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Beraud-Martínez LK, Betancourt-Lozano M, Gómez-Gil B, Asaff-Torres A, Monroy-Hermosillo OA, Franco-Nava MÁ. Methylotrophic methanogenesis induced by ammonia nitrogen in an anaerobic digestion system. Anaerobe 2024; 88:102877. [PMID: 38866129 DOI: 10.1016/j.anaerobe.2024.102877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Revised: 05/08/2024] [Accepted: 06/06/2024] [Indexed: 06/14/2024]
Abstract
OBJECTIVES This lab-scale study aimed to investigate the effect of total ammonia nitrogen (TAN) stress on the methanogenic activity and the taxonomic and functional profiles of the microbial community of anaerobic sludge (AS) from a full-scale bioreactor. METHODS The AS was subjected to a stepwise increase in TAN every 14 days at concentrations of 1, 2, 2.5, 3, 3.5, and 4 g TAN/L (Acclimated-AS or AAS). This acclimation stage was followed by an ammonia stress stage (4 g/L). A blank-AS (BAS) was maintained without TAN during the acclimation stage. In the second stress stage (ST), the BAS was divided into two new treatments: a control (BAS') and one that received a shock load of TAN of 4 g/L (SBAS'). Methane production was measured, and a metagenomic analysis was conducted to describe the microbial community. RESULTS A decrease in the relative abundance of Methanothrix soehngenii of 16 % was related to a decrease of 23 % in the methanogenic capacity of AAS when comparing with the final stage of BAS. However, recovery was observed at 3.5 g TAN/L, and a shift to methylotrophic metabolism occurred, indicated by a 4-fold increase in abundance of Methanosarcina mazei. The functional analysis of sludge metagenomes indicated that no statistical differences (p > 0.05, RM ANOVA) were found in the relative abundance of methanogenic genes that initiate acetoclastic and hydrogenotrophic pathways (acetyl-CoA synthetase, ACSS; acetate kinase, ackA; phosphate acetyltransferase, pta; and formylmethanofuran dehydrogenase subunit A, fwdA) into the BAS and AAS during the acclimation phase. The same was observed between groups of genes associated with methanogenesis from methylated compounds. In contrast, statistical differences (p < 0.05, one-way ANOVA) in the relative abundance of these genes were recorded during ST. The functional profiles of the genes involved in acetoclastic, hydrogenotrophic, and methylotrophic methanogenic pathways were brought to light for acclimatation and stress experimental stages. CONCLUSIONS TAN inhibited methanogenic activity and acetoclastic metabolism. The gradual acclimatization to TAN leads to metabolic and taxonomic changes that allow for the subsequent recovery of methanogenic functionality. The study highlights the importance of adequate management of anaerobic bioprocesses with high nitrogen loads to maintain the methanogenic functionality of the microbial community.
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Affiliation(s)
- Liov Karel Beraud-Martínez
- Centro de Investigación en Alimentación y Desarrollo (CIAD), A. C. Unidad Mazatlán, Avenida Sábalo-Cerritos s/n, Mazatlán, Sinaloa, 82112, Mexico
| | - Miguel Betancourt-Lozano
- Centro de Investigación en Alimentación y Desarrollo (CIAD), A. C. Unidad Mazatlán, Avenida Sábalo-Cerritos s/n, Mazatlán, Sinaloa, 82112, Mexico
| | - Bruno Gómez-Gil
- Centro de Investigación en Alimentación y Desarrollo (CIAD), A. C. Unidad Mazatlán, Avenida Sábalo-Cerritos s/n, Mazatlán, Sinaloa, 82112, Mexico
| | - Ali Asaff-Torres
- Centro de Investigación en Alimentación y Desarrollo (CIAD), A.C. Unidad Hermosillo, Carretera Gustavo Enrique Astiazarán Rosas, No. 46, Col. La Victoria, CP. 83304, Hermosillo, Sonora, Mexico
| | - Oscar Armando Monroy-Hermosillo
- Universidad Autónoma Metropolitana. Biotechnology Department, Av. San Rafael Atlixco 186, Col. Vicentina, 09340, Iztapalapa, Cd. México, Mexico
| | - Miguel Ángel Franco-Nava
- Tecnológico Nacional de México, Campus Mazatlán, Calle Corsario 1 No. 203 Col. Urías, A.P. 757, Mazatlán, Sinaloa, 82070, Mexico.
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Thompson MEH, Raizada MN. The Microbiome of Fertilization-Stage Maize Silks (Style) Encodes Genes and Expresses Traits That Potentially Promote Survival in Pollen/Style Niches and Host Reproduction. Microorganisms 2024; 12:1473. [PMID: 39065240 PMCID: PMC11278993 DOI: 10.3390/microorganisms12071473] [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: 06/27/2024] [Revised: 07/16/2024] [Accepted: 07/17/2024] [Indexed: 07/28/2024] Open
Abstract
Within flowers, the style channel receives pollen and transmits male gametes inside elongating pollen tubes to ovules. The styles of maize/corn are called silks. Fertilization-stage silks possess complex microbiomes, which may partially derive from pollen. These microbiomes lack functional analysis. We hypothesize that fertilization-stage silk microbiomes promote host fertilization to ensure their own vertical transmission. We further hypothesize that these microbes encode traits to survive stresses within the silk (water/nitrogen limitation) and pollen (dehydration/aluminum) habitats. Here, bacteria cultured from fertilization-stage silks of 14 North American maize genotypes underwent genome mining and functional testing, which revealed osmoprotection, nitrogen-fixation, and aluminum-tolerance traits. Bacteria contained auxin biosynthesis genes, and testing confirmed indole compound secretion, which is relevant, since pollen delivers auxin to silks to stimulate egg cell maturation. Some isolates encoded biosynthetic/transport compounds known to regulate pollen tube guidance/growth. The isolates encoded ACC deaminase, which degrades the precursor for ethylene that otherwise accelerates silk senescence. The findings suggest that members of the microbiome of fertilization-stage silks encode adaptations to survive the stress conditions of silk/pollen and have the potential to express signaling compounds known to impact reproduction. Overall, whereas these microbial traits have traditionally been assumed to primarily promote vegetative plant growth, this study proposes they may also play selfish roles during host reproduction.
