1
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Wu Y, Zhang S, York DM, Wang L. Adsorption of Flavonoids in a Transcriptional Regulator TtgR: Relative Binding Free Energies and Intermolecular Interactions. J Phys Chem B 2024; 128:6529-6541. [PMID: 38935925 DOI: 10.1021/acs.jpcb.4c02303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/29/2024]
Abstract
Antimicrobial resistance in bacteria often arises from their ability to actively identify and expel toxic compounds. The bacterium strain Pseudomonas putida DOT-T1E utilizes its TtgABC efflux pump to confer robust resistance against antibiotics, flavonoids, and organic solvents. This resistance mechanism is intricately regulated at the transcriptional level by the TtgR protein. Through molecular dynamics and alchemical free energy simulations, we systematically examine the binding of seven flavonoids and their derivatives with the TtgR transcriptional regulator. Our simulations reveal distinct binding geometries and free energies for the flavonoids in the active site of the protein, which are driven by a range of noncovalent forces encompassing van der Waals, electrostatic, and hydrogen bonding interactions. The interplay of molecular structures, substituent patterns, and intermolecular interactions effectively stabilizes the bound flavonoids, confining their movements within the TtgR binding pocket. These findings yield valuable insights into the molecular determinants that govern ligand recognition in TtgR and shed light on the mechanism of antimicrobial resistance in P. putida DOT-T1E.
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Affiliation(s)
- Yuxuan Wu
- Department of Chemistry and Chemical Biology, Institute for Quantitative Biomedicine, Laboratory for Biomolecular Simulation Research, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Shi Zhang
- Department of Chemistry and Chemical Biology, Institute for Quantitative Biomedicine, Laboratory for Biomolecular Simulation Research, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Darrin M York
- Department of Chemistry and Chemical Biology, Institute for Quantitative Biomedicine, Laboratory for Biomolecular Simulation Research, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Lu Wang
- Department of Chemistry and Chemical Biology, Institute for Quantitative Biomedicine, Laboratory for Biomolecular Simulation Research, Rutgers University, Piscataway, New Jersey 08854, United States
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2
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Nabila DS, Chan R, Syamsuri RRP, Nurlilasari P, Wan-Mohtar WAAQI, Ozturk AB, Rossiana N, Doni F. Biobutanol production from underutilized substrates using Clostridium: Unlocking untapped potential for sustainable energy development. CURRENT RESEARCH IN MICROBIAL SCIENCES 2024; 7:100250. [PMID: 38974669 PMCID: PMC11225672 DOI: 10.1016/j.crmicr.2024.100250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/09/2024] Open
Abstract
The increasing demand for sustainable energy has brought biobutanol as a potential substitute for fossil fuels. The Clostridium genus is deemed essential for biobutanol synthesis due to its capability to utilize various substrates. However, challenges in maintaining fermentation continuity and achieving commercialization persist due to existing barriers, including butanol toxicity to Clostridium, low substrate utilization rates, and high production costs. Proper substrate selection significantly impacts fermentation efficiency, final product quality, and economic feasibility in Clostridium biobutanol production. This review examines underutilized substrates for biobutanol production by Clostridium, which offer opportunities for environmental sustainability and a green economy. Extensive research on Clostridium, focusing on strain development and genetic engineering, is essential to enhance biobutanol production. Additionally, critical suggestions for optimizing substrate selection to enhance Clostridium biobutanol production efficiency are also provided in this review. In the future, cost reduction and advancements in biotechnology may make biobutanol a viable alternative to fossil fuels.
