1
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Zhao ZM, Liu ZH, Zhang T, Meng R, Gong Z, Li Y, Hu J, Ragauskas AJ, Li BZ, Yuan YJ. Unleashing the capacity of Rhodococcus for converting lignin into lipids. Biotechnol Adv 2024; 70:108274. [PMID: 37913947 DOI: 10.1016/j.biotechadv.2023.108274] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 09/11/2023] [Accepted: 10/22/2023] [Indexed: 11/03/2023]
Abstract
Bioconversion of bioresources/wastes (e.g., lignin, chemical pulping byproducts) represents a promising approach for developing a bioeconomy to help address growing energy and materials demands. Rhodococcus, a promising microbial strain, utilizes numerous carbon sources to produce lipids, which are precursors for synthesizing biodiesel and aviation fuels. However, compared to chemical conversion, bioconversion involves living cells, which is a more complex system that needs further understanding and upgrading. Various wastes amenable to bioconversion are reviewed herein to highlight the potential of Rhodococci for producing lipid-derived bioproducts. In light of the abundant availability of these substrates, Rhodococcus' metabolic pathways converting them to lipids are analyzed from a "beginning-to-end" view. Based on an in-depth understanding of microbial metabolic routes, genetic modifications of Rhodococcus by employing emerging tools (e.g., multiplex genome editing, biosensors, and genome-scale metabolic models) are presented for promoting the bioconversion. Co-solvent enhanced lignocellulose fractionation (CELF) strategy facilitates the generation of a lignin-derived aromatic stream suitable for the Rhodococcus' utilization. Novel alkali sterilization (AS) and elimination of thermal sterilization (ETS) approaches can significantly enhance the bioaccessibility of lignin and its derived aromatics in aqueous fermentation media, which promotes lipid titer significantly. In order to achieve value-added utilization of lignin, biodiesel and aviation fuel synthesis from lignin and lipids are further discussed. The possible directions for unleashing the capacity of Rhodococcus through synergistically modifying microbial strains, substrates, and fermentation processes are proposed toward a sustainable biological lignin valorization.
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Affiliation(s)
- Zhi-Min Zhao
- Frontiers Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China; Department of Chemical & Biomolecular Engineering, University of Tennessee, Knoxville, TN 37996, United States; Key Laboratory of Ecology and Resource Use of the Mongolian Plateau (Ministry of Education), School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China
| | - Zhi-Hua Liu
- Frontiers Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Tongtong Zhang
- Key Laboratory of Ecology and Resource Use of the Mongolian Plateau (Ministry of Education), School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China
| | - Rongqian Meng
- Key Laboratory of Ecology and Resource Use of the Mongolian Plateau (Ministry of Education), School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China
| | - Zhiqun Gong
- Key Laboratory of Ecology and Resource Use of the Mongolian Plateau (Ministry of Education), School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China
| | - Yibing Li
- Key Laboratory of Ecology and Resource Use of the Mongolian Plateau (Ministry of Education), School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China
| | - Jing Hu
- Key Laboratory of Ecology and Resource Use of the Mongolian Plateau (Ministry of Education), School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China
| | - Arthur J Ragauskas
- Department of Chemical & Biomolecular Engineering, University of Tennessee, Knoxville, TN 37996, United States; Joint Institute of Biological Science, Biosciences Division, Oak Ridge National Laboratory (ORNL), Oak Ridge, TN 37831, United States; Department of Forestry, Wildlife, and Fisheries, Center for Renewable Carbon, University of Tennessee Institute of Agriculture, Knoxville, TN 37996, United States.
| | - Bing-Zhi Li
- Frontiers Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China.
| | - Ying-Jin Yuan
- Frontiers Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
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2
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Roell G, Schenk C, Anthony WE, Carr RR, Ponukumati A, Kim J, Akhmatskaya E, Foston M, Dantas G, Moon TS, Tang YJ, García Martín H. A High-Quality Genome-Scale Model for Rhodococcus opacus Metabolism. ACS Synth Biol 2023; 12:1632-1644. [PMID: 37186551 PMCID: PMC10278598 DOI: 10.1021/acssynbio.2c00618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Indexed: 05/17/2023]
Abstract
Rhodococcus opacus is a bacterium that has a high tolerance to aromatic compounds and can produce significant amounts of triacylglycerol (TAG). Here, we present iGR1773, the first genome-scale model (GSM) of R. opacus PD630 metabolism based on its genomic sequence and associated data. The model includes 1773 genes, 3025 reactions, and 1956 metabolites, was developed in a reproducible manner using CarveMe, and was evaluated through Metabolic Model tests (MEMOTE). We combine the model with two Constraint-Based Reconstruction and Analysis (COBRA) methods that use transcriptomics data to predict growth rates and fluxes: E-Flux2 and SPOT (Simplified Pearson Correlation with Transcriptomic data). Growth rates are best predicted by E-Flux2. Flux profiles are more accurately predicted by E-Flux2 than flux balance analysis (FBA) and parsimonious FBA (pFBA), when compared to 44 central carbon fluxes measured by 13C-Metabolic Flux Analysis (13C-MFA). Under glucose-fed conditions, E-Flux2 presents an R2 value of 0.54, while predictions based on pFBA had an inferior R2 of 0.28. We attribute this improved performance to the extra activity information provided by the transcriptomics data. For phenol-fed metabolism, in which the substrate first enters the TCA cycle, E-Flux2's flux predictions display a high R2 of 0.96 while pFBA showed an R2 of 0.93. We also show that glucose metabolism and phenol metabolism function with similar relative ATP maintenance costs. These findings demonstrate that iGR1773 can help the metabolic engineering community predict aromatic substrate utilization patterns and perform computational strain design.
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Affiliation(s)
- Garrett
W. Roell
- Department
of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Christina Schenk
- BCAM
- Basque Center for Applied Mathematics, Bilbao 48009, Spain
- Biological
Systems and Engineering Division, Lawrence
Berkeley National Lab, Berkeley, California 94720, United States
| | - Winston E. Anthony
- The Edison
Family Center for Genome Sciences and Systems Biology, Washington University in St. Louis School of Medicine, St. Louis, Missouri 63110, United States
- Department
of Pathology and Immunology, Washington
University in St. Louis School of Medicine, St. Louis, Missouri 63108, United States
| | - Rhiannon R. Carr
- Department
of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Aditya Ponukumati
- Department
of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Joonhoon Kim
- DOE
Agile BioFoundry, Emeryville, California 94608, United States
- DOE
Joint BioEnergy Institute, Emeryville, California 94608, United States
| | - Elena Akhmatskaya
- BCAM
- Basque Center for Applied Mathematics, Bilbao 48009, Spain
- Biological
Systems and Engineering Division, Lawrence
Berkeley National Lab, Berkeley, California 94720, United States
- IKERBASQUE,
Basque Foundation for Science, Bilbao 48009, Spain
| | - Marcus Foston
- Department
of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Gautam Dantas
- The Edison
Family Center for Genome Sciences and Systems Biology, Washington University in St. Louis School of Medicine, St. Louis, Missouri 63110, United States
- Department
of Pathology and Immunology, Washington
University in St. Louis School of Medicine, St. Louis, Missouri 63108, United States
- Department
of Biomedical Engineering, Washington University
in St. Louis, St Louis, Missouri 63130, United States
- Department
of Molecular Microbiology, Washington University
in St. Louis School of Medicine, St. Louis, Missouri 63108, United States
- Department
of Pediatrics, Washington University School
of Medicine in St Louis, St Louis, Missouri 63110, United States
| | - Tae Seok Moon
- Department
of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Yinjie J. Tang
- Department
of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Hector García Martín
- BCAM
- Basque Center for Applied Mathematics, Bilbao 48009, Spain
- DOE
Agile BioFoundry, Emeryville, California 94608, United States
- Biological
Systems and Engineering Division, Lawrence
Berkeley National Lab, Berkeley, California 94720, United States
- DOE
Joint BioEnergy Institute, Emeryville, California 94608, United States
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3
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Wu W, Dijkstra P, Hungate BA, Shi L, Dippold MA. In situ diversity of metabolism and carbon use efficiency among soil bacteria. SCIENCE ADVANCES 2022; 8:eabq3958. [PMID: 36332015 PMCID: PMC9635821 DOI: 10.1126/sciadv.abq3958] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 09/16/2022] [Indexed: 06/16/2023]
Abstract
The central carbon (C) metabolic network harvests energy to power the cell and feed biosynthesis for growth. In pure cultures, bacteria use some but not all of the network's major pathways, such as glycolysis and pentose phosphate and Entner-Doudoroff pathways. However, how these pathways are used in microorganisms in intact soil communities is unknown. Here, we analyzed the incorporation of 13C from glucose isotopomers into phospholipid fatty acids. We showed that groups of Gram-positive and Gram-negative bacteria in an intact agricultural soil used different pathways to metabolize glucose. They also differed in C use efficiency (CUE), the efficiency with which a substrate is used for biosynthesis. Our results provide experimental evidence for diversity among microbes in the organization of their central carbon metabolic network and CUE under in situ conditions. These results have important implications for our understanding of how community composition affects soil C cycling and organic matter formation.
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Affiliation(s)
- Weichao Wu
- Biogeochemistry of Agroecosystem, University of Goettingen, Goettingen, Germany
- Department of Environmental Science, Stockholm University, Stockholm, Sweden
- Shanghai Engineering Research Center of Hadal Science and Technology, College of Marine Science, Shanghai Ocean University, Shanghai, China
| | - Paul Dijkstra
- Center for Ecosystem Science and Society and Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Bruce A. Hungate
- Center for Ecosystem Science and Society and Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Lingling Shi
- Key Laboratory of Economics Plants and Biotechnology, Institute of Botany, Chinese Academy of Sciences, Kunming, China
- World Agroforestry Centre, China and East-Asia Office, Kunming, China
- Geo-Biosphere Interactions, Department of Geosciences, University of Tuebingen, Tuebingen, Germany
| | - Michaela A. Dippold
- Biogeochemistry of Agroecosystem, University of Goettingen, Goettingen, Germany
- Geo-Biosphere Interactions, Department of Geosciences, University of Tuebingen, Tuebingen, Germany
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4
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Usman M, Shi Z, Dutta N, Ashraf MA, Ishfaq B, El-Din MG. Current challenges of hydrothermal treated wastewater (HTWW) for environmental applications and their perspectives: A review. ENVIRONMENTAL RESEARCH 2022; 212:113532. [PMID: 35618004 DOI: 10.1016/j.envres.2022.113532] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 05/11/2022] [Accepted: 05/18/2022] [Indexed: 06/15/2023]
Abstract
Hydrothermal treatment (HT) is an emerged thermochemical approach for the utilization of biomass. In the last decade, intense research has been conducted on bio-oil and hydrochar, during which extensive amount of hydrothermal treated wastewater (HTWW) is produced, containing large amount of organic compounds along with several toxic chemicals. The composition of HTWW is highly dependent on the process conditions and organic composition of biomass, which determines its further utilization. The current study provides a comprehensive overview of recent advancements in HTWW utilization and its properties which can be changed by varying different parameters like temperature, residence time, solid concentration, mass ratio and catalyst including types of biomasses. HTWW characterization, parameters, reaction mechanism and its application were also summarized. By considering the challenges of HTWW, some suggestions and proposed methodology to overcome the bottleneck are provided.