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Affiliation(s)
| | - Manish N. Raizada
- Department of Plant Agriculture, University of Guelph, Guelph, ON N1G 2W1, Canada;
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Kim M, Kim W, Park Y, Jung J, Park W. Lineage-specific evolution of Aquibium, a close relative of Mesorhizobium, during habitat adaptation. Appl Environ Microbiol 2024; 90:e0209123. [PMID: 38412007 PMCID: PMC10952388 DOI: 10.1128/aem.02091-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Accepted: 02/06/2024] [Indexed: 02/28/2024] Open
Abstract
The novel genus Aquibium that lacks nitrogenase was recently reclassified from the Mesorhizobium genus. The genomes of Aquibium species isolated from water were smaller and had higher GC contents than those of Mesorhizobium species. Six Mesorhizobium species lacking nitrogenase were found to exhibit low similarity in the average nucleotide identity values to the other 24 Mesorhizobium species. Therefore, they were classified as the non-N2-fixing Mesorhizobium lineage (N-ML), an evolutionary intermediate species. The results of our phylogenomic analyses and the loss of Rhizobiales-specific fur/mur indicated that Mesorhizobium species may have evolved from Aquibium species through an ecological transition. Halotolerant and alkali-resistant Aquibium and Mesorhizobium microcysteis belonging to N-ML possessed many tripartite ATP-independent periplasmic transporter and sodium/proton antiporter subunits composed of seven genes (mrpABCDEFG). These genes were not present in the N2-fixing Mesorhizobium lineage (ML), suggesting that genes acquired for adaptation to highly saline and alkaline environments were lost during the evolution of ML as the habitat changed to soil. Land-to-water habitat changes in Aquibium species, close relatives of Mesorhizobium species, could have influenced their genomic evolution by the gain and loss of genes. Our study indicated that lineage-specific evolution could have played a significant role in shaping their genome architecture and conferring their ability to thrive in different habitats.IMPORTANCEPhylogenetic analyses revealed that the Aquibium lineage (AL) and non-N2-fixing Mesorhizobium lineage (N-ML) were monophyletically grouped into distinct clusters separate from the N2-fixing Mesorhizobium lineage (ML). The N-ML, an evolutionary intermediate species having characteristics of both ancestral and descendant species, could provide a genomic snapshot of the genetic changes that occur during adaptation. Genomic analyses of AL, N-ML, and ML revealed that changes in the levels of genes related to transporters, chemotaxis, and nitrogen fixation likely reflect adaptations to different environmental conditions. Our study sheds light on the complex and dynamic nature of the evolution of rhizobia in response to changes in their environment and highlights the crucial role of genomic analysis in understanding these processes.
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Affiliation(s)
- Minkyung Kim
- Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Seoul, South Korea
| | - Wonjae Kim
- Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Seoul, South Korea
| | - Yerim Park
- Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Seoul, South Korea
| | - Jaejoon Jung
- Department of Life Science, Chung-Ang University, Seoul, South Korea
| | - Woojun Park
- Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Seoul, South Korea
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Hu Q, Sun S, Zhang Z, Liu W, Yi X, He H, Scrutton NS, Chen GQ. Ectoine hyperproduction by engineered Halomonas bluephagenesis. Metab Eng 2024; 82:238-249. [PMID: 38401747 DOI: 10.1016/j.ymben.2024.02.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Accepted: 02/19/2024] [Indexed: 02/26/2024]
Abstract
Ectoine, a crucial osmoprotectant for salt adaptation in halophiles, has gained growing interest in cosmetics and medical industries. However, its production remains challenged by stringent fermentation process in model microorganisms and low production level in its native producers. Here, we systematically engineered the native ectoine producer Halomonas bluephagenesis for ectoine production by overexpressing ectABC operon, increasing precursors availability, enhancing product transport system and optimizing its growth medium. The final engineered H. bluephagenesis produced 85 g/L ectoine in 52 h under open unsterile incubation in a 7 L bioreactor in the absence of plasmid, antibiotic or inducer. Furthermore, it was successfully demonstrated the feasibility of decoupling salt concentration with ectoine synthesis and co-production with bioplastic P(3HB-co-4HB) by the engineered H. bluephagenesis. The unsterile fermentation process and significantly increased ectoine titer indicate that H. bluephagenesis as the chassis of Next-Generation Industrial Biotechnology (NGIB), is promising for the biomanufacturing of not only intracellular bioplastic PHA but also small molecular compound such as ectoine.
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Affiliation(s)
- Qitiao Hu
- School of Life Sciences, Tsinghua University, Beijing, 100084, China; Manchester Institute of Biotechnology, Department of Chemistry, The University of Manchester, Manchester, M1 7DN, UK
| | - Simian Sun
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Zhongnan Zhang
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Wei Liu
- PhaBuilder Biotechnology Co. Ltd., Shunyi District, Beijing 101309, China
| | - Xueqing Yi
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Hongtao He
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Nigel S Scrutton
- Manchester Institute of Biotechnology, Department of Chemistry, The University of Manchester, Manchester, M1 7DN, UK
| | - Guo-Qiang Chen
- School of Life Sciences, Tsinghua University, Beijing, 100084, China; Manchester Institute of Biotechnology, Department of Chemistry, The University of Manchester, Manchester, M1 7DN, UK; Center for Synthetic and Systems Biology, Tsinghua University, Beijing 100084, China.
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Feng Y, Qiu M, Shao L, Jiang Y, Zhang W, Jiang W, Xin F, Jiang M. Strategies for the biological production of ectoine by using different chassis strains. Biotechnol Adv 2024; 70:108306. [PMID: 38157997 DOI: 10.1016/j.biotechadv.2023.108306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 11/27/2023] [Accepted: 12/23/2023] [Indexed: 01/03/2024]
Abstract
As an amino acid derivative and a typical compatible solute, ectoine can assist microorganisms in resisting high osmotic pressure. Own to its long-term moisturizing effects, ectoine shows extensive applications in cosmetics, medicine and other fields. With the rapid development of synthetic biology and fermentation engineering, many biological strategies have been developed to improve the ectoine production and simplify the production process. Currently, the microbial fermentation has been widely used for large scaling ectoine production. Accordingly, this review will introduce the metabolic pathway for ectoine synthesis and also comprehensively evaluate both wild-type and genetically modified strains for ectoine production. Furthermore, process parameters affecting the ectoine production efficiency and adoption of low cost substrates will be evaluated. Lastly, future prospects on the improvement of ectoine production will be proposed.