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Affiliation(s)
- Devina Syifa Nabila
- Department of Biology, Faculty of Mathematics and Natural Sciences, Universitas Padjadjaran, Jatinangor, West Java 45363, Indonesia
| | - Rosamond Chan
- Department of Biology, Faculty of Mathematics and Natural Sciences, Universitas Padjadjaran, Jatinangor, West Java 45363, Indonesia
| | | | - Puspita Nurlilasari
- Department of Agro-industrial Technology, Faculty of Agro-industrial Technology, Universitas Padjadjaran, Jatinangor, West Java 45363, Indonesia
| | - Wan Abd Al Qadr Imad Wan-Mohtar
- Functional Omics and Bioprocess Development Laboratory, Institute of Biological Sciences, Faculty of Science, Universiti Malaya, Kuala Lumpur 50603, Malaysia
| | - Abdullah Bilal Ozturk
- Department of Chemical Engineering, Faculty of Chemical and Metallurgical Engineering, Yildiz Technical University, Esenler, Istanbul 34220, Türkiye
| | - Nia Rossiana
- Department of Biology, Faculty of Mathematics and Natural Sciences, Universitas Padjadjaran, Jatinangor, West Java 45363, Indonesia
| | - Febri Doni
- Department of Biology, Faculty of Mathematics and Natural Sciences, Universitas Padjadjaran, Jatinangor, West Java 45363, Indonesia
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3
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Cárdenas Espinosa MJ, Schmidgall T, Pohl J, Wagner G, Wynands B, Wierckx N, Heipieper HJ, Eberlein C. Assessment of New and Genome-Reduced Pseudomonas Strains Regarding Their Robustness as Chassis in Biotechnological Applications. Microorganisms 2023; 11:microorganisms11040837. [PMID: 37110260 PMCID: PMC10144732 DOI: 10.3390/microorganisms11040837] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 03/12/2023] [Accepted: 03/23/2023] [Indexed: 03/29/2023] Open
Abstract
Organic olvent-tolerant strains of the Gram-negative bacterial genus Pseudomonas are discussed as potential biocatalysts for the biotechnological production of various chemicals. However, many current strains with the highest tolerance are belonging to the species P. putida and are classified as biosafety level 2 strains, which makes them uninteresting for the biotechnological industry. Therefore, it is necessary to identify other biosafety level 1 Pseudomonas strains with high tolerance towards solvents and other forms of stress, which are suitable for establishing production platforms of biotechnological processes. In order to exploit the native potential of Pseudomonas as a microbial cell factory, the biosafety level 1 strain P. taiwanensis VLB120 and its genome-reduced chassis (GRC) variants as well as the plastic-degrading strain P. capeferrum TDA1 were assessed regarding their tolerance towards different n-alkanols (1-butanol, 1-hexanol, 1-octanol, 1-decanol). Toxicity of the solvents was investigated by their effects on bacterial growth rates given as the EC50 concentrations. Hereby, both toxicities as well as the adaptive responses of P. taiwanensis GRC3 and P. capeferrum TDA1 showed EC50 values up to two-fold higher than those previously detected for P. putida DOT-T1E (biosafety level 2), one of the best described solvent-tolerant bacteria. Furthermore, in two-phase solvent systems, all the evaluated strains were adapted to 1-decanol as a second organic phase (i.e., OD560 was at least 0.5 after 24 h of incubation with 1% (v/v) 1-decanol), which shows the potential use of these strains as platforms for the bio-production of a wide variety of chemicals at industrial level.
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Affiliation(s)
- María José Cárdenas Espinosa
- Department of Environmental Biotechnology, Helmholtz Centre for Environmental Research—UFZ, 04318 Leipzig, Germany
| | - Tabea Schmidgall
- Department of Environmental Biotechnology, Helmholtz Centre for Environmental Research—UFZ, 04318 Leipzig, Germany
| | - Jessica Pohl
- Department of Environmental Biotechnology, Helmholtz Centre for Environmental Research—UFZ, 04318 Leipzig, Germany
| | - Georg Wagner
- Department of Environmental Biotechnology, Helmholtz Centre for Environmental Research—UFZ, 04318 Leipzig, Germany
| | - Benedikt Wynands
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich, 52428 Jülich, Germany
| | - Nick Wierckx
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich, 52428 Jülich, Germany
| | - Hermann J. Heipieper
- Department of Environmental Biotechnology, Helmholtz Centre for Environmental Research—UFZ, 04318 Leipzig, Germany
| | - Christian Eberlein
- Department of Environmental Biotechnology, Helmholtz Centre for Environmental Research—UFZ, 04318 Leipzig, Germany
- Correspondence:
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4
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Huang T, Ma Y. Advances in biosynthesis of higher alcohols in Escherichia coli. World J Microbiol Biotechnol 2023; 39:125. [PMID: 36941474 DOI: 10.1007/s11274-023-03580-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 03/13/2023] [Indexed: 03/23/2023]
Abstract
In recent years, the development of green energy to replace fossil fuels has been the focus of research. Higher alcohols are important biofuels and chemicals. The production of higher alcohols in microbes has gained attention due to its environmentally friendly character. Higher alcohols have been synthesized in model microorganism Escherichia coli, and the production has reached the gram level through enhancement of metabolic flow, the balance of reducing power and the optimization of fermentation processes. Sustainable bio-higher alcohols production is expected to replace fossil fuels as a green and renewable energy source. Therefore, this review summarizes the latest developments in producing higher alcohols (C3-C6) by E. coli, elucidate the main bottlenecks limiting the biosynthesis of higher alcohols, and proposes potential engineering strategies of improving the production of biological higher alcohols. This review would provide a theoretical basis for further research on higher alcohols production by E. coli.
