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Im C, Kim M, Kim JR, Valgepea K, Modin O, Nygård Y, Franzén CJ. Low electric current in a bioelectrochemical system facilitates ethanol production from CO using CO-enriched mixed culture. Front Microbiol 2024; 15:1438758. [PMID: 39268540 PMCID: PMC11390636 DOI: 10.3389/fmicb.2024.1438758] [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] [Received: 05/26/2024] [Accepted: 07/24/2024] [Indexed: 09/15/2024] Open
Abstract
Fossil resources must be replaced by renewable resources in production systems to mitigate green-house gas emissions and combat climate change. Electro-fermentation utilizes a bioelectrochemical system (BES) to valorize industrial and municipal waste. Current electro-fermentation research is mainly focused on microbial electrosynthesis using CO2 for producing commodity chemicals and replacing petroleum-based infrastructures. However, slow production rates and low titers of metabolites during CO2-based microbial electrosynthesis impede its implementation to the real application in the near future. On the other hand, CO is a highly reactive gas and an abundant feedstock discharged from fossil fuel-based industry. Here, we investigated CO and CO2 electro-fermentation, using a CO-enriched culture. Fresh cow fecal waste was enriched under an atmosphere of 50% CO and 20% CO2 in N2 using serial cultivation. The CO-enriched culture was dominated by Clostridium autoethanogenum (≥89%) and showed electro-activity in a BES reactor with CO2 sparging. When 50% CO was included in the 20% CO2 gas with 10 mA applied current, acetate and ethanol were produced up to 12.9 ± 2.7 mM and 2.7 ± 1.1 mM, respectively. The coulombic efficiency was estimated to 148% ± 8% without an electron mediator. At 25 mA, the culture showed faster initial growth and acetate production but no ethanol production, and only at 86% ± 4% coulombic efficiency. The maximum optical density (OD) of 10 mA and 25 mA reactors were 0.29 ± 0.07 and 0.41 ± 0.03, respectively, whereas it was 0.77 ± 0.19 without electric current. These results show that CO electro-fermentation at low current can be an alternative way of valorizing industrial waste gas using a bioelectrochemical system.
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Affiliation(s)
- Chaeho Im
- Division of Industrial Biotechnology, Department of Life Sciences, Chalmers University of Technology, Göteborg, Sweden
| | - Minsoo Kim
- School of Chemical Engineering, Pusan National University, Busan, Republic of Korea
| | - Jung Rae Kim
- School of Chemical Engineering, Pusan National University, Busan, Republic of Korea
| | - Kaspar Valgepea
- Institute of Bioengineering, University of Tartu, Tartu, Estonia
| | - Oskar Modin
- Division of Water Environment Technology, Department of Architecture and Civil Engineering, Chalmers University of Technology, Göteborg, Sweden
| | - Yvonne Nygård
- Division of Industrial Biotechnology, Department of Life Sciences, Chalmers University of Technology, Göteborg, Sweden
- VTT Technical Research Centre of Finland, Espoo, Finland
| | - Carl Johan Franzén
- Division of Industrial Biotechnology, Department of Life Sciences, Chalmers University of Technology, Göteborg, Sweden
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2
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Wang D, Liu N, Qiao M, Xu C. Gallic acid as biofilm inhibitor can improve transformation efficiency of Ruminiclostridium papyrosolvens. Biotechnol Lett 2024:10.1007/s10529-024-03522-y. [PMID: 39162860 DOI: 10.1007/s10529-024-03522-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2024] [Revised: 07/26/2024] [Accepted: 08/03/2024] [Indexed: 08/21/2024]
Abstract
Ruminiclostridium papyrosolvens is an anaerobic, mesophilic, and cellulolytic clostridia, promising consolidated bioprocessing (CBP) candidate for producing renewable green chemicals from cellulose, but its genetic transformation has been severely impeded by extracellular biofilm. Here, we analyzed the effects of five different inhibitors with gradient concentrations on R. papyrosolvens growth and biofilm formation. Gallic acid was proved to be a potent inhibitor of biofilm synthesis of R. papyrosolvens. Furthermore, the transformation efficiency of R. papyrosolvens was significantly increased when the cells were treated by the gallic acid, and the mutant strain was successfully obtained by the improved transformation method. Thus, inhibition of biofilm formation of R. papyrosolvens by using gallic acid will contribute to its genetic transformation and efficient metabolic engineering.
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Affiliation(s)
- Duodong Wang
- School of Life Science, Shanxi University, Taiyuan, 030006, Shanxi, China
- College of Animal Science and Technology & College of Veterinary Medicine, Zhejiang A&F University, Hangzhou, 311300, Zhejiang Province, China
| | - Na Liu
- School of Life Science, Shanxi University, Taiyuan, 030006, Shanxi, China
| | - Mingqiang Qiao
- School of Life Science, Shanxi University, Taiyuan, 030006, Shanxi, China.
| | - Chenggang Xu
- College of Animal Science and Technology & College of Veterinary Medicine, Zhejiang A&F University, Hangzhou, 311300, Zhejiang Province, China.
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3
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Javed MQ, Kovalchuk I, Yevtushenko D, Yang X, Stanford K. Relationship between Desiccation Tolerance and Biofilm Formation in Shiga Toxin-Producing Escherichia coli. Microorganisms 2024; 12:243. [PMID: 38399647 PMCID: PMC10891874 DOI: 10.3390/microorganisms12020243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 01/12/2024] [Accepted: 01/22/2024] [Indexed: 02/25/2024] Open
Abstract
Shiga toxin-producing Escherichia coli (STEC) is a major concern in the food industry and requires effective control measures to prevent foodborne illnesses. Previous studies have demonstrated increased difficulty in the control of biofilm-forming STEC. Desiccation, achieved through osmotic stress and water removal, has emerged as a potential antimicrobial hurdle. This study focused on 254 genetically diverse E. coli strains collected from cattle, carcass hides, hide-off carcasses, and processing equipment. Of these, 141 (55.51%) were STEC and 113 (44.48%) were generic E. coli. The biofilm-forming capabilities of these isolates were assessed, and their desiccation tolerance was investigated to understand the relationships between growth temperature, relative humidity (RH), and bacterial survival. Only 28% of the STEC isolates had the ability to form biofilms, compared to 60% of the generic E. coli. Stainless steel surfaces were exposed to different combinations of temperature (0 °C or 35 °C) and relative humidity (75% or 100%), and the bacterial attachment and survival rates were measured over 72 h and compared to controls. The results revealed that all the strains exposed to 75% relative humidity (RH) at any temperature had reduced growth (p < 0.001). In contrast, 35 °C and 100% RH supported bacterial proliferation, except for isolates forming the strongest biofilms. The ability of E. coli to form a biofilm did not impact growth reduction at 75% RH. Therefore, desiccation treatment at 75% RH at temperatures of 0 °C or 35 °C holds promise as a novel antimicrobial hurdle for the removal of biofilm-forming E. coli from challenging-to-clean surfaces and equipment within food processing facilities.
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Affiliation(s)
- Muhammad Qasim Javed
- Department of Biological Sciences, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada; (M.Q.J.); (I.K.); (D.Y.)
| | - Igor Kovalchuk
- Department of Biological Sciences, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada; (M.Q.J.); (I.K.); (D.Y.)
| | - Dmytro Yevtushenko
- Department of Biological Sciences, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada; (M.Q.J.); (I.K.); (D.Y.)
| | - Xianqin Yang
- Agriculture and Agri-Food Canada, Lacombe, AB T4L 1V7, Canada;
| | - Kim Stanford
- Department of Biological Sciences, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada; (M.Q.J.); (I.K.); (D.Y.)
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4
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Buenaño-Vargas C, Gagliano MC, Paulo LM, Bartle A, Graham A, van Veelen HPJ, O'Flaherty V. Acclimation of microbial communities to low and moderate salinities in anaerobic digestion. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 906:167470. [PMID: 37778560 DOI: 10.1016/j.scitotenv.2023.167470] [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: 07/14/2023] [Revised: 09/27/2023] [Accepted: 09/28/2023] [Indexed: 10/03/2023]
Abstract
In recent years anaerobic digestion (AD) has been investigated as suitable biotechnology to treat wastewater at elevated salinities. However, when starting up AD reactors with inocula that are not adapted to salinity, low concentrations of sodium (Na+) in the influent can already cause disintegration of microbial aggregates and wash-out. This study investigated biomass acclimation to 5 g Na+/L of two different non-adapted inocula in two lab-scale hybrid expanded granular sludge bed (EGSB)-anaerobic filter (AF) reactors fed with synthetic wastewater. After an initial biomass disintegration, new aggregates were formed relatively fast (i.e., after 95 days of operation), indicating microbial community adaptation. The newly formed microbial aggregates accumulated Na+ at the expense of calcium (Ca2+), but this did not hamper biomass retention or process performance. The hybrid reactor configuration, including a pumice stone filter in the upper section, and the low up-flow velocities applied, were key features for retaining the biomass within the system. This reactor configuration can be easily applied and represents a low-cost alternative for acclimating biomass to saline effluents, even in existing digesters. When the acclimated biomass was transferred from EGSB to an up-flow anaerobic sludge blanket (UASB) reactor configuration also fed with saline synthetic wastewater, more dense aggregates in the form of granules were obtained. The performances of the UASB inoculated with the acclimated biomass were comparable to another reactor seeded with saline-adapted granular sludge from a full-scale plant. Regardless of the inoculum origin, a defined core microbiome of Bacteria (Thermovirga, Bacteroidetes vadinHA17, Blvii28 wastewater-sludge group, Mesotoga, and Synergistaceae) and Archaea (Methanosaeta and Methanobacterium) was detected, highlighting the importance of these microbial groups in developing halotolerance and maintaining AD process stability.
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Affiliation(s)
- Claribel Buenaño-Vargas
- Microbial Ecology Laboratory, School of Biological and Chemical Sciences and Ryan Institute, University of Galway, University Road, Ireland
| | - M Cristina Gagliano
- Wetsus - European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911MA Leeuwarden, the Netherlands
| | - Lara M Paulo
- Microbial Ecology Laboratory, School of Biological and Chemical Sciences and Ryan Institute, University of Galway, University Road, Ireland
| | - Andrew Bartle
- Microbial Ecology Laboratory, School of Biological and Chemical Sciences and Ryan Institute, University of Galway, University Road, Ireland
| | - Alison Graham
- Microbial Ecology Laboratory, School of Biological and Chemical Sciences and Ryan Institute, University of Galway, University Road, Ireland
| | - H Pieter J van Veelen
- Wetsus - European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911MA Leeuwarden, the Netherlands
| | - Vincent O'Flaherty
- Microbial Ecology Laboratory, School of Biological and Chemical Sciences and Ryan Institute, University of Galway, University Road, Ireland.
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Dessì P, Buenaño-Vargas C, Martínez-Sosa S, Mills S, Trego A, Ijaz UZ, Pant D, Puig S, O'Flaherty V, Farràs P. Microbial electrosynthesis of acetate from CO 2 in three-chamber cells with gas diffusion biocathode under moderate saline conditions. ENVIRONMENTAL SCIENCE AND ECOTECHNOLOGY 2023; 16:100261. [PMID: 37089695 PMCID: PMC10120373 DOI: 10.1016/j.ese.2023.100261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 02/23/2023] [Accepted: 03/10/2023] [Indexed: 05/03/2023]
Abstract
The industrial adoption of microbial electrosynthesis (MES) is hindered by high overpotentials deriving from low electrolyte conductivity and inefficient cell designs. In this study, a mixed microbial consortium originating from an anaerobic digester operated under saline conditions (∼13 g L-1 NaCl) was adapted for acetate production from bicarbonate in galvanostatic (0.25 mA cm-2) H-type cells at 5, 10, 15, or 20 g L-1 NaCl concentration. The acetogenic communities were successfully enriched only at 5 and 10 g L-1 NaCl, revealing an inhibitory threshold of about 6 g L-1 Na+. The enriched planktonic communities were then used as inoculum for 3D printed, three-chamber cells equipped with a gas diffusion biocathode. The cells were fed with CO2 gas and operated galvanostatically (0.25 or 1.00 mA cm-2). The highest production rate of 55.4 g m-2 d-1 (0.89 g L-1 d-1), with 82.4% Coulombic efficiency, was obtained at 5 g L-1 NaCl concentration and 1 mA cm-2 applied current, achieving an average acetate production of 44.7 kg MWh-1. Scanning electron microscopy and 16S rRNA sequencing analysis confirmed the formation of a cathodic biofilm dominated by Acetobacterium sp. Finally, three 3D printed cells were hydraulically connected in series to simulate an MES stack, achieving three-fold production rates than with the single cell at 0.25 mA cm-2. This confirms that three-chamber MES cells are an efficient and scalable technology for CO2 bio-electro recycling to acetate and that moderate saline conditions (5 g L-1 NaCl) can help reduce their power demand while preserving the activity of acetogens.