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Affiliation(s)
- Yifan Feng
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, PR China
| | - Min Qiu
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, PR China
| | - Lei Shao
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, PR China
| | - Yujia Jiang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, PR China; Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing 211816, PR China
| | - Wenming Zhang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, PR China; Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing 211816, PR China
| | - Wankui Jiang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, PR China.
| | - Fengxue Xin
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, PR China; Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing 211816, PR China.
| | - Min Jiang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, PR China; Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing 211816, PR China
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Hernández-Soto LM, Martínez-Abarca F, Ramírez-Saad H, López-Pérez M, Aguirre-Garrido JF. Genome analysis of haloalkaline isolates from the soda saline crater lake of Isabel Island; comparative genomics and potential metabolic analysis within the genus Halomonas. BMC Genomics 2023; 24:696. [PMID: 37986038 PMCID: PMC10662389 DOI: 10.1186/s12864-023-09800-9] [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: 06/23/2023] [Accepted: 11/10/2023] [Indexed: 11/22/2023] Open
Abstract
BACKGROUND Isabel Island is a Mexican volcanic island primarily composed of basaltic stones. It features a maar known as Laguna Fragatas, which is classified as a meromictic thalassohaline lake. The constant deposition of guano in this maar results in increased levels of phosphorus, nitrogen, and carbon. The aim of this study was to utilize high-quality genomes from the genus Halomonas found in specialized databases as a reference for genome mining of moderately halophilic bacteria isolated from Laguna Fragatas. This research involved genomic comparisons employing phylogenetic, pangenomic, and metabolic-inference approaches. RESULTS The Halomonas genus exhibited a large open pangenome, but several genes associated with salt metabolism and homeostatic regulation (ectABC and betABC), nitrogen intake through nitrate and nitrite transporters (nasA, and narGI), and phosphorus uptake (pstABCS) were shared among the Halomonas isolates. CONCLUSIONS The isolated bacteria demonstrate consistent adaptation to high salt concentrations, and their nitrogen and phosphorus uptake mechanisms are highly optimized. This optimization is expected in an extremophile environment characterized by minimal disturbances or abrupt seasonal variations. The primary significance of this study lies in the dearth of genomic information available for this saline and low-disturbance environment. This makes it important for ecosystem conservation and enabling an exploration of its biotechnological potential. Additionally, the study presents the first two draft genomes of H. janggokensis.
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Affiliation(s)
- Luis Mario Hernández-Soto
- Doctorado en Ciencias Biológicas y de La Salud, Universidad Autónoma Metropolitana, Mexico City, Mexico
| | - Francisco Martínez-Abarca
- Estructura, Dinámica y Función de Genomas de Rizobacterias, Departamento de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín-CSIC, Granada, Spain
| | - Hugo Ramírez-Saad
- Departamento Sistemas Biológicos, Universidad Autónoma Metropolitana-Xochimilco, Ciudad de Mexico, México
| | - Marcos López-Pérez
- Departamento de Ciencias Ambientales, Universidad Autónoma Metropolitana-Lerma, Estado de México, Lerma, México
| | - José Félix Aguirre-Garrido
- Departamento de Ciencias Ambientales, Universidad Autónoma Metropolitana-Lerma, Estado de México, Lerma, México.
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Rodero MDR, Carmona-Martínez AA, Martínez-Fraile C, Herrero-Lobo R, Rodríguez E, García-Encina PA, Peña M, Muñoz R. Ectoines production from biogas in pilot bubble column bioreactors and their subsequent extraction via bio-milking. WATER RESEARCH 2023; 245:120665. [PMID: 37801795 DOI: 10.1016/j.watres.2023.120665] [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: 04/11/2023] [Revised: 09/17/2023] [Accepted: 09/22/2023] [Indexed: 10/08/2023]
Abstract
Despite the potential of biogas from waste/wastewater treatment as a renewable energy source, the presence of pollutants and the rapid decrease in the levelized cost of solar and wind power constrain the use of biogas for energy generation. Biogas conversion into ectoine, one of the most valuable bioproducts (1000 €/kg), constitutes a new strategy to promote a competitive biogas market. The potential for a stand-alone 20 L bubble column bioreactor operating at 6% NaCl and two 10 L interconnected bioreactors (at 0 and 6% NaCl, respectively) for ectoine production from biogas was comparatively assessed. The stand-alone reactor supported the best process performance due to its highest robustness and efficiency for ectoine accumulation (20-52 mgectoine/gVSS) and CH4 degradation (up to 84%). The increase in N availability and internal gas recirculation did not enhance ectoine synthesis. However, a 2-fold increase in the internal gas recirculation resulted in an approximately 1.3-fold increase in CH4 removal efficiency. Finally, the recovery of ectoine through bacterial bio-milking resulted in efficiencies of >70% without any negative impact of methanotrophic cell recycling to the bioreactors on CH4 biodegradation or ectoine synthesis.