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Affiliation(s)
- Tong Huang
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, People's Republic of China
| | - Yuanyuan Ma
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, People's Republic of China.
- School of Marin Science and Technology, Tianjin University, Tianjin, 300072, China.
- R&D Center for Petrochemical Technology, Tianjin University, Tianjin, 300072, China.
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Singh B, Kumar A, Saini AK, Saini RV, Thakur R, Mohammed SA, Tuli HS, Gupta VK, Areeshi MY, Faidah H, Jalal NA, Haque S. Strengthening microbial cell factories for efficient production of bioactive molecules. Biotechnol Genet Eng Rev 2023:1-34. [PMID: 36809927 DOI: 10.1080/02648725.2023.2177039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 01/21/2023] [Indexed: 02/24/2023]
Abstract
High demand of bioactive molecules (food additives, antibiotics, plant growth enhancers, cosmetics, pigments and other commercial products) is the prime need for the betterment of human life where the applicability of the synthetic chemical product is on the saturation due to associated toxicity and ornamentations. It has been noticed that the discovery and productivity of such molecules in natural scenarios are limited due to low cellular yields as well as less optimized conventional methods. In this respect, microbial cell factories timely fulfilling the requirement of synthesizing bioactive molecules by improving production yield and screening more promising structural homologues of the native molecule. Where the robustness of the microbial host can be potentially achieved by taking advantage of cell engineering approaches such as tuning functional and adjustable factors, metabolic balancing, adapting cellular transcription machinery, applying high throughput OMICs tools, stability of genotype/phenotype, organelle optimizations, genome editing (CRISPER/Cas mediated system) and also by developing accurate model systems via machine-learning tools. In this article, we provide an overview from traditional to recent trends and the application of newly developed technologies, for strengthening the systemic approaches and providing future directions for enhancing the robustness of microbial cell factories to speed up the production of biomolecules for commercial purposes.
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Affiliation(s)
- Bharat Singh
- Department of Biotechnology and Central Research Cell, MMEC, Maharishi Markandeshwar (Deemed to be University), Mullana-Ambala, India
| | - Ankit Kumar
- TERI-Deakin Nanobiotechnology Centre, TERI Gram, The Energy and Resources Institute, Gurugram, India
| | - Adesh Kumar Saini
- Department of Biotechnology and Central Research Cell, MMEC, Maharishi Markandeshwar (Deemed to be University), Mullana-Ambala, India
| | - Reena Vohra Saini
- Department of Biotechnology and Central Research Cell, MMEC, Maharishi Markandeshwar (Deemed to be University), Mullana-Ambala, India
| | - Rahul Thakur
- Department of Biotechnology and Central Research Cell, MMEC, Maharishi Markandeshwar (Deemed to be University), Mullana-Ambala, India
| | - Shakeel A Mohammed
- Department of Biotechnology and Central Research Cell, MMEC, Maharishi Markandeshwar (Deemed to be University), Mullana-Ambala, India
| | - Hardeep Singh Tuli
- Department of Biotechnology and Central Research Cell, MMEC, Maharishi Markandeshwar (Deemed to be University), Mullana-Ambala, India
| | - Vijai Kumar Gupta
- Biorefining and Advanced Materials Research Centre, Scotland's Rural College (SRUC), Edinburgh, UK
| | - Mohammed Y Areeshi
- Medical Laboratory Technology Department, College of Applied Medical Sciences, Jazan University, Jazan, Saudi Arabia
- Research and Scientific Studies Unit, College of Nursing and Allied Health Sciences, Jazan University, Jazan, Saudi Arabia
| | - Hani Faidah
- Department of Microbiology, Faculty of Medicine, Umm Al-Qura University, Makkah, Saudi Arabia
| | - Naif A Jalal
- Department of Microbiology, Faculty of Medicine, Umm Al-Qura University, Makkah, Saudi Arabia
| | - Shafiul Haque
- Research and Scientific Studies Unit, College of Nursing and Allied Health Sciences, Jazan University, Jazan, Saudi Arabia
- Gilbert and Rose-Marie Chagoury School of Medicine, Lebanese American University, Beirut, Lebanon
- Centre of Medical and Bio-Allied Health Sciences Research, Ajman University, Ajman, United Arab Emirates
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6
