gallagher
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
| | - Chong Liu
- Department of Chemistry, University of California, Berkeley, CA 94720; Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - Yude Su
- Department of Chemistry, University of California, Berkeley, CA 94720
| | - Joaquin Resasco
- Department of Chemical Engineering, University of California, Berkeley, CA 94720
| | - Yi Yu
- Department of Chemistry, University of California, Berkeley, CA 94720
| | - Yujie Sun
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT 84322
| | - Peidong Yang
- Department of Chemistry, University of California, Berkeley, CA 94720; Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720; Department of Materials Science and Engineering, University of California, Berkeley, CA 94720; Kavli Energy NanoSciences Institute, Berkeley, CA 94720;
| | - Michelle C Y Chang
- Department of Chemistry, University of California, Berkeley, CA 94720; Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720; Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720;
| | - Christopher J Chang
- Department of Chemistry, University of California, Berkeley, CA 94720; Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720; Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720; Howard Hughes Medical Institute, University of California, Berkeley, CA 94720
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314
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Lin PP, Mi L, Morioka AH, Yoshino KM, Konishi S, Xu SC, Papanek BA, Riley LA, Guss AM, Liao JC. Consolidated bioprocessing of cellulose to isobutanol using Clostridium thermocellum. Metab Eng 2015; 31:44-52. [DOI: 10.1016/j.ymben.2015.07.001] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Revised: 06/06/2015] [Accepted: 07/01/2015] [Indexed: 10/23/2022]
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315
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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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316
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Blombach B, Takors R. CO2 - Intrinsic Product, Essential Substrate, and Regulatory Trigger of Microbial and Mammalian Production Processes. Front Bioeng Biotechnol 2015; 3:108. [PMID: 26284242 PMCID: PMC4522908 DOI: 10.3389/fbioe.2015.00108] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 07/13/2015] [Indexed: 11/22/2022] Open
Abstract
Carbon dioxide formation mirrors the final carbon oxidation steps of aerobic metabolism in microbial and mammalian cells. As a consequence, CO2/HCO3− dissociation equilibria arise in fermenters by the growing culture. Anaplerotic reactions make use of the abundant CO2/HCO3− levels for refueling citric acid cycle demands and for enabling oxaloacetate-derived products. At the same time, CO2 is released manifold in metabolic reactions via decarboxylation activity. The levels of extracellular CO2/HCO3− depend on cellular activities and physical constraints such as hydrostatic pressures, aeration, and the efficiency of mixing in large-scale bioreactors. Besides, local CO2/HCO3− levels might also act as metabolic inhibitors or transcriptional effectors triggering regulatory events inside the cells. This review gives an overview about fundamental physicochemical properties of CO2/HCO3− in microbial and mammalian cultures effecting cellular physiology, production processes, metabolic activity, and transcriptional regulation.
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Affiliation(s)
- Bastian Blombach
- Institute of Biochemical Engineering, University of Stuttgart , Stuttgart , Germany
| | - Ralf Takors
- Institute of Biochemical Engineering, University of Stuttgart , Stuttgart , Germany
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317
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Gong F, Liu G, Zhai X, Zhou J, Cai Z, Li Y. Quantitative analysis of an engineered CO2-fixing Escherichia coli reveals great potential of heterotrophic CO2 fixation. BIOTECHNOLOGY FOR BIOFUELS 2015; 8:86. [PMID: 26097503 PMCID: PMC4475311 DOI: 10.1186/s13068-015-0268-1] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 06/05/2015] [Indexed: 06/01/2023]
Abstract
BACKGROUND Production of fuels from the abundant and wasteful CO2 is a promising approach to reduce carbon emission and consumption of fossil fuels. Autotrophic microbes naturally assimilate CO2 using energy from light, hydrogen, and/or sulfur. However, their slow growth rates call for investigation of the possibility of heterotrophic CO2 fixation. Although preliminary research has suggested that CO2 fixation in heterotrophic microbes is feasible after incorporation of a CO2-fixing bypass into the central carbon metabolic pathway, it remains unclear how much and how efficient that CO2 can be fixed by a heterotrophic microbe. RESULTS A simple metabolic flux index was developed to indicate the relative strength of the CO2-fixation flux. When two sequential enzymes of the cyanobacterial Calvin cycle were incorporated into an E. coli strain, the flux of the CO2-fixing bypass pathway accounts for 13 % of that of the central carbon metabolic pathway. The value was increased to 17 % when the carbonic anhydrase involved in the cyanobacterial carbon concentrating mechanism was introduced, indicating that low intracellular CO2 concentration is one limiting factor for CO2 fixation in E. coli. The engineered CO2-fixing E. coli with carbonic anhydrase was able to fix CO2 at a rate of 19.6 mg CO2 L(-1) h(-1) or the specific rate of 22.5 mg CO2 g DCW(-1) h(-1). This CO2-fixation rate is comparable with the reported rates of 14 autotrophic cyanobacteria and algae (10.5-147.0 mg CO2 L(-1) h(-1) or the specific rates of 3.5-23.7 mg CO2 g DCW(-1) h(-1)). CONCLUSIONS The ability of CO2 fixation was created and improved in E. coli by incorporating partial cyanobacterial Calvin cycle and carbon concentrating mechanism, respectively. Quantitative analysis revealed that the CO2-fixation rate of this strain is comparable with that of the autotrophic cyanobacteria and algae, demonstrating great potential of heterotrophic CO2 fixation.
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Affiliation(s)
- Fuyu Gong
- />CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, No. 1 West Beichen Road Chaoyang District, Beijing, 100101 China
- />University of the Chinese Academy of Sciences, Beijing, China
| | - Guoxia Liu
- />CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, No. 1 West Beichen Road Chaoyang District, Beijing, 100101 China
| | - Xiaoyun Zhai
- />CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, No. 1 West Beichen Road Chaoyang District, Beijing, 100101 China
- />University of the Chinese Academy of Sciences, Beijing, China
| | - Jie Zhou
- />CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, No. 1 West Beichen Road Chaoyang District, Beijing, 100101 China
| | - Zhen Cai
- />CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, No. 1 West Beichen Road Chaoyang District, Beijing, 100101 China
| | - Yin Li
- />CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, No. 1 West Beichen Road Chaoyang District, Beijing, 100101 China
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318
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Zhen G, Kobayashi T, Lu X, Xu K. Understanding methane bioelectrosynthesis from carbon dioxide in a two-chamber microbial electrolysis cells (MECs) containing a carbon biocathode. BIORESOURCE TECHNOLOGY 2015; 186:141-148. [PMID: 25812818 DOI: 10.1016/j.biortech.2015.03.064] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2014] [Revised: 03/07/2015] [Accepted: 03/12/2015] [Indexed: 06/04/2023]
Abstract
To better understand the underlying mechanisms for methane bioelectrosynthesis, a two-chamber MECs containing a carbon biocathode was developed and studied. Methane production substantially increased with increasing cathode potential. Considerable methane yield was achieved at a poised potential of -0.9 V (vs. Ag/AgCl), reaching 2.30±0.34 mL after 5 h of operation with a faradaic efficiency of 24.2±4.7%. Confirmatory tests done at 0.9 V by switching the type of flushed substrates (CO2/N2) or the electrical exposure modes (ON/OFF) demonstrated that cathode serving as an electron donor was the vital driving force for methanogenesis occurring at microbe-electrode surface. Fluorescence in situ hybridization reveled Methanobacteriaceae (particularly Methanobacterium) was the predominant methanogens, supporting the mechanisms of direct electron transfer between cell-electrode. Additionally, the analysis of scanning electron microscope confirmed that the multiple pathways of electron transfer, including direct cathode-to-cell, interspecies exchange and semi-conductive conduits all together ensured the successful electromethanogenesis process.
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Affiliation(s)
- Guangyin Zhen
- Center for Material Cycles and Waste Management Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan.
| | - Takuro Kobayashi
- Center for Material Cycles and Waste Management Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan
| | - Xueqin Lu
- Department of Civil and Environmental Engineering, Graduate School of Engineering, Tohoku University, Sendai, Miyagi 980-8579, Japan
| | - Kaiqin Xu
- Center for Material Cycles and Waste Management Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan.
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319
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320
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Spakowicz DJ, Strobel SA. Biosynthesis of hydrocarbons and volatile organic compounds by fungi: bioengineering potential. Appl Microbiol Biotechnol 2015; 99:4943-51. [PMID: 25957494 DOI: 10.1007/s00253-015-6641-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Revised: 04/22/2015] [Accepted: 04/29/2015] [Indexed: 01/05/2023]
Abstract
Recent advances in the biological production of fuels have relied on the optimization of pathways involving genes from diverse organisms. Several recent articles have highlighted the potential to expand the pool of useful genes by looking to filamentous fungi. This review highlights the enzymes and organisms used for the production of a variety of fuel types and commodity chemicals with a focus on the usefulness and promise of those from filamentous fungi.
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Affiliation(s)
- Daniel J Spakowicz
- Department of Molecular Biophysics and Biochemistry, Yale University, 260/266 Whitney Avenue, PO Box 208114, New Haven, CT, 06520-8114, USA
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321
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Zeng AP, Kaltschmitt M. Green electricity and biowastes via biogas to bulk-chemicals and fuels: The next move toward a sustainable bioeconomy. Eng Life Sci 2015. [DOI: 10.1002/elsc.201400262] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- An-Ping Zeng
- Institute of Bioprocess and Biosystems Engineering, Hamburg University of Technology (TUHH); Hamburg Germany
| | - Martin Kaltschmitt
- Institute of Environmental Technology and Energy Economics; Hamburg University of Technology (TUHH); Hamburg Germany
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322
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Nybo SE, Khan NE, Woolston BM, Curtis WR. Metabolic engineering in chemolithoautotrophic hosts for the production of fuels and chemicals. Metab Eng 2015; 30:105-120. [PMID: 25959019 DOI: 10.1016/j.ymben.2015.04.008] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Revised: 04/06/2015] [Accepted: 04/29/2015] [Indexed: 12/19/2022]
Abstract
The ability of autotrophic organisms to fix CO2 presents an opportunity to utilize this 'greenhouse gas' as an inexpensive substrate for biochemical production. Unlike conventional heterotrophic microorganisms that consume carbohydrates and amino acids, prokaryotic chemolithoautotrophs have evolved the capacity to utilize reduced chemical compounds to fix CO2 and drive metabolic processes. The use of chemolithoautotrophic hosts as production platforms has been renewed by the prospect of metabolically engineered commodity chemicals and fuels. Efforts such as the ARPA-E electrofuels program highlight both the potential and obstacles that chemolithoautotrophic biosynthetic platforms provide. This review surveys the numerous advances that have been made in chemolithoautotrophic metabolic engineering with a focus on hydrogen oxidizing bacteria such as the model chemolithoautotrophic organism (Ralstonia), the purple photosynthetic bacteria (Rhodobacter), and anaerobic acetogens. Two alternative strategies of microbial chassis development are considered: (1) introducing or enhancing autotrophic capabilities (carbon fixation, hydrogen utilization) in model heterotrophic organisms, or (2) improving tools for pathway engineering (transformation methods, promoters, vectors etc.) in native autotrophic organisms. Unique characteristics of autotrophic growth as they relate to bioreactor design and process development are also discussed in the context of challenges and opportunities for genetic manipulation of organisms as production platforms.
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Affiliation(s)
- S Eric Nybo
- Department of Pharmaceutical Sciences, College of Pharmacy, Ferris State University, Big Rapids, MI, United States
| | - Nymul E Khan
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, United States
| | - Benjamin M Woolston
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Wayne R Curtis
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, United States.
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323
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Engineering biological systems toward a sustainable bioeconomy. J Ind Microbiol Biotechnol 2015; 42:813-38. [PMID: 25845304 DOI: 10.1007/s10295-015-1606-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Accepted: 03/09/2015] [Indexed: 01/07/2023]
Abstract
The nature of our major global risks calls for sustainable innovations to decouple economic growth from greenhouse gases emission. The development of sustainable technologies has been negatively impacted by several factors including sugar production costs, production scale, economic crises, hydraulic fracking development and the market inability to capture externality costs. However, advances in engineering of biological systems allow bridging the gap between exponential growth of knowledge about biology and the creation of sustainable value chains for a broad range of economic sectors. Additionally, industrial symbiosis of different biobased technologies can increase competitiveness and sustainability, leading to the development of eco-industrial parks. Reliable policies for carbon pricing and revenue reinvestments in disruptive technologies and in the deployment of eco-industrial parks could boost the welfare while addressing our major global risks toward the transition from a fossil to a biobased economy.
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324
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Tremblay PL, Zhang T. Electrifying microbes for the production of chemicals. Front Microbiol 2015; 6:201. [PMID: 25814988 PMCID: PMC4356085 DOI: 10.3389/fmicb.2015.00201] [Citation(s) in RCA: 118] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Accepted: 02/24/2015] [Indexed: 01/06/2023] Open
Abstract
Powering microbes with electrical energy to produce valuable chemicals such as biofuels has recently gained traction as a biosustainable strategy to reduce our dependence on oil. Microbial electrosynthesis (MES) is one of the bioelectrochemical approaches developed in the last decade that could have critical impact on the current methods of chemical synthesis. MES is a process in which electroautotrophic microbes use electrical current as electron source to reduce CO2 to multicarbon organics. Electricity necessary for MES can be harvested from renewable resources such as solar energy, wind turbine, or wastewater treatment processes. The net outcome is that renewable energy is stored in the covalent bonds of organic compounds synthesized from greenhouse gas. This review will discuss the future of MES and the challenges that lie ahead for its development into a mature technology.
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Affiliation(s)
- Pier-Luc Tremblay
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Hørsholm Denmark
| | - Tian Zhang
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Hørsholm Denmark
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325
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Computational protein design enables a novel one-carbon assimilation pathway. Proc Natl Acad Sci U S A 2015; 112:3704-9. [PMID: 25775555 DOI: 10.1073/pnas.1500545112] [Citation(s) in RCA: 212] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
We describe a computationally designed enzyme, formolase (FLS), which catalyzes the carboligation of three one-carbon formaldehyde molecules into one three-carbon dihydroxyacetone molecule. The existence of FLS enables the design of a new carbon fixation pathway, the formolase pathway, consisting of a small number of thermodynamically favorable chemical transformations that convert formate into a three-carbon sugar in central metabolism. The formolase pathway is predicted to use carbon more efficiently and with less backward flux than any naturally occurring one-carbon assimilation pathway. When supplemented with enzymes carrying out the other steps in the pathway, FLS converts formate into dihydroxyacetone phosphate and other central metabolites in vitro. These results demonstrate how modern protein engineering and design tools can facilitate the construction of a completely new biosynthetic pathway.
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326
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Harnisch F, Rosa LFM, Kracke F, Virdis B, Krömer JO. Electrifying white biotechnology: engineering and economic potential of electricity-driven bio-production. CHEMSUSCHEM 2015; 8:758-66. [PMID: 25504806 DOI: 10.1002/cssc.201402736] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Revised: 09/21/2014] [Indexed: 05/19/2023]
Abstract
The production of fuels and chemicals by electricity-driven bio-production (i.e., using electric energy to drive biosynthesis) holds great promises. However, this electrification of white biotechnology is particularly challenging to achieve because of the different optimal operating conditions of electrochemical and biochemical reactions. In this article, we address the technical parameters and obstacles to be taken into account when engineering microbial bioelectrochemical systems (BES) for bio-production. In addition, BES-based bio-production processes reported in the literature are compared against industrial needs showing that a still large gap has to be closed. Finally, the feasibility of BES bio-production is analysed based on bulk electricity prices. Using the example of lysine production from sucrose, we demonstrate that there is a realistic market potential as cost savings of 8.4 % (in EU) and 18.0 % (in US) could be anticipated, if the necessary yields can be obtained.
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Affiliation(s)
- Falk Harnisch
- UFZ-Helmholtz-Centre for Environmental Research, Department of Environmental Microbiology, Permoserstrasse 15, 04318 Leipzig (Germany), Fax: (+49) 341-235-1351.
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327
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Li H, Liao JC. A synthetic anhydrotetracycline-controllable gene expression system in Ralstonia eutropha H16. ACS Synth Biol 2015; 4:101-6. [PMID: 24702232 DOI: 10.1021/sb4001189] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Controllable gene expression systems that are orthogonal to the host's native gene regulation network are invaluable tools for synthetic biology. In Ralstonia eutropha H16, such systems are extremely limited despite the importance of this organism in microbiological research and biotechnological application. Here we developed an anhydrotetracycline (aTc)-inducible gene expression system, which is composed of a synthetic promoter containing the operator tetO, the repressor TetR, and the inducer aTc. Using a reporter-activity based promoter library screen, we first identified the active hybrids between the tetO operators and the R. eutropha native rrsC promoter (PrrsC). Next, we showed that the hybrid promoters are repressable by TetR. To optimize the dynamic range of the system, a high-throughput screening of 300 mutants of R. eutropha phaC1 promoter was conducted to identify suitable promoters to tune the tetR expression level. The final controllable expression system contains the modified PrrsC with two copies of the tetO1 operator integrated and the tetR driven by the mutated PphaC1. The system has decreased basal expression level and can be tuned by different aTc concentrations with greater than 10-fold dynamic range. The system was used to alleviate cellular toxicity caused by AlsS overexpression, which impeded our metabolic engineering work on isobutanol and 3-methyl-1-butanol production in R. eutropha H16.
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Affiliation(s)
- Han Li
- Department of Chemical and Biomolecular Engineering, ‡The Molecular Biology Institute, §Department of Chemistry & Biochemistry, ∥Institute of Genomics and Proteomics, University of California, Los Angeles, California 90095, United States
| | - James C. Liao
- Department of Chemical and Biomolecular Engineering, ‡The Molecular Biology Institute, §Department of Chemistry & Biochemistry, ∥Institute of Genomics and Proteomics, University of California, Los Angeles, California 90095, United States
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328
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Efficient solar-to-fuels production from a hybrid microbial-water-splitting catalyst system. Proc Natl Acad Sci U S A 2015; 112:2337-42. [PMID: 25675518 DOI: 10.1073/pnas.1424872112] [Citation(s) in RCA: 213] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Photovoltaic cells have considerable potential to satisfy future renewable-energy needs, but efficient and scalable methods of storing the intermittent electricity they produce are required for the large-scale implementation of solar energy. Current solar-to-fuels storage cycles based on water splitting produce hydrogen and oxygen, which are attractive fuels in principle but confront practical limitations from the current energy infrastructure that is based on liquid fuels. In this work, we report the development of a scalable, integrated bioelectrochemical system in which the bacterium Ralstonia eutropha is used to efficiently convert CO2, along with H2 and O2 produced from water splitting, into biomass and fusel alcohols. Water-splitting catalysis was performed using catalysts that are made of earth-abundant metals and enable low overpotential water splitting. In this integrated setup, equivalent solar-to-biomass yields of up to 3.2% of the thermodynamic maximum exceed that of most terrestrial plants. Moreover, engineering of R. eutropha enabled production of the fusel alcohol isopropanol at up to 216 mg/L, the highest bioelectrochemical fuel yield yet reported by >300%. This work demonstrates that catalysts of biotic and abiotic origin can be interfaced to achieve challenging chemical energy-to-fuels transformations.
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329
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Yim KJ, Song DK, Kim CS, Kim NG, Iwaki T, Ogi T, Okuyama K, Lee SE, Kim TO. Selective, high efficiency reduction of CO2 in a non-diaphragm-based electrochemical system at low applied voltage. RSC Adv 2015. [DOI: 10.1039/c4ra14427a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Electrochemical CO2 reduction in a diaphragm-less cell selectively afforded CH4 and H2 in methanolic NaOH and KOH electrolytes, respectively.
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Affiliation(s)
- Kwang-Jin Yim
- Department of Environmental Engineering
- Kumoh National Institute of Technology
- Gumi
- Republic of Korea
| | - Dong-Keun Song
- Department of Eco-Machinery Systems
- Environmental and Energy Systems Research Division
- Korea Institute of Machinery and Materials
- Daejeon 305-343
- Republic of Korea
| | - Chan-Soo Kim
- Marine Energy Convergence & Integration Laboratory
- Jeju Global Research Center
- Korea Institute of Energy Research
- Republic of Korea
| | - Nam-Gyu Kim
- Department of Environmental Engineering
- Kumoh National Institute of Technology
- Gumi
- Republic of Korea
| | - Toru Iwaki
- Department of Chemical Engineering
- Graduate School of Engineering
- Hiroshima University
- Higashi Hiroshima 739-8527
- Japan
| | - Takashi Ogi
- Department of Chemical Engineering
- Graduate School of Engineering
- Hiroshima University
- Higashi Hiroshima 739-8527
- Japan
| | - Kikuo Okuyama
- Department of Chemical Engineering
- Graduate School of Engineering
- Hiroshima University
- Higashi Hiroshima 739-8527
- Japan
| | - Sung-Eun Lee
- School of Applied Biosciences
- Kyungpook National University
- Daegu 702-701
- Republic of Korea
| | - Tae-Oh Kim
- Department of Environmental Engineering
- Kumoh National Institute of Technology
- Gumi
- Republic of Korea
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330
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Navarrete A, Muñoz S, Sanz-Moral LM, Brandner JJ, Pfeifer P, Martín Á, Dittmeyer R, Cocero MJ. Novel windows for “solar commodities”: a device for CO2 reduction using plasmonic catalyst activation. Faraday Discuss 2015; 183:249-59. [DOI: 10.1039/c5fd00109a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A novel plasmonic reactor concept is proposed and tested to work as a visible energy harvesting device while allowing reactions to transform CO2 to be carried out. Particularly the reverse water gas shift (RWGS) reaction has been tested as a means to introduce renewable energy into the economy. The development of the new reactor concept involved the synthesis of a new composite capable of plasmonic activation with light, the development of an impregnation method to create a single catalyst reactor entity, and finally the assembly of a reaction system to test the reaction. The composite developed was based on a Cu/ZnO catalyst dispersed into transparent aerogels. This allows efficient light transmission and a high surface area for the catalyst. An effective yet simple impregnation method was developed that allowed introduction of the composites into glass microchannels. The activation of the reaction was made using LEDs that covered all the sides of the reactor allowing a high power delivery. The results of the reaction show a stable process capable of low temperature transformations.
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Affiliation(s)
- Alexander Navarrete
- University of Valladolid
- Department of Chemical Engineering and Environmental
- Technology
- High Pressure Processes Group
- 47005 Valladolid
| | - Sergio Muñoz
- University of Valladolid
- Department of Chemical Engineering and Environmental
- Technology
- High Pressure Processes Group
- 47005 Valladolid
| | - Luis M. Sanz-Moral
- University of Valladolid
- Department of Chemical Engineering and Environmental
- Technology
- High Pressure Processes Group
- 47005 Valladolid
| | - Juergen J. Brandner
- Institute for Micro Process Engineering
- Karlsruhe Institute for Technology
- Germany
| | - Peter Pfeifer
- Institute for Micro Process Engineering
- Karlsruhe Institute for Technology
- Germany
| | - Ángel Martín
- University of Valladolid
- Department of Chemical Engineering and Environmental
- Technology
- High Pressure Processes Group
- 47005 Valladolid
| | - Roland Dittmeyer
- Institute for Micro Process Engineering
- Karlsruhe Institute for Technology
- Germany
| | - María J. Cocero
- University of Valladolid
- Department of Chemical Engineering and Environmental
- Technology
- High Pressure Processes Group
- 47005 Valladolid
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331
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Lee HM, Youn IS, Saleh M, Lee JW, Kim KS. Interactions of CO2with various functional molecules. Phys Chem Chem Phys 2015; 17:10925-33. [DOI: 10.1039/c5cp00673b] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
We report the CO2-interactions with diverse functional molecules. Useful functional molecules such as melamine showing very large adsorption enthalpy for CO2are reported.
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Affiliation(s)
- Han Myoung Lee
- Center for Superfunctional Materials
- Department of Chemistry
- Ulsan National Institute of Science and Technology (UNIST)
- Ulsan 689-798
- Korea
| | - Il Seung Youn
- Center for Superfunctional Materials
- Department of Chemistry
- Ulsan National Institute of Science and Technology (UNIST)
- Ulsan 689-798
- Korea
| | - Muhammad Saleh
- Center for Superfunctional Materials
- Department of Chemistry
- Ulsan National Institute of Science and Technology (UNIST)
- Ulsan 689-798
- Korea
| | - Jung Woo Lee
- Center for Superfunctional Materials
- Department of Chemistry
- Ulsan National Institute of Science and Technology (UNIST)
- Ulsan 689-798
- Korea
| | - Kwang S. Kim
- Center for Superfunctional Materials
- Department of Chemistry
- Ulsan National Institute of Science and Technology (UNIST)
- Ulsan 689-798
- Korea
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332
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Thakker C, Martínez I, Li W, San KY, Bennett GN. Metabolic engineering of carbon and redox flow in the production of small organic acids. J Ind Microbiol Biotechnol 2014; 42:403-22. [PMID: 25502283 DOI: 10.1007/s10295-014-1560-y] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 11/24/2014] [Indexed: 11/26/2022]
Abstract
The review describes efforts toward metabolic engineering of production of organic acids. One aspect of the strategy involves the generation of an appropriate amount and type of reduced cofactor needed for the designed pathway. The ability to capture reducing power in the proper form, NADH or NADPH for the biosynthetic reactions leading to the organic acid, requires specific attention in designing the host and also depends on the feedstock used and cell energetic requirements for efficient metabolism during production. Recent work on the formation and commercial uses of a number of small mono- and diacids is discussed with redox differences, major biosynthetic precursors and engineering strategies outlined. Specific attention is given to those acids that are used in balancing cell redox or providing reduction equivalents for the cell, such as formate, which can be used in conjunction with metabolic engineering of other products to improve yields. Since a number of widely studied acids derived from oxaloacetate as an important precursor, several of these acids are covered with the general strategies and particular components summarized, including succinate, fumarate and malate. Since malate and fumarate are less reduced than succinate, the availability of reduction equivalents and level of aerobiosis are important parameters in optimizing production of these compounds in various hosts. Several other more oxidized acids are also discussed as in some cases, they may be desired products or their formation is minimized to afford higher yields of more reduced products. The placement and connections among acids in the typical central metabolic network are presented along with the use of a number of specific non-native enzymes to enhance routes to high production, where available alternative pathways and strategies are discussed. While many organic acids are derived from a few precursors within central metabolism, each organic acid has its own special requirements for high production and best compatibility with host physiology.
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Affiliation(s)
- Chandresh Thakker
- Department of Biochemistry and Cell Biology, Rice University, Houston, TX, USA
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333
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Przybylski D, Rohwerder T, Dilßner C, Maskow T, Harms H, Müller RH. Exploiting mixtures of H2, CO2, and O2 for improved production of methacrylate precursor 2-hydroxyisobutyric acid by engineered Cupriavidus necator strains. Appl Microbiol Biotechnol 2014; 99:2131-45. [DOI: 10.1007/s00253-014-6266-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Revised: 11/23/2014] [Accepted: 11/24/2014] [Indexed: 12/23/2022]
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334
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Tashiro Y, Rodriguez GM, Atsumi S. 2-Keto acids based biosynthesis pathways for renewable fuels and chemicals. J Ind Microbiol Biotechnol 2014; 42:361-73. [PMID: 25424696 DOI: 10.1007/s10295-014-1547-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 11/11/2014] [Indexed: 11/30/2022]
Abstract
Global energy and environmental concerns have driven the development of biological chemical production from renewable sources. Biological processes using microorganisms are efficient and have been traditionally utilized to convert biomass (i.e., glucose) to useful chemicals such as amino acids. To produce desired fuels and chemicals with high yield and rate, metabolic pathways have been enhanced and expanded with metabolic engineering and synthetic biology approaches. 2-Keto acids, which are key intermediates in amino acid biosynthesis, can be converted to a wide range of chemicals. 2-Keto acid pathways were engineered in previous research efforts and these studies demonstrated that 2-keto acid pathways have high potential for novel metabolic routes with high productivity. In this review, we discuss recently developed 2-keto acid-based pathways.
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Affiliation(s)
- Yohei Tashiro
- Department of Chemistry, University of California-Davis, Davis, CA, USA
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335
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A hybrid synthetic pathway for butanol production by a hyperthermophilic microbe. Metab Eng 2014; 27:101-106. [PMID: 25461832 DOI: 10.1016/j.ymben.2014.11.004] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Revised: 10/04/2014] [Accepted: 11/12/2014] [Indexed: 01/19/2023]
Abstract
Biologically produced alcohols are of great current interest for renewable solvents and liquid transportation fuels. While bioethanol is now produced on a massive scale, butanol has superior fuel characteristics and an additional value as a solvent and chemical feedstock. Butanol production has been demonstrated at ambient temperatures in metabolically-engineered mesophilic organisms, but the ability to engineer a microbe for in vivo high-temperature production of commodity chemicals has several distinct advantages. These include reduced contamination risk, facilitated removal of volatile products, and a wide temperature range to modulate and balance both the engineered pathway and the host׳s metabolism. We describe a synthetic metabolic pathway assembled from genes obtained from three different sources for conversion of acetyl-CoA to 1-butanol, and 1-butanol generation from glucose was demonstrated near 70°C in a microorganism that grows optimally near 100°C. The module could also be used in thermophiles capable of degrading plant biomass.
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336
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Kang P, Chen Z, Brookhart M, Meyer TJ. Electrocatalytic Reduction of Carbon Dioxide: Let the Molecules Do the Work. Top Catal 2014. [DOI: 10.1007/s11244-014-0344-y] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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337
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Spatially programmed assembling of oxidoreductases with single-stranded DNA for cofactor-required reactions. Appl Microbiol Biotechnol 2014; 99:3469-77. [DOI: 10.1007/s00253-014-6172-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Revised: 10/13/2014] [Accepted: 10/14/2014] [Indexed: 10/24/2022]
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338
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Bacterial production of isobutanol without expensive reagents. Appl Microbiol Biotechnol 2014; 99:991-9. [DOI: 10.1007/s00253-014-6173-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 10/15/2014] [Accepted: 10/16/2014] [Indexed: 10/24/2022]
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339
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de Campos Rodrigues T, Rosenbaum MA. Microbial Electroreduction: Screening for New Cathodic Biocatalysts. ChemElectroChem 2014. [DOI: 10.1002/celc.201402239] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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340
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Abstract
Due to the increasing concerns about limited fossil resources and environmental problems, there has been much interest in developing biofuels from renewable biomass. Ethanol is currently used as a major biofuel, as it can be easily produced by existing fermentation technology, but it is not the best biofuel due to its low energy density, high vapor pressure, hygroscopy, and incompatibility with current infrastructure. Higher alcohols, including 1-propanol, 1-butanol, isobutanol, 2-methyl-1-butanol, and 3-methyl-1-butanol, which possess fuel properties more similar to those of petroleum-based fuel, have attracted particular interest as alternatives to ethanol. Since microorganisms isolated from nature do not allow production of these alcohols at high enough efficiencies, metabolic engineering has been employed to enhance their production. Here, we review recent advances in metabolic engineering of microorganisms for the production of higher alcohols.
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341
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Nozzi NE, Desai SH, Case AE, Atsumi S. Metabolic engineering for higher alcohol production. Metab Eng 2014; 25:174-82. [DOI: 10.1016/j.ymben.2014.07.007] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 07/16/2014] [Accepted: 07/16/2014] [Indexed: 10/25/2022]
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342
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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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343
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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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344
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Kang P, Zhang S, Meyer TJ, Brookhart M. Rapid Selective Electrocatalytic Reduction of Carbon Dioxide to Formate by an Iridium Pincer Catalyst Immobilized on Carbon Nanotube Electrodes. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201310722] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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345
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Kang P, Zhang S, Meyer TJ, Brookhart M. Rapid Selective Electrocatalytic Reduction of Carbon Dioxide to Formate by an Iridium Pincer Catalyst Immobilized on Carbon Nanotube Electrodes. Angew Chem Int Ed Engl 2014; 53:8709-13. [DOI: 10.1002/anie.201310722] [Citation(s) in RCA: 200] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 04/29/2014] [Indexed: 11/11/2022]
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346
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Li X, Mercado R, Kernan T, West AC, Banta S. Addition of citrate to Acidithiobacillus ferrooxidans cultures enables precipitate-free growth at elevated pH and reduces ferric inhibition. Biotechnol Bioeng 2014; 111:1940-8. [PMID: 24771134 DOI: 10.1002/bit.25268] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2014] [Revised: 04/08/2014] [Accepted: 04/15/2014] [Indexed: 11/10/2022]
Abstract
Acidithiobacillus ferrooxidans is an acidophilic chemolithoautotroph that is important in biomining and other biotechnological operations. The cells are able to oxidize inorganic iron, but the insolubility and product inhibition by Fe(3+) complicates characterization of these cultures. Here we explore the growth kinetics of A. ferrooxidans in iron-based medium in a pH range from 1.6 to 2.2. It was found that as the pH was increased from 1.6 to 2.0, the maintenance coefficient decreased while both the growth kinetics and maximum cell yield increased in the precipitate-free, low Fe(2+) concentration medium. In higher iron media a similar trend was observed at low pH, but the formation of precipitates at higher pH (2.0) hampered cell growth and lowered the specific growth rate and maximum cell yield. In order to eliminate ferric precipitates, chelating agents were introduced into the medium. Citric acid was found to be relatively non-toxic and did not appear to interfere with iron oxidation at a maximum concentration of 70 mM. Inclusion of citric acid prevented precipitation and A. ferrooxidans growth parameters resumed their trends as a function of pH. The addition of citrate also decreased the apparent substrate saturation constant (KS ) indicating a reduction in the competitive inhibition of growth by ferric ions. These results indicate that continuous cultures of A. ferrooxidans in the presence of citrate at elevated pH will enable enhanced cell yields and productivities. This will be critical as these cells are used in the development of new biotechnological applications such as electrofuel production.
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Affiliation(s)
- Xiaozheng Li
- Department of Chemical Engineering, Columbia University, 500W 120th Street, New York, New York, 10027
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347
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Lin PP, Rabe KS, Takasumi JL, Kadisch M, Arnold FH, Liao JC. Isobutanol production at elevated temperatures in thermophilic Geobacillus thermoglucosidasius. Metab Eng 2014; 24:1-8. [PMID: 24721011 DOI: 10.1016/j.ymben.2014.03.006] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2014] [Accepted: 03/31/2014] [Indexed: 11/19/2022]
Abstract
The potential advantages of biological production of chemicals or fuels from biomass at high temperatures include reduced enzyme loading for cellulose degradation, decreased chance of contamination, and lower product separation cost. In general, high temperature production of compounds that are not native to the thermophilic hosts is limited by enzyme stability and the lack of suitable expression systems. Further complications can arise when the pathway includes a volatile intermediate. Here we report the engineering of Geobacillus thermoglucosidasius to produce isobutanol at 50°C. We prospected various enzymes in the isobutanol synthesis pathway and characterized their thermostabilities. We also constructed an expression system based on the lactate dehydrogenase promoter from Geobacillus thermodenitrificans. With the best enzyme combination and the expression system, 3.3g/l of isobutanol was produced from glucose and 0.6g/l of isobutanol from cellobiose in G. thermoglucosidasius within 48h at 50°C. This is the first demonstration of isobutanol production in recombinant bacteria at an elevated temperature.
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Affiliation(s)
- Paul P Lin
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, CA 90095, USA
| | - Kersten S Rabe
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Mail Code 210-41, Pasadena, CA 91125, USA
| | - Jennifer L Takasumi
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, CA 90095, USA
| | - Marvin Kadisch
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Mail Code 210-41, Pasadena, CA 91125, USA
| | - Frances H Arnold
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Mail Code 210-41, Pasadena, CA 91125, USA
| | - James C Liao
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, CA 90095, USA.
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348
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Yong YC, Yu YY, Zhang X, Song H. Highly Active Bidirectional Electron Transfer by a Self-Assembled Electroactive Reduced-Graphene-Oxide-Hybridized Biofilm. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201400463] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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349
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Yong YC, Yu YY, Zhang X, Song H. Highly active bidirectional electron transfer by a self-assembled electroactive reduced-graphene-oxide-hybridized biofilm. Angew Chem Int Ed Engl 2014; 53:4480-3. [PMID: 24644059 DOI: 10.1002/anie.201400463] [Citation(s) in RCA: 182] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Indexed: 11/07/2022]
Abstract
Low extracellular electron transfer performance is often a bottleneck in developing high-performance bioelectrochemical systems. Herein, we show that the self-assembly of graphene oxide and Shewanella oneidensis MR-1 formed an electroactive, reduced-graphene-oxide-hybridized, three-dimensional macroporous biofilm, which enabled highly efficient bidirectional electron transfers between Shewanella and electrodes owing to high biomass incorporation and enhanced direct contact-based extracellular electron transfer. This 3D electroactive biofilm delivered a 25-fold increase in the outward current (oxidation current, electron flux from bacteria to electrodes) and 74-fold increase in the inward current (reduction current, electron flux from electrodes to bacteria) over that of the naturally occurring biofilms.
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Affiliation(s)
- Yang-Chun Yong
- Biofuels Institute, School of the Environment, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, Jiangsu Province (China)
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350
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Choi KY, Wernick DG, Tat CA, Liao JC. Consolidated conversion of protein waste into biofuels and ammonia using Bacillus subtilis. Metab Eng 2014; 23:53-61. [PMID: 24566040 DOI: 10.1016/j.ymben.2014.02.007] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Revised: 01/23/2014] [Accepted: 02/11/2014] [Indexed: 01/24/2023]
Abstract
The non-recyclable use of nitrogen fertilizers in microbial production of fuels and chemicals remains environmentally detrimental. Conversion of protein wastes into biofuels and ammonia by engineering nitrogen flux in Escherichia coli has been demonstrated as a method to reclaim reduced-nitrogen and curb its environmental deposition. However, protein biomass requires a proteolysis process before it can be taken up and converted by any microbe. Here, we metabolically engineered Bacillus subtilis to hydrolyze polypeptides through its secreted proteases and to convert amino acids into advanced biofuels and ammonia fertilizer. Redirection of B. subtilis metabolism for amino-acid conversion required inactivation of the branched-chain amino-acid (BCAA) global regulator CodY. Additionally, the lipoamide acyltransferase (bkdB) was deleted to prevent conversion of branched-chain 2-keto acids into their acyl-CoA derivatives. With these deletions and heterologous expression of a keto-acid decarboxylase and an alcohol dehydrogenase, the final strain produced biofuels and ammonia from an amino-acid media with 18.9% and 46.6% of the maximum theoretical yield. The process was also demonstrated on several waste proteins. The results demonstrate the feasibility of direct microbial conversion of polypeptides into sustainable products.
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Affiliation(s)
- Kwon-Young Choi
- Department of Chemical and Biomolecular Engineering, University of California, 7523 Boelter Hall, 420 Westwood Plaza, Los Angeles, CA 90095, USA; Department of Environmental Engineering, College of Engineering, Ajou University, Suwon, Gyeonggi-do, South Korea
| | - David G Wernick
- Department of Chemical and Biomolecular Engineering, University of California, 7523 Boelter Hall, 420 Westwood Plaza, Los Angeles, CA 90095, USA
| | - Christine A Tat
- Department of Chemical and Biomolecular Engineering, University of California, 7523 Boelter Hall, 420 Westwood Plaza, Los Angeles, CA 90095, USA
| | - James C Liao
- Department of Chemical and Biomolecular Engineering, University of California, 7523 Boelter Hall, 420 Westwood Plaza, Los Angeles, CA 90095, USA; Department of Chemistry and Biochemistry, University of California, 607 Charles E. Young Drive East, Los Angeles, CA 90095, USA; Institute for Genomics and Proteomics, University of California, 201 Boyer Hall, 611 Charles E. Young Drive East, Los Angeles, CA 90095, USA; The Molecular Biology Institute, University of California, Paul D. Boyer Hall Box 951570, 611 Charles E. Young Drive East, Los Angeles, CA 90095, USA.
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