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Affiliation(s)
- María Del Rosario Rodero
- Institute of Sustainable Processes, University of Valladolid, Valladolid 47011, Spain; Department of Chemical Engineering and Environmental Technology, University of Valladolid, Dr. Mergelina s/n., Valladolid 47011, Spain
| | - Alessandro A Carmona-Martínez
- Institute of Sustainable Processes, University of Valladolid, Valladolid 47011, Spain; Department of Chemical Engineering and Environmental Technology, University of Valladolid, Dr. Mergelina s/n., Valladolid 47011, Spain
| | - Cristina Martínez-Fraile
- Institute of Sustainable Processes, University of Valladolid, Valladolid 47011, Spain; Department of Chemical Engineering and Environmental Technology, University of Valladolid, Dr. Mergelina s/n., Valladolid 47011, Spain
| | - Raquel Herrero-Lobo
- Institute of Sustainable Processes, University of Valladolid, Valladolid 47011, Spain; Department of Chemical Engineering and Environmental Technology, University of Valladolid, Dr. Mergelina s/n., Valladolid 47011, Spain
| | - Elisa Rodríguez
- Institute of Sustainable Processes, University of Valladolid, Valladolid 47011, Spain; Department of Chemical Engineering and Environmental Technology, University of Valladolid, Dr. Mergelina s/n., Valladolid 47011, Spain
| | - Pedro A García-Encina
- Institute of Sustainable Processes, University of Valladolid, Valladolid 47011, Spain; Department of Chemical Engineering and Environmental Technology, University of Valladolid, Dr. Mergelina s/n., Valladolid 47011, Spain
| | - Mar Peña
- Institute of Sustainable Processes, University of Valladolid, Valladolid 47011, Spain; Department of Chemical Engineering and Environmental Technology, University of Valladolid, Dr. Mergelina s/n., Valladolid 47011, Spain
| | - Raúl Muñoz
- Institute of Sustainable Processes, University of Valladolid, Valladolid 47011, Spain; Department of Chemical Engineering and Environmental Technology, University of Valladolid, Dr. Mergelina s/n., Valladolid 47011, Spain.
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Faulkner M, Hoeven R, Kelly PP, Sun Y, Park H, Liu LN, Toogood HS, Scrutton NS. Chemoautotrophic production of gaseous hydrocarbons, bioplastics and osmolytes by a novel Halomonas species. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:152. [PMID: 37821908 PMCID: PMC10568851 DOI: 10.1186/s13068-023-02404-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Accepted: 09/25/2023] [Indexed: 10/13/2023]
Abstract
BACKGROUND Production of relatively low value, bulk commodity chemicals and fuels by microbial species requires a step-change in approach to decrease the capital and operational costs associated with scaled fermentation. The utilisation of the robust and halophilic industrial host organisms of the genus Halomonas could dramatically decrease biomanufacturing costs owing to their ability to grow in seawater, using waste biogenic feedstocks, under non-sterile conditions. RESULTS We describe the isolation of Halomonas rowanensis, a novel facultative chemoautotrophic species of Halomonas from a natural brine spring. We investigated the ability of this species to produce ectoine, a compound of considerable industrial interest, under heterotrophic conditions. Fixation of radiolabelled NaH14CO3 by H. rowanensis was confirmed in mineral medium supplied with thiosulfate as an energy source. Genome sequencing suggested carbon fixation proceeds via a reductive tricarboxylic acid cycle, and not the Calvin-Bensen-Bassham cycle. The mechanism of energy generation to support chemoautotrophy is unknown owing to the absence of an annotated SOX-based thiosulfate-mediated energy conversion system. We investigated further the biotechnological potential of the isolated H. rowanensis by demonstrating production of the gaseous hydrocarbon (bio-propane), bioplastics (poly-3-hydroxybutyrate) and osmolytes (ectoine) under heterotrophic and autotrophic CO2 fixation growth conditions. CONCLUSIONS This proof-of-concept study illustrates the value of recruiting environmental isolates as industrial hosts for chemicals biomanufacturing, where CO2 utilisation could replace, or augment, the use of biogenic feedstocks in non-sterile, industrialised bioreactors.
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Affiliation(s)
- Matthew Faulkner
- Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK
| | - Robin Hoeven
- C3 Biotechnologies Ltd, 20 Mannin Way, Caton Road, Lancaster, LA1 35W, Lancashire, UK
- Engineering Building A, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Paul P Kelly
- Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK
| | - Yaqi Sun
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Biosciences Building, Crown Street, Liverpool, L69 7BE, UK
| | - Helen Park
- Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK
| | - Lu-Ning Liu
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Biosciences Building, Crown Street, Liverpool, L69 7BE, UK
| | - Helen S Toogood
- Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK.
- C3 Biotechnologies Ltd, 20 Mannin Way, Caton Road, Lancaster, LA1 35W, Lancashire, UK.
| | - Nigel S Scrutton
- Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK.
- C3 Biotechnologies Ltd, 20 Mannin Way, Caton Road, Lancaster, LA1 35W, Lancashire, UK.
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Xing Q, Mesbah NM, Wang H, Zhang Y, Li J, Zhao B. Tandem mass tag-based quantitative proteomics reveals osmotic adaptation mechanisms in Alkalicoccus halolimnae BZ-SZ-XJ29 T , a halophilic bacterium with a broad salinity range for optimal growth. Environ Microbiol 2023; 25:1967-1987. [PMID: 37271582 DOI: 10.1111/1462-2920.16428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 05/10/2023] [Indexed: 06/06/2023]
Abstract
The moderate halophilic bacterium Alkalicoccus halolimnae BZ-SZ-XJ29T exhibits optimum growth over a wide range of NaCl concentrations (8.3-12.3%, w/v; 1.42-2.1 mol L-1 ). However, its adaptive mechanisms to cope with high salt-induced osmotic stress remain unclear. Using TMT-based quantitative proteomics, the cellular proteome was assessed under low (4% NaCl, 0.68 mol L-1 NaCl, control (CK) group), moderate (8% NaCl, 1.37 mol L-1 NaCl), high (12% NaCl, 2.05 mol L-1 NaCl), and extremely high (16% NaCl, 2.74 mol L-1 NaCl) salinity conditions. Digital droplet PCR confirmed the transcription of candidate genes related to salinity. A. halolimnae utilized distinct adaptation strategies to cope with different salinity conditions. Mechanisms such as accumulating different amounts and types of compatible solutes (i.e., ectoine, glycine betaine, glutamate, and glutamine) and the uptake of glycine betaine and glutamate were employed to cope with osmotic stress. Ectoine synthesis and accumulation were critical to the salt adaptation of A. halolimnae. The expression of EctA, EctB, and EctC, as well as the intracellular accumulation of ectoine, significantly and consistently increased with increasing salinity. Glycine betaine and glutamate concentrations remained constant under the four NaCl concentrations. The total content of glutamine and glutamate maintained a dynamic balance and, when exposed to different salinities, may play a role in low salinity-induced osmoadaptation. Moreover, cellular metabolism was severely affected at high salt concentrations, but the synthesis of amino acids, carbohydrate metabolism, and membrane transport related to haloadptation was preserved to maintain cytoplasmic concentration at high salinity. These findings provide insights into the osmoadaptation mechanisms of moderate halophiles and can serve as a theoretical underpinning for industrial production and application of compatible solutes.