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Patakova P, Branska B, Vasylkivska M, Jureckova K, Musilova J, Provaznik I, Sedlar K. Transcriptomic studies of solventogenic clostridia, Clostridium acetobutylicum and Clostridium beijerinckii. Biotechnol Adv 2021; 58:107889. [PMID: 34929313 DOI: 10.1016/j.biotechadv.2021.107889] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 12/10/2021] [Accepted: 12/14/2021] [Indexed: 12/13/2022]
Abstract
Solventogenic clostridia are not a strictly defined group within the genus Clostridium but its representatives share some common features, i.e. they are anaerobic, non-pathogenic, non-toxinogenic and endospore forming bacteria. Their main metabolite is typically 1-butanol but depending on species and culture conditions, they can form other metabolites such as acetone, isopropanol, ethanol, butyric, lactic and acetic acids, and hydrogen. Although these organisms were previously used for the industrial production of solvents, they later fell into disuse, being replaced by more efficient chemical production. A return to a more biological production of solvents therefore requires a thorough understanding of clostridial metabolism. Transcriptome analysis, which reflects the involvement of individual genes in all cellular processes within a population, at any given (sampling) moment, is a valuable tool for gaining a deeper insight into clostridial life. In this review, we describe techniques to study transcription, summarize the evolution of these techniques and compare methods for data processing and visualization of solventogenic clostridia, particularly the species Clostridium acetobutylicum and Clostridium beijerinckii. Individual approaches for evaluating transcriptomic data are compared and their contributions to advancements in the field are assessed. Moreover, utilization of transcriptomic data for reconstruction of computational clostridial metabolic models is considered and particular models are described. Transcriptional changes in glucose transport, central carbon metabolism, the sporulation cycle, butanol and butyrate stress responses, the influence of lignocellulose-derived inhibitors on growth and solvent production, and other respective topics, are addressed and common trends are highlighted.
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Affiliation(s)
- Petra Patakova
- University of Chemistry and Technology Prague, Technicka 5, 16628 Prague 6, Czech Republic.
| | - Barbora Branska
- University of Chemistry and Technology Prague, Technicka 5, 16628 Prague 6, Czech Republic
| | - Maryna Vasylkivska
- University of Chemistry and Technology Prague, Technicka 5, 16628 Prague 6, Czech Republic
| | | | - Jana Musilova
- Brno University of Technology, Technicka 10, 61600 Brno, Czech Republic
| | - Ivo Provaznik
- Brno University of Technology, Technicka 10, 61600 Brno, Czech Republic
| | - Karel Sedlar
- Brno University of Technology, Technicka 10, 61600 Brno, Czech Republic
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7
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Semanti P, Robin RS, Purvaja R, Ramesh R. Fatty acid signatures of sediment microbial community in the chronically polluted mangrove ecosystem. MARINE POLLUTION BULLETIN 2021; 172:112885. [PMID: 34461371 DOI: 10.1016/j.marpolbul.2021.112885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 08/14/2021] [Accepted: 08/17/2021] [Indexed: 06/13/2023]
Abstract
Phospholipid fatty acid (PLFA) analysis was used to examine variation in the distribution of microbial communities in heavily polluted mangrove sediments of Thane creek, west coast of India. A total of 40 individual PLFAs representing 11 functional groups were identified in the sediment and were mainly dominated by saturated fatty acids (anaerobic prokaryotes) >50%. Significant dominance of PUFA, 16:3 ω6c (34.2%) indicators of micro-eukaryotes, in subsurface depth (p < 0.05) suggests input from the remnants of marine microalgae. Declined mean relative abundance of fungi (<6%) and actinomycetes (<1%) were detected in the sediment indicating their sensitivity to anthropic stressors. Homogenous profile of microbial diversity indicating active bioturbation. Cumulative metabolic stress evident from SAT/MUFA (>1), B/F (>1) and G+/G- (<1) ratio and prolonged hypoxia to be prevalent in the creek during the study. In conclusion, PLFA signatures can thus be used as potential biomarkers of environmental monitoring and proxy for interpreting ecosystem health.