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Affiliation(s)
- Muhammad Usman
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, AB T6G 2W2, Canada; Bioproducts, Sciences and Engineering Laboratory (BSEL), Washington State University, Tri-Cities, Richland, WA, 99354, United States; Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science and Engineering, Fudan University, Shanghai, 200433, China; Shanghai Technical Service Platform for Pollution Control and Resource Utilization of Organic Wastes, Shanghai, 200438, China.
| | - Zhijian Shi
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science and Engineering, Fudan University, Shanghai, 200433, China; Shanghai Technical Service Platform for Pollution Control and Resource Utilization of Organic Wastes, Shanghai, 200438, China
| | - Nalok Dutta
- Bioproducts, Sciences and Engineering Laboratory (BSEL), Washington State University, Tri-Cities, Richland, WA, 99354, United States
| | - Muhammad Awais Ashraf
- State Key Laboratory of Multiphase Complex Systems, CAS Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, PR China
| | - Bushra Ishfaq
- Food Technology Section, Post-harvest Research Center, Ayub Agricultural Research Institute, Faisalabad, Pakistan
| | - Mohamed Gamal El-Din
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, AB T6G 2W2, Canada.
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5
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Alvarez HM, Hernández MA, Lanfranconi MP, Silva RA, Villalba MS. Rhodococcus as Biofactories for Microbial Oil Production. Molecules 2021; 26:molecules26164871. [PMID: 34443455 PMCID: PMC8401914 DOI: 10.3390/molecules26164871] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 08/05/2021] [Accepted: 08/06/2021] [Indexed: 01/20/2023] Open
Abstract
Bacteria belonging to the Rhodococcus genus are frequent components of microbial communities in diverse natural environments. Some rhodococcal species exhibit the outstanding ability to produce significant amounts of triacylglycerols (TAG) (>20% of cellular dry weight) in the presence of an excess of the carbon source and limitation of the nitrogen source. For this reason, they can be considered as oleaginous microorganisms. As occurs as well in eukaryotic single-cell oil (SCO) producers, these bacteria possess specific physiological properties and molecular mechanisms that differentiate them from other microorganisms unable to synthesize TAG. In this review, we summarized several of the well-characterized molecular mechanisms that enable oleaginous rhodococci to produce significant amounts of SCO. Furthermore, we highlighted the ability of these microorganisms to degrade a wide range of carbon sources coupled to lipogenesis. The qualitative and quantitative oil production by rhodococci from diverse industrial wastes has also been included. Finally, we summarized the genetic and metabolic approaches applied to oleaginous rhodococci to improve SCO production. This review provides a comprehensive and integrating vision on the potential of oleaginous rhodococci to be considered as microbial biofactories for microbial oil production.
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6
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DeLorenzo DM, Diao J, Carr R, Hu Y, Moon TS. An Improved CRISPR Interference Tool to Engineer Rhodococcus opacus. ACS Synth Biol 2021; 10:786-798. [PMID: 33787248 DOI: 10.1021/acssynbio.0c00591] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Rhodococcus opacus is a nonmodel bacterium that is well suited for valorizing lignin. Despite recent advances in our systems-level understanding of its versatile metabolism, studies of its gene functions at a single gene level are still lagging. Elucidating gene functions in nonmodel organisms is challenging due to limited genetic engineering tools that are convenient to use. To address this issue, we developed a simple gene repression system based on CRISPR interference (CRISPRi). This gene repression system uses a T7 RNA polymerase system to express a small guide RNA, demonstrating improved repression compared to the previously demonstrated CRISPRi system (i.e., the maximum repression efficiency improved from 58% to 85%). Additionally, our cloning strategy allows for building multiple CRISPRi plasmids in parallel without any PCR step, facilitating the engineering of this GC-rich organism. Using the improved CRISPRi system, we confirmed the annotated roles of four metabolic pathway genes, which had been identified by our previous transcriptomic analysis to be related to the consumption of benzoate, vanillate, catechol, and acetate. Furthermore, we showed our tool's utility by demonstrating the inducible accumulation of muconate that is a precursor of adipic acid, an important monomer for nylon production. While the maximum muconate yield obtained using our tool was 30% of the yield obtained using gene knockout, our tool showed its inducibility and partial repressibility. Our CRISPRi tool will be useful to facilitate functional studies of this nonmodel organism and engineer this promising microbial chassis for lignin valorization.
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Affiliation(s)
- Drew M. DeLorenzo
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Jinjin Diao
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Rhiannon Carr
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Yifeng Hu
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Tae Seok Moon
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
- Division of Biology and Biomedical Sciences, Washington University in St. Louis, St. Louis, Missouri 63130, United States
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7
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Biological insights into non-model microbial hosts through stable-isotope metabolic flux analysis. Curr Opin Biotechnol 2020; 64:32-38. [DOI: 10.1016/j.copbio.2019.09.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 09/09/2019] [Accepted: 09/10/2019] [Indexed: 12/16/2022]
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8
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Chatterjee A, DeLorenzo DM, Carr R, Moon TS. Bioconversion of renewable feedstocks by Rhodococcus opacus. Curr Opin Biotechnol 2020; 64:10-16. [DOI: 10.1016/j.copbio.2019.08.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 08/19/2019] [Accepted: 08/25/2019] [Indexed: 12/18/2022]
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9
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Sundararaghavan A, Mukherjee A, Suraishkumar GK. Investigating the potential use of an oleaginous bacterium, Rhodococcus opacus PD630, for nano-TiO 2 remediation. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:27394-27406. [PMID: 31493086 DOI: 10.1007/s11356-019-06388-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 08/30/2019] [Indexed: 06/10/2023]
Abstract
The occurrence of titanium dioxide nanoparticles (nTiO2), in the effluents released from wastewater treatment plants, has raised concerns. The fate of nTiO2 and their potential impact on organisms from different ecosystems are widely investigated. For the first time, in this work, we report the responses of an oleaginous bacteria Rhodococcus opacus PD630, belonging to an ecologically important genus Rhodococcus to environmentally relevant concentrations of nTiO2, under dark and UV light conditions. We observed a dose-dependent increase in nTiO2 uptake by the bacteria that reached a maximum of 1.4 mg nTiO2 (g cell)-1 under mid-log UV exposure, corresponding to 97% uptake. The nTiO2 induced oxidative stress in bacteria that increased from 25.1 to a maximum of 100.3, 44.1, and 51.7 μmol .OH (g cell)-1 under dark, continuous, and mid-log UV, respectively. However, nTiO2 did not affect bacterial viability. Further, due to oxidative stress, the triacylglycerol (biodiesel) content from bacteria increased from 30% to a maximum of 54% CDW. Based on our findings, we propose an application of R. opacus PD 630 in nTiO2 remediation due to their high nTiO2 uptake and resistance.
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Affiliation(s)
- Archanaa Sundararaghavan
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences building, Indian Institute of Technology Madras, Chennai, 600036, India
| | - Amitava Mukherjee
- Centre for Nanobiotechnology, VIT University, Vellore, 632014, India
| | - Gadi K Suraishkumar
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences building, Indian Institute of Technology Madras, Chennai, 600036, India.
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10
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Roell GW, Carr RR, Campbell T, Shang Z, Henson WR, Czajka JJ, Martín HG, Zhang F, Foston M, Dantas G, Moon TS, Tang YJ. A concerted systems biology analysis of phenol metabolism in Rhodococcus opacus PD630. Metab Eng 2019; 55:120-130. [DOI: 10.1016/j.ymben.2019.06.013] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 06/19/2019] [Accepted: 06/30/2019] [Indexed: 01/28/2023]
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11
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Long CP, Antoniewicz MR. High-resolution 13C metabolic flux analysis. Nat Protoc 2019; 14:2856-2877. [PMID: 31471597 DOI: 10.1038/s41596-019-0204-0] [Citation(s) in RCA: 113] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Accepted: 06/03/2019] [Indexed: 02/07/2023]
Abstract
Precise quantification of metabolic pathway fluxes in biological systems is of major importance in guiding efforts in metabolic engineering, biotechnology, microbiology, human health, and cell culture. 13C metabolic flux analysis (13C-MFA) is the predominant technique used for determining intracellular fluxes. Here, we present a protocol for 13C-MFA that incorporates recent advances in parallel labeling experiments, isotopic labeling measurements, and statistical analysis, as well as best practices developed through decades of experience. Experimental design to ensure that fluxes are estimated with the highest precision is an integral part of the protocol. The protocol is based on growing microbes in two (or more) parallel cultures with 13C-labeled glucose tracers, followed by gas chromatography-mass spectrometry (GC-MS) measurements of isotopic labeling of protein-bound amino acids, glycogen-bound glucose, and RNA-bound ribose. Fluxes are then estimated using software for 13C-MFA, such as Metran, followed by comprehensive statistical analysis to determine the goodness of fit and calculate confidence intervals of fluxes. The presented protocol can be completed in 4 d and quantifies metabolic fluxes with a standard deviation of ≤2%, a substantial improvement over previous implementations. The presented protocol is exemplified using an Escherichia coli ΔtpiA case study with full supporting data, providing a hands-on opportunity to step through a complex troubleshooting scenario. Although applications to prokaryotic microbial systems are emphasized, this protocol can be easily adjusted for application to eukaryotic organisms.
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Affiliation(s)
- Christopher P Long
- Metabolic Engineering and Systems Biology Laboratory, Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE, USA.,Ginkgo Bioworks, Boston, MA, USA
| | - Maciek R Antoniewicz
- Metabolic Engineering and Systems Biology Laboratory, Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE, USA.
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12
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Abstract
Some species belonging to the Rhodococcus genus, such as Rhodococcus opacus, R. jostii, and R. wratislaviensis, are known to be oleaginous microorganisms, since they are able to accumulate triacylglycerols (TAG) at more than 20% of their weight (dry weight). Oleaginous rhodococci are promising microbial cell factories for the production of lipids to be used as fuels and chemicals. Cells could be engineered to create strains capable of producing high quantities of oils from industrial wastes and a variety of high-value lipids. The comprehensive understanding of carbon metabolism and its regulation will contribute to the design of a reliable process for bacterial oil production. Bacterial oleagenicity requires an integral configuration of metabolism and regulatory processes rather than the sole existence of an efficient lipid biosynthesis pathway. In recent years, several studies have been focused on basic aspects of TAG biosynthesis and accumulation using R. opacus PD630 and R. jostii RHA1 strains as models of oleaginous bacteria. The combination of results obtained in these studies allows us to propose a metabolic landscape for oleaginous rhodococci. In this context, this article provides a comprehensive and integrative view of different metabolic and regulatory attributes and innovations that explain the extraordinary ability of these bacteria to synthesize and accumulate TAG. We hope that the accessibility to such information in an integrated way will help researchers to rationally select new targets for further studies in the field.