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Affiliation(s)
- Qinghua Xing
- Graduate School, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Noha M Mesbah
- Faculty of Pharmacy, Suez Canal University, Ismailia, Egypt
| | - Haisheng Wang
- Graduate School, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yingjie Zhang
- China Patent Technology Development Co, Beijing, China
| | - Jun Li
- Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Baisuo Zhao
- Graduate School, Chinese Academy of Agricultural Sciences, Beijing, China
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10
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Lai G, Yu J, Wang J, Li W, Liu G, Wang Z, Guo M, Tang Y. Machine learning methods for predicting the key metabolic parameters of Halomonas elongata DSM 2581 T. Appl Microbiol Biotechnol 2023:10.1007/s00253-023-12633-x. [PMID: 37421474 DOI: 10.1007/s00253-023-12633-x] [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: 01/02/2023] [Revised: 03/28/2023] [Accepted: 06/07/2023] [Indexed: 07/10/2023]
Abstract
Ectoine is generally produced by the fermentation process of Halomonas elongata DSM 2581 T, which is one of the primary industrial ectoine production techniques. To effectively monitor and control the fermentation process, the important parameters require accurate real-time measurement. However, for ectoine fermentation, three critical parameters (cell optical density, glucose, and product concentration) cannot be measured conveniently in real-time due to time variation, strong coupling, and other constraints. As a result, our work effectively created a series of hybrid models to predict the values of these three parameters incorporating both fermentation kinetics and machine learning approaches. Compared with the traditional machine learning models, our models solve the problem of insufficient data which is common in fermentation. In addition, a simple kinetic modeling is only applicable to specific physical conditions, so different physical conditions require refitting the function, which is tedious to operate. However, our models also overcome this limitation. In this work, we compared different hybrid models based on 5 feature engineering methods, 11 machine-learning approaches, and 2 kinetic models. The best models for predicting three key parameters, respectively, are as follows: CORR-Ensemble (R2: 0.983 ± 0.0, RMSE: 0.086 ± 0.0, MAE: 0.07 ± 0.0), SBE-Ensemble (R2: 0.972 ± 0.0, RMSE: 0.127 ± 0.0, MAE: 0.078 ± 0.0), and SBE-Ensemble (R2:0.98 ± 0.0, RMSE: 0.023 ± 0.001, MAE: 0.018 ± 0.001). To verify the universality and stability of constructed models, we have done an experimental verification, and its results showed that our proposed models have excellent performance. KEY POINTS: • Using the kinetic models for producing simulated data • Through different feature engineering methods for dimension reduction • Creating a series of hybrid models to predict the values of three parameters in the fermentation process of Halomonas elongata DSM 2581 T.
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Affiliation(s)
- Guanxue Lai
- Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, School of Pharmacy, East China University of Science and Technology, Shanghai, 200237, China
| | - Junxiong Yu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, China
| | - Jing Wang
- Department of Chemical Engineering for Energy Resources, East China University of Science and Technology, Shanghai, 200237, China
| | - Weihua Li
- Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, School of Pharmacy, East China University of Science and Technology, Shanghai, 200237, China
| | - Guixia Liu
- Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, School of Pharmacy, East China University of Science and Technology, Shanghai, 200237, China
| | - Zejian Wang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, China.
| | - Meijin Guo
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, China.
| | - Yun Tang
- Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, School of Pharmacy, East China University of Science and Technology, Shanghai, 200237, China.
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Galisteo C, de la Haba RR, Sánchez-Porro C, Ventosa A. A step into the rare biosphere: genomic features of the new genus Terrihalobacillus and the new species Aquibacillus salsiterrae from hypersaline soils. Front Microbiol 2023; 14:1192059. [PMID: 37228371 PMCID: PMC10203224 DOI: 10.3389/fmicb.2023.1192059] [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: 03/22/2023] [Accepted: 04/12/2023] [Indexed: 05/27/2023] Open
Abstract
Hypersaline soils are a source of prokaryotic diversity that has been overlooked until very recently. The phylum Bacillota, which includes the genus Aquibacillus, is one of the 26 phyla that inhabit the heavy metal contaminated soils of the Odiel Saltmarshers Natural Area (Southwest Spain), according to previous research. In this study, we isolated a total of 32 strains closely related to the genus Aquibacillus by the traditional dilution-plating technique. Phylogenetic studies clustered them into two groups, and comparative genomic analyses revealed that one of them represents a new species within the genus Aquibacillus, whereas the other cluster constitutes a novel genus of the family Bacillaceae. We propose the designations Aquibacillus salsiterrae sp. nov. and Terrihalobacillus insolitus gen. nov., sp. nov., respectively, for these two new taxa. Genome mining analysis revealed dissimilitude in the metabolic traits of the isolates and their closest related genera, remarkably the distinctive presence of the well-conserved pathway for the biosynthesis of molybdenum cofactor in the species of the genera Aquibacillus and Terrihalobacillus, along with genes that encode molybdoenzymes and molybdate transporters, scarcely found in metagenomic dataset from this area. In-silico studies of the osmoregulatory strategy revealed a salt-out mechanism in the new species, which harbor the genes for biosynthesis and transport of the compatible solutes ectoine and glycine betaine. Comparative genomics showed genes related to heavy metal resistance, which seem required due to the contamination in the sampling area. The low values in the genome recruitment analysis indicate that the new species of the two genera, Terrihalobacillus and Aquibacillus, belong to the rare biosphere of representative hypersaline environments.