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Affiliation(s)
- Paolo Dessì
- School of Biological and Chemical Sciences and Energy Research Centre, Ryan Institute, University of Galway, University Road, H91 CF50, Galway, Ireland
- LEQUiA, Institute of the Environment, University of Girona, Carrer Maria Aurèlia Capmany 69, E-17003, Girona, Spain
- Corresponding author. LEQUiA, Institute of the Environment, University of Girona, Carrer Maria Aurèlia Capmany 69, E-17003, Girona, Spain.
| | - Claribel Buenaño-Vargas
- Microbiology Department, School of Natural Sciences, University of Galway, University Road, H91 TK33, Galway, Ireland
| | - Santiago Martínez-Sosa
- School of Biological and Chemical Sciences and Energy Research Centre, Ryan Institute, University of Galway, University Road, H91 CF50, Galway, Ireland
| | - Simon Mills
- Microbiology Department, School of Natural Sciences, University of Galway, University Road, H91 TK33, Galway, Ireland
| | - Anna Trego
- Microbiology Department, School of Natural Sciences, University of Galway, University Road, H91 TK33, Galway, Ireland
| | - Umer Z. Ijaz
- Infrastructure and Environment Research Division, School of Engineering, University of Glasgow, Glasgow, United Kingdom
| | - Deepak Pant
- Separation and Conversion Technology, Flemish Institute for Technological Research (VITO), Boeretang 200, 2400, Mol, Belgium
| | - Sebastià Puig
- LEQUiA, Institute of the Environment, University of Girona, Carrer Maria Aurèlia Capmany 69, E-17003, Girona, Spain
| | - Vincent O'Flaherty
- Microbiology Department, School of Natural Sciences, University of Galway, University Road, H91 TK33, Galway, Ireland
| | - Pau Farràs
- School of Biological and Chemical Sciences and Energy Research Centre, Ryan Institute, University of Galway, University Road, H91 CF50, Galway, Ireland
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6
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López-García E, Benítez-Cabello A, Tronchoni J, Arroyo-López FN. Understanding the transcriptomic response of Lactiplantibacillus pentosus LPG1 during Spanish-style green table olive fermentations. Front Microbiol 2023; 14:1264341. [PMID: 37808291 PMCID: PMC10556671 DOI: 10.3389/fmicb.2023.1264341] [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] [Received: 07/20/2023] [Accepted: 09/08/2023] [Indexed: 10/10/2023] Open
Abstract
Lactiplantibacillus pentosus (Lbp. pentosus) is a species of lactic acid bacteria with a great relevance during the table olive fermentation process, with ability to form non-pathogenic biofilms on olive epidermis. The objective of this work is to deepen into the genetic mechanisms of adaptation of Lpb. pentosus LPG1 during Spanish-style green table olive fermentations, as well as to obtain a better understanding of the mechanisms of adherence of this species to the fruit surface. For this purpose, we have carried out a transcriptomic analysis of the differential gene expression of this bacterium during 60 days of fermentation in both brine and biofilms ecosystems. In brines, it was noticed that a total of 235 genes from Lpb. pentosus LPG1 were differentially expressed during course of fermentation and grouped into 9 clusters according to time-course analysis. Transport and metabolism of carbohydrates and amino acids, energy production, lactic acid and exopolysaccharide synthesis genes increased their expression in the planktonic cells during course of fermentation. On the other hand, expression of genes associated to stress response, bacteriocin synthesis and membrane protein decreased. A total of 127 genes showed significant differential expression between Lpb. pentosus LPG1 planktonic (brine) and sessile (biofilms) cells at the end of fermentation process (60 days). Among the 64 upregulated genes in biofilms, we found genes involved in adhesion (strA), exopolysaccharide production (ywqD, ywqE, and wbnH), cell shape and elongation (MreB), and well as prophage excision. Deeping into the genetic bases of beneficial biofilm formation by Lpb. pentosus strains with probiotic potential will help to turn this fermented vegetable into a carrier of beneficial microorganisms to the final consumers.
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Affiliation(s)
- Elio López-García
- Department of Food Biotechnology, Instituto de la Grasa (CSIC), Campus Universitario Pablo de Olavide, Seville, Spain
| | - Antonio Benítez-Cabello
- Department of Food Biotechnology, Instituto de la Grasa (CSIC), Campus Universitario Pablo de Olavide, Seville, Spain
| | - Jordi Tronchoni
- Universidad Internacional de Valencia, Comunidad Valencia, Spain
| | - Francisco Noé Arroyo-López
- Department of Food Biotechnology, Instituto de la Grasa (CSIC), Campus Universitario Pablo de Olavide, Seville, Spain
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7
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Misra T, Tare M, Jha PN. Characterization of functional amyloid curli in biofilm formation of an environmental isolate Enterobacter cloacae SBP-8. Antonie Van Leeuwenhoek 2023:10.1007/s10482-023-01843-y. [PMID: 37243862 DOI: 10.1007/s10482-023-01843-y] [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: 12/19/2022] [Accepted: 05/12/2023] [Indexed: 05/29/2023]
Abstract
The biofilm formation by bacteria is a complex process that is strongly mediated by various genetic and environmental factors. Biofilms contribute to disease infestation, especially in chronic infections. It is, therefore important to understand the factors affecting biofilm formation. This study reports the role of a functional amyloid curli in biofilm formation at various abiotic surfaces, including medical devices, by an environmental isolate of Enterobacter cloacae (SBP-8) which has been known for its pathogenic potential. A knockout mutant of csgA, the gene encoding the major structural unit of curli, was created to study the effect of curli on biofilm formation by E. cloacae SBP-8. Our findings confirm the production of curli at 25 °C and 37 °C in the wild-type strain. We further investigated the role of curli in the attachment of E. cloacae SBP-8 to glass, enteral feeding tube, and foley latex catheter. Contrary to the previous studies reporting the curli production below 30 °C in the majority of biofilm-forming bacterial species, we observed its production in E. cloacae SBP-8 at 37 °C. The formation of more intense biofilm in wild-type strain on various surfaces compared to curli-deficient strain (ΔcsgA) at both 25 °C and 37 °C suggested a prominent role of curli in biofilm formation. Further, electron and confocal microscopy studies demonstrated the formation of diffused monolayers of microbial cells on the abiotic surfaces by ΔcsgA strain as compared to the thick biofilm by respective wild-type strain, indicating the involvement of curli in biofilm formation by E. cloacae SBP-8. Overall, our findings provide insight into biofilm formation mediated by curli in E. cloacae SBP-8. Further, we show that it can be expressed at a physiological temperature on all surfaces, thereby indicating the potential role of curli in pathogenesis.
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Affiliation(s)
- Tripti Misra
- Department of Biological Sciences, Birla Institute of Technology and Science, Pilani, Rajasthan, 333031, India
| | - Meghana Tare
- Department of Biological Sciences, Birla Institute of Technology and Science, Pilani, Rajasthan, 333031, India.
| | - Prabhat Nath Jha
- Department of Biological Sciences, Birla Institute of Technology and Science, Pilani, Rajasthan, 333031, India.
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8
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Pavao A, Girinathan B, Peltier J, Altamirano Silva P, Dupuy B, Muti IH, Malloy C, Cheng LL, Bry L. Elucidating dynamic anaerobe metabolism with HRMAS 13C NMR and genome-scale modeling. Nat Chem Biol 2023; 19:556-564. [PMID: 36894723 PMCID: PMC10154198 DOI: 10.1038/s41589-023-01275-9] [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: 08/24/2022] [Accepted: 01/30/2023] [Indexed: 03/11/2023]
Abstract
Anaerobic microbial metabolism drives critical functions within global ecosystems, host-microbiota interactions, and industrial applications, yet remains ill-defined. Here we advance a versatile approach to elaborate cellular metabolism in obligate anaerobes using the pathogen Clostridioides difficile, an amino acid and carbohydrate-fermenting Clostridia. High-resolution magic angle spinning nuclear magnetic resonance (NMR) spectroscopy of C. difficile, grown with fermentable 13C substrates, informed dynamic flux balance analysis (dFBA) of the pathogen's genome-scale metabolism. Analyses identified dynamic recruitment of oxidative and supporting reductive pathways, with integration of high-flux amino acid and glycolytic metabolism at alanine's biosynthesis to support efficient energy generation, nitrogen handling and biomass generation. Model predictions informed an approach leveraging the sensitivity of 13C NMR spectroscopy to simultaneously track cellular carbon and nitrogen flow from [U-13C]glucose and [15N]leucine, confirming the formation of [13C,15N]alanine. Findings identify metabolic strategies used by C. difficile to support its rapid colonization and expansion in gut ecosystems.
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Affiliation(s)
- Aidan Pavao
- Massachusetts Host-Microbiome Center, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Brintha Girinathan
- Massachusetts Host-Microbiome Center, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
- Ginkgo Bioworks, The Innovation and Design Building, Boston, MA, USA
| | - Johann Peltier
- Laboratoire Pathogenèse des Bactéries Anaérobies, F-75015, Institut Pasteur, Université Paris-Cité, UMR-CNRS 6047, Paris, France
- Institute for Integrative Biology of the Cell (I2BC), 91198, University of Paris-Saclay, CEA, CNRS, Gif-sur-Yvette, France
| | - Pamela Altamirano Silva
- Centre for Investigations in Tropical Diseases, Faculty of Microbiology, University of Costa Rica, San José, Costa Rica
| | - Bruno Dupuy
- Laboratoire Pathogenèse des Bactéries Anaérobies, F-75015, Institut Pasteur, Université Paris-Cité, UMR-CNRS 6047, Paris, France
| | - Isabella H Muti
- Departments of Radiology and Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Craig Malloy
- Department of Radiology, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Leo L Cheng
- Departments of Radiology and Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
| | - Lynn Bry
- Massachusetts Host-Microbiome Center, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
- Clinical Microbiology Laboratory, Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
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9
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Formation of biofilm changed the responses of Tetragenococcus halophilus to ethanol stress revealed by transcriptomic and proteomic analyses. Food Res Int 2022; 161:111817. [DOI: 10.1016/j.foodres.2022.111817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Revised: 08/01/2022] [Accepted: 08/18/2022] [Indexed: 11/23/2022]
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10
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Misra T, Tare M, Jha PN. Insights Into the Dynamics and Composition of Biofilm Formed by Environmental Isolate of Enterobacter cloacae. Front Microbiol 2022; 13:877060. [PMID: 35865928 PMCID: PMC9294512 DOI: 10.3389/fmicb.2022.877060] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 05/27/2022] [Indexed: 11/13/2022] Open
Abstract
Bacterial biofilms are clinically admissible and illustrate an influential role in infections, particularly those related to the implant of medical devices. The characterization of biofilms is important to understand the etiology of the diseases. Enterobacter cloacae are known for causing infections by forming biofilms on various abiotic surfaces, such as medical devices. However, a detailed characterization in terms of morphology and the molecular composition of the formed biofilms by this bacterium is sparse. The present study provides insights into the biofilm formation of E. cloacae SBP-8, an environmental isolate, on various surfaces. We performed assays to understand the biofilm-forming capability of the SBP-8 strain and characterized the adhering potential of the bacteria on the surface of different medical devices (foley latex catheter, enteral feeding tube, and glass) at different temperatures. We found that medical devices exhibited strong colonization by E. cloacae SBP-8. Using field emission-scanning electron microscopy (FE-SEM) studies, we characterized the biofilms as a function of time. It indicated stronger biofilm formation in terms of cellular density and EPS production on the surfaces. Further, we characterized the biofilm employing surface-enhanced Raman spectroscopy (SERS) and identified the vast heterogenic nature of the biofilm-forming molecules. Interestingly, we also found that this heterogeneity varies from the initial stages of biofilm formation until the maturation and dispersion. Our studies provide insights into biofilm composition over a period of time, which might aid in understanding the biofilm dispersion phases, to enhance the presently available treatment strategies.
