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Kountz DJ, Balskus EP. A diversified, widespread microbial gene cluster encodes homologs of methyltransferases involved in methanogenesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.31.551370. [PMID: 37577662 PMCID: PMC10418091 DOI: 10.1101/2023.07.31.551370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
Analyses of microbial genomes have revealed unexpectedly wide distributions of enzymes from specialized metabolism, including methanogenesis, providing exciting opportunities for discovery. Here, we identify a family of gene clusters (the type 1 mlp gene clusters (MGCs)) that encodes homologs of the soluble coenzyme M methyltransferases (SCMTs) involved in methylotrophic methanogenesis and is widespread in bacteria and archaea. Type 1 MGCs are expressed and regulated in medically, environmentally, and industrially important organisms, making them likely to be physiologically relevant. Enzyme annotation, analysis of genomic context, and biochemical experiments suggests these gene clusters play a role in methyl-sulfur and/or methyl-selenide metabolism in numerous anoxic environments, including the human gut microbiome, potentially impacting sulfur and selenium cycling in diverse, anoxic environments.
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Affiliation(s)
- Duncan J. Kountz
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Emily P. Balskus
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
- Howard Hughes Medical Institute, Harvard University, Cambridge, Massachusetts 02138, United States
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2
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Utilization of Monosaccharides by Hungateiclostridium thermocellum ATCC 27405 through Adaptive Evolution. Microorganisms 2021; 9:microorganisms9071445. [PMID: 34361881 PMCID: PMC8303734 DOI: 10.3390/microorganisms9071445] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 06/30/2021] [Accepted: 07/02/2021] [Indexed: 12/13/2022] Open
Abstract
Hungateiclostridium thermocellum ATCC 27405 is a promising bacterium for consolidated bioprocessing with a robust ability to degrade lignocellulosic biomass through a multienzyme cellulosomal complex. The bacterium uses the released cellodextrins, glucose polymers of different lengths, as its primary carbon source and energy. In contrast, the bacterium exhibits poor growth on monosaccharides such as fructose and glucose. This phenomenon raises many important questions concerning its glycolytic pathways and sugar transport systems. Until now, the detailed mechanisms of H. thermocellum adaptation to growth on hexose sugars have been relatively poorly explored. In this study, adaptive laboratory evolution was applied to train the bacterium in hexose sugars-based media, and genome resequencing was used to detect the genes that got mutated during adaptation period. RNA-seq data of the first culture growing on either fructose or glucose revealed that several glycolytic genes in the Embden–Mayerhof–Parnas pathway were expressed at lower levels in these cells than in cellobiose-grown cells. After seven consecutive transfer events on fructose and glucose (~42 generations for fructose-adapted cells and ~40 generations for glucose-adapted cells), several genes in the EMP glycolysis of the evolved strains increased the levels of mRNA expression, accompanied by a faster growth, a greater biomass yield, a higher ethanol titer than those in their parent strains. Genomic screening also revealed several mutation events in the genomes of the evolved strains, especially in those responsible for sugar transport and central carbon metabolism. Consequently, these genes could be applied as potential targets for further metabolic engineering to improve this bacterium for bio-industrial usage.
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3
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Garcia S, Thompson RA, Giannone RJ, Dash S, Maranas CD, Trinh CT. Development of a Genome-Scale Metabolic Model of Clostridium thermocellum and Its Applications for Integration of Multi-Omics Datasets and Computational Strain Design. Front Bioeng Biotechnol 2020; 8:772. [PMID: 32974289 PMCID: PMC7471609 DOI: 10.3389/fbioe.2020.00772] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 06/18/2020] [Indexed: 01/29/2023] Open
Abstract
Solving environmental and social challenges such as climate change requires a shift from our current non-renewable manufacturing model to a sustainable bioeconomy. To lower carbon emissions in the production of fuels and chemicals, plant biomass feedstocks can replace petroleum using microorganisms as biocatalysts. The anaerobic thermophile Clostridium thermocellum is a promising bacterium for bioconversion due to its capability to efficiently degrade lignocellulosic biomass. However, the complex metabolism of C. thermocellum is not fully understood, hindering metabolic engineering to achieve high titers, rates, and yields of targeted molecules. In this study, we developed an updated genome-scale metabolic model of C. thermocellum that accounts for recent metabolic findings, has improved prediction accuracy, and is standard-conformant to ensure easy reproducibility. We illustrated two applications of the developed model. We first formulated a multi-omics integration protocol and used it to understand redox metabolism and potential bottlenecks in biofuel (e.g., ethanol) production in C. thermocellum. Second, we used the metabolic model to design modular cells for efficient production of alcohols and esters with broad applications as flavors, fragrances, solvents, and fuels. The proposed designs not only feature intuitive push-and-pull metabolic engineering strategies, but also present novel manipulations around important central metabolic branch-points. We anticipate the developed genome-scale metabolic model will provide a useful tool for system analysis of C. thermocellum metabolism to fundamentally understand its physiology and guide metabolic engineering strategies to rapidly generate modular production strains for effective biosynthesis of biofuels and biochemicals from lignocellulosic biomass.