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12
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Barut D, Enuh BM, Derkuş B, Güler Ü, Salih B, Aytar Çelik P. The relationship between bacterial outer membrane vesicles and halophilic adaptation. Mol Omics 2023; 19:174-181. [PMID: 36597842 DOI: 10.1039/d2mo00259k] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Many cells are known to actively release nano-sized outer membrane vesicles (OMVs) that contain bioactive proteins, lipids, and nucleic acids into the extracellular environment. These vesicles have been associated with adaptation to environmental stress in other species, but their role in halophilic salt stress adaptation is not known. This study aimed to isolate and characterize the OMVs of Halomonas caseinilytica KB2 at various salt concentrations [6% (KB2-6), 12% (KB2-12), and 18% (KB2-18)] and to identify the patterns of adaptations to increasing salinity in its structure, protein composition, and expression. Also, a comparison with the composition of OMVs of E. coli, a mesophilic bacterium, was performed. Bioinformatics and statistical analysis were carried out to elucidate the underlying proteome differences that may exist as a result of increasing salinity. The results show that OMV production in H. caseinilytica KB2 is promoted by a decrease in salinity. OMVs also revealed possible structural and metabolic changes happening in the cells which led to the deduction that cells become more stable with increasing salt concentrations. Cell wall integrity, protein expression and folding are important. Although H. caseinilytica KB2 OMVs show cellular changes with changing salt concentration, they may not play a direct role in adaptation to changing salinity.
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Affiliation(s)
- Dilan Barut
- Department of Biotechnology and Biosafety, Graduate School of Natural and Applied Science, Eskisehir Osmangazi University, 26040 Eskisehir, Turkey.
| | - Blaise M Enuh
- Department of Biotechnology and Biosafety, Graduate School of Natural and Applied Science, Eskisehir Osmangazi University, 26040 Eskisehir, Turkey.
| | - Burak Derkuş
- Department of Chemistry, Faculty of Science, Ankara University, 06560, Ankara, Turkey
| | - Ülkü Güler
- Department of Chemistry, Hacettepe University, Ankara 06800, Turkey
| | - Bekir Salih
- Department of Chemistry, Hacettepe University, Ankara 06800, Turkey
| | - Pınar Aytar Çelik
- Department of Biotechnology and Biosafety, Graduate School of Natural and Applied Science, Eskisehir Osmangazi University, 26040 Eskisehir, Turkey. .,Environmental Protection and Control Program, Eskişehir Osmangazi University, Eskişehir 26110, Turkey
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Genome Analysis of Halomonas elongata Strain 153B and Insights Into Polyhydroxyalkanoate Synthesis and Adaptive Mechanisms to High Saline Environments. Curr Microbiol 2022; 80:18. [PMID: 36460760 DOI: 10.1007/s00284-022-03115-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 11/07/2022] [Indexed: 12/03/2022]
Abstract
Species of the Halomonas genus are gram-negative, aerobic, moderately halophilic bacteria that synthesize polyhydroxyalkanoates (PHAs) and other high-value products that have a wide range of potential uses in the food, feed, cosmetics, pharmaceutical, and chemical sectors. Genome sequencing studies allow for the description and comparison of genetic traits with other strains and species, allowing for the exploration of the organism's potential, necessary to further biotechnology applications. Here, the genome of Halomonas elongata strain 153B was sequenced, its features compared to 5 other strains and 7 species, and a description of features for adaptations to hypersaline environments and bioproducts synthesis was done. Whole-genome analysis showed H. elongata 153B has more similar features to the reference strain H. elongata DSM 2581 compared to 4 other reported strains. Comparative genomics showed 2064 core genomic clusters between the strains and 666 singletons for strain 153B. Several genes in transport and signaling, osmoregulation, and oxidative stress that have roles in adaptation to environments with high osmolarity were also revealed. These appear to form an intricate network of overlapping systems carefully coordinated to bring about adaptation. H. elongata 153B genes for the synthesis of PHAs, ectoine, vitamins, and the degradation of drugs and aromatic compounds were described. The results will aid in the study of halophile physiology, provide a mine for valuable enzymes, and help speed up research for other biotechnology applications.
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Lee JY, Kim DH. Genomic Analysis of Halotolerant Bacterial Strains Martelella soudanensis NC18 T and NC20. J Microbiol Biotechnol 2022; 32:1427-1434. [PMID: 36330756 PMCID: PMC9720073 DOI: 10.4014/jmb.2208.08011] [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: 08/09/2022] [Revised: 09/23/2022] [Accepted: 10/05/2022] [Indexed: 11/06/2022]
Abstract
Two novel, halotolerant strains of Martelella soudanensis, NC18T and NC20, were isolated from deep subsurface sediment, deeply sequenced, and comparatively analyzed with related strains. Based on a phylogenetic analysis using 16S rRNA gene sequences, the two strains grouped with members of the genus Martelella. Here, we sequenced the complete genomes of NC18T and NC20 to understand the mechanisms of their halotolerance. The genome sizes and G+C content of the strains were 6.1 Mb and 61.8 mol%, respectively. Moreover, NC18T and NC20 were predicted to contain 5,849 and 5,830 genes, and 5,502 and 5,585 protein-coding genes, respectively. Both strains contain the identically predicted 6 rRNAs and 48 tRNAs. The harboring of halotolerant-associated genes revealed that strains NC18T and NC20 might tolerate high salinity through the accumulation of potassium ions in a "salt-in" strategy induced by K+ uptake protein (kup) and the K+ transport system (trkAH and kdpFABC). These two strains also use the ectoine transport system (dctPQM), the glycine betaine transport system (proVWX), and glycine betaine uptake protein (opu) to accumulate "compatible solutes," such as ectoine and glycine betaine, to protect cells from salt stress. This study reveals the halotolerance mechanism of strains NC18T and NC20 in high salt environments and suggests potential applications for these halotolerant and halophilic strains in environmental biotechnology.