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Affiliation(s)
| | - Meghana Tare
- Department of Biological Sciences, Birla Institute of Technology and Science, Pilani, India
| | - Prabhat Nath Jha
- Department of Biological Sciences, Birla Institute of Technology and Science, Pilani, India
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11
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Podrzaj L, Burtscher J, Domig KJ. Comparative Genomics Provides Insights Into Genetic Diversity of Clostridium tyrobutyricum and Potential Implications for Late Blowing Defects in Cheese. Front Microbiol 2022; 13:889551. [PMID: 35722315 PMCID: PMC9201417 DOI: 10.3389/fmicb.2022.889551] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 05/16/2022] [Indexed: 11/24/2022] Open
Abstract
Clostridium tyrobutyricum has been recognized as the main cause of late blowing defects (LBD) in cheese leading to considerable economic losses for the dairy industry. Although differences in spoilage ability among strains of this species have been acknowledged, potential links to the genetic diversity and functional traits remain unknown. In the present study, we aimed to investigate and characterize genomic variation, pan-genomic diversity and key traits of C. tyrobutyricum by comparing the genomes of 28 strains. A comparative genomics analysis revealed an “open” pangenome comprising 9,748 genes and a core genome of 1,179 genes shared by all test strains. Among those core genes, the majority of genes encode proteins related to translation, ribosomal structure and biogenesis, energy production and conversion, and amino acid metabolism. A large part of the accessory genome is composed of sets of unique, strain-specific genes ranging from about 5 to more than 980 genes. Furthermore, functional analysis revealed several strain-specific genes related to replication, recombination and repair, cell wall, membrane and envelope biogenesis, and defense mechanisms that might facilitate survival under stressful environmental conditions. Phylogenomic analysis divided strains into two clades: clade I contained human, mud, and silage isolates, whereas clade II comprised cheese and milk isolates. Notably, these two groups of isolates showed differences in certain hypothetical proteins, transcriptional regulators and ABC transporters involved in resistance to oxidative stress. To the best of our knowledge, this is the first study to provide comparative genomics of C. tyrobutyricum strains related to LBD. Importantly, the findings presented in this study highlight the broad genetic diversity of C. tyrobutyricum, which might help us understand the diversity in spoilage potential of C. tyrobutyricum in cheese and provide some clues for further exploring the gene modules responsible for the spoilage ability of this species.
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Affiliation(s)
- Lucija Podrzaj
- Department of Food Science and Technology, Institute of Food Science, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Johanna Burtscher
- Department of Food Science and Technology, Institute of Food Science, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Konrad J Domig
- Department of Food Science and Technology, Institute of Food Science, University of Natural Resources and Life Sciences, Vienna, Austria
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12
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Gagliano MC, Sampara P, Plugge CM, Temmink H, Sudmalis D, Ziels RM. Functional Insights of Salinity Stress-Related Pathways in Metagenome-Resolved Methanothrix Genomes. Appl Environ Microbiol 2022; 88:e0244921. [PMID: 35477253 PMCID: PMC9128505 DOI: 10.1128/aem.02449-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 04/11/2022] [Indexed: 12/15/2022] Open
Abstract
Recently, methanogenic archaea belonging to the genus Methanothrix were reported to have a fundamental role in maintaining stable ecosystem functioning in anaerobic bioreactors under different configurations/conditions. In this study, we reconstructed three Methanothrix metagenome-assembled genomes (MAGs) from granular sludge collected from saline upflow anaerobic sludge blanket (UASB) reactors, where Methanothrix harundinacea was previously implicated with the formation of compact and stable granules under elevated salinity levels (up to 20 g/L Na+). Genome annotation and pathway analysis of the Methanothrix MAGs revealed a genetic repertoire supporting their growth under high salinity. Specifically, the most dominant Methanothrix (MAG_279), classified as a subspecies of Methanothrix_A harundinacea_D, had the potential to augment its salinity resistance through the production of different glycoconjugates via the N-glycosylation process, and via the production of compatible solutes as Nε-acetyl-β-lysine and ectoine. The stabilization and reinforcement of the cell membrane via the production of isoprenoids was identified as an additional stress-related pathway in this microorganism. The improved understanding of the salinity stress-related mechanisms of M. harundinacea highlights its ecological niche in extreme conditions, opening new perspectives for high-efficiency methanisation of organic waste at high salinities, as well as the possible persistence of this methanogen in highly-saline natural anaerobic environments. IMPORTANCE Using genome-centric metagenomics, we discovered a new Methanothrix harundinacea subspecies that appears to be a halotolerant acetoclastic methanogen with the flexibility for adaptation in the anaerobic digestion process both at low (5 g/L Na+) and high salinity conditions (20 g/L Na+). Annotation of the recovered M. harundinacea genome revealed salinity stress-related functions, including the modification of EPS glycoconjugates and the production of compatible solutes. This is the first study reporting these genomic features within a Methanothrix sp., a milestone further supporting previous studies that identified M. harundinacea as a key-driver in anaerobic granulation under high salinity stress.
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Affiliation(s)
- Maria Cristina Gagliano
- Wetsus – European Centre of Excellence for Sustainable Water Technology, Leeuwarden, the Netherlands
- Laboratory of Microbiology, Wageningen University and Research, Wageningen, the Netherlands
| | - Pranav Sampara
- Civil Engineering, University of British Columbia, Vancouver, British Columbia, Canada
| | - Caroline M. Plugge
- Wetsus – European Centre of Excellence for Sustainable Water Technology, Leeuwarden, the Netherlands
- Laboratory of Microbiology, Wageningen University and Research, Wageningen, the Netherlands
| | - Hardy Temmink
- Wetsus – European Centre of Excellence for Sustainable Water Technology, Leeuwarden, the Netherlands
- Department of Environmental Technology, Wageningen University and Research, Wageningen, the Netherlands
| | - Dainis Sudmalis
- Department of Environmental Technology, Wageningen University and Research, Wageningen, the Netherlands
| | - Ryan M. Ziels
- Civil Engineering, University of British Columbia, Vancouver, British Columbia, Canada
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13
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Du B, Wang S, Chen G, Wang G, Liu L. Nutrient starvation intensifies chlorine disinfection-stressed biofilm formation. CHEMOSPHERE 2022; 295:133827. [PMID: 35122818 DOI: 10.1016/j.chemosphere.2022.133827] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 12/09/2021] [Accepted: 01/29/2022] [Indexed: 06/14/2023]
Abstract
Bacterial surface attachment and subsequent biofilm expansion represent an essential adaptation to environmental signals and stresses, which are of great concern for many natural and engineered ecosystems. Yet the underlying mechanisms and driving forces of biofilm formation in a chlorinated and nutrient-restricted system remain sketchy. In this study, we coupled an experimental investigation and modeling simulation to understand how chlorination and nutrient limitation conspire to form biofilm using Pseudomonas aeruginosa as a model bacterium. Experimental results showed that moderate chlorination at 1.0 mg/L led to biofilm development amplified to 2.6 times of those without chlorine, while additional nutrient limitation (of 1/50-diluted or 0.4 g/L LB broth culture) achieved 4.6 times increment as compared to those of undiluted scenarios (of 20 g/L LB broth culture) with absence of chlorination after 24 h exposure. Meanwhile, intermediate chlorination stimulated instant flagellar motility and subsequently extracellular polymeric substances (EPS) secretion, particularly under limited nutrient condition (of 1/50-diluted or 0.4 g/L LB broth culture) that retarded chlorine consumption and provoked bacterial nutrient-limitation response. From our simulations, chlorine and resource levels along with associated spatio-temporal variations collectively drove bacterial cell movement and EPS excretion. Our results demonstrated that restraining nutrient intensified chlorination-excited cell movement and EPS production that reinforced biological and cell-surface interactions, thereby encouraging bacterial surface attachment and subsequent biofilm development. The findings provide the insights into the linkage of disinfectant and nutrient-regulated bacterial functional responses with consequent micro-habitats and biofilm dynamics.
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Affiliation(s)
- Bang Du
- School of Civil Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Shudong Wang
- School of Civil Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Guowei Chen
- School of Civil Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Gang Wang
- Department of Soil and Water Sciences, China Agricultural University, Beijing, 100193, China
| | - Li Liu
- School of Civil Engineering, Hefei University of Technology, Hefei, 230009, China.
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14
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Marcel M, Darina E, Patrick K, Aline H, Gabriele P, Stefan J, Jochen B. Impact of different trace elements on metabolic routes during heterotrophic growth of C. ljungdahlii investigated through online measurement of the carbon dioxide transfer rate. Biotechnol Prog 2022; 38:e3263. [PMID: 35434968 DOI: 10.1002/btpr.3263] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 03/30/2022] [Accepted: 04/15/2022] [Indexed: 11/09/2022]
Abstract
Synthesis gas fermentation using acetogenic clostridia is a rapidly increasing research area. It offers the possibility to produce platform chemicals from sustainable C1 carbon sources. The Wood-Ljungdahl pathway (WLP), which allows acetogens to grow autotrophically, is also active during heterotrophic growth. It acts as an electron sink and allows for the utilization of a wide variety of soluble substrates and increases ATP yields during heterotrophic growth. While glycolysis leads to CO2 evolution, WLP activity results in CO2 fixation. Thus, a reduction of net CO2 emissions during growth with sugars is an indicator of WLP activity. To study the effect of trace elements and ventilation rates on the interaction between glycolysis and the WLP, the model acetogen Clostridium ljungdahlii was cultivated in YTF medium, a complex medium generally employed for heterotrophic growth, with fructose as growth substrate. The recently reported anaRAMOS device was used for online measurement of metabolic activity, in form of CO2 evolution. The addition of multiple trace elements (iron, cobalt, manganese, zinc, nickel, copper, selenium, and tungsten) was tested, to study the interaction between glycolysis and the Wood ljungdahl pathway. While the addition of iron(II) increased growth rates and ethanol production, added nickel(II) increased WLP activity and acetate formation, reducing net CO2 production by 28%. Also, higher CO2 availability through reduced volumetric gas flow resulted in 25% reduction of CO2 evolution. These online metabolic data demonstrate that the anaRAMOS is a valuable tool in the investigation of metabolic responses i.e. to determine nutrient requirements that results in reduced CO2 production. Thereby the media composition can be optimized depending on the specific goal. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Mann Marcel
- RWTH Aachen University, AVT - Biochemical Engineering, Aachen, Germany
| | - Effert Darina
- RWTH Aachen University, AVT - Biochemical Engineering, Aachen, Germany
| | - Kottenhahn Patrick
- RWTH Aachen University, AVT - Biochemical Engineering, Aachen, Germany.,Department for Industrial Biotechnology, Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstr. 6, Aachen, Germany
| | - Hüser Aline
- RWTH Aachen University, AVT - Biochemical Engineering, Aachen, Germany
| | - Philipps Gabriele
- Department for Industrial Biotechnology, Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstr. 6, Aachen, Germany
| | - Jennewein Stefan
- Department for Industrial Biotechnology, Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstr. 6, Aachen, Germany
| | - Büchs Jochen
- RWTH Aachen University, AVT - Biochemical Engineering, Aachen, Germany
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15
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Yao S, Hao L, Zhou R, Jin Y, Huang J, Wu C. Formation of Biofilm by Tetragenococcus halophilus Benefited Stress Tolerance and Anti-biofilm Activity Against S. aureus and S. Typhimurium. Front Microbiol 2022; 13:819302. [PMID: 35300476 PMCID: PMC8921937 DOI: 10.3389/fmicb.2022.819302] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Accepted: 01/18/2022] [Indexed: 02/05/2023] Open
Abstract
Tetragenococcus halophilus, a halophilic lactic acid bacterium (LAB), plays an important role in the production of high-salt fermented foods. Generally, formation of biofilm benefits the fitness of cells when faced with competitive and increasingly hostile fermented environments. In this work, the biofilm-forming capacity of T. halophilus was investigated. The results showed that the optimal conditions for biofilm formation by T. halophilus were at 3–9% salt content, 0–6% ethanol content, pH 7.0, 30°C, and on the surface of stainless steel. Confocal laser scanning microscopy (CLSM) analysis presented a dense and flat biofilm with a thickness of about 24 μm, and higher amounts of live cells were located near the surface of biofilm and more dead cells located at the bottom. Proteins, polysaccharides, extracellular-DNA (eDNA), and humic-like substances were all proved to take part in biofilm formation. Higher basic surface charge, greater hydrophilicity, and lower intracellular lactate dehydrogenase (LDH) activities were detected in T. halophilus grown in biofilms. Atomic force microscopy (AFM) imaging revealed that biofilm cultures of T. halophilus had stronger surface adhesion forces than planktonic cells. Cells in biofilm exhibited higher cell viability under acid stress, ethanol stress, heat stress, and oxidative stress. In addition, T. halophilus biofilms exhibited aggregation activity and anti-biofilm activity against Staphylococcus aureus and Salmonella Typhimurium. Results presented in the study may contribute to enhancing stress tolerance of T. halophilus and utilize their antagonistic activities against foodborne pathogens during the production of fermented foods.