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Affiliation(s)
- Sergio Garcia
- Department of Chemical and Biomolecular Engineering, The University of Tennessee, Knoxville, TN, United States.,Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - R Adam Thompson
- Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, United States.,Bredesen Center for Interdisciplinary Research and Graduate Education, The University of Tennessee, Knoxville, TN, United States.,Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Richard J Giannone
- Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, United States.,Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Satyakam Dash
- Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, United States.,Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, United States
| | - Costas D Maranas
- Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, United States.,Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, United States
| | - Cong T Trinh
- Department of Chemical and Biomolecular Engineering, The University of Tennessee, Knoxville, TN, United States.,Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, United States.,Bredesen Center for Interdisciplinary Research and Graduate Education, The University of Tennessee, Knoxville, TN, United States.,Oak Ridge National Laboratory, Oak Ridge, TN, United States
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4
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Sander K, Chung D, Hyatt D, Westpheling J, Klingeman DM, Rodriguez M, Engle NL, Tschaplinski TJ, Davison BH, Brown SD. Rex in Caldicellulosiruptor bescii: Novel regulon members and its effect on the production of ethanol and overflow metabolites. Microbiologyopen 2019; 8:e00639. [PMID: 29797457 PMCID: PMC6391272 DOI: 10.1002/mbo3.639] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 03/03/2018] [Accepted: 03/05/2018] [Indexed: 11/23/2022] Open
Abstract
Rex is a global redox-sensing transcription factor that senses and responds to the intracellular [NADH]/[NAD+ ] ratio to regulate genes for central metabolism, and a variety of metabolic processes in Gram-positive bacteria. We decipher and validate four new members of the Rex regulon in Caldicellulosiruptor bescii; a gene encoding a class V aminotransferase, the HydG FeFe Hydrogenase maturation protein, an oxidoreductase, and a gene encoding a hypothetical protein. Structural genes for the NiFe and FeFe hydrogenases, pyruvate:ferredoxin oxidoreductase, as well as the rex gene itself are also members of this regulon, as has been predicted previously in different organisms. A C. bescii rex deletion strain constructed in an ethanol-producing strain made 54% more ethanol (0.16 mmol/L) than its genetic parent after 36 hr of fermentation, though only under nitrogen limited conditions. Metabolomic interrogation shows this rex-deficient ethanol-producing strain synthesizes other reduced overflow metabolism products likely in response to more reduced intracellular redox conditions and the accumulation of pyruvate. These results suggest ethanol production is strongly dependent on the native intracellular redox state in C. bescii, and highlight the combined promise of using this gene and manipulation of culture conditions to yield strains capable of producing ethanol at higher yields and final titer.
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Affiliation(s)
- Kyle Sander
- Department of Chemical and Biomolecular EngineeringUniversity of TennesseeKnoxvilleTennessee
- Bredesen Center for Interdisciplinary Graduate Research and EducationUniversity of TennesseeKnoxvilleTennessee
- BioEnergy Sciences CenterOak Ridge National LaboratoryOak RidgeTennessee
| | - Daehwan Chung
- BioEnergy Sciences CenterOak Ridge National LaboratoryOak RidgeTennessee
- Department of GeneticsUniversity of GeorgiaAthensGeorgia
- Present address:
National Renewable Energy LaboratoryGoldenCO
| | - Doug Hyatt
- BioEnergy Sciences CenterOak Ridge National LaboratoryOak RidgeTennessee
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTennessee
| | - Janet Westpheling
- BioEnergy Sciences CenterOak Ridge National LaboratoryOak RidgeTennessee
- Department of GeneticsUniversity of GeorgiaAthensGeorgia
| | - Dawn M. Klingeman
- BioEnergy Sciences CenterOak Ridge National LaboratoryOak RidgeTennessee
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTennessee
| | - Miguel Rodriguez
- BioEnergy Sciences CenterOak Ridge National LaboratoryOak RidgeTennessee
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTennessee
| | - Nancy L. Engle
- BioEnergy Sciences CenterOak Ridge National LaboratoryOak RidgeTennessee
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTennessee
| | - Timothy J. Tschaplinski
- BioEnergy Sciences CenterOak Ridge National LaboratoryOak RidgeTennessee
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTennessee
| | - Brian H. Davison
- Department of Chemical and Biomolecular EngineeringUniversity of TennesseeKnoxvilleTennessee
- Bredesen Center for Interdisciplinary Graduate Research and EducationUniversity of TennesseeKnoxvilleTennessee