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Affiliation(s)
- Jung-Yun Lee
- Groundwater Environment Research Center, Korea Institute of Geoscience and Mineral Resources, Daejeon 34132, Republic of Korea,Department of Biological Science and Biotechnology, Microbiology and Biotechnology, Chungbuk National University, Cheongju 28644, Republic of Korea
| | - Dong-Hun Kim
- Groundwater Environment Research Center, Korea Institute of Geoscience and Mineral Resources, Daejeon 34132, Republic of Korea,Corresponding author Phone: +82-42-868-3113 Fax: +82-42-868-3414 E-mail:
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Biswas J, Jana SK, Mandal S. Biotechnological impacts of Halomonas: a promising cell factory for industrially relevant biomolecules. Biotechnol Genet Eng Rev 2022:1-30. [PMID: 36253947 DOI: 10.1080/02648725.2022.2131961] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 09/27/2022] [Indexed: 11/02/2022]
Abstract
Extremophiles are the most fascinating life forms for their special adaptations and ability to offer unique extremozymes or bioactive molecules. Halophiles, the natural inhabitants of hypersaline environments, are one among them. Halomonas are the common genus of halophilic bacteria. To support growth in unusual environments, Halomonas produces various hydrolytic enzymes, compatible solutes, biopolymers like extracellular polysaccharides (EPS) and polyhydroxy alkaloates (PHA), antibiotics, biosurfactants, pigments, etc. Many of such molecules are being produced in large-scale bioreactors for commercial use. However, the prospect of the remaining bioactive molecules with industrial relevance is far from their application. Furthermore, the genetic engineering of the respective gene clusters could open up a new path to bio-prospect these molecules by overproducing their products through heterologous expression. The present survey on Halomonas highlights their ecological diversity, application potential of the their various industrially relevant biomolecules and impact of these biomolecules on respective fields.
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Affiliation(s)
- Jhuma Biswas
- Laboratory of Molecular Bacteriology, Department of Microbiology, University of Calcutta, Kolkata, India
| | - Santosh Kumar Jana
- Laboratory of Molecular Bacteriology, Department of Microbiology, University of Calcutta, Kolkata, India
| | - Sukhendu Mandal
- Laboratory of Molecular Bacteriology, Department of Microbiology, University of Calcutta, Kolkata, India
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Halomonas spp., as chassis for low-cost production of chemicals. Appl Microbiol Biotechnol 2022; 106:6977-6992. [PMID: 36205763 DOI: 10.1007/s00253-022-12215-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 09/26/2022] [Accepted: 09/27/2022] [Indexed: 11/02/2022]
Abstract
Halomonas spp. are the well-studied platform organisms or chassis for next-generation industrial biotechnology (NGIB) due to their contamination-resistant nature combined with their fast growth property. Several Halomonas spp. have been studied regarding their genomic information and molecular engineering approaches. Halomonas spp., especially Halomonas bluephagenesis, have been engineered to produce various biopolyesters such as polyhydroxyalkanoates (PHA), proteins including surfactants and enzymes, small molecular compounds including amino acids and derivates, as well as organic acids. This paper reviews all the progress reported in the last 10 years regarding this robust microbial cell factory. KEY POINTS: • Halomonas spp. are robust chassis for low-cost production of chemicals • Genomic information of some Halomonas spp. has been revealed • Molecular tools and approaches for Halomonas spp. have been developed • Halomonas spp. are becoming more and more important for biotechnology.
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Czech L, Gertzen C, Smits SHJ, Bremer E. Guilty by association: importers, exporters and
MscS
‐type mechanosensitive channels encoded in biosynthetic gene clusters for the stress‐protectant ectoine. Environ Microbiol 2022; 24:5306-5331. [DOI: 10.1111/1462-2920.16203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 09/07/2022] [Indexed: 11/28/2022]
Affiliation(s)
- Laura Czech
- Department of Biology, Laboratory for Microbiology and Center for Synthetic Microbiology (SYNMIKRO) Philipps‐University Marburg Marburg Germany
- Department of Chemistry and Center for Synthetic Microbiology (SYNMIKRO) Philipps‐University Marburg Marburg Germany
| | - Christoph Gertzen
- Center for Structural Studies (CSS) Heinrich‐Heine‐University Düsseldorf Düsseldorf Germany
- Institute of Pharmaceutical and Medicinal Chemistry Heinrich‐Heine‐University Düsseldorf Düsseldorf Germany
| | - Sander H. J. Smits
- Center for Structural Studies (CSS) Heinrich‐Heine‐University Düsseldorf Düsseldorf Germany
- Institute of Biochemistry Heinrich Heine University Düsseldorf Düsseldorf Germany
| | - Erhard Bremer
- Department of Biology, Laboratory for Microbiology and Center for Synthetic Microbiology (SYNMIKRO) Philipps‐University Marburg Marburg Germany
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Yu J, Wang Z, Wang J, Mohisn A, Liu H, Zhang Y, Zhuang Y, Guo M. Physiological metabolic topology analysis of Halomonas elongata DSM 2581 T in response to sodium chloride stress. Biotechnol Bioeng 2022; 119:3509-3525. [PMID: 36062959 DOI: 10.1002/bit.28222] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 08/25/2022] [Accepted: 08/30/2022] [Indexed: 11/06/2022]
Abstract
The halophilic bacterium Halomonas elongata DSM 2581T generally adapts well to high level of salinity by biosynthesizing ectoine, which functions as an important compatible solute protecting the cell against external salinity environment. Halophilic bacteria have specific metabolic activities under high-salt conditions and are gradually applied in various industries. The present study focuses on investigating the physiological and metabolic mechanism of Halomonas elongata DSM 2581T driven by the external salinity environment. The physiological metabolic dynamics under salt stress were investigated to evaluate the effect of NaCl stress on the metabolism of H. elongata. The obtained results demonstrated that ectoine biosynthesis transited from a non-growth-related process to a growth-related process when the NaCl concentration varied from 1% to 13% (w/v). The maximum biomass (Xm =41.37 g/L), and highest ectoine production (Pm =12.91 g/L) were achieved under 8% NaCl. Moreover, the maximum biomass (Xm ) and the maximum specific growth rates (μm ) showed a first rising and then declining trend with the increased NaCl stress. Furthermore, the transcriptome analysis of H. elongata under different NaCl concentrations demonstrated that both 8% and 13% NaCl conditions resulted in increased expressions of genes involved in the pentose phosphate pathway (PPP), Entner-Doudoroff (ED) pathway, Flagellar assembly pathway and ectoine metabolism, but negatively affected the tricarboxylic acid (TCA) cycle and Fatty acid metabolism. At last, the proposed possible adaptation mechanism under the optimum NaCl concentration in H. elongata was described. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Junxiong Yu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Rd, Shanghai, 200237, China