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Affiliation(s)
- Shangjie Yao
- College of Biomass Science and Engineering, Sichuan University, Chengdu, China.,Key Laboratory of Leather Chemistry and Engineering, Ministry of Education, Sichuan University, Chengdu, China
| | - Liying Hao
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Rongqing Zhou
- College of Biomass Science and Engineering, Sichuan University, Chengdu, China.,Key Laboratory of Leather Chemistry and Engineering, Ministry of Education, Sichuan University, Chengdu, China
| | - Yao Jin
- College of Biomass Science and Engineering, Sichuan University, Chengdu, China.,Key Laboratory of Leather Chemistry and Engineering, Ministry of Education, Sichuan University, Chengdu, China
| | - Jun Huang
- College of Biomass Science and Engineering, Sichuan University, Chengdu, China.,Key Laboratory of Leather Chemistry and Engineering, Ministry of Education, Sichuan University, Chengdu, China
| | - Chongde Wu
- College of Biomass Science and Engineering, Sichuan University, Chengdu, China.,Key Laboratory of Leather Chemistry and Engineering, Ministry of Education, Sichuan University, Chengdu, China
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16
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The de novo Purine Biosynthesis Pathway Is the Only Commonly Regulated Cellular Pathway during Biofilm Formation in TSB-Based Medium in Staphylococcus aureus and Enterococcus faecalis. Microbiol Spectr 2021; 9:e0080421. [PMID: 34935415 PMCID: PMC8693917 DOI: 10.1128/spectrum.00804-21] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacterial biofilms are involved in chronic infections and confer 10 to 1,000 times more resistance to antibiotics compared with planktonic growth, leading to complications and treatment failure. When transitioning from a planktonic lifestyle to biofilms, some Gram-positive bacteria are likely to modulate several cellular pathways, including central carbon metabolism, biosynthesis pathways, and production of secondary metabolites. These metabolic adaptations might play a crucial role in biofilm formation by Gram-positive pathogens such as Staphylococcus aureus and Enterococcus faecalis. Here, we performed a transcriptomic approach to identify cellular pathways that might be similarly regulated during biofilm formation in these bacteria. Different strains and biofilm-inducing media were used to identify a set of regulated genes that are common and independent of the environment or accessory genomes analyzed. Our approach highlighted that the de novo purine biosynthesis pathway was upregulated in biofilms of both species when using a tryptone soy broth-based medium but not so when a brain heart infusion-based medium was used. We did not identify other pathways commonly regulated between both pathogens. Gene deletions and usage of a drug targeting a key enzyme showed the importance of this pathway in biofilm formation of S. aureus. The importance of the de novo purine biosynthesis pathway might reflect an important need for purine during biofilm establishment, and thus could constitute a promising drug target. IMPORTANCE Biofilms are often involved in nosocomial infections and can cause serious chronic infections if not treated properly. Current anti-biofilm strategies rely on antibiotic usage, but they have a limited impact because of the biofilm intrinsic tolerance to drugs. Metabolism remodeling likely plays a central role during biofilm formation. Using comparative transcriptomics of different strains of Staphylococcus aureus and Enterococcus faecalis, we determined that almost all cellular adaptations are not shared between strains and species. Interestingly, we observed that the de novo purine biosynthesis pathway was upregulated during biofilm formation by both species in a specific medium. The requirement for purine could constitute an interesting new anti-biofilm target with a wide spectrum that could also prevent resistance evolution. These results are also relevant to a better understanding of the physiology of biofilm formation.
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17
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Ayol A, Peixoto L, Keskin T, Abubackar HN. Reactor Designs and Configurations for Biological and Bioelectrochemical C1 Gas Conversion: A Review. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph182111683. [PMID: 34770196 PMCID: PMC8583215 DOI: 10.3390/ijerph182111683] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 10/22/2021] [Accepted: 11/03/2021] [Indexed: 11/16/2022]
Abstract
Microbial C1 gas conversion technologies have developed into a potentially promising technology for converting waste gases (CO2, CO) into chemicals, fuels, and other materials. However, the mass transfer constraint of these poorly soluble substrates to microorganisms is an important challenge to maximize the efficiencies of the processes. These technologies have attracted significant scientific interest in recent years, and many reactor designs have been explored. Syngas fermentation and hydrogenotrophic methanation use molecular hydrogen as an electron donor. Furthermore, the sequestration of CO2 and the generation of valuable chemicals through the application of a biocathode in bioelectrochemical cells have been evaluated for their great potential to contribute to sustainability. Through a process termed microbial chain elongation, the product portfolio from C1 gas conversion may be expanded further by carefully driving microorganisms to perform acetogenesis, solventogenesis, and reverse β-oxidation. The purpose of this review is to provide an overview of the various kinds of bioreactors that are employed in these microbial C1 conversion processes.
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Affiliation(s)
- Azize Ayol
- Department of Environmental Engineering, Dokuz Eylul University, Izmir 35390, Turkey;
| | - Luciana Peixoto
- Centre of Biological Engineering (CEB), University of Minho, 4710-057 Braga, Portugal;
| | - Tugba Keskin
- Department of Environmental Protection Technologies, Izmir Democracy University, Izmir 35140, Turkey;
| | - Haris Nalakath Abubackar
- Chemical Engineering Laboratory, BIOENGIN Group, Faculty of Sciences and Centre for Advanced Scientific Research (CICA), University of A Coruña, 15008 A Coruña, Spain
- Correspondence:
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18
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Wang Y, Jiang Z, Lai Z, Yuan H, Zhang X, Jia Y, Zhang X. The self-adaption capability of microalgal biofilm under different light intensities: Photosynthetic parameters and biofilm microstructures. ALGAL RES 2021. [DOI: 10.1016/j.algal.2021.102383] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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19
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Elisiário MP, De Wever H, Van Hecke W, Noorman H, Straathof AJJ. Membrane bioreactors for syngas permeation and fermentation. Crit Rev Biotechnol 2021; 42:856-872. [PMID: 34525894 DOI: 10.1080/07388551.2021.1965952] [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: 10/20/2022]
Abstract
Syngas fermentation to biofuels and chemicals is an emerging technology in the biobased economy. Mass transfer is usually limiting the syngas fermentation rate, due to the low aqueous solubilities of the gaseous substrates. Membrane bioreactors, as efficient gas-liquid contactors, are a promising configuration for overcoming this gas-to-liquid mass transfer limitation, so that sufficient productivity can be achieved. We summarize the published performances of these reactors. Moreover, we highlight numerous parameters settings that need to be used for the enhancement of membrane bioreactor performance. To facilitate this enhancement, we relate mass transfer and other performance indicators to the type of membrane material, module, and flow configuration. Hollow fiber modules with dense or asymmetric membranes on which biofilm might form seem suitable. A model-based approach is advocated to optimize their performance.
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Affiliation(s)
- Marina P Elisiário
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - Heleen De Wever
- Flemish Institute for Technological Research (VITO), Mol, Belgium
| | - Wouter Van Hecke
- Flemish Institute for Technological Research (VITO), Mol, Belgium
| | - Henk Noorman
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands.,DSM Biotechnology Center, Delft, The Netherlands
| | - Adrie J J Straathof
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
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20
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Li F, Xiong XS, Yang YY, Wang JJ, Wang MM, Tang JW, Liu QH, Wang L, Gu B. Effects of NaCl Concentrations on Growth Patterns, Phenotypes Associated With Virulence, and Energy Metabolism in Escherichia coli BW25113. Front Microbiol 2021; 12:705326. [PMID: 34484145 PMCID: PMC8415458 DOI: 10.3389/fmicb.2021.705326] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 07/21/2021] [Indexed: 12/02/2022] Open
Abstract
According to the sit-and-wait hypothesis, long-term environmental survival is positively correlated with increased bacterial pathogenicity because high durability reduces the dependence of transmission on host mobility. Many indirectly transmitted bacterial pathogens, such as Mycobacterium tuberculosis and Burkhoderia pseudomallei, have high durability in the external environment and are highly virulent. It is possible that abiotic stresses may activate certain pathways or the expressions of certain genes, which might contribute to bacterial durability and virulence, synergistically. Therefore, exploring how bacterial phenotypes change in response to environmental stresses is important for understanding their potentials in host infections. In this study, we investigated the effects of different concentrations of salt (sodium chloride, NaCl), on survival ability, phenotypes associated with virulence, and energy metabolism of the lab strain Escherichia coli BW25113. In particular, we investigated how NaCl concentrations influenced growth patterns, biofilm formation, oxidative stress resistance, and motile ability. In terms of energy metabolism that is central to bacterial survival, glucose consumption, glycogen accumulation, and trehalose content were measured in order to understand their roles in dealing with the fluctuation of osmolarity. According to the results, trehalose is preferred than glycogen at high NaCl concentration. In order to dissect the molecular mechanisms of NaCl effects on trehalose metabolism, we further checked how the impairment of trehalose synthesis pathway (otsBA operon) via single-gene mutants influenced E. coli durability and virulence under salt stress. After that, we compared the transcriptomes of E. coli cultured at different NaCl concentrations, through which differentially expressed genes (DEGs) and differential pathways with statistical significance were identified, which provided molecular insights into E. coli responses to NaCl concentrations. In sum, this study explored the in vitro effects of NaCl concentrations on E. coli from a variety of aspects and aimed to facilitate our understanding of bacterial physiological changes under salt stress, which might help clarify the linkages between bacterial durability and virulence outside hosts under environmental stresses.
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Affiliation(s)
- Fen Li
- Medical Technology School of Xuzhou Medical University, Xuzhou, China
| | - Xue-Song Xiong
- Medical Technology School of Xuzhou Medical University, Xuzhou, China
| | - Ying-Ying Yang
- School of Life Sciences, Xuzhou Medical University, Xuzhou, China
| | - Jun-Jiao Wang
- Department of Bioinformatics, School of Medical Informatics and Engineering, Xuzhou Medical University, Xuzhou, China
| | - Meng-Meng Wang
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, School of Pharmacy, Xuzhou Medical University, Xuzhou, China.,Department of Pharmaceutical Analysis, School of Pharmacy, Xuzhou Medical University, Xuzhou, China
| | - Jia-Wei Tang
- Department of Bioinformatics, School of Medical Informatics and Engineering, Xuzhou Medical University, Xuzhou, China
| | - Qing-Hua Liu
- State Key Laboratory of Quality Research in Chinese Medicines, Macau University of Science and Technology, Taipa, China
| | - Liang Wang
- Department of Bioinformatics, School of Medical Informatics and Engineering, Xuzhou Medical University, Xuzhou, China.,Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
| | - Bing Gu
- Medical Technology School of Xuzhou Medical University, Xuzhou, China.,Laboratory Medicine, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
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21
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Costa P, Usai G, Re A, Manfredi M, Mannino G, Bertea CM, Pessione E, Mazzoli R. Clostridium cellulovorans Proteomic Responses to Butanol Stress. Front Microbiol 2021; 12:674639. [PMID: 34367082 PMCID: PMC8336468 DOI: 10.3389/fmicb.2021.674639] [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: 03/01/2021] [Accepted: 06/14/2021] [Indexed: 12/16/2022] Open
Abstract
Combination of butanol-hyperproducing and hypertolerant phenotypes is essential for developing microbial strains suitable for industrial production of bio-butanol, one of the most promising liquid biofuels. Clostridium cellulovorans is among the microbial strains with the highest potential for direct production of n-butanol from lignocellulosic wastes, a process that would significantly reduce the cost of bio-butanol. However, butanol exhibits higher toxicity compared to ethanol and C. cellulovorans tolerance to this solvent is low. In the present investigation, comparative gel-free proteomics was used to study the response of C. cellulovorans to butanol challenge and understand the tolerance mechanisms activated in this condition. Sequential Window Acquisition of all Theoretical fragment ion spectra Mass Spectrometry (SWATH-MS) analysis allowed identification and quantification of differentially expressed soluble proteins. The study data are available via ProteomeXchange with the identifier PXD024183. The most important response concerned modulation of protein biosynthesis, folding and degradation. Coherent with previous studies on other bacteria, several heat shock proteins (HSPs), involved in protein quality control, were up-regulated such as the chaperones GroES (Cpn10), Hsp90, and DnaJ. Globally, our data indicate that protein biosynthesis is reduced, likely not to overload HSPs. Several additional metabolic adaptations were triggered by butanol exposure such as the up-regulation of V- and F-type ATPases (involved in ATP synthesis/generation of proton motive force), enzymes involved in amino acid (e.g., arginine, lysine, methionine, and branched chain amino acids) biosynthesis and proteins involved in cell envelope re-arrangement (e.g., the products of Clocel_4136, Clocel_4137, Clocel_4144, Clocel_4162 and Clocel_4352, involved in the biosynthesis of saturated fatty acids) and a redistribution of carbon flux through fermentative pathways (acetate and formate yields were increased and decreased, respectively). Based on these experimental findings, several potential gene targets for metabolic engineering strategies aimed at improving butanol tolerance in C. cellulovorans are suggested. This includes overexpression of HSPs (e.g., GroES, Hsp90, DnaJ, ClpC), RNA chaperone Hfq, V- and F-type ATPases and a number of genes whose function in C. cellulovorans is currently unknown.