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Affiliation(s)
- P Semanti
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Chennai 600 025, India
| | - R S Robin
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Chennai 600 025, India
| | - R Purvaja
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Chennai 600 025, India
| | - R Ramesh
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Chennai 600 025, India.
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8
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Exposure to 1-Butanol Exemplifies the Response of the Thermoacidophilic Archaeon Sulfolobus acidocaldarius to Solvent Stress. Appl Environ Microbiol 2021; 87:AEM.02988-20. [PMID: 33741627 PMCID: PMC8208165 DOI: 10.1128/aem.02988-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 03/09/2021] [Indexed: 12/18/2022] Open
Abstract
Sulfolobus acidocaldarius is a thermoacidophilic crenarchaeon with optimal growth at 80°C and pH 2 to 3. Due to its unique physiological properties, allowing life at environmental extremes, and the recent availability of genetic tools, this extremophile has received increasing interest for biotechnological applications. In order to elucidate the potential of tolerating process-related stress conditions, we investigated the response of S. acidocaldarius toward the industrially relevant organic solvent 1-butanol. In response to butanol exposure, biofilm formation of S. acidocaldarius was enhanced and occurred at up to 1.5% (vol/vol) 1-butanol, while planktonic growth was observed at up to 1% (vol/vol) 1-butanol. Confocal laser-scanning microscopy revealed that biofilm architecture changed with the formation of denser and higher tower-like structures. Concomitantly, changes in the extracellular polymeric substances with enhanced carbohydrate and protein content were determined in 1-butanol-exposed biofilms. Using scanning electron microscopy, three different cell morphotypes were observed in response to 1-butanol. Transcriptome and proteome analyses were performed comparing the response of planktonic and biofilm cells in the absence and presence of 1-butanol. In response to 1% (vol/vol) 1-butanol, transcript levels of genes encoding motility and cell envelope structures, as well as membrane proteins, were reduced. Cell division and/or vesicle formation were upregulated. Furthermore, changes in immune and defense systems, as well as metabolism and general stress responses, were observed. Our findings show that the extreme lifestyle of S. acidocaldarius coincided with a high tolerance to organic solvents. This study provides what may be the first insights into biofilm formation and membrane/cell stress caused by organic solvents in S. acidocaldarius IMPORTANCE Archaea are unique in terms of metabolic and cellular processes, as well as the adaptation to extreme environments. In the past few years, the development of genetic systems and biochemical, genetic, and polyomics studies has provided deep insights into the physiology of some archaeal model organisms. In this study, we used S. acidocaldarius, which is adapted to the two extremes of low pH and high temperature, to study its tolerance and robustness as well as its global cellular response toward organic solvents, as exemplified by 1-butanol. We were able to identify biofilm formation as a primary cellular response to 1-butanol. Furthermore, the triggered cell/membrane stress led to significant changes in culture heterogeneity accompanied by changes in central cellular processes, such as cell division and cellular defense systems, thus suggesting a global response for the protection at the population level.
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9
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Liu S, Qureshi N, Bischoff K, Darie CC. Proteomic Analysis Identifies Dysregulated Proteins in Butanol-Tolerant Gram-Positive Lactobacillus mucosae BR0713-33. ACS OMEGA 2021; 6:4034-4043. [PMID: 33644533 PMCID: PMC7906490 DOI: 10.1021/acsomega.0c06028] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 01/18/2021] [Indexed: 06/12/2023]
Abstract
Butanol can be produced biologically through fermentation of lignocellulosic biomass-derived sugars by Gram-positive Clostridium species. For cost-effective production, increased butanol fermentation titers are desired. However, the currently available butanol-fermenting microbes do not tolerate sufficiently high butanol concentrations; thus, new butanol-tolerant strains are desired. One promising strategy is to genetically modify Clostridium species by introducing stress tolerance-associated genes. This study was aimed to seek butanol tolerance genes from other Gram-positive species, which might be better suited than those from Gram-negative E. coli or eukaryotic Saccharomyces cerevisiae. Several butanol-tolerant lactobacilli were reported previously, and Lactobacillus mucosae BR0713-33, which showed the most robust anaerobic growth in 4% butanol, was used here for proteomics analyses. Cellular proteins that responded to 2, 3, and 4% butanol were characterized. Twenty-nine proteins that were identified were dysregulated in response to increased concentrations of butanol in L. mucosae . Seventeen genes involved in coding for stress-tolerant proteins GroES, GroEL, and DnaK and genes involved in substrate utilization, fatty acid metabolism, and nucleotide synthesis were induced by increased butanol, and 12 genes involving energy production (F0F1ATP synthases) and redox balance preservation were repressed by increased butanol. These results can help guide targeted engineering strategies to improve tolerance and production of biobutanol.
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Affiliation(s)
- Siqing Liu
- Renewable
Product Technology Research Unit, National Center for Agricultural
Utilization Research, Agricultural Research Service, U.S. Department
of Agriculture, Peoria, Illinois 61604, United States
| | - Nasib Qureshi
- Bioenery
Research Unit, National Center for Agricultural Utilization Research,
Agricultural Research Service, U.S. Department of Agriculture, Peoria, Illinois 61604, United States
| | - Kenneth Bischoff
- Renewable
Product Technology Research Unit, National Center for Agricultural
Utilization Research, Agricultural Research Service, U.S. Department
of Agriculture, Peoria, Illinois 61604, United States
| | - Costel C. Darie
- Biochemistry
& Proteomics Group, Department of Chemistry & Biomolecular
Science, Clarkson University, Potsdam, New York 13699, United States
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10
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Branska B, Vasylkivska M, Raschmanova H, Jureckova K, Sedlar K, Provaznik I, Patakova P. Changes in efflux pump activity of Clostridium beijerinckii throughout ABE fermentation. Appl Microbiol Biotechnol 2021; 105:877-889. [PMID: 33409609 DOI: 10.1007/s00253-020-11072-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 12/05/2020] [Accepted: 12/17/2020] [Indexed: 01/08/2023]
Abstract
Pumping toxic substances through a cytoplasmic membrane by protein transporters known as efflux pumps represents one bacterial mechanism involved in the stress response to the presence of toxic compounds. The active efflux might also take part in exporting low-molecular-weight alcohols produced by intrinsic cell metabolism; in the case of solventogenic clostridia, predominantly acetone, butanol and ethanol (ABE). However, little is known about this active efflux, even though some evidence exists that membrane pumps might be involved in solvent tolerance. In this study, we investigated changes in overall active efflux during ABE fermentation, employing a flow cytometric protocol adjusted for Clostridia and using ethidium bromide (EB) as a fluorescence marker for quantification of direct efflux. A fluctuation in efflux during the course of standard ABE fermentation was observed, with a maximum reached during late acidogenesis, a high efflux rate during early and mid-solventogenesis and an apparent decrease in EB efflux rate in late solventogenesis. The fluctuation in efflux activity was in accordance with transcriptomic data obtained for various membrane exporters in a former study. Surprisingly, under altered cultivation conditions, when solvent production was attenuated, and extended acidogenesis was promoted, stable low efflux activity was reached after an initial peak that appeared in the stage comparable to standard ABE fermentation. This study confirmed that efflux pump activity is not constant during ABE fermentation and suggests that undisturbed solvent production might be a trigger for activation of pumps involved in solvent efflux. KEY POINTS: • Flow cytometric assay for efflux quantification in Clostridia was established. • Efflux rate peaked in late acidogenesis and in early solventogenesis. • Impaired solventogenesis led to an overall decrease in efflux.
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Affiliation(s)
- Barbora Branska
- Department of Biotechnology, University of Chemistry and Technology Prague, Technicka 5, 166 28, Prague, Czech Republic.
| | - Maryna Vasylkivska
- Department of Biotechnology, University of Chemistry and Technology Prague, Technicka 5, 166 28, Prague, Czech Republic
| | - Hana Raschmanova
- Department of Biotechnology, University of Chemistry and Technology Prague, Technicka 5, 166 28, Prague, Czech Republic
| | - Katerina Jureckova
- Department of Biomedical Engineering, Faculty of Electrical Engineering and Communication, Brno University of Technology, Technicka 12, 616 00, Brno, Czech Republic
| | - Karel Sedlar
- Department of Biomedical Engineering, Faculty of Electrical Engineering and Communication, Brno University of Technology, Technicka 12, 616 00, Brno, Czech Republic
| | - Ivo Provaznik
- Department of Biomedical Engineering, Faculty of Electrical Engineering and Communication, Brno University of Technology, Technicka 12, 616 00, Brno, Czech Republic
| | - Petra Patakova
- Department of Biotechnology, University of Chemistry and Technology Prague, Technicka 5, 166 28, Prague, Czech Republic
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11
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Vasylkivska M, Branska B, Sedlar K, Jureckova K, Provaznik I, Patakova P. Phenotypic and Genomic Analysis of Clostridium beijerinckii NRRL B-598 Mutants With Increased Butanol Tolerance. Front Bioeng Biotechnol 2020; 8:598392. [PMID: 33224939 PMCID: PMC7674653 DOI: 10.3389/fbioe.2020.598392] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 10/20/2020] [Indexed: 11/19/2022] Open
Abstract
N-Butanol, a valuable solvent and potential fuel extender, can be produced via acetone-butanol-ethanol (ABE) fermentation. One of the main drawbacks of ABE fermentation is the high toxicity of butanol to producing cells, leading to cell membrane disruption, low culture viability and, consequently, low produced concentrations of butanol. The goal of this study was to obtain mutant strains of Clostridium beijerinckii NRRL B-598 with improved butanol tolerance using random chemical mutagenesis, describe changes in their phenotypes compared to the wild-type strain and reveal changes in the genome that explain improved tolerance or other phenotypic changes. Nine mutant strains with stable improved features were obtained by three different approaches and, for two of them, ethidium bromide (EB), a known substrate of efflux pumps, was used for either selection or as a mutagenic agent. It is the first utilization of this approach for the development of butanol-tolerant mutants of solventogenic clostridia, for which generally there is a lack of knowledge about butanol efflux or efflux mechanisms and their regulation. Mutant strains exhibited increase in butanol tolerance from 36% up to 127% and the greatest improvement was achieved for the strains for which EB was used as a mutagenic agent. Additionally, increased tolerance to other substrates of efflux pumps, EB and ethanol, was observed in all mutants and higher antibiotic tolerance in some of the strains. The complete genomes of mutant strains were sequenced and revealed that improved butanol tolerance can be attributed to mutations in genes encoding typical stress responses (chemotaxis, autolysis or changes in cell membrane structure), but, also, to mutations in genes X276_07980 and X276_24400, encoding efflux pump regulators. The latter observation confirms the importance of efflux in butanol stress response of the strain and offers new targets for rational strain engineering.
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Affiliation(s)
- Maryna Vasylkivska
- Department of Biotechnology, University of Chemistry and Technology, Prague, Prague, Czechia
| | - Barbora Branska
- Department of Biotechnology, University of Chemistry and Technology, Prague, Prague, Czechia
| | - Karel Sedlar
- Department of Biomedical Engineering, Faculty of Electrical Engineering and Communication, Brno University of Technology, Brno, Czechia
| | - Katerina Jureckova
- Department of Biomedical Engineering, Faculty of Electrical Engineering and Communication, Brno University of Technology, Brno, Czechia
| | - Ivo Provaznik
- Department of Biomedical Engineering, Faculty of Electrical Engineering and Communication, Brno University of Technology, Brno, Czechia
| | - Petra Patakova
- Department of Biotechnology, University of Chemistry and Technology, Prague, Prague, Czechia
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