| | - Zejian Wang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Rd, Shanghai, 200237, China
| | - Jing Wang
- Department of Chemical Engineering for Energy Resources, East China University of Science and Technology, 130 Meilong Rd, Shanghai, 200237, China
| | - Ali Mohisn
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Rd, Shanghai, 200237, China
| | - Hao Liu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Rd, Shanghai, 200237, China
| | - Yue Zhang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Rd, Shanghai, 200237, China
| | - Yingping Zhuang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Rd, Shanghai, 200237, China
| | - Meijin Guo
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Rd, Shanghai, 200237, China
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Hobmeier K, Oppermann M, Stasinski N, Kremling A, Pflüger-Grau K, Kunte HJ, Marin-Sanguino A. Metabolic engineering of Halomonas elongata: Ectoine secretion is increased by demand and supply driven approaches. Front Microbiol 2022; 13:968983. [PMID: 36090101 PMCID: PMC9453808 DOI: 10.3389/fmicb.2022.968983] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 07/29/2022] [Indexed: 11/30/2022] Open
Abstract
The application of naturally-derived biomolecules in everyday products, replacing conventional synthetic manufacturing, is an ever-increasing market. An example of this is the compatible solute ectoine, which is contained in a plethora of treatment formulations for medicinal products and cosmetics. As of today, ectoine is produced in a scale of tons each year by the natural producer Halomonas elongata. In this work, we explore two complementary approaches to obtain genetically improved producer strains for ectoine production. We explore the effect of increased precursor supply (oxaloacetate) on ectoine production, as well as an implementation of increased ectoine demand through the overexpression of a transporter. Both approaches were implemented on an already genetically modified ectoine-excreting strain H. elongata KB2.13 (ΔteaABC ΔdoeA) and both led to new strains with higher ectoine excretion. The supply driven approach led to a 45% increase in ectoine titers in two different strains. This increase was attributed to the removal of phosphoenolpyruvate carboxykinase (PEPCK), which allowed the conversion of 17.9% of the glucose substrate to ectoine. For the demand driven approach, we investigated the potential of the TeaBC transmembrane proteins from the ectoine-specific Tripartite ATP-Independent Periplasmic (TRAP) transporter as export channels to improve ectoine excretion. In the absence of the substrate-binding protein TeaA, an overexpression of both subunits TeaBC facilitated a three-fold increased excretion rate of ectoine. Individually, the large subunit TeaC showed an approximately five times higher extracellular ectoine concentration per dry weight compared to TeaBC shortly after its expression was induced. However, the detrimental effect on growth and ectoine titer at the end of the process hints toward a negative impact of TeaC overexpression on membrane integrity and possibly leads to cell lysis. By using either strategy, the ectoine synthesis and excretion in H. elongata could be boosted drastically. The inherent complementary nature of these approaches point at a coordinated implementation of both as a promising strategy for future projects in Metabolic Engineering. Moreover, a wide variation of intracelllular ectoine levels was observed between the strains, which points at a major disruption of mechanisms responsible for ectoine regulation in strain KB2.13.
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Affiliation(s)
- Karina Hobmeier
- Professorship for Systems Biotechnology, Technical University of Munich, Garching, Germany
| | - Martin Oppermann
- Professorship for Systems Biotechnology, Technical University of Munich, Garching, Germany
| | - Natalie Stasinski
- Professorship for Systems Biotechnology, Technical University of Munich, Garching, Germany
| | - Andreas Kremling
- Professorship for Systems Biotechnology, Technical University of Munich, Garching, Germany
| | - Katharina Pflüger-Grau
- Professorship for Systems Biotechnology, Technical University of Munich, Garching, Germany
| | - Hans Jörg Kunte
- Division Biodeterioration and Reference Organisms, Bundesanstalt für Materialforschung und-prüfung (BAM), Berlin, Germany
| | - Alberto Marin-Sanguino
- Professorship for Systems Biotechnology, Technical University of Munich, Garching, Germany
- Departament de Ciències Mèdiques Bàsiques, Universitat de Lleida, Lleida, Spain
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Nitrogen Fixation Activity and Genome Analysis of a Moderately Haloalkaliphilic Anoxygenic Phototrophic Bacterium Rhodovulum tesquicola. Microorganisms 2022; 10:microorganisms10081615. [PMID: 36014033 PMCID: PMC9412634 DOI: 10.3390/microorganisms10081615] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 07/23/2022] [Accepted: 07/25/2022] [Indexed: 11/16/2022] Open
Abstract
The genome of the moderately haloalkaliphilic diazotrophic anoxygenic phototrophic bacterium Rhodovulum tesquicola A-36sT isolated from an alkaline lake was analyzed and compared to the genomes of the closest species Rhodovulum steppense A-20sT and Rhodovulum strictum DSM 11289T. The genomic features of three organisms are quite similar, reflecting their ecological and physiological role of facultative photoheterotrophs. Nevertheless, the nitrogenase activity of the pure cultures of the studied bacteria differed significantly: the highest rate (4066 nmoles C2H2/mg of dry weight per hour) was demonstrated by Rhodovulum strictum while the rates in Rhodovulum tesquicola and Rhodovulum steppense were an order of magnitude lower (278 and 523 nmoles C2H2/mg of dry weight per hour, respectively). This difference can be attributed to the presence of an additional nitrogenase operon found exclusively in R. strictum and to the structural variation in nitrogenase operon in R. tesquicola.
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Du R, Gao D, Wang Y, Liu L, Cheng J, Liu J, Zhang XH, Yu M. Heterotrophic Sulfur Oxidation of