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Affiliation(s)
- Paolo Costa
- Structural and Functional Biochemistry, Laboratory of Proteomics and Metabolic Engineering of Prokaryotes, Department of Life Sciences and Systems Biology, University of Turin, Turin, Italy
| | - Giulia Usai
- Structural and Functional Biochemistry, Laboratory of Proteomics and Metabolic Engineering of Prokaryotes, Department of Life Sciences and Systems Biology, University of Turin, Turin, Italy.,Centre for Sustainable Future Technologies, Fondazione Istituto Italiano di Tecnologia, Turin, Italy.,Department of Applied Science and Technology, Politecnico di Torino, Turin, Italy
| | - Angela Re
- Centre for Sustainable Future Technologies, Fondazione Istituto Italiano di Tecnologia, Turin, Italy
| | - Marcello Manfredi
- Center for Translational Research on Autoimmune and Allergic Diseases, Università del Piemonte Orientale, Novara, Italy.,Department of Translational Medicine, Università del Piemonte Orientale, Novara, Italy
| | - Giuseppe Mannino
- Plant Physiology Unit, Department of Life Sciences and Systems Biology, University of Turin, Turin, Italy
| | - Cinzia Margherita Bertea
- Plant Physiology Unit, Department of Life Sciences and Systems Biology, University of Turin, Turin, Italy
| | - Enrica Pessione
- Structural and Functional Biochemistry, Laboratory of Proteomics and Metabolic Engineering of Prokaryotes, Department of Life Sciences and Systems Biology, University of Turin, Turin, Italy
| | - Roberto Mazzoli
- Structural and Functional Biochemistry, Laboratory of Proteomics and Metabolic Engineering of Prokaryotes, Department of Life Sciences and Systems Biology, University of Turin, Turin, Italy
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22
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Wang T, Flint S, Palmer J. Heterogeneous response of Geobacillus stearothermophilus biofilms to calcium. Int Dairy J 2021. [DOI: 10.1016/j.idairyj.2020.104961] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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23
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Diallo M, Kengen SWM, López-Contreras AM. Sporulation in solventogenic and acetogenic clostridia. Appl Microbiol Biotechnol 2021; 105:3533-3557. [PMID: 33900426 PMCID: PMC8102284 DOI: 10.1007/s00253-021-11289-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 04/03/2021] [Accepted: 04/07/2021] [Indexed: 02/07/2023]
Abstract
The Clostridium genus harbors compelling organisms for biotechnological production processes; while acetogenic clostridia can fix C1-compounds to produce acetate and ethanol, solventogenic clostridia can utilize a wide range of carbon sources to produce commercially valuable carboxylic acids, alcohols, and ketones by fermentation. Despite their potential, the conversion by these bacteria of carbohydrates or C1 compounds to alcohols is not cost-effective enough to result in economically viable processes. Engineering solventogenic clostridia by impairing sporulation is one of the investigated approaches to improve solvent productivity. Sporulation is a cell differentiation process triggered in bacteria in response to exposure to environmental stressors. The generated spores are metabolically inactive but resistant to harsh conditions (UV, chemicals, heat, oxygen). In Firmicutes, sporulation has been mainly studied in bacilli and pathogenic clostridia, and our knowledge of sporulation in solvent-producing or acetogenic clostridia is limited. Still, sporulation is an integral part of the cellular physiology of clostridia; thus, understanding the regulation of sporulation and its connection to solvent production may give clues to improve the performance of solventogenic clostridia. This review aims to provide an overview of the triggers, characteristics, and regulatory mechanism of sporulation in solventogenic clostridia. Those are further compared to the current knowledge on sporulation in the industrially relevant acetogenic clostridia. Finally, the potential applications of spores for process improvement are discussed.Key Points• The regulatory network governing sporulation initiation varies in solventogenic clostridia.• Media composition and cell density are the main triggers of sporulation.• Spores can be used to improve the fermentation process.
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Affiliation(s)
- Mamou Diallo
- Wageningen Food and Biobased Research, Wageningen, The Netherlands.
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, The Netherlands.
| | - Servé W M Kengen
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, The Netherlands
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Dissecting the Structural and Conductive Functions of Nanowires in Geobacter sulfurreducens Electroactive Biofilms. mBio 2021; 13:e0382221. [PMID: 35164556 PMCID: PMC8844916 DOI: 10.1128/mbio.03822-21] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Conductive nanowires are thought to contribute to long-range electron transfer (LET) in Geobacter sulfurreducens anode biofilms. Three types of nanowires have been identified: pili, OmcS, and OmcZ. Previous studies highlighted their conductive function in anode biofilms, yet a structural function also has to be considered. We present here a comprehensive analysis of the function of nanowires in LET by inhibiting the expression of each nanowire. Meanwhile, flagella with poor conductivity were expressed to recover the structural function but not the conductive function of nanowires in the corresponding nanowire mutant strain. The results demonstrated that pili played a structural but not a conductive function in supporting biofilm formation. In contrast, the OmcS nanowire played a conductive but not a structural function in facilitating electron transfer in the biofilm. The OmcZ nanowire played both a structural and a conductive function to contribute to current generation. Expression of the poorly conductive flagellum was shown to enhance biofilm formation, subsequently increasing current generation. These data support a model in which multiheme cytochromes facilitate long-distance electron transfer in G. sulfurreducens biofilms. Our findings also suggest that the formation of a thicker biofilm, which contributed to a higher current generation by G. sulfurreducens, was confined by the biofilm formation deficiency, and this has applications in microbial electrochemical systems. IMPORTANCE The low power generation of microbial fuel cells limits their utility. Many factors can affect power generation, including inefficient electron transfer in the anode biofilm. Thus, understanding the mechanism(s) of electron transfer provides a pathway for increasing the power density of microbial fuel cells. Geobacter sulfurreducens was shown to form a thick biofilm on the anode. Cells far away from the anode reduce the anode through long-range electron transfer. Based on their conductive properties, three types of nanowires have been hypothesized to directly facilitate long-range electron transfer: pili, OmcS, and OmcZ nanowires. However, their structural contributions to electron transfer in anode biofilm have not been elucidated. Based on studies of mutants lacking one or more of these facilitators, our results support a cytochrome-mediated electron transfer process in Geobacter biofilms and highlight the structural contribution of nanowires in anode biofilm formation, which contributes to biofilm formation and current generation, thereby providing a strategy to increase current generation.
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Jourdin L, Burdyny T. Microbial Electrosynthesis: Where Do We Go from Here? Trends Biotechnol 2020; 39:359-369. [PMID: 33279279 DOI: 10.1016/j.tibtech.2020.10.014] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 10/22/2020] [Accepted: 10/30/2020] [Indexed: 10/22/2022]
Abstract
The valorization of CO2 to valuable products via microbial electrosynthesis (MES) is a technology transcending the disciplines of microbiology, (electro)chemistry, and engineering, bringing opportunities and challenges. As the field looks to the future, further emphasis is expected to be placed on engineering efficient reactors for biocatalysts, to thrive and overcome factors which may be limiting performance. Meanwhile, ample opportunities exist to take the lessons learned in traditional and adjacent electrochemical fields to shortcut learning curves. As the technology transitions into the next decade, research into robust and adaptable biocatalysts will then be necessary as reactors shape into larger and more efficient configurations, as well as presenting more extreme temperature, salinity, and pressure conditions.
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Affiliation(s)
- Ludovic Jourdin
- Department of Biotechnology, Delft University of Technology, 2629 HZ Delft, The Netherlands.
| | - Thomas Burdyny
- Department of Chemical Engineering, Delft University of Technology, 2629 HZ Delft, The Netherlands
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Huynh D, Norambuena J, Boldt C, Kaschabek SR, Levicán G, Schlömann M. Effect of Sodium Chloride on Pyrite Bioleaching and Initial Attachment by Sulfobacillus thermosulfidooxidans. Front Microbiol 2020; 11:2102. [PMID: 33013767 PMCID: PMC7516052 DOI: 10.3389/fmicb.2020.02102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 08/10/2020] [Indexed: 12/02/2022] Open
Abstract
Biomining applies microorganisms to extract valuable metals from usually sulfidic ores. However, acidophilic iron (Fe)-oxidizing bacteria tend to be sensitive to chloride ions which may be present in biomining operations. This study investigates the bioleaching of pyrite (FeS2), as well as the attachment to FeS2 by Sulfobacillus thermosulfidooxidans DSM 9293T in the presence of elevated sodium chloride (NaCl) concentrations. The bacteria were still able to oxidize iron in the presence of up to 0.6M NaCl (35 g/L), and the addition of NaCl in concentrations up to 0.2M (~12 g/L) did not inhibit iron oxidation and growth of S. thermosulfidooxidans in leaching cultures within the first 7 days. However, after approximately 7 days of incubation, ferrous iron (Fe2+) concentrations were gradually increased in leaching assays with NaCl, indicating that iron oxidation activity over time was reduced in those assays. Although the inhibition by 0.1M NaCl (~6 g/L) of bacterial growth and iron oxidation activity was not evident at the beginning of the experiment, over extended leaching duration NaCl was likely to have an inhibitory effect. Thus, after 36 days of the experiment, bioleaching of FeS2 with 0.1M NaCl was reduced significantly in comparison to control assays without NaCl. Pyrite dissolution decreased with the increase of NaCl. Nevertheless, pyrite bioleaching by S. thermosulfidooxidans was still possible at NaCl concentrations as high as 0.4M (~23 g/L NaCl). Besides, cell attachment in the presence of different concentrations of NaCl was investigated. Cells of S. thermosulfidooxidans attached heterogeneously on pyrite surfaces regardless of NaCl concentration. Noticeably, bacteria were able to adhere to pyrite surfaces in the presence of NaCl as high as 0.4M. Although NaCl addition inhibited iron oxidation activity and bioleaching of FeS2, the presence of 0.2M seemed to enhance bacterial attachment of S. thermosulfidooxidans on pyrite surfaces in comparison to attachment without NaCl.