- BioEnergy Sciences CenterOak Ridge National LaboratoryOak RidgeTennessee
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTennessee
| | - Steven D. Brown
- Bredesen Center for Interdisciplinary Graduate Research and EducationUniversity of TennesseeKnoxvilleTennessee
- BioEnergy Sciences CenterOak Ridge National LaboratoryOak RidgeTennessee
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTennessee
- Present address:
LanzaTechSkokieIL
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Papanek B, O’Dell KB, Manga P, Giannone RJ, Klingeman DM, Hettich RL, Brown SD, Guss AM. Transcriptomic and proteomic changes from medium supplementation and strain evolution in high-yielding Clostridium thermocellum strains. ACTA ACUST UNITED AC 2018; 45:1007-1015. [DOI: 10.1007/s10295-018-2073-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2018] [Accepted: 08/18/2018] [Indexed: 01/05/2023]
Abstract
Abstract
Clostridium thermocellum is a potentially useful organism for the production of lignocellulosic biofuels because of its ability to directly deconstruct cellulose and convert it into ethanol. Previously engineered C. thermocellum strains have achieved higher yields and titers of ethanol. These strains often initially grow more poorly than the wild type. Adaptive laboratory evolution and medium supplementation have been used to improve growth, but the mechanism(s) by which growth improves remain(s) unclear. Here, we studied (1) wild-type C. thermocellum, (2) the slow-growing and high-ethanol-yielding mutant AG553, and (3) the faster-growing evolved mutant AG601, each grown with and without added formate. We used a combination of transcriptomics and proteomics to understand the physiological impact of the metabolic engineering, evolution, and medium supplementation. Medium supplementation with formate improved growth in both AG553 and AG601. Expression of C1 metabolism genes varied with formate addition, supporting the hypothesis that the primary benefit of added formate is the supply of C1 units for biosynthesis. Expression of stress response genes such as those involved in the sporulation cascade was dramatically over-represented in AG553, even after the addition of formate, suggesting that the source of the stress may be other issues such as redox imbalances. The sporulation response is absent in evolved strain AG601, suggesting that sporulation limits the growth of engineered strain AG553. A better understanding of the stress response and mechanisms of improved growth hold promise for informing rational improvement of C. thermocellum for lignocellulosic biofuel production.
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Affiliation(s)
- Beth Papanek
- 0000 0004 0446 2659 grid.135519.a Biosciences Division Oak Ridge National Laboratory Oak Ridge TN USA
- 0000 0001 2315 1184 grid.411461.7 Bredesen Center for Interdisciplinary Research and Graduate Education University of Tennessee-Knoxville Knoxville TN USA
- 0000 0004 1936 9991 grid.35403.31 Integrated Bioprocessing Research Laboratory University of Illinois-Urbana-Champaign Urbana IL USA
| | - Kaela B O’Dell
- 0000 0004 0446 2659 grid.135519.a Biosciences Division Oak Ridge National Laboratory Oak Ridge TN USA
| | - Punita Manga
- 0000 0004 0446 2659 grid.135519.a Biosciences Division Oak Ridge National Laboratory Oak Ridge TN USA
- 0000 0001 2315 1184 grid.411461.7 The Graduate School of Genome Science and Technology University of Tennessee-Knoxville Knoxville TN USA
| | - Richard J Giannone
- 0000 0004 0446 2659 grid.135519.a Biosciences Division Oak Ridge National Laboratory Oak Ridge TN USA
| | - Dawn M Klingeman
- 0000 0004 0446 2659 grid.135519.a Biosciences Division Oak Ridge National Laboratory Oak Ridge TN USA
| | - Robert L Hettich
- 0000 0004 0446 2659 grid.135519.a Biosciences Division Oak Ridge National Laboratory Oak Ridge TN USA
| | - Steven D Brown
- 0000 0004 0446 2659 grid.135519.a Biosciences Division Oak Ridge National Laboratory Oak Ridge TN USA
- 0000 0001 2315 1184 grid.411461.7 The Graduate School of Genome Science and Technology University of Tennessee-Knoxville Knoxville TN USA
- LanzaTech Inc 8045 Lamon Ave, Suite 400 60077 Skokie IL USA
| | - Adam M Guss
- 0000 0004 0446 2659 grid.135519.a Biosciences Division Oak Ridge National Laboratory Oak Ridge TN USA
- 0000 0001 2315 1184 grid.411461.7 Bredesen Center for Interdisciplinary Research and Graduate Education University of Tennessee-Knoxville Knoxville TN USA
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6
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Liu YJ, Qi K, Zhang J, Chen C, Cui Q, Feng Y. Firmicutes-enriched IS 1447 represents a group of IS 3-family insertion sequences exhibiting unique + 1 transcriptional slippage. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:300. [PMID: 30410575 PMCID: PMC6211511 DOI: 10.1186/s13068-018-1304-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 10/27/2018] [Indexed: 05/12/2023]
Abstract