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13
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DeLorenzo DM, Moon TS. Construction of Genetic Logic Gates Based on the T7 RNA Polymerase Expression System in Rhodococcus opacus PD630. ACS Synth Biol 2019; 8:1921-1930. [PMID: 31362487 DOI: 10.1021/acssynbio.9b00213] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Rhodococcus opacus PD630 (R. opacus) is a nonmodel, Gram-positive bacterium that holds promise as a biological catalyst for the conversion of lignocellulosic biomass to value-added products. In particular, it demonstrates both a high tolerance for and an ability to consume inhibitory lignin-derived aromatics, generates large quantities of lipids, exhibits a relatively rapid growth rate, and has a growing genetic toolbox for engineering. However, the availability of genetic parts for tunable, high-activity gene expression is still limited in R. opacus. Furthermore, genetic logic circuits for sophisticated gene regulation have never been demonstrated in Rhodococcus spp. To address these shortcomings, two inducible T7 RNA polymerase-based expression systems were implemented for the first time in R. opacus and applied to the construction of AND and NAND genetic logic gates. Additionally, three isopropyl β-d-1-thiogalactopyranoside (IPTG)-inducible promoters were created by inserting LacI binding sites into newly characterized constitutive promoters. Furthermore, four novel aromatic sensors for 4-hydroxybenzoic acid, vanillic acid, sodium benzoate, and guaiacol were developed, expanding the gene expression toolbox. Finally, the T7 RNA polymerase platform was combined with a synthetic IPTG-inducible promoter to create an IMPLY logic gate. Overall, this work represents the first demonstration of a heterologous RNA polymerase system and synthetic genetic logic in R. opacus, enabling complex and tunable gene regulation in this promising nonmodel host for bioproduction.
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Affiliation(s)
- Drew M. DeLorenzo
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Tae Seok Moon
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
- Division of Biology and Biomedical Sciences, Washington University in St. Louis, St. Louis, Missouri 63130, United States
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14
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Javed M, Baghaei-Yazdi N. Nutritional optimization for anaerobic growth ofBacillus steaothermophilusLLD-16. JOURNAL OF RADIATION RESEARCH AND APPLIED SCIENCES 2019. [DOI: 10.1016/j.jrras.2015.12.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Muhammad Javed
- Biotech Consultants Limited (BTCL), 263 Frimley Green Road, Frimley Green, Camberley, Surrey, GU16 6LD, UK
| | - Namdar Baghaei-Yazdi
- Biotech Consultants Limited (BTCL), 263 Frimley Green Road, Frimley Green, Camberley, Surrey, GU16 6LD, UK
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15
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Correia DM, Sargo CR, Silva AJ, Santos ST, Giordano RC, Ferreira EC, Zangirolami TC, Ribeiro MPA, Rocha I. Mapping Salmonella typhimurium pathways using 13C metabolic flux analysis. Metab Eng 2019; 52:303-314. [PMID: 30529284 DOI: 10.1016/j.ymben.2018.11.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 11/26/2018] [Accepted: 11/28/2018] [Indexed: 12/20/2022]
Abstract
In the last years, Salmonella has been extensively studied not only due to its importance as a pathogen, but also as a host to produce pharmaceutical compounds. However, the full exploitation of Salmonella as a platform for bioproduct delivery has been hampered by the lack of information about its metabolism. Genome-scale metabolic models can be valuable tools to delineate metabolic engineering strategies as long as they closely represent the actual metabolism of the target organism. In the present study, a 13C-MFA approach was applied to map the fluxes at the central carbon pathways of S. typhimurium LT2 growing at glucose-limited chemostat cultures. The experiments were carried out in a 2L bioreactor, using defined medium enriched with 20% 13C-labeled glucose. Metabolic flux distributions in central carbon pathways of S. typhimurium LT2 were estimated using OpenFLUX2 based on the labeling pattern of biomass protein hydrolysates together with biomass composition. The results suggested that pentose phosphate is used to catabolize glucose, with minor fluxes through glycolysis. In silico simulations, using Optflux and pFBA as simulation method, allowed to study the performance of the genome-scale metabolic model. In general, the accuracy of in silico simulations was improved by the superimposition of estimated intracellular fluxes to the existing genome-scale metabolic model, showing a better fitting to the experimental extracellular fluxes, whereas the intracellular fluxes of pentose phosphate and anaplerotic reactions were poorly described.
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Affiliation(s)
- Daniela M Correia
- Graduate Program of Chemical Engineering, Federal University of São Carlos, Rodovia Washington Luís, Km 235, São Carlos, SP 13565-905, Brazil
| | - Cintia R Sargo
- Graduate Program of Chemical Engineering, Federal University of São Carlos, Rodovia Washington Luís, Km 235, São Carlos, SP 13565-905, Brazil
| | - Adilson J Silva
- Graduate Program of Chemical Engineering, Federal University of São Carlos, Rodovia Washington Luís, Km 235, São Carlos, SP 13565-905, Brazil
| | - Sophia T Santos
- CEB-Centre of Biological Engineering, University of Minho, Campus De Gualtar, Braga 4710-057, Portugal
| | - Roberto C Giordano
- Graduate Program of Chemical Engineering, Federal University of São Carlos, Rodovia Washington Luís, Km 235, São Carlos, SP 13565-905, Brazil
| | - Eugénio C Ferreira
- CEB-Centre of Biological Engineering, University of Minho, Campus De Gualtar, Braga 4710-057, Portugal
| | - Teresa C Zangirolami
- Graduate Program of Chemical Engineering, Federal University of São Carlos, Rodovia Washington Luís, Km 235, São Carlos, SP 13565-905, Brazil
| | - Marcelo P A Ribeiro
- Graduate Program of Chemical Engineering, Federal University of São Carlos, Rodovia Washington Luís, Km 235, São Carlos, SP 13565-905, Brazil
| | - Isabel Rocha
- CEB-Centre of Biological Engineering, University of Minho, Campus De Gualtar, Braga 4710-057, Portugal; Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB-NOVA), Oeiras, Portugal.
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16
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Anthony WE, Carr RR, DeLorenzo DM, Campbell TP, Shang Z, Foston M, Moon TS, Dantas G. Development of Rhodococcus opacus as a chassis for lignin valorization and bioproduction of high-value compounds. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:192. [PMID: 31404385 PMCID: PMC6683499 DOI: 10.1186/s13068-019-1535-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 07/24/2019] [Indexed: 05/09/2023]
Abstract
The current extraction and use of fossil fuels has been linked to extensive negative health and environmental outcomes. Lignocellulosic biomass-derived biofuels and bioproducts are being actively considered as renewable alternatives to the fuels, chemicals, and materials produced from fossil fuels. A major challenge limiting large-scale, economic deployment of second-generation biorefineries is the insufficient product yield, diversity, and value that current conversion technologies can extract from lignocellulose, in particular from the underutilized lignin fraction. Rhodococcus opacus PD630 is an oleaginous gram-positive bacterium with innate catabolic pathways and tolerance mechanisms for the inhibitory aromatic compounds found in depolymerized lignin, as well as native or engineered pathways for hexose and pentose sugars found in the carbohydrate fractions of biomass. As a result, R. opacus holds potential as a biological chassis for the conversion of lignocellulosic biomass into biodiesel precursors and other value-added products. This review begins by examining the important role that lignin utilization will play in the future of biorefineries and by providing a concise survey of the current lignin conversion technologies. The genetic machinery and capabilities of R. opacus that allow the bacterium to tolerate and metabolize aromatic compounds and depolymerized lignin are also discussed, along with a synopsis of the genetic toolbox and synthetic biology methods now available for engineering this organism. Finally, we summarize the different feedstocks that R. opacus has been demonstrated to consume, and the high-value products that it has been shown to produce. Engineered R. opacus will enable lignin valorization over the coming years, leading to cost-effective conversion of lignocellulose into fuels, chemicals, and materials.
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Affiliation(s)
- Winston E. Anthony
- The Edison Family Center for Genome Sciences and Systems Biology, Washington University in St. Louis School of Medicine, St. Louis, MO 63110 USA
| | - Rhiannon R. Carr
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO 63130 USA
| | - Drew M. DeLorenzo
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO 63130 USA
| | - Tayte P. Campbell
- The Edison Family Center for Genome Sciences and Systems Biology, Washington University in St. Louis School of Medicine, St. Louis, MO 63110 USA
| | - Zeyu Shang
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO 63130 USA
| | - Marcus Foston
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO 63130 USA
| | - Tae Seok Moon
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO 63130 USA
| | - Gautam Dantas
- The Edison Family Center for Genome Sciences and Systems Biology, Washington University in St. Louis School of Medicine, St. Louis, MO 63110 USA
- Department of Pathology and Immunology, Washington University in St. Louis School of Medicine, St. Louis, MO 63108 USA
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130 USA
- Department of Molecular Microbiology, Washington University in St. Louis School of Medicine, St. Louis, MO 63108 USA
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17
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Hollinshead W, He L, Tang YJ. 13C-Fingerprinting and Metabolic Flux Analysis of Bacterial Metabolisms. Methods Mol Biol 2019; 1927:215-230. [PMID: 30788795 DOI: 10.1007/978-1-4939-9142-6_15] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
13C-assisted metabolism analysis provides rigorous calculations of the intracellular reaction rates (i.e., fluxes) within the central metabolism of microbial hosts. This mapping of the intracellular network within microbes has proven to be essential for understanding the cell physiology. The approach is also a key to identifying central metabolic nodes, probing the rigidity of a metabolic network, revealing cofactor balances, and delineating hidden pathways. Here we present the methodology of using stable isotopic carbon substrates for both qualitative (13C-fingerprinting of functional pathways) and quantitative (Metabolic Flux Analysis) metabolism studies on bacterial species. In this methodology, we include step-by-step instructions to use the open source WUflux software for the steady-state flux calculations based on labeling information of amino acids or free metabolites.
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Affiliation(s)
- Whitney Hollinshead
- Department of Energy, Environmental and Chemical Engineering, Washington University, St. Louis, MO, USA
| | - Lian He
- Department of Energy, Environmental and Chemical Engineering, Washington University, St. Louis, MO, USA
| | - Yinjie J Tang
- Department of Energy, Environmental and Chemical Engineering, Washington University, St. Louis, MO, USA.
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18
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Li X, He Y, Zhang L, Xu Z, Ben H, Gaffrey MJ, Yang Y, Yang S, Yuan JS, Qian WJ, Yang B. Discovery of potential pathways for biological conversion of poplar wood into lipids by co-fermentation of Rhodococci strains. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:60. [PMID: 30923568 PMCID: PMC6423811 DOI: 10.1186/s13068-019-1395-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 03/06/2019] [Indexed: 05/23/2023]
Abstract
BACKGROUND Biological routes for utilizing both carbohydrates and lignin are important to reach the ultimate goal of bioconversion of full carbon in biomass into biofuels and biochemicals. Recent biotechnology advances have shown promises toward facilitating biological transformation of lignin into lipids. Natural and engineered Rhodococcus strains (e.g., R. opacus PD630, R. jostii RHA1, and R. jostii RHA1 VanA-) have been demonstrated to utilize lignin for lipid production, and co-culture of them can promote lipid production from lignin. RESULTS In this study, a co-fermentation module of natural and engineered Rhodococcus strains with significant improved lignin degradation and/or lipid biosynthesis capacities was established, which enabled simultaneous conversion of glucose, lignin, and its derivatives into lipids. Although Rhodococci sp. showed preference to glucose over lignin, nearly half of the lignin was quickly depolymerized to monomers by these strains for cell growth and lipid synthesis after glucose was nearly consumed up. Profiles of metabolites produced by Rhodococcus strains growing on different carbon sources (e.g., glucose, alkali lignin, and dilute acid flowthrough-pretreated poplar wood slurry) confirmed lignin conversion during co-fermentation, and indicated novel metabolic capacities and unexplored metabolic pathways in these organisms. Proteome profiles suggested that lignin depolymerization by Rhodococci sp. involved multiple peroxidases with accessory oxidases. Besides the β-ketoadipate pathway, the phenylacetic acid (PAA) pathway was another potential route for the in vivo ring cleavage activity. In addition, deficiency of reducing power and cellular oxidative stress probably led to lower lipid production using lignin as the sole carbon source than that using glucose. CONCLUSIONS This work demonstrated a potential strategy for efficient bioconversion of both lignin and glucose into lipids by co-culture of multiple natural and engineered Rhodococcus strains. In addition, the involvement of PAA pathway in lignin degradation can help to further improve lignin utilization, and the combinatory proteomics and bioinformatics strategies used in this study can also be applied into other systems to reveal the metabolic and regulatory pathways for balanced cellular metabolism and to select genetic targets for efficient conversion of both lignin and carbohydrates into biofuels.
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Affiliation(s)
- Xiaolu Li
- Bioproducts, Sciences and Engineering Laboratory, Department of Biological Systems Engineering, Washington State University, 2710 Crimson Way, Richland, WA 99354 USA
| | - Yucai He
- Bioproducts, Sciences and Engineering Laboratory, Department of Biological Systems Engineering, Washington State University, 2710 Crimson Way, Richland, WA 99354 USA
| | - Libing Zhang
- Bioproducts, Sciences and Engineering Laboratory, Department of Biological Systems Engineering, Washington State University, 2710 Crimson Way, Richland, WA 99354 USA
| | - Zhangyang Xu
- Bioproducts, Sciences and Engineering Laboratory, Department of Biological Systems Engineering, Washington State University, 2710 Crimson Way, Richland, WA 99354 USA
| | - Haoxi Ben
- Bioproducts, Sciences and Engineering Laboratory, Department of Biological Systems Engineering, Washington State University, 2710 Crimson Way, Richland, WA 99354 USA
| | - Matthew J. Gaffrey
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352 USA
| | - Yongfu Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Shihui Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Joshua S. Yuan
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77840 USA
| | - Wei-Jun Qian
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352 USA
| | - Bin Yang
- Bioproducts, Sciences and Engineering Laboratory, Department of Biological Systems Engineering, Washington State University, 2710 Crimson Way, Richland, WA 99354 USA
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352 USA
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19
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Henson WR, Hsu FF, Dantas G, Moon TS, Foston M. Lipid metabolism of phenol-tolerant Rhodococcus opacus strains for lignin bioconversion. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:339. [PMID: 30607174 PMCID: PMC6309088 DOI: 10.1186/s13068-018-1337-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Accepted: 12/11/2018] [Indexed: 06/09/2023]
Abstract
BACKGROUND Lignin is a recalcitrant aromatic polymer that is a potential feedstock for renewable fuel and chemical production. Rhodococcus opacus PD630 is a promising strain for the biological upgrading of lignin due to its ability to tolerate and utilize lignin-derived aromatic compounds. To enhance its aromatic tolerance, we recently applied adaptive evolution using phenol as a sole carbon source and characterized a phenol-adapted R. opacus strain (evol40) and the wild-type (WT) strain by whole genome and RNA sequencing. While this effort increased our understanding of the aromatic tolerance, the tolerance mechanisms were not completely elucidated. RESULTS We hypothesize that the composition of lipids plays an important role in phenol tolerance. To test this hypothesis, we applied high-resolution mass spectrometry analysis to lipid samples obtained from the WT and evol40 strains grown in 1 g/L glucose (glucose), 0.75 g/L phenol (low phenol), or 1.5 g/L phenol (high phenol, evol40 only) as a sole carbon source. This analysis identified > 100 lipid species of mycolic acids, phosphatidylethanolamines (PEs), phosphatidylinositols (PIs), and triacylglycerols. In both strains, mycolic acids had fewer double bond numbers in phenol conditions than the glucose condition, and evol40 had significantly shorter mycolic acid chain lengths than the WT strain in phenol conditions. These results indicate that phenol adaptation affected mycolic acid membrane composition. In addition, the percentage of unsaturated phospholipids decreased for both strains in phenol conditions compared to the glucose condition. Moreover, the PI content increased for both strains in the low phenol condition compared to the glucose condition, and the PI content increased further for evol40 in the high phenol condition relative to the low phenol condition. CONCLUSIONS This work represents the first comprehensive lipidomic study on the membrane of R. opacus grown using phenol as a sole carbon source. Our results suggest that the alteration of the mycolic acid and phospholipid membrane composition may be a strategy of R. opacus for phenol tolerance.
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Affiliation(s)
- William R. Henson
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO 63130 USA
| | - Fong-Fu Hsu
- Mass Spectrometry Resource, Division of Endocrinology, Diabetes, Metabolism, and Lipid Research, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO 63110 USA
| | - Gautam Dantas
- Department of Pathology and Immunology, Washington University in St. Louis School of Medicine, St. Louis, MO 63108 USA
- The Edison Family Center for Genome Sciences and Systems Biology, Washington University in St. Louis School of Medicine, St. Louis, MO 63110 USA
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130 USA
- Department of Molecular Microbiology, Washington University in St. Louis, St. Louis, MO 63108 USA
| | - Tae Seok Moon
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO 63130 USA
| | - Marcus Foston
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO 63130 USA
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20
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Selection of stable reference genes for RT-qPCR in Rhodococcus opacus PD630. Sci Rep 2018; 8:6019. [PMID: 29662144 PMCID: PMC5902447 DOI: 10.1038/s41598-018-24486-w] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 04/04/2018] [Indexed: 01/28/2023] Open
Abstract
Rhodococcus opacus PD630 is a gram-positive bacterium with promising attributes for the conversion of lignin into valuable fuels and chemicals. To develop an organism as a cellular factory, it is necessary to have a deep understanding of its metabolism and any heterologous pathways being expressed. For the purpose of quantifying gene transcription, reverse transcription quantitative PCR (RT-qPCR) is the gold standard due to its sensitivity and reproducibility. However, RT-qPCR requires the use of reference genes whose expression is stable across distinct growth or treatment conditions to normalize the results. Unfortunately, no in-depth analysis of stable reference genes has been conducted in Rhodococcus, inhibiting the utilization of RT-qPCR in R. opacus. In this work, ten candidate reference genes, chosen based on previously collected RNA sequencing data or literature, were examined under four distinct growth conditions using three mathematical programs (BestKeeper, Normfinder, and geNorm). Based on this analysis, the minimum number of reference genes required was found to be two, and two separate pairs of references genes were identified as optimal normalization factors for when ribosomal RNA is either present or depleted. This work represents the first validation of reference genes for Rhodococcus, providing a valuable starting point for future research.
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21
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DeLorenzo DM, Rottinghaus AG, Henson WR, Moon TS. Molecular Toolkit for Gene Expression Control and Genome Modification in Rhodococcus opacus PD630. ACS Synth Biol 2018; 7:727-738. [PMID: 29366319 DOI: 10.1021/acssynbio.7b00416] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Rhodococcus opacus PD630 is a non-model Gram-positive bacterium that possesses desirable traits for lignocellulosic biomass conversion. In particular, it has a relatively rapid growth rate, exhibits genetic tractability, produces high quantities of lipids, and can tolerate and consume toxic lignin-derived aromatic compounds. Despite these unique, industrially relevant characteristics, R. opacus has been underutilized because of a lack of reliable genetic parts and engineering tools. In this work, we developed a molecular toolbox for reliable gene expression control and genome modification in R. opacus. To facilitate predictable gene expression, a constitutive promoter library spanning ∼45-fold in output was constructed. To improve the characterization of available plasmids, the copy numbers of four heterologous and nine endogenous plasmids were determined using quantitative PCR. The molecular toolbox was further expanded by screening a previously unreported antibiotic resistance marker (HygR) and constructing a curable plasmid backbone for temporary gene expression (pB264). Furthermore, a system for genome modification was devised, and three neutral integration sites were identified using a novel combination of transcriptomic data, genomic architecture, and growth rate analysis. Finally, the first reported system for targeted, tunable gene repression in Rhodococcus was developed by utilizing CRISPR interference (CRISPRi). Overall, this work greatly expands the ability to manipulate and engineer R. opacus, making it a viable new chassis for bioproduction from renewable feedstocks.
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Affiliation(s)
- Drew M. DeLorenzo
- Department of Energy, Environmental
and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Austin G. Rottinghaus
- Department of Energy, Environmental
and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - William R. Henson
- Department of Energy, Environmental
and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Tae Seok Moon
- Department of Energy, Environmental
and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
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22
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Yaguchi A, Robinson A, Mihealsick E, Blenner M. Metabolism of aromatics by Trichosporon oleaginosus while remaining oleaginous. Microb Cell Fact 2017; 16:206. [PMID: 29149902 PMCID: PMC5693591 DOI: 10.1186/s12934-017-0820-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 11/11/2017] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND The oleaginous yeast, Trichosporon oleaginosus, has been extensively studied for its ability to metabolize non-conventional feedstocks. These include phenol-containing waste streams, such as distillery wastewater, or streams consisting of non-conventional sugars, such as hydrolyzed biomass and various bagasse. An initial BLAST search suggests this yeast has putative aromatic metabolizing genes. Given the desirability to valorize underutilized feedstocks such as lignin, we investigated the ability of T. oleaginosus to tolerate and metabolize lignin-derived aromatic compounds. RESULTS Trichosporon oleaginosus can tolerate and metabolize model lignin monoaromatics and associated intermediates within funneling pathways. Growth rates and biomass yield were similar to glucose when grown in 4-hydroxybenzoic acid (pHBA) and resorcinol, but had an increased lag phase when grown in phenol. Oleaginous behavior was observed using resorcinol as a sole carbon source. Fed-batch feeding resulted in lipid accumulation of 69.5% on a dry weight basis. CONCLUSIONS Though the exact pathway of aromatic metabolism remains to be determined for T. oleaginosus, the results presented in this work motivate use of this organism for lignin valorization and phenolic wastewater bioremediation. Trichosporon oleaginosus is the first yeast shown to be oleaginous while growing on aromatic substrates, and shows great promise as a model industrial microbe for biochemical and biofuel production from depolymerized lignin.
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Affiliation(s)
- Allison Yaguchi
- Department of Chemical and Biomolecular Engineering, Clemson University, 206 S. Palmetto Blvd., Clemson, SC 29634 USA
| | - Alana Robinson
- Department of Chemical and Biomolecular Engineering, Clemson University, 206 S. Palmetto Blvd., Clemson, SC 29634 USA
| | - Erin Mihealsick
- Department of Chemical and Biomolecular Engineering, Clemson University, 206 S. Palmetto Blvd., Clemson, SC 29634 USA
| | - Mark Blenner
- Department of Chemical and Biomolecular Engineering, Clemson University, 206 S. Palmetto Blvd., Clemson, SC 29634 USA
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23
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DeLorenzo DM, Henson WR, Moon TS. Development of Chemical and Metabolite Sensors for Rhodococcus opacus PD630. ACS Synth Biol 2017; 6:1973-1978. [PMID: 28745867 DOI: 10.1021/acssynbio.7b00192] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Rhodococcus opacus PD630 is a nonmodel, Gram-positive bacterium that possesses desirable traits for biomass conversion, including consumption capabilities for lignocellulose-based sugars and toxic lignin-derived aromatic compounds, significant triacylglycerol accumulation, relatively rapid growth rate, and genetic tractability. However, few genetic elements have been directly characterized in R. opacus, limiting its application for lignocellulose bioconversion. Here, we report the characterization and development of genetic tools for tunable gene expression in R. opacus, including: (1) six fluorescent reporters for quantifying promoter output, (2) three chemically inducible promoters for variable gene expression, and (3) two classes of metabolite sensors derived from native R. opacus promoters that detect nitrogen levels or aromatic compounds. Using these tools, we also provide insights into native aromatic consumption pathways in R. opacus. Overall, this work expands the ability to control and characterize gene expression in R. opacus for future lignocellulose-based fuel and chemical production.
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Affiliation(s)
- Drew M. DeLorenzo
- Department of Energy, Environmental
and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - William R. Henson
- Department of Energy, Environmental
and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Tae Seok Moon
- Department of Energy, Environmental
and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
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24
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Czajka J, Wang Q, Wang Y, Tang YJ. Synthetic biology for manufacturing chemicals: constraints drive the use of non-conventional microbial platforms. Appl Microbiol Biotechnol 2017; 101:7427-7434. [PMID: 28884354 DOI: 10.1007/s00253-017-8489-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 08/16/2017] [Accepted: 08/19/2017] [Indexed: 11/25/2022]
Abstract
Genetically modified microbes have had much industrial success producing protein-based products (such as antibodies and enzymes). However, engineering microbial workhorses for biomanufacturing of commodity compounds remains challenging. First, microbes cannot afford burdens with both overexpression of multiple enzymes and metabolite drainage for product synthesis. Second, synthetic circuits and introduced heterologous pathways are not yet as "robust and reliable" as native pathways due to hosts' innate regulations, especially under suboptimal fermentation conditions. Third, engineered enzymes may lack channeling capabilities for cascade-like transport of metabolites to overcome diffusion barriers or to avoid intermediate toxicity in the cytoplasmic environment. Fourth, moving engineered hosts from laboratory to industry is unreliable because genetic mutations and non-genetic cell-to-cell variations impair the large-scale fermentation outcomes. Therefore, synthetic biology strains often have unsatisfactory industrial performance (titer/yield/productivity). To overcome these problems, many different species are being explored for their metabolic strengths that can be leveraged to synthesize specific compounds. Here, we provide examples of non-conventional and genetically amenable species for industrial manufacturing, including the following: Corynebacterium glutamicum for its TCA cycle-derived biosynthesis, Yarrowia lipolytica for its biosynthesis of fatty acids and carotenoids, cyanobacteria for photosynthetic production from its sugar phosphate pathways, and Rhodococcus for its ability to biotransform recalcitrant feedstock. Finally, we discuss emerging technologies (e.g., genome-to-phenome mapping, single cell methods, and knowledge engineering) that may facilitate the development of novel cell factories.
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Affiliation(s)
- Jeffrey Czajka
- Department of Energy, Environmental and Chemical Engineering, Washington University, Saint Louis, MO, 63130, USA
| | - Qinhong Wang
- CAS Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences (CAS), Tianjin, 300308, China
| | - Yechun Wang
- Arch Innotek, LLC, 4320 Forest Park Ave, St Louis, MO, 63108, USA.
| | - Yinjie J Tang
- Department of Energy, Environmental and Chemical Engineering, Washington University, Saint Louis, MO, 63130, USA.
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25
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Chen Z, Wan C. Co-fermentation of lignocellulose-based glucose and inhibitory compounds for lipid synthesis by Rhodococcus jostii RHA1. Process Biochem 2017. [DOI: 10.1016/j.procbio.2017.03.023] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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26
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Wan N, DeLorenzo DM, He L, You L, Immethun CM, Wang G, Baidoo EEK, Hollinshead W, Keasling JD, Moon TS, Tang YJ. Cyanobacterial carbon metabolism: Fluxome plasticity and oxygen dependence. Biotechnol Bioeng 2017; 114:1593-1602. [DOI: 10.1002/bit.26287] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 12/21/2016] [Accepted: 03/06/2017] [Indexed: 01/19/2023]
Affiliation(s)
- Ni Wan
- Department of Energy, Environmental and Chemical EngineeringWashington University in St. LouisSt. LouisMissouri 63130
| | - Drew M. DeLorenzo
- Department of Energy, Environmental and Chemical EngineeringWashington University in St. LouisSt. LouisMissouri 63130
| | - Lian He
- Department of Energy, Environmental and Chemical EngineeringWashington University in St. LouisSt. LouisMissouri 63130
| | - Le You
- Department of Energy, Environmental and Chemical EngineeringWashington University in St. LouisSt. LouisMissouri 63130
| | - Cheryl M. Immethun
- Department of Energy, Environmental and Chemical EngineeringWashington University in St. LouisSt. LouisMissouri 63130
| | - George Wang
- Joint Bio‐Energy InstituteEmeryvilleCalifornia
- Biological Systems and Engineering DivisionLawrence Berkeley National LaboratoryBerkeleyCalifornia
| | - Edward E. K. Baidoo
- Joint Bio‐Energy InstituteEmeryvilleCalifornia
- Biological Systems and Engineering DivisionLawrence Berkeley National LaboratoryBerkeleyCalifornia
| | - Whitney Hollinshead
- Department of Energy, Environmental and Chemical EngineeringWashington University in St. LouisSt. LouisMissouri 63130
| | - Jay D. Keasling
- Joint Bio‐Energy InstituteEmeryvilleCalifornia
- Biological Systems and Engineering DivisionLawrence Berkeley National LaboratoryBerkeleyCalifornia
- California Institute of Quantitative Biosciences (QB3)University of CaliforniaBerkeleyCalifornia
- Department of BioengineeringUniversity of CaliforniaBerkeleyCalifornia
- Department of Chemical and Biomolecular EngineeringUniversity of CaliforniaBerkeleyCalifornia
| | - Tae Seok Moon
- Department of Energy, Environmental and Chemical EngineeringWashington University in St. LouisSt. LouisMissouri 63130
| | - Yinjie J. Tang
- Department of Energy, Environmental and Chemical EngineeringWashington University in St. LouisSt. LouisMissouri 63130
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Guo W, Sheng J, Feng X. Synergizing 13C Metabolic Flux Analysis and Metabolic Engineering for Biochemical Production. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2017; 162:265-299. [PMID: 28424826 DOI: 10.1007/10_2017_2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Metabolic engineering of industrial microorganisms to produce chemicals, fuels, and drugs has attracted increasing interest as it provides an environment-friendly and renewable route that does not depend on depleting petroleum sources. However, the microbial metabolism is so complex that metabolic engineering efforts often have difficulty in achieving a satisfactory yield, titer, or productivity of the target chemical. To overcome this challenge, 13C Metabolic Flux Analysis (13C-MFA) has been developed to investigate rigorously the cell metabolism and quantify the carbon flux distribution in central metabolic pathways. In the past decade, 13C-MFA has been widely used in academic labs and the biotechnology industry to pinpoint the key issues related to microbial-based chemical production and to guide the development of the appropriate metabolic engineering strategies for improving the biochemical production. In this chapter we introduce the basics of 13C-MFA and illustrate how 13C-MFA has been applied to synergize with metabolic engineering to identify and tackle the rate-limiting steps in biochemical production.
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Affiliation(s)
- Weihua Guo
- Department of Biological Systems Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA
| | - Jiayuan Sheng
- Department of Biological Systems Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA
| | - Xueyang Feng
- Department of Biological Systems Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA.
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28
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He Y, Li X, Xue X, Swita MS, Schmidt AJ, Yang B. Biological conversion of the aqueous wastes from hydrothermal liquefaction of algae and pine wood by Rhodococci. BIORESOURCE TECHNOLOGY 2017; 224:457-464. [PMID: 27806887 DOI: 10.1016/j.biortech.2016.10.059] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 10/10/2016] [Accepted: 10/19/2016] [Indexed: 05/10/2023]
Abstract
In this study, R. opacus PD630, R. jostii RHA1, R. jostii RHA1 VanA-, and their co-culture were employed to convert hydrothermal liquefaction aqueous waste (HTLAW) into lipids. After 11days, the COD reduction of algal-HTLAW reached 93.4% and 92.7% by R. jostii RHA1 and its mutant VanA-, respectively. Woody-HTLAW promoted lipid accumulation of 0.43glipid/gcell dry weight in R. opacus PD630 cells. Additionally, the total number of chemicals in HTLAW decreased by over 1/3 after 7days of coculture, and 0.10g/L and 0.46g/L lipids were incrementally accumulated in the cellular mass during the fermentation of wood- and algal-HTLAW, respectively. The GC-MS data supported that different metabolism pathways were followed when these Rhodococci strains degraded algae- and woody-HTLAW. These results indicated promising potential of bioconversion of under-utilized carbon and toxic compounds in HTLAW into useful products by selected Rhodococci.
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Affiliation(s)
- Yucai He
- Bioproducts, Sciences and Engineering Laboratory and Department of Biological Systems Engineering, Washington State University, Richland, WA 99354, United States
| | - Xiaolu Li
- Bioproducts, Sciences and Engineering Laboratory and Department of Biological Systems Engineering, Washington State University, Richland, WA 99354, United States
| | - Xiaoyun Xue
- Bioproducts, Sciences and Engineering Laboratory and Department of Biological Systems Engineering, Washington State University, Richland, WA 99354, United States
| | - Marie S Swita
- Energy and Efficiency Division and the Bioproduct Sciences and Engineering Laboratory, Pacific Northwest National Laboratory, Richland, WA 99354, United States
| | - Andrew J Schmidt
- Energy and Efficiency Division and the Bioproduct Sciences and Engineering Laboratory, Pacific Northwest National Laboratory, Richland, WA 99354, United States
| | - Bin Yang
- Bioproducts, Sciences and Engineering Laboratory and Department of Biological Systems Engineering, Washington State University, Richland, WA 99354, United States.
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29
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Qi H, Lv M, Song K, Wen J. Integration of parallel13C-labeling experiments and in silico pathway analysis for enhanced production of ascomycin. Biotechnol Bioeng 2016; 114:1036-1044. [DOI: 10.1002/bit.26223] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 11/06/2016] [Accepted: 11/16/2016] [Indexed: 12/20/2022]
Affiliation(s)
- Haishan Qi
- Key Laboratory of Systems Bioengineering (Ministry of Education); Tianjin University; Tianjin 300072 People's Republic of China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin); School of Chemical Engineering and Technology, Tianjin University; Tianjin People's Republic of China
| | - Mengmeng Lv
- Key Laboratory of Systems Bioengineering (Ministry of Education); Tianjin University; Tianjin 300072 People's Republic of China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin); School of Chemical Engineering and Technology, Tianjin University; Tianjin People's Republic of China
| | - Kejing Song
- Key Laboratory of Systems Bioengineering (Ministry of Education); Tianjin University; Tianjin 300072 People's Republic of China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin); School of Chemical Engineering and Technology, Tianjin University; Tianjin People's Republic of China
| | - Jianping Wen
- Key Laboratory of Systems Bioengineering (Ministry of Education); Tianjin University; Tianjin 300072 People's Republic of China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin); School of Chemical Engineering and Technology, Tianjin University; Tianjin People's Republic of China
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Recent applications of metabolomics to advance microbial biofuel production. Curr Opin Biotechnol 2016; 43:118-126. [PMID: 27883952 DOI: 10.1016/j.copbio.2016.11.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 10/31/2016] [Accepted: 11/01/2016] [Indexed: 12/26/2022]
Abstract
Biofuel production from plant biomass is a promising source of renewable energy [1]. However, efficient biofuel production involves the complex task of engineering high-performance microorganisms, which requires detailed knowledge of metabolic function and regulation. This review highlights the potential of mass-spectrometry-based metabolomic analysis to guide rational engineering of biofuel-producing microbes. We discuss recent studies that apply knowledge gained from metabolomic analyses to increase the productivity of engineered pathways, characterize the metabolism of emerging biofuel producers, generate novel bioproducts, enable utilization of lignocellulosic feedstock, and improve the stress tolerance of biofuel producers.
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31
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Recent advances in high-throughput 13C-fluxomics. Curr Opin Biotechnol 2016; 43:104-109. [PMID: 27838571 DOI: 10.1016/j.copbio.2016.10.010] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 10/21/2016] [Accepted: 10/25/2016] [Indexed: 12/11/2022]
Abstract
The rise of high throughput (HT) strain engineering tools accompanying the area of synthetic biology is supporting the generation of a large number of microbial cell factories. A current bottleneck in process development is our limited capacity to rapidly analyze the metabolic state of the engineered strains, and in particular their intracellular fluxes. HT 13C-fluxomics workflows have not yet become commonplace, despite the existence of several HT tools at each of the required stages. This includes cultivation and sampling systems, analytics for isotopic analysis, and software for data processing and flux calculation. Here, we review recent advances in the field and highlight bottlenecks that must be overcome to allow the emergence of true HT 13C-fluxomics workflows.
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He L, Wu SG, Zhang M, Chen Y, Tang YJ. WUFlux: an open-source platform for 13C metabolic flux analysis of bacterial metabolism. BMC Bioinformatics 2016; 17:444. [PMID: 27814681 PMCID: PMC5096001 DOI: 10.1186/s12859-016-1314-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2016] [Accepted: 10/26/2016] [Indexed: 12/21/2022] Open
Abstract
Background Flux analyses, including flux balance analysis (FBA) and 13C-metabolic flux analysis (13C-MFA), offer direct insights into cell metabolism, and have been widely used to characterize model and non-model microbial species. Nonetheless, constructing the 13C-MFA model and performing flux calculation are demanding for new learners, because they require knowledge of metabolic networks, carbon transitions, and computer programming. To facilitate and standardize the 13C-MFA modeling work, we set out to publish a user-friendly and programming-free platform (WUFlux) for flux calculations in MATLAB®. Results We constructed an open-source platform for steady-state 13C-MFA. Using GUIDE (graphical user interface design environment) in MATLAB, we built a user interface that allows users to modify models based on their own experimental conditions. WUFlux is capable of directly correcting mass spectrum data of TBDMS (N-tert-butyldimethylsilyl-N-methyltrifluoroacetamide)-derivatized proteinogenic amino acids by removing background noise. To simplify 13C-MFA of different prokaryotic species, the software provides several metabolic network templates, including those for chemoheterotrophic bacteria and mixotrophic cyanobacteria. Users can modify the network and constraints, and then analyze the microbial carbon and energy metabolisms of various carbon substrates (e.g., glucose, pyruvate/lactate, acetate, xylose, and glycerol). WUFlux also offers several ways of visualizing the flux results with respect to the constructed network. To validate our model’s applicability, we have compared and discussed the flux results obtained from WUFlux and other MFA software. We have also illustrated how model constraints of cofactor and ATP balances influence fluxome results. Conclusion Open-source software for 13C-MFA, WUFlux, with a user-friendly interface and easy-to-modify templates, is now available at http://www.13cmfa.org/or (http://tang.eece.wustl.edu/ToolDevelopment.htm). We will continue documenting curated models of non-model microbial species and improving WUFlux performance. Electronic supplementary material The online version of this article (doi:10.1186/s12859-016-1314-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Lian He
- Department of Energy, Environmental and Chemical Engineering, Washington University, St. Louis, MO, 63130, USA.
| | - Stephen G Wu
- Department of Energy, Environmental and Chemical Engineering, Washington University, St. Louis, MO, 63130, USA
| | - Muhan Zhang
- Department of Computer Science and Engineering, Washington University, St. Louis, MO, 63130, USA
| | - Yixin Chen
- Department of Computer Science and Engineering, Washington University, St. Louis, MO, 63130, USA
| | - Yinjie J Tang
- Department of Energy, Environmental and Chemical Engineering, Washington University, St. Louis, MO, 63130, USA.
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Xiong X, Lian J, Yu X, Garcia-Perez M, Chen S. Engineering levoglucosan metabolic pathway in Rhodococcus jostii RHA1 for lipid production. J Ind Microbiol Biotechnol 2016; 43:1551-1560. [PMID: 27558782 DOI: 10.1007/s10295-016-1832-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 08/15/2016] [Indexed: 11/28/2022]
Abstract
Oleaginous strains of Rhodococcus including R. jostii RHA1 have attracted considerable attention due to their ability to accumulate triacylglycerols (TAGs), robust growth properties and genetic tractability. In this study, a novel metabolic pathway was introduced into R. jostii by heterogenous expression of the well-characterized gene, lgk encoding levoglucosan kinase from Lipomyces starkeyi YZ-215. This enables the recombinant R. jostii RHA1 to produce TAGs from the anhydrous sugar, levoglucosan, which can be generated efficiently as the major molecule from the pyrolysis of cellulose. The recombinant R. jostii RHA1 could grow on levoglucosan as the sole carbon source, and the consumption rate of levoglucosan was determined. Furthermore, expression of one more copy of lgk increased the enzymatic activity of LGK in the recombinant. However, the growth performance of the recombinant bearing two copies of lgk on levoglucosan was not improved. Although expression of lgk in the recombinants was not repressed by the glucose present in the media, glucose in the sugar mixture still affected consumption of levoglucosan. Under nitrogen limiting conditions, lipid produced from levoglucosan by the recombinant bearing lgk was up to 43.54 % of the cell dry weight, which was comparable to the content of lipid accumulated from glucose. This work demonstrated the technical feasibility of producing lipid from levoglucosan, an anhydrosugar derived from the pyrolysis of lignocellulosic materials, by the genetically modified rhodococci strains.
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Affiliation(s)
- Xiaochao Xiong
- Department of Biological Systems Engineering, Washington State University, L. J. Smith Hall, P.O. Box 646120, Pullman, WA, 99164-6120, USA
| | - Jieni Lian
- Department of Biological Systems Engineering, Washington State University, L. J. Smith Hall, P.O. Box 646120, Pullman, WA, 99164-6120, USA.,Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, 50011, USA
| | - Xiaochen Yu
- Department of Biological Systems Engineering, Washington State University, L. J. Smith Hall, P.O. Box 646120, Pullman, WA, 99164-6120, USA.,Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA, 50011, USA
| | - Manuel Garcia-Perez
- Department of Biological Systems Engineering, Washington State University, L. J. Smith Hall, P.O. Box 646120, Pullman, WA, 99164-6120, USA
| | - Shulin Chen
- Department of Biological Systems Engineering, Washington State University, L. J. Smith Hall, P.O. Box 646120, Pullman, WA, 99164-6120, USA.
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34
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Current state and challenges for dynamic metabolic modeling. Curr Opin Microbiol 2016; 33:97-104. [PMID: 27472025 DOI: 10.1016/j.mib.2016.07.008] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Revised: 06/28/2016] [Accepted: 07/06/2016] [Indexed: 01/06/2023]
Abstract
While the stoichiometry of metabolism is probably the best studied cellular level, the dynamics in metabolism can still not be well described, predicted and, thus, engineered. Unknowns in the metabolic flux behavior arise from kinetic interactions, especially allosteric control mechanisms. While the stoichiometry of enzymes is preserved in vitro, their activity and kinetic behavior differs from the in vivo situation. Next to this challenge, it is infeasible to test the interaction of each enzyme with each intracellular metabolite in vitro exhaustively. As a consequence, the whole interacting metabolome has to be studied in vivo to identify the relevant enzymes properties. In this review we discuss current approaches for in vivo perturbation experiments, that is, stimulus response experiments using different setups and quantitative analytical approaches, including dynamic carbon tracing. Next to reliable and informative data, advanced modeling approaches and computational tools are required to identify kinetic mechanisms and their parameters.
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35
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Optimal tracers for parallel labeling experiments and 13C metabolic flux analysis: A new precision and synergy scoring system. Metab Eng 2016; 38:10-18. [PMID: 27267409 DOI: 10.1016/j.ymben.2016.06.001] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 06/01/2016] [Accepted: 06/03/2016] [Indexed: 12/11/2022]
Abstract
13C-Metabolic flux analysis (13C-MFA) is a widely used approach in metabolic engineering for quantifying intracellular metabolic fluxes. The precision of fluxes determined by 13C-MFA depends largely on the choice of isotopic tracers and the specific set of labeling measurements. A recent advance in the field is the use of parallel labeling experiments for improved flux precision and accuracy. However, as of today, no systemic methods exist for identifying optimal tracers for parallel labeling experiments. In this contribution, we have addressed this problem by introducing a new scoring system and evaluating thousands of different isotopic tracer schemes. Based on this extensive analysis we have identified optimal tracers for 13C-MFA. The best single tracers were doubly 13C-labeled glucose tracers, including [1,6-13C]glucose, [5,6-13C]glucose and [1,2-13C]glucose, which consistently produced the highest flux precision independent of the metabolic flux map (here, 100 random flux maps were evaluated). Moreover, we demonstrate that pure glucose tracers perform better overall than mixtures of glucose tracers. For parallel labeling experiments the optimal isotopic tracers were [1,6-13C]glucose and [1,2-13C]glucose. Combined analysis of [1,6-13C]glucose and [1,2-13C]glucose labeling data improved the flux precision score by nearly 20-fold compared to widely use tracer mixture 80% [1-13C]glucose +20% [U-13C]glucose.
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36
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Cereijo AE, Asencion Diez MD, Dávila Costa JS, Alvarez HM, Iglesias AA. On the Kinetic and Allosteric Regulatory Properties of the ADP-Glucose Pyrophosphorylase from Rhodococcus jostii: An Approach to Evaluate Glycogen Metabolism in Oleaginous Bacteria. Front Microbiol 2016; 7:830. [PMID: 27313571 PMCID: PMC4890535 DOI: 10.3389/fmicb.2016.00830] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 05/17/2016] [Indexed: 01/29/2023] Open
Abstract
Rhodococcus spp. are oleaginous bacteria that accumulate glycogen during exponential growth. Despite the importance of these microorganisms in biotechnology, little is known about the regulation of carbon and energy storage, mainly the relationship between glycogen and triacylglycerols metabolisms. Herein, we report the molecular cloning and heterologous expression of the gene coding for ADP-glucose pyrophosphorylase (EC 2.7.7.27) of Rhodococcus jostii, strain RHA1. The recombinant enzyme was purified to electrophoretic homogeneity to accurately characterize its oligomeric, kinetic, and regulatory properties. The R. jostii ADP-glucose pyrophosphorylase is a homotetramer of 190 kDa exhibiting low basal activity to catalyze synthesis of ADP-glucose, which is markedly influenced by different allosteric effectors. Glucose-6P, mannose-6P, fructose-6P, ribose-5P, and phosphoenolpyruvate were major activators; whereas, NADPH and 6P-gluconate behaved as main inhibitors of the enzyme. The combination of glucose-6P and other effectors (activators or inhibitors) showed a cross-talk effect suggesting that the different metabolites could orchestrate a fine regulation of ADP-glucose pyrophosphorylase in R. jostii. The enzyme exhibited some degree of affinity toward ATP, GTP, CTP, and other sugar-1P substrates. Remarkably, the use of glucosamine-1P was sensitive to allosteric activation. The relevance of the fine regulation of R. jostii ADP-glucose pyrophosphorylase is further analyzed in the framework of proteomic studies already determined for the bacterium. Results support a critical role for glycogen as a temporal reserve that provides a pool of carbon able of be re-routed to produce long-term storage of lipids under certain conditions.
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Affiliation(s)
- Antonela E Cereijo
- Laboratorio de Enzimología Molecular, Instituto de Agrobiotecnología del Litoral, CONICET, Centro Científico Tecnológico, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral Santa Fe, Argentina
| | - Matías D Asencion Diez
- Laboratorio de Enzimología Molecular, Instituto de Agrobiotecnología del Litoral, CONICET, Centro Científico Tecnológico, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral Santa Fe, Argentina
| | - José S Dávila Costa
- Centro Regional de Investigación y Desarrollo Científico Tecnológico, Facultad de Ciencias Naturales Universidad Nacional de la Patagonia San Juan Bosco Comodoro Rivadavia, Argentina
| | - Héctor M Alvarez
- Centro Regional de Investigación y Desarrollo Científico Tecnológico, Facultad de Ciencias Naturales Universidad Nacional de la Patagonia San Juan Bosco Comodoro Rivadavia, Argentina
| | - Alberto A Iglesias
- Laboratorio de Enzimología Molecular, Instituto de Agrobiotecnología del Litoral, CONICET, Centro Científico Tecnológico, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral Santa Fe, Argentina
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Xiong X, Wang X, Chen S. Engineering of an L-arabinose metabolic pathway in Rhodococcus jostii RHA1 for biofuel production. J Ind Microbiol Biotechnol 2016; 43:1017-25. [PMID: 27143134 DOI: 10.1007/s10295-016-1778-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Accepted: 04/11/2016] [Indexed: 01/17/2023]
Abstract
The oleaginous bacterium, Rhodococcus jostii RHA1 has attracted considerable attention due to its capability to accumulate significant levels of triacylglycerol as renewable hydrocarbon. To enable the strain to utilize arabinose derived from lignocellulosic biomass, the metabolic pathway of L-arabinose utilization was introduced into R. jostii RHA1 by heterogenous expression of the operon, araBAD from Escherichia coli. The results showed that recombinant bearing araBAD could grow on L-arabinose as the sole carbon source, and additional expression of araFGH encoding the arabinose transporter from E. coli could improve the cell biomass yield from high contents of arabinose. We further increased the content of lipid produced from arabinose in the recombinants from 47.9 to 56.8 % of the cell dry weight (CDW) by overexpression of a gene, atf1 encoding a diglyceride acyltransferase from R. opacus PD630. This work demonstrated the feasibility of producing lipid from arabinose by genetic modification of the rhodococci strain.
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Affiliation(s)
- Xiaochao Xiong
- Department of Biological Systems Engineering, Washington State University, L.J. Smith Hall, P.O. Box 646120, Pullman, WA, 99164-6120, USA
| | - Xi Wang
- Department of Biological Systems Engineering, Washington State University, L.J. Smith Hall, P.O. Box 646120, Pullman, WA, 99164-6120, USA
| | - Shulin Chen
- Department of Biological Systems Engineering, Washington State University, L.J. Smith Hall, P.O. Box 646120, Pullman, WA, 99164-6120, USA.
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Croyal M, Bourgeois R, Ouguerram K, Billon-Crossouard S, Aguesse A, Nguyen P, Krempf M, Ferchaud-Roucher V, Nobécourt E. Comparison of gas chromatography-mass spectrometry and gas chromatography-combustion-isotope ratio mass spectrometry analysis for in vivo estimates of metabolic fluxes. Anal Biochem 2016; 500:63-5. [PMID: 26898306 DOI: 10.1016/j.ab.2016.02.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 12/31/2015] [Accepted: 02/04/2016] [Indexed: 12/11/2022]
Abstract
Gas chromatography-mass spectrometry (GC-MS) was compared with gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) for measurements of cholesterol (13)C enrichment after infusion of labeled precursor ([(13)C1,2]acetate). Paired results were significantly correlated, although GC-MS was less accurate than GC-C-IRMS for higher enrichments. Nevertheless, only GC-MS was able to provide information on isotopologue distribution, bringing new insights to lipid metabolism. Therefore, we assessed the isotopologue distribution of cholesterol in humans and dogs known to present contrasted cholesterol metabolic pathways. The labeled tracer incorporation was different in both species, highlighting the subsidiarity of GC-MS and GC-C-IRMS to analyze in vivo stable isotope studies.
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Affiliation(s)
- Mikaël Croyal
- INRA, UMR 1280, Physiologie des Adaptations Nutritionnelles, CHU Hôtel-Dieu, F-44000 Nantes, France; CRNH, Human Nutrition Research Center, CHU Hôtel-Dieu, F-44093 Nantes, France
| | - Raphaëlle Bourgeois
- INRA, UMR 1280, Physiologie des Adaptations Nutritionnelles, CHU Hôtel-Dieu, F-44000 Nantes, France; CRNH, Human Nutrition Research Center, CHU Hôtel-Dieu, F-44093 Nantes, France
| | - Khadija Ouguerram
- INRA, UMR 1280, Physiologie des Adaptations Nutritionnelles, CHU Hôtel-Dieu, F-44000 Nantes, France; CRNH, Human Nutrition Research Center, CHU Hôtel-Dieu, F-44093 Nantes, France
| | - Stéphanie Billon-Crossouard
- INRA, UMR 1280, Physiologie des Adaptations Nutritionnelles, CHU Hôtel-Dieu, F-44000 Nantes, France; CRNH, Human Nutrition Research Center, CHU Hôtel-Dieu, F-44093 Nantes, France
| | - Audrey Aguesse
- INRA, UMR 1280, Physiologie des Adaptations Nutritionnelles, CHU Hôtel-Dieu, F-44000 Nantes, France; CRNH, Human Nutrition Research Center, CHU Hôtel-Dieu, F-44093 Nantes, France
| | - Patrick Nguyen
- CRNH, Human Nutrition Research Center, CHU Hôtel-Dieu, F-44093 Nantes, France; Oniris, National College of Veterinary Medicine, Food Science, and Engineering, Nutrition and Endocrinology Unit, F-44307 Nantes, France
| | - Michel Krempf
- INRA, UMR 1280, Physiologie des Adaptations Nutritionnelles, CHU Hôtel-Dieu, F-44000 Nantes, France; CRNH, Human Nutrition Research Center, CHU Hôtel-Dieu, F-44093 Nantes, France; Endocrinology, G and R Laennec Hospital, F-44093 Nantes, France.
| | - Véronique Ferchaud-Roucher
- INRA, UMR 1280, Physiologie des Adaptations Nutritionnelles, CHU Hôtel-Dieu, F-44000 Nantes, France; CRNH, Human Nutrition Research Center, CHU Hôtel-Dieu, F-44093 Nantes, France
| | - Estelle Nobécourt
- INRA, UMR 1280, Physiologie des Adaptations Nutritionnelles, CHU Hôtel-Dieu, F-44000 Nantes, France; CRNH, Human Nutrition Research Center, CHU Hôtel-Dieu, F-44093 Nantes, France; Endocrinology, G and R Laennec Hospital, F-44093 Nantes, France
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Yoneda A, Henson WR, Goldner NK, Park KJ, Forsberg KJ, Kim SJ, Pesesky MW, Foston M, Dantas G, Moon TS. Comparative transcriptomics elucidates adaptive phenol tolerance and utilization in lipid-accumulating Rhodococcus opacus PD630. Nucleic Acids Res 2016; 44:2240-54. [PMID: 26837573 PMCID: PMC4797299 DOI: 10.1093/nar/gkw055] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 01/20/2016] [Indexed: 12/29/2022] Open
Abstract
Lignin-derived (e.g. phenolic) compounds can compromise the bioconversion of lignocellulosic biomass to fuels and chemicals due to their toxicity and recalcitrance. The lipid-accumulating bacterium Rhodococcus opacus PD630 has recently emerged as a promising microbial host for lignocellulose conversion to value-added products due to its natural ability to tolerate and utilize phenolics. To gain a better understanding of its phenolic tolerance and utilization mechanisms, we adaptively evolved R. opacus over 40 passages using phenol as its sole carbon source (up to 373% growth improvement over wild-type), and extensively characterized two strains from passages 33 and 40. The two adapted strains showed higher phenol consumption rates (∼20 mg/l/h) and ∼2-fold higher lipid production from phenol than the wild-type strain. Whole-genome sequencing and comparative transcriptomics identified highly-upregulated degradation pathways and putative transporters for phenol in both adapted strains, highlighting the important linkage between mechanisms of regulated phenol uptake, utilization, and evolved tolerance. Our study shows that the R. opacus mutants are likely to use their transporters to import phenol rather than export them, suggesting a new aromatic tolerance mechanism. The identified tolerance genes and pathways are promising candidates for future metabolic engineering in R. opacus for improved lignin conversion to lipid-based products.
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Affiliation(s)
- Aki Yoneda
- Department of Pathology & Immunology, Washington University in St. Louis School of Medicine, St. Louis, MO 63108, USA Center for Genome Sciences & Systems Biology, Washington University in St. Louis School of Medicine, St. Louis, MO 63108, USA
| | - William R Henson
- Department of Energy, Environmental & Chemical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Nicholas K Goldner
- Center for Genome Sciences & Systems Biology, Washington University in St. Louis School of Medicine, St. Louis, MO 63108, USA
| | - Kun Joo Park
- Department of Energy, Environmental & Chemical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Kevin J Forsberg
- Center for Genome Sciences & Systems Biology, Washington University in St. Louis School of Medicine, St. Louis, MO 63108, USA
| | - Soo Ji Kim
- Department of Energy, Environmental & Chemical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Mitchell W Pesesky
- Center for Genome Sciences & Systems Biology, Washington University in St. Louis School of Medicine, St. Louis, MO 63108, USA
| | - Marcus Foston
- Department of Energy, Environmental & Chemical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Gautam Dantas
- Department of Pathology & Immunology, Washington University in St. Louis School of Medicine, St. Louis, MO 63108, USA Center for Genome Sciences & Systems Biology, Washington University in St. Louis School of Medicine, St. Louis, MO 63108, USA Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA Department of Molecular Microbiology, Washington University in St. Louis School of Medicine, St. Louis, MO 63108, USA
| | - Tae Seok Moon
- Department of Energy, Environmental & Chemical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
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Yao R, Xiong D, Hu H, Wakayama M, Yu W, Zhang X, Shimizu K. Elucidation of the co-metabolism of glycerol and glucose in Escherichia coli by genetic engineering, transcription profiling, and (13)C metabolic flux analysis. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:175. [PMID: 27555881 PMCID: PMC4994220 DOI: 10.1186/s13068-016-0591-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 08/15/2016] [Indexed: 05/21/2023]
Abstract
BACKGROUND Glycerol, a byproduct of biodiesel, has become a readily available and inexpensive carbon source for the production of high-value products. However, the main drawback of glycerol utilization is the low consumption rate and shortage of NADPH formation, which may limit the production of NADPH-requiring products. To overcome these problems, we constructed a carbon catabolite repression-negative ΔptsGglpK* mutant by both blocking a key glucose PTS transporter and enhancing the glycerol conversion. The mutant can recover normal growth by co-utilization of glycerol and glucose after loss of glucose PTS transporter. To reveal the metabolic potential of the ΔptsGglpK* mutant, this study examined the flux distributions and regulation of the co-metabolism of glycerol and glucose in the mutant. RESULTS By labeling experiments using [1,3-(13)C]glycerol and [1-(13)C]glucose, (13)C metabolic flux analysis was employed to decipher the metabolisms of both the wild-type strain and the ΔptsGglpK* mutant in chemostat cultures. When cells were maintained at a low dilution rate (0.1 h(-1)), the two strains showed similar fluxome profiles. When the dilution rate was increased, both strains upgraded their pentose phosphate pathway, glycolysis and anaplerotic reactions, while the ΔptsGglpK* mutant was able to catabolize much more glycerol than glucose (more than tenfold higher). Compared with the wild-type strain, the mutant repressed its flux through the TCA cycle, resulting in higher acetate overflow. The regulation of fluxomes was consistent with transcriptional profiling of several key genes relevant to the TCA cycle and transhydrogenase, namely gltA, icdA, sdhA and pntA. In addition, cofactor fluxes and their pool sizes were determined. The ΔptsGglpK* mutant affected the redox NADPH/NADH state and reduced the ATP level. Redox signaling activated the ArcA regulatory system, which was responsible for TCA cycle repression. CONCLUSIONS This work employs both (13)C-MFA and transcription/metabolite analysis for quantitative investigation of the co-metabolism of glycerol and glucose in the ΔptsGglpK* mutant. The ArcA regulatory system dominates the control of flux redistribution. The ΔptsGglpK* mutant can be used as a platform for microbial cell factories for the production of biofuels and biochemicals, since most of fuel molecule (e.g., alcohols) synthesis requires excess reducing equivalents.
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Affiliation(s)
- Ruilian Yao
- State Key Laboratory of Microbial Metabolism and School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240 China
| | - Dewang Xiong
- State Key Laboratory of Microbial Metabolism and School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240 China
| | - Hongbo Hu
- State Key Laboratory of Microbial Metabolism and School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240 China
| | - Masataka Wakayama
- Institute for Advanced Biosciences, Keio University, 246-2, Mizukami, Kakuganji, Tsuruoka, Yamagata 997-0052 Japan
| | - Wenjuan Yu
- Instrumental Analysis Center, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240 China
| | - Xuehong Zhang
- State Key Laboratory of Microbial Metabolism and School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240 China
| | - Kazuyuki Shimizu
- Institute for Advanced Biosciences, Keio University, 246-2, Mizukami, Kakuganji, Tsuruoka, Yamagata 997-0052 Japan
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Hollinshead WD, Rodriguez S, Martin HG, Wang G, Baidoo EEK, Sale KL, Keasling JD, Mukhopadhyay A, Tang YJ. Examining Escherichia coli glycolytic pathways, catabolite repression, and metabolite channeling using Δ pfk mutants. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:212. [PMID: 27766116 PMCID: PMC5057261 DOI: 10.1186/s13068-016-0630-y] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 09/28/2016] [Indexed: 05/09/2023]
Abstract
BACKGROUND Glycolysis breakdowns glucose into essential building blocks and ATP/NAD(P)H for the cell, occupying a central role in its growth and bio-production. Among glycolytic pathways, the Entner Doudoroff pathway (EDP) is a more thermodynamically favorable pathway with fewer enzymatic steps than either the Embden-Meyerhof-Parnas pathway (EMPP) or the oxidative pentose phosphate pathway (OPPP). However, Escherichia coli do not use their native EDP for glucose metabolism. RESULTS Overexpression of edd and eda in E. coli to enhance EDP activity resulted in only a small shift in the flux directed through the EDP (~20 % of glycolysis flux). Disrupting the EMPP by phosphofructokinase I (pfkA) knockout increased flux through OPPP (~60 % of glycolysis flux) and the native EDP (~14 % of glycolysis flux), while overexpressing edd and eda in this ΔpfkA mutant directed ~70 % of glycolytic flux through the EDP. The downregulation of EMPP via the pfkA deletion significantly decreased the growth rate, while EDP overexpression in the ΔpfkA mutant failed to improve its growth rates due to metabolic burden. However, the reorganization of E. coli glycolytic strategies did reduce glucose catabolite repression. The ΔpfkA mutant in glucose medium was able to cometabolize acetate via the citric acid cycle and gluconeogenesis, while EDP overexpression in the ΔpfkA mutant repressed acetate flux toward gluconeogenesis. Moreover, 13C-pulse experiments in the ΔpfkA mutants showed unsequential labeling dynamics in glycolysis intermediates, possibly suggesting metabolite channeling (metabolites in glycolysis are pass from enzyme to enzyme without fully equilibrating within the cytosol medium). CONCLUSIONS We engineered E. coli to redistribute its native glycolytic flux. The replacement of EMPP by EDP did not improve E. coli glucose utilization or biomass growth, but alleviated catabolite repression. More importantly, our results supported the hypothesis of channeling in the glycolytic pathways, a potentially overlooked mechanism for regulating glucose catabolism and coutilization of other substrates. The presence of channeling in native pathways, if proven true, would affect synthetic biology applications and metabolic modeling.
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Affiliation(s)
- Whitney D. Hollinshead
- Department of Energy, Environmental and Chemical Engineering, Washington University, St. Louis, MO USA
| | - Sarah Rodriguez
- Sandia National Laboratory, Livermore, CA USA
- Joint BioEnergy Institute, Emeryville, CA USA
| | - Hector Garcia Martin
- Joint BioEnergy Institute, Emeryville, CA USA
- Lawrence Berkeley National Laboratory, Biological Systems and Engineering Division, Berkeley, CA USA
| | - George Wang
- Joint BioEnergy Institute, Emeryville, CA USA
- Lawrence Berkeley National Laboratory, Biological Systems and Engineering Division, Berkeley, CA USA
| | - Edward E. K. Baidoo
- Joint BioEnergy Institute, Emeryville, CA USA
- Lawrence Berkeley National Laboratory, Biological Systems and Engineering Division, Berkeley, CA USA
| | - Kenneth L. Sale
- Joint BioEnergy Institute, Emeryville, CA USA
- Lawrence Berkeley National Laboratory, Biological Systems and Engineering Division, Berkeley, CA USA
| | - Jay D. Keasling
- Joint BioEnergy Institute, Emeryville, CA USA
- Lawrence Berkeley National Laboratory, Biological Systems and Engineering Division, Berkeley, CA USA
- California Institute of Quantitative Biosciences (QB3), University of California, Berkeley, CA USA
- Department of Bioengineering, University of California, Berkeley, CA USA
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA USA
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kogle Allé, DK2970 Hørsholm, Denmark
| | - Aindrila Mukhopadhyay
- Joint BioEnergy Institute, Emeryville, CA USA
- Lawrence Berkeley National Laboratory, Biological Systems and Engineering Division, Berkeley, CA USA
| | - Yinjie J. Tang
- Department of Energy, Environmental and Chemical Engineering, Washington University, St. Louis, MO USA
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13C-Metabolic Flux Analysis: An Accurate Approach to Demystify Microbial Metabolism for Biochemical Production. Bioengineering (Basel) 2015; 3:bioengineering3010003. [PMID: 28952565 PMCID: PMC5597161 DOI: 10.3390/bioengineering3010003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 12/10/2015] [Accepted: 12/18/2015] [Indexed: 12/15/2022] Open
Abstract
Metabolic engineering of various industrial microorganisms to produce chemicals, fuels, and drugs has raised interest since it is environmentally friendly, sustainable, and independent of nonrenewable resources. However, microbial metabolism is so complex that only a few metabolic engineering efforts have been able to achieve a satisfactory yield, titer or productivity of the target chemicals for industrial commercialization. In order to overcome this challenge, 13C Metabolic Flux Analysis (13C-MFA) has been continuously developed and widely applied to rigorously investigate cell metabolism and quantify the carbon flux distribution in central metabolic pathways. In the past decade, many 13C-MFA studies have been performed in academic labs and biotechnology industries to pinpoint key issues related to microbe-based chemical production. Insightful information about the metabolic rewiring has been provided to guide the development of the appropriate metabolic engineering strategies for improving the biochemical production. In this review, we will introduce the basics of 13C-MFA and illustrate how 13C-MFA has been applied via integration with metabolic engineering to identify and tackle the rate-limiting steps in biochemical production for various host microorganisms
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