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Affiliation(s)
- Dieu Huynh
- Environmental Microbiology, Institute of Biosciences, TU Bergakademie Freiberg, Freiberg, Germany
| | - Javiera Norambuena
- Environmental Microbiology, Institute of Biosciences, TU Bergakademie Freiberg, Freiberg, Germany
| | - Christin Boldt
- Environmental Microbiology, Institute of Biosciences, TU Bergakademie Freiberg, Freiberg, Germany
| | - Stefan R. Kaschabek
- Environmental Microbiology, Institute of Biosciences, TU Bergakademie Freiberg, Freiberg, Germany
| | - Gloria Levicán
- Biology Department, Universidad de Santiago de Chile, Santiago, Chile
| | - Michael Schlömann
- Environmental Microbiology, Institute of Biosciences, TU Bergakademie Freiberg, Freiberg, Germany
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Llama‐Palacios A, Potupa O, Sánchez MC, Figuero E, Herrera D, Sanz M. Proteomic analysis ofFusobacterium nucleatumgrowth in biofilm versus planktonic state. Mol Oral Microbiol 2020; 35:168-180. [DOI: 10.1111/omi.12303] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Revised: 06/01/2020] [Accepted: 06/11/2020] [Indexed: 01/04/2023]
Affiliation(s)
- Arancha Llama‐Palacios
- Oral Microbiology Laboratory at the Faculty of Odontology University Complutense Madrid Spain
- ETEP (Etiology and Therapy of Periodontal Diseases) Research Group University Complutense Madrid Spain
| | - Oksana Potupa
- Oral Microbiology Laboratory at the Faculty of Odontology University Complutense Madrid Spain
| | - María C. Sánchez
- Oral Microbiology Laboratory at the Faculty of Odontology University Complutense Madrid Spain
- ETEP (Etiology and Therapy of Periodontal Diseases) Research Group University Complutense Madrid Spain
| | - Elena Figuero
- ETEP (Etiology and Therapy of Periodontal Diseases) Research Group University Complutense Madrid Spain
| | - David Herrera
- ETEP (Etiology and Therapy of Periodontal Diseases) Research Group University Complutense Madrid Spain
| | - Mariano Sanz
- ETEP (Etiology and Therapy of Periodontal Diseases) Research Group University Complutense Madrid Spain
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Influence of Plasma Characteristics on the Inactivation Mechanism of Cold Atmospheric Plasma (CAP) for Listeria monocytogenes and Salmonella Typhimurium Biofilms. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10093198] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This research aimed to take a next step towards unravelling the CAP inactivation mechanism for mature (Listeria monocytogenes (Gram positive) and Salmonella Typhimurium (Gram negative)) model biofilms, which will support the further optimization this novel technology. More specifically, we examined how the inactivation mechanism was influenced by the applied processing conditions, i.e., by the electrode configuration, the composition of the gas flow, and the power of the discharge. For each combination of plasma characteristics, we examined if the applied CAP treatment had an effect on (i) the cell membrane, (ii) the intracellular DNA, and (iii) the EPS matrix. In addition, we assessed which (reactive) CAP species were responsible for this lethal/damaging effect and whether these species were able to diffuse into the deeper layers of the biofilms. The results indicated that the inactivation mechanism was indeed influenced by the applied processing conditions. Nevertheless, the bactericidal effect of CAP was always a combination of both damage to the membrane and the DNA, caused by (i) the generation of (intracellular) ROS and RNS, (ii) a drop in pH, and/or (iii) the potential generation of a small amount of UV photons. Moreover, the plasma species were able to penetrate into the deeper layers of the model biofilms and some treatment conditions resulted in an increased biofilm porosity.
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Fredendall RJ, Stone JL, Pehl MJ, Orwin PM. Transcriptome profiling of Variovorax paradoxus EPS under different growth conditions reveals regulatory and structural novelty in biofilm formation. Access Microbiol 2020; 2:acmi000121. [PMID: 32974586 PMCID: PMC7494200 DOI: 10.1099/acmi.0.000121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 02/07/2020] [Indexed: 12/15/2022] Open
Abstract
We used transcriptome analysis by paired-end strand-specific RNA-seq to evaluate the specific changes in gene expression associated with the transition to static biofilm growth in the rhizosphere plant growth-promoting bacterium Variovorax paradoxus EPS. Triplicate biological samples of exponential growth, stationary phase and static biofilm samples were examined. DESeq2 and Rockhopper were used to identify robust and widespread shifts in gene expression specific to each growth phase. We identified 1711 protein-coding genes (28%) using DESeq2 that had altered expression greater than twofold specifically in biofilms compared to exponential growth. Fewer genes were specifically differentially expressed in stationary-phase culture (757, 12%). A small set of genes (103/6020) were differentially expressed in opposing fashions in biofilm and stationary phase, indicating potentially substantial shifts in phenotype. Gene-ontology analysis showed that the only class of genes specifically upregulated in biofilms was associated with nutrient transport, highlighting the importance of nutrient uptake in the biofilm. The biofilm-specific genes did not overlap substantially with the loci identified by mutagenesis studies, although some were present in both sets. The most highly upregulated biofilm-specific gene is predicted to be a part of the RNA degradosome, which indicates that RNA stability is used to regulate the biofilm phenotype. Two small putative proteins, Varpa_0407 and Varpa_3832, are highly expressed specifically in biofilms and are predicted to be secreted DNA-binding proteins, which may stabilize extracellular DNA as a component of the biofilm matrix. An flp/tad type-IV pilus locus (Varpa_5148-60) is strongly downregulated specifically in biofilms, in contrast with results from other systems for these pili. Mutagenesis confirms that this locus is important in surface motility rather than biofilm formation. These experimental results suggest that V. paradoxus EPS biofilms have substantial regulatory and structural novelty.
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Affiliation(s)
- Richard J. Fredendall
- Biology Department, California State University San Bernardino, San Bernardino, CA, USA
| | - Jenny L. Stone
- Biology Department, California State University San Bernardino, San Bernardino, CA, USA
| | - Michael J. Pehl
- Biology Department, California State University San Bernardino, San Bernardino, CA, USA
| | - Paul M. Orwin
- Biology Department, California State University San Bernardino, San Bernardino, CA, USA
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Almeida Benalcázar E, Noorman H, Maciel Filho R, Posada JA. Modeling ethanol production through gas fermentation: a biothermodynamics and mass transfer-based hybrid model for microbial growth in a large-scale bubble column bioreactor. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:59. [PMID: 32231709 PMCID: PMC7102449 DOI: 10.1186/s13068-020-01695-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 03/05/2020] [Indexed: 05/08/2023]
Abstract
BACKGROUND Ethanol production through fermentation of gas mixtures containing CO, CO2 and H2 has just started operating at commercial scale. However, quantitative schemes for understanding and predicting productivities, yields, mass transfer rates, gas flow profiles and detailed energy requirements have been lacking in literature; such are invaluable tools for process improvements and better systems design. The present study describes the construction of a hybrid model for simulating ethanol production inside a 700 m3 bubble column bioreactor fed with gas of two possible compositions, i.e., pure CO and a 3:1 mixture of H2 and CO2. RESULTS Estimations made using the thermodynamics-based black-box model of microbial reactions on substrate threshold concentrations, biomass yields, as well as CO and H2 maximum specific uptake rates agreed reasonably well with data and observations reported in literature. According to the bioreactor simulation, there is a strong dependency of process performance on mass transfer rates. When mass transfer coefficients were estimated using a model developed from oxygen transfer to water, ethanol productivity reached 5.1 g L-1 h-1; when the H2/CO2 mixture is fed to the bioreactor, productivity of CO fermentation was 19% lower. Gas utilization reached 23 and 17% for H2/CO2 and CO fermentations, respectively. If mass transfer coefficients were 100% higher than those estimated, ethanol productivity and gas utilization may reach 9.4 g L-1 h-1 and 38% when feeding the H2/CO2 mixture at the same process conditions. The largest energetic requirements for a complete manufacturing plant were identified for gas compression and ethanol distillation, being higher for CO fermentation due to the production of CO2. CONCLUSIONS The thermodynamics-based black-box model of microbial reactions may be used to quantitatively assess and consolidate the diversity of reported data on CO, CO2 and H2 threshold concentrations, biomass yields, maximum substrate uptake rates, and half-saturation constants for CO and H2 for syngas fermentations by acetogenic bacteria. The maximization of ethanol productivity in the bioreactor may come with a cost: low gas utilization. Exploiting the model flexibility, multi-objective optimizations of bioreactor performance might reveal how process conditions and configurations could be adjusted to guide further process development.
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Affiliation(s)
- Eduardo Almeida Benalcázar
- Department of Product and Process Development, Faculty of Chemical Engineering, State University of Campinas, Av. Albert Einstein 500, Cidade Universitária, Campinas, SP 13083-852 Brazil
- Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Henk Noorman
- Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
- DSM Biotechnology Center, A. Fleminglaan 1, 2613 AX Delft, The Netherlands
| | - Rubens Maciel Filho
- Department of Product and Process Development, Faculty of Chemical Engineering, State University of Campinas, Av. Albert Einstein 500, Cidade Universitária, Campinas, SP 13083-852 Brazil
| | - John A. Posada
- Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
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Heinz J, Waajen AC, Airo A, Alibrandi A, Schirmack J, Schulze-Makuch D. Bacterial Growth in Chloride and Perchlorate Brines: Halotolerances and Salt Stress Responses of Planococcus halocryophilus. ASTROBIOLOGY 2019; 19:1377-1387. [PMID: 31386567 PMCID: PMC6818489 DOI: 10.1089/ast.2019.2069] [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] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 06/26/2019] [Indexed: 06/10/2023]
Abstract
Extraterrestrial environments encompass physicochemical conditions and habitats that are unknown on Earth, such as perchlorate-rich brines that can be at least temporarily stable on the martian surface. To better understand the potential for life in these cold briny environments, we determined the maximum salt concentrations suitable for growth (MSCg) of six different chloride and perchlorate salts at 25°C and 4°C for the extremotolerant cold- and salt-adapted bacterial strain Planococcus halocryophilus. Growth was measured through colony-forming unit (CFU) counts, while cellular and colonial phenotypic stress responses were observed through visible light, fluorescence, and scanning electron microscopy. Our data show the following: (1) The tolerance to high salt concentrations can be increased through a stepwise inoculation toward higher concentrations. (2) Ion-specific factors are more relevant for the growth limitation of P. halocryophilus in saline solutions than single physicochemical parameters like ionic strength or water activity. (3) P. halocryophilus shows the highest microbial sodium perchlorate tolerance described so far. However, (4) MSCg values are higher for all chlorides compared to perchlorates. (5) The MSCg for calcium chloride was increased by lowering the temperature from 25°C to 4°C, while sodium- and magnesium-containing salts can be tolerated at 25°C to higher concentrations than at 4°C. (6) Depending on salt type and concentration, P. halocryophilus cells show distinct phenotypic stress responses such as novel types of colony morphology on agar plates and biofilm-like cell clustering, encrustation, and development of intercellular nanofilaments. This study, taken in context with previous work on the survival of extremophiles in Mars-like environments, suggests that high-concentrated perchlorate brines on Mars might not be habitable to any present organism on Earth, but extremophilic microorganisms might be able to evolve thriving in such environments.
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Affiliation(s)
- Jacob Heinz
- Center of Astronomy and Astrophysics, Astrobiology Research Group, Technical University of Berlin, Berlin, Germany
| | - Annemiek C. Waajen
- Center of Astronomy and Astrophysics, Astrobiology Research Group, Technical University of Berlin, Berlin, Germany
- UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh, Edinburgh, UK
| | - Alessandro Airo
- Center of Astronomy and Astrophysics, Astrobiology Research Group, Technical University of Berlin, Berlin, Germany
| | - Armando Alibrandi
- Center of Astronomy and Astrophysics, Astrobiology Research Group, Technical University of Berlin, Berlin, Germany
| | - Janosch Schirmack
- Center of Astronomy and Astrophysics, Astrobiology Research Group, Technical University of Berlin, Berlin, Germany
| | - Dirk Schulze-Makuch
- Center of Astronomy and Astrophysics, Astrobiology Research Group, Technical University of Berlin, Berlin, Germany
- School of the Environment, Washington State University, Pullman, Washington, USA
- GFZ German Center for Geoscience, Section Geomicrobiology, Potsdam, Germany
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Department of Experimental Limnology, Stechlin, Germany
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Karthikeyan R, Singh R, Bose A. Microbial electron uptake in microbial electrosynthesis: a mini-review. ACTA ACUST UNITED AC 2019; 46:1419-1426. [DOI: 10.1007/s10295-019-02166-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 03/23/2019] [Indexed: 10/27/2022]
Abstract
Abstract
Microbial electron uptake (EU) is the biological capacity of microbes to accept electrons from electroconductive solid materials. EU has been leveraged for sustainable bioproduction strategies via microbial electrosynthesis (MES). MES often involves the reduction of carbon dioxide to multi-carbon molecules, with electrons derived from electrodes in a bioelectrochemical system. EU can be indirect or direct. Indirect EU-based MES uses electron mediators to transfer electrons to microbes. Although an excellent initial strategy, indirect EU requires higher electrical energy. In contrast, the direct supply of cathodic electrons to microbes (direct EU) is more sustainable and energy efficient. Nonetheless, low product formation due to low electron transfer rates during direct EU remains a major challenge. Compared to indirect EU, direct EU is less well-studied perhaps due to the more recent discovery of this microbial capability. This mini-review focuses on the recent advances and challenges of direct EU in relation to MES.