BACKGROUND Bacterial insertion sequences (ISs) are ubiquitous mobile genetic elements that play important roles in genome plasticity, cell adaptability, and function evolution. ISs of various families and subgroups contain significantly diverse molecular features and functional mechanisms that are not fully understood. RESULTS IS1447 is a member of the widespread IS3 family and was previously detected to have transposing activity in a typical thermophilic and cellulolytic microorganism Clostridium thermocellum. Phylogenetic analysis showed that IS1447-like elements are widely distributed in Firmicutes and possess unique features in the IS3 family. Therefore, IS1447 may represent a novel subgroup of the IS3 family. Unlike other well-known IS3 subgroups performing programmed - 1 translational frameshifting for the expression of the transposase, IS1447 exhibits transcriptional slippage in both the + 1 and - 1 directions, each with a frequency of ~ 16%, and only + 1 slippage results in full-length and functional transposase. The slippage-prone region of IS1447 contains a run of nine A nucleotides following a stem-loop structure in mRNA, but mutagenesis analysis indicated that seven of them are sufficient for the observed slippage. Western blot analysis indicated that IS1447 produces three types of transposases with alternative initiations. Furthermore, the IS1447-subgroup elements are abundant in the genomes of several cellulolytic bacteria. CONCLUSION Our result indicated that IS1447 represents a new Firmicutes-enriched subgroup of the IS3 family. The characterization of the novel IS3-family member will enrich our understanding of the transposition behavior of IS elements and may provide insight into developing IS-based mutagenesis tools for thermophiles.
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Affiliation(s)
- Ya-Jun Liu
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
- Dalian National Laboratory for Clean Energy, Dalian, China
| | - Kuan Qi
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
- Dalian National Laboratory for Clean Energy, Dalian, China
- University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, China
| | - Jie Zhang
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
- Dalian National Laboratory for Clean Energy, Dalian, China
- University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, China
- Present Address: Department of Biosystems Engineering, Auburn University, Auburn, AL 36849 USA
| | - Chao Chen
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
- Dalian National Laboratory for Clean Energy, Dalian, China
| | - Qiu Cui
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
- Dalian National Laboratory for Clean Energy, Dalian, China
| | - Yingang Feng
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
- Dalian National Laboratory for Clean Energy, Dalian, China
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7
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Gilna P, Lynd LR, Mohnen D, Davis MF, Davison BH. Progress in understanding and overcoming biomass recalcitrance: a BioEnergy Science Center (BESC) perspective. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:285. [PMID: 29213324 PMCID: PMC5707806 DOI: 10.1186/s13068-017-0971-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 11/15/2017] [Indexed: 06/07/2023]
Abstract
The DOE BioEnergy Science Center has operated as a virtual center with multiple partners for a decade targeting overcoming biomass recalcitrance. BESC has redefined biomass recalcitrance from an observable phenotype to a better understood and manipulatable fundamental and operational property. These manipulations are the result of deeper biological understanding and can be combined with other advanced biotechnology improvements in biomass conversion to improve bioenergy processes and markets. This article provides an overview of key accomplishments in overcoming recalcitrance via better plants, better microbes, and better tools and combinations. A perspective on the aspects of successful center operation is presented.
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Affiliation(s)
- Paul Gilna
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Biosciences Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Bldg. 1505, Rm. 100A, Oak Ridge, TN 37831-6037 USA
| | - Lee R. Lynd
- Biosciences Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Bldg. 1505, Rm. 100A, Oak Ridge, TN 37831-6037 USA
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755 USA
| | - Debra Mohnen
- Biosciences Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Bldg. 1505, Rm. 100A, Oak Ridge, TN 37831-6037 USA
- Complex Carbohydrate Research Center and Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602 USA
| | - Mark F. Davis
- Biosciences Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Bldg. 1505, Rm. 100A, Oak Ridge, TN 37831-6037 USA
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Brian H. Davison
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Biosciences Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Bldg. 1505, Rm. 100A, Oak Ridge, TN 37831-6037 USA
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