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Affiliation(s)
- Rengasamy Karthikeyan
- grid.4367.6 0000 0001 2355 7002 Department of Biology Washington University in Saint Louis One Brookings Drive 63130 St. Louis MO USA
| | - Rajesh Singh
- grid.4367.6 0000 0001 2355 7002 Department of Biology Washington University in Saint Louis One Brookings Drive 63130 St. Louis MO USA
| | - Arpita Bose
- grid.4367.6 0000 0001 2355 7002 Department of Biology Washington University in Saint Louis One Brookings Drive 63130 St. Louis MO USA
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Cantos-Parra E, Ramió-Pujol S, Colprim J, Puig S, Bañeras L. Specific detection of "Clostridium autoethanogenum", Clostridium ljungdahlii and Clostridium carboxidivorans in complex bioreactor samples. FEMS Microbiol Lett 2019; 365:5062789. [PMID: 30084932 DOI: 10.1093/femsle/fny191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Accepted: 07/30/2018] [Indexed: 11/13/2022] Open
Abstract
The high genetic similarity between some carboxydotrophic bacteria does not allow for the use of common sequencing techniques targeting the 16S rRNA gene for species identification. 16S rRNA sequencing fails to discriminate among Clostridium ljungdahlii and 'Clostridium autoethanogenum', despite this two species exhibit significant differences in CO2 assimilation and alcohol production. In this work we designed PCR primers targeting for the DNA gyrase subunit A (gyrA) and a putative formate/nitrite transporter (fnt) to specifically detect the presence of 'C. autoethanogenum', C. ljungdahlii or Clostridium carboxidivorans. We could confirm the simultaneous presence of C. ljungdahlii and 'C. autoethanogenum' in different bioreactors, and a preference of the latter for high CO2 content.
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Affiliation(s)
- Ester Cantos-Parra
- Group of Molecular Microbial Ecology, Institute of Aquatic Ecology (IEA), University of Girona, Campus Montilivi, Carrer Maria Aurèlia Capmany, 40, E-17003 Girona, Catalonia, Spain
| | - Sara Ramió-Pujol
- Group of Molecular Microbial Ecology, Institute of Aquatic Ecology (IEA), University of Girona, Campus Montilivi, Carrer Maria Aurèlia Capmany, 40, E-17003 Girona, Catalonia, Spain.,GoodGut, Centre d'Empreses Giroemprèn, Parc Científic i Tecnològic UdG, Carrer Pic de Peguera, 11, E-17003 Girona, Catalonia, Spain
| | - Jesús Colprim
- LEQUiA, Institute of the Environment. University of Girona, Campus Montilivi, Carrer Maria Aurèlia Capmany, 69, E-17003 Girona, Catalonia, Spain
| | - Sebastià Puig
- LEQUiA, Institute of the Environment. University of Girona, Campus Montilivi, Carrer Maria Aurèlia Capmany, 69, E-17003 Girona, Catalonia, Spain
| | - Lluís Bañeras
- Group of Molecular Microbial Ecology, Institute of Aquatic Ecology (IEA), University of Girona, Campus Montilivi, Carrer Maria Aurèlia Capmany, 40, E-17003 Girona, Catalonia, Spain
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Vanoppen M, van Vooren T, Gutierrez L, Roman M, Croué LJP, Verbeken K, Philips J, Verliefde A. Secondary treated domestic wastewater in reverse electrodialysis: What is the best pre-treatment? Sep Purif Technol 2019. [DOI: 10.1016/j.seppur.2018.12.057] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Bajracharya S, Vanbroekhoven K, Buisman CJN, Strik DPBTB, Pant D. Bioelectrochemical conversion of CO 2 to chemicals: CO 2 as a next generation feedstock for electricity-driven bioproduction in batch and continuous modes. Faraday Discuss 2019; 202:433-449. [PMID: 28657636 DOI: 10.1039/c7fd00050b] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The recent concept of microbial electrosynthesis (MES) has evolved as an electricity-driven production technology for chemicals from low-value carbon dioxide (CO2) using micro-organisms as biocatalysts. MES from CO2 comprises bioelectrochemical reduction of CO2 to multi-carbon organic compounds using the reducing equivalents produced at the electrically-polarized cathode. The use of CO2 as a feedstock for chemicals is gaining much attention, since CO2 is abundantly available and its use is independent of the food supply chain. MES based on CO2 reduction produces acetate as a primary product. In order to elucidate the performance of the bioelectrochemical CO2 reduction process using different operation modes (batch vs. continuous), an investigation was carried out using a MES system with a flow-through biocathode supplied with 20 : 80 (v/v) or 80 : 20 (v/v) CO2 : N2 gas. The highest acetate production rate of 149 mg L-1 d-1 was observed with a 3.1 V applied cell-voltage under batch mode. While running in continuous mode, high acetate production was achieved with a maximum rate of 100 mg L-1 d-1. In the continuous mode, the acetate production was not sustained over long-term operation, likely due to insufficient microbial biocatalyst retention within the biocathode compartment (i.e. suspended micro-organisms were washed out of the system). Restarting batch mode operations resulted in a renewed production of acetate. This showed an apparent domination of suspended biocatalysts over the attached (biofilm forming) biocatalysts. Long term CO2 reduction at the biocathode resulted in the accumulation of acetate, and more reduced compounds like ethanol and butyrate were also formed. Improvements in the production rate and different biomass retention strategies (e.g. selecting for biofilm forming micro-organisms) should be investigated to enable continuous biochemical production from CO2 using MES. Certainly, other process optimizations will be required to establish MES as an innovative sustainable technology for manufacturing biochemicals from CO2 as a next generation feedstock.
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Affiliation(s)
- Suman Bajracharya
- Separation and Conversion Technology, Flemish Institute for Technological Research (VITO), Boeretang 200, Mol 2400, Belgium.
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Misra S, Dixit VK, Mishra SK, Chauhan PS. Demonstrating the potential of abiotic stress-tolerant Jeotgalicoccus huakuii NBRI 13E for plant growth promotion and salt stress amelioration. ANN MICROBIOL 2019. [DOI: 10.1007/s13213-018-1428-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
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Rodrigues S, Paillard C, Van Dillen S, Tahrioui A, Berjeaud JM, Dufour A, Bazire A. Relation between Biofilm and Virulence in Vibrio tapetis: A Transcriptomic Study. Pathogens 2018; 7:pathogens7040092. [PMID: 30486310 PMCID: PMC6313714 DOI: 10.3390/pathogens7040092] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 11/20/2018] [Accepted: 11/23/2018] [Indexed: 02/05/2023] Open
Abstract
Marine pathogenic bacteria are able to form biofilms on many surfaces, such as mollusc shells, and they can wait for the appropriate opportunity to induce their virulence. Vibrio tapetis can develop such biofilms on the inner surface of shells of the Ruditapes philippinarum clam, leading to the formation of a brown conchiolin deposit in the form of a ring, hence the name of the disease: Brown Ring Disease. The virulence of V. tapetis is presumed to be related to its capacity to form biofilms, but the link has never been clearly established at the physiological or genetic level. In the present study, we used RNA-seq analysis to identify biofilm- and virulence-related genes displaying altered expression in biofilms compared to the planktonic condition. A flow cell system was employed to grow biofilms to obtain both structural and transcriptomic views of the biofilms. We found that 3615 genes were differentially expressed, confirming that biofilm and planktonic lifestyles are very different. As expected, the differentially expressed genes included those involved in biofilm formation, such as motility- and polysaccharide synthesis-related genes. The data show that quorum sensing is probably mediated by the AI-2/LuxO system in V. tapetis biofilms. The expression of genes encoding the Type VI Secretion System and associated exported proteins are strongly induced, suggesting that V. tapetis activates this virulence factor when living in biofilm.
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Affiliation(s)
- Sophie Rodrigues
- Laboratoire de Biotechnologie et Chimie Marines (LBCM), EA 3884, LBCM, IUEM Université de Bretagne-Sud, 56100 Lorient, France.
| | - Christine Paillard
- UMR6539, Laboratoire des Sciences de l'Environnement Marin (LEMAR), Centre National de la Recherche Scientifique, Institut Universitaire Européen de la Mer, Université de Brest, UBO, IRD, Ifremer, 29280 Plouzané, France.
| | - Sabine Van Dillen
- DuPont Nutrition and Health, Danisco France SAS, BP10, F-86220 Dangé-Saint-Romain, France.
| | - Ali Tahrioui
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, University Rouen-Normandy, 27000 Evreux, France.
| | - Jean-Marc Berjeaud
- UMR 7267, Laboratoire d'Ecologie et Biologie des interactions (EBI), Université de Poitiers, 86000 Poitiers, France.
| | - Alain Dufour
- Laboratoire de Biotechnologie et Chimie Marines (LBCM), EA 3884, LBCM, IUEM Université de Bretagne-Sud, 56100 Lorient, France.
| | - Alexis Bazire
- Laboratoire de Biotechnologie et Chimie Marines (LBCM), EA 3884, LBCM, IUEM Université de Bretagne-Sud, 56100 Lorient, France.
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Eze EC, Chenia HY, El Zowalaty ME. Acinetobacter baumannii biofilms: effects of physicochemical factors, virulence, antibiotic resistance determinants, gene regulation, and future antimicrobial treatments. Infect Drug Resist 2018; 11:2277-2299. [PMID: 30532562 PMCID: PMC6245380 DOI: 10.2147/idr.s169894] [Citation(s) in RCA: 140] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Acinetobacter baumannii is a leading cause of nosocomial infections due to its increased antibiotic resistance and virulence. The ability of A. baumannii to form biofilms contributes to its survival in adverse environmental conditions including hospital environments and medical devices. A. baumannii has undoubtedly propelled the interest of biomedical researchers due to its broad range of associated infections especially in hospital intensive care units. The interplay among microbial physicochemistry, alterations in the phenotype and genotypic determinants, and the impact of existing ecological niche and the chemistry of antimicrobial agents has led to enhanced biofilm formation resulting in limited access of drugs to their specific targets. Understanding the triggers to biofilm formation is a step towards limiting and containing biofilm-associated infections and development of biofilm-specific countermeasures. The present review therefore focused on explaining the impact of environmental factors, antimicrobial resistance, gene alteration and regulation, and the prevailing microbial ecology in A. baumannii biofilm formation and gives insights into prospective anti-infective treatments.
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Affiliation(s)
- Emmanuel C Eze
- Virology and Microbiology Research Group, School of Health Sciences, College of Health Sciences, University of KwaZulu-Natal, Durban, South Africa,
| | - Hafizah Y Chenia
- Discipline of Microbiology, School of Life Sciences, College of Agriculture, Engineering and Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Mohamed E El Zowalaty
- Virology and Microbiology Research Group, School of Health Sciences, College of Health Sciences, University of KwaZulu-Natal, Durban, South Africa,
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Philips J, Monballyu E, Georg S, De Paepe K, Prévoteau A, Rabaey K, Arends JBA. AnAcetobacteriumstrain isolated with metallic iron as electron donor enhances iron corrosion by a similar mechanism asSporomusa sphaeroides. FEMS Microbiol Ecol 2018; 95:5184449. [DOI: 10.1093/femsec/fiy222] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 11/14/2018] [Indexed: 02/02/2023] Open
Affiliation(s)
- Jo Philips
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, Ghent 9000, Belgium
| | - Eva Monballyu
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, Ghent 9000, Belgium
| | - Steffen Georg
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, Ghent 9000, Belgium
| | - Kim De Paepe
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, Ghent 9000, Belgium
| | - Antonin Prévoteau
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, Ghent 9000, Belgium
| | - Korneel Rabaey
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, Ghent 9000, Belgium
| | - Jan B A Arends
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, Ghent 9000, Belgium
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Jang N, Yasin M, Kang H, Lee Y, Park GW, Park S, Chang IS. Bubble coalescence suppression driven carbon monoxide (CO)-water mass transfer increase by electrolyte addition in a hollow fiber membrane bioreactor (HFMBR) for microbial CO conversion to ethanol. BIORESOURCE TECHNOLOGY 2018; 263:375-384. [PMID: 29763801 DOI: 10.1016/j.biortech.2018.05.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 04/30/2018] [Accepted: 05/02/2018] [Indexed: 06/08/2023]
Abstract
This study investigated the effects of electrolytes (CaCl2, K2HPO4, MgSO4, NaCl, and NH4Cl) on CO mass transfer and ethanol production in a HFMBR. The hollow fiber membranes (HFM) were found to generate tiny gas bubbles; the bubble coalescence was significantly suppressed in electrolyte solution. The volumetric gas-liquid mass transfer coefficients (kLa) increased up to 414% compared to the control. Saturated CO (C∗) decreased as electrolyte concentrations increased. Overall, the maximum mass transfer rate (Rmax) in electrolyte solution ranged from 106% to 339% of the value obtained in water. The electrolyte toxicity on cell growth was tested using Clostridium autoethanogenum. Most electrolytes, except for MgSO4, inhibited cell growth. The HFMBR operation using a medium containing 1% MgSO4 achieved 119% ethanol production compared to that without electrolytes. Finally, a kinetic simulation using the parameters got from the 1% MgSO4 medium predicted a higher ethanol production compared to the control.
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Affiliation(s)
- Nulee Jang
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
| | - Muhammad Yasin
- Bioenergy & Environmental Sustainable Membrane Technology (BEST) Research Group, Department of Chemical Engineering, COMSATS Institute of Information Technology (CIIT), Lahore, Pakistan
| | - Hyunsoo Kang
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
| | - Yeubin Lee
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
| | - Gwon Woo Park
- Gwangju Bio/Energy R&D Center, Korea Institute of Energy Research (KIER), Gwangju 61003, Republic of Korea
| | - Shinyoung Park
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
| | - In Seop Chang
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea.
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41
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Govaert M, Smet C, Baka M, Janssens T, Impe JV. Influence of incubation conditions on the formation of model biofilms by Listeria monocytogenes and Salmonella Typhimurium on abiotic surfaces. J Appl Microbiol 2018; 125:1890-1900. [PMID: 30117654 DOI: 10.1111/jam.14071] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 07/10/2018] [Accepted: 08/14/2018] [Indexed: 01/12/2023]
Abstract
AIMS This research aims to develop strongly adherent and mature model biofilms (on a 20 cm² polystyrene surface) for two pathogenic species, i.e. Listeria monocytogenes and Salmonella Typhimurium. These model biofilms can be used as standards to study biofilms or to study/compare the influence of different inactivation technologies. METHODS AND RESULTS Three influencing factors on the formation of biofilms are investigated, i.e. growth medium, incubation temperature and incubation time, which are three easily controllable environmental factors. Optical density measurement and plate counts were used to evaluate the adherence and the maturity of the biofilms, respectively. Confocal laser scanning microscopy was used to verify most important findings obtained with previously mentioned assays. Results indicated that mature and strongly adherent L. monocytogenes biofilms are obtained following 13 h of incubation at 30°C with BHI as growth medium. For S. Typhimurium, an incubation period of 19 h at 25°C was required with 20-fold diluted TSB as growth medium. CONCLUSIONS Based on previously mentioned assays, a protocol for the formation of reproducible model biofilms was obtained. SIGNIFICANCE AND IMPACT OF THE STUDY The developed model biofilms can be applied as a standard to study biofilms (in different research fields) and their subsequent inactivation by different methods. In addition, the results of this study could be used to control biofilm formation (e.g. by setting a maximum allowed surface temperature).
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Affiliation(s)
- M Govaert
- CPMF2 - Flemish Cluster Predictive Microbiology in Foods, Ghent, Belgium
- OPTEC - Optimization in Engineering Center-of-Excellence, KU Leuven, Belgium
- BioTeC - Chemical and Biochemical Process Technology and Control, Department of Chemical Engineering, KU Leuven, Ghent, Belgium
| | - C Smet
- CPMF2 - Flemish Cluster Predictive Microbiology in Foods, Ghent, Belgium
- OPTEC - Optimization in Engineering Center-of-Excellence, KU Leuven, Belgium
- BioTeC - Chemical and Biochemical Process Technology and Control, Department of Chemical Engineering, KU Leuven, Ghent, Belgium
| | - M Baka
- CPMF2 - Flemish Cluster Predictive Microbiology in Foods, Ghent, Belgium
- OPTEC - Optimization in Engineering Center-of-Excellence, KU Leuven, Belgium
- BioTeC - Chemical and Biochemical Process Technology and Control, Department of Chemical Engineering, KU Leuven, Ghent, Belgium
| | - T Janssens
- BioTeC - Chemical and Biochemical Process Technology and Control, Department of Chemical Engineering, KU Leuven, Ghent, Belgium
| | - J Van Impe
- CPMF2 - Flemish Cluster Predictive Microbiology in Foods, Ghent, Belgium
- OPTEC - Optimization in Engineering Center-of-Excellence, KU Leuven, Belgium
- BioTeC - Chemical and Biochemical Process Technology and Control, Department of Chemical Engineering, KU Leuven, Ghent, Belgium
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Pierra M, Golozar M, Zhang X, Prévoteau A, De Volder M, Reynaerts D, Rabaey K. Growth and current production of mixed culture anodic biofilms remain unaffected by sub-microscale surface roughness. Bioelectrochemistry 2018; 122:213-220. [DOI: 10.1016/j.bioelechem.2018.04.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Revised: 04/04/2018] [Accepted: 04/06/2018] [Indexed: 12/21/2022]
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Gagliano MC, Neu TR, Kuhlicke U, Sudmalis D, Temmink H, Plugge CM. EPS Glycoconjugate Profiles Shift as Adaptive Response in Anaerobic Microbial Granulation at High Salinity. Front Microbiol 2018; 9:1423. [PMID: 30013532 PMCID: PMC6036115 DOI: 10.3389/fmicb.2018.01423] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 06/11/2018] [Indexed: 11/22/2022] Open
Abstract
Anaerobic granulation at elevated salinities has been discussed in several analytical and engineering based studies. They report either enhanced or decreased efficiencies in relation to different Na+ levels. To evaluate this discrepancy, we focused on the microbial and structural dynamics of granules formed in two upflow anaerobic sludge blanket (UASB) reactors treating synthetic wastewater at low (5 g/L Na+) and high (20 g/L Na+) salinity conditions. Granules were successfully formed in both conditions, but at high salinity, the start-up inoculum quickly formed larger granules having a thicker gel layer in comparison to granules developed at low salinity. Granules retained high concentrations of sodium without any negative effect on biomass activity and structure. 16S rRNA gene analysis and Fluorescence in Situ Hybridization (FISH) identified the acetotrophic Methanosaeta harundinacea as the dominant microorganism at both salinities. Fluorescence lectin bar coding (FLBC) screening highlighted a significant shift in the glycoconjugate pattern between granules grown at 5 and 20 g/L of Na+, and the presence of different extracellular domains. The excretion of a Mannose-rich cloud-like glycoconjugate matrix, which seems to form a protective layer for some methanogenic cells clusters, was found to be the main distinctive feature of the microbial community grown at high salinity conditions.
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Affiliation(s)
- Maria C Gagliano
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, Netherlands
| | - Thomas R Neu
- Helmholtz Centre for Environmental Research, Magdeburg, Germany
| | - Ute Kuhlicke
- Helmholtz Centre for Environmental Research, Magdeburg, Germany
| | - Dainis Sudmalis
- Sub-department of Environmental Technology, Wageningen University & Research, Wageningen, Netherlands
| | - Hardy Temmink
- Sub-department of Environmental Technology, Wageningen University & Research, Wageningen, Netherlands
| | - Caroline M Plugge
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, Netherlands
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44
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Overcoming the energetic limitations of syngas fermentation. Curr Opin Chem Biol 2017; 41:84-92. [DOI: 10.1016/j.cbpa.2017.10.003] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2017] [Revised: 09/28/2017] [Accepted: 10/03/2017] [Indexed: 01/05/2023]
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45
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Transcriptomic profiles of Clostridium ljungdahlii during lithotrophic growth with syngas or H 2 and CO 2 compared to organotrophic growth with fructose. Sci Rep 2017; 7:13135. [PMID: 29030620 PMCID: PMC5640608 DOI: 10.1038/s41598-017-12712-w] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 09/14/2017] [Indexed: 01/13/2023] Open
Abstract
Clostridium ljungdahlii derives energy by lithotrophic and organotrophic acetogenesis. C. ljungdahlii was grown organotrophically with fructose and also lithotrophically, either with syngas - a gas mixture containing hydrogen (H2), carbon dioxide (CO2), and carbon monoxide (CO), or with H2 and CO2. Gene expression was compared quantitatively by microarrays using RNA extracted from all three conditions. Gene expression with fructose and with H2/CO2 was compared by RNA-Seq. Upregulated genes with both syngas and H2/CO2 (compared to fructose) point to the urea cycle, uptake and degradation of peptides and amino acids, response to sulfur starvation, potentially NADPH-producing pathways involving (S)-malate and ornithine, quorum sensing, sporulation, and cell wall remodeling, suggesting a global and multicellular response to lithotrophic conditions. With syngas, the upregulated (R)-lactate dehydrogenase gene represents a route of electron transfer from ferredoxin to NAD. With H2/CO2, flavodoxin and histidine biosynthesis genes were upregulated. Downregulated genes corresponded to an intracytoplasmic microcompartment for disposal of methylglyoxal, a toxic byproduct of glycolysis, as 1-propanol. Several cytoplasmic and membrane-associated redox-active protein genes were differentially regulated. The transcriptomic profiles of C. ljungdahlii in lithotrophic and organotrophic growth modes indicate large-scale physiological and metabolic differences, observations that may guide biofuel and commodity chemical production with this species.
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Jia K, Wang G, Liang L, Wang M, Wang H, Xu X. Preliminary Transcriptome Analysis of Mature Biofilm and Planktonic Cells of Salmonella Enteritidis Exposure to Acid Stress. Front Microbiol 2017; 8:1861. [PMID: 29018430 PMCID: PMC5622974 DOI: 10.3389/fmicb.2017.01861] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 09/12/2017] [Indexed: 11/13/2022] Open
Abstract
Salmonella has emerged as a well-recognized food-borne pathogen, with many strains able to form biofilms and thus cause cross-contamination in food processing environments where acid-based disinfectants are widely encountered. In the present study, RNA sequencing was employed to establish complete transcriptome profiles of Salmonella Enteritidis in the forms of planktonic and biofilm-associated cells cultured in Tryptic Soytone Broth (TSB) and acidic TSB (aTSB). The gene expression patterns of S. Enteritidis significantly differed between biofilm-associated and planktonic cells cultivated under the same conditions. The assembled transcriptome of S. Enteritidis in this study contained 5,442 assembled transcripts, including 3,877 differentially expressed genes (DEGs) identified in biofilm and planktonic cells. These DEGs were enriched in terms such as regulation of biological process, metabolic process, macromolecular complex, binding and transferase activity, which may play crucial roles in the biofilm formation of S. Enteritidis cultivated in aTSB. Three significant pathways were observed to be enriched under acidic conditions: bacterial chemotaxis, porphyrin-chlorophyll metabolism and sulfur metabolism. In addition, 15 differentially expressed novel non-coding small RNAs (sRNAs) were identified, and only one was found to be up-regulated in mature biofilms. This preliminary study of the S. Enteritidis transcriptome serves as a basis for future investigations examining the complex network systems that regulate Salmonella biofilm in acidic environments, which provide information on biofilm formation and acid stress interaction that may facilitate the development of novel disinfection procedures in the food processing industry.
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Affiliation(s)
- Kun Jia
- National Center of Meat Quality and Safety Control, Nanjing Agricultural University, Nanjing, China
| | - Guangyu Wang
- Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Nanjing Agricultural University, Nanjing, China
| | - Lijiao Liang
- National Center of Meat Quality and Safety Control, Nanjing Agricultural University, Nanjing, China
| | - Meng Wang
- National Center of Meat Quality and Safety Control, Nanjing Agricultural University, Nanjing, China
| | - Huhu Wang
- National Center of Meat Quality and Safety Control, Nanjing Agricultural University, Nanjing, China
| | - Xinglian Xu
- Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Nanjing Agricultural University, Nanjing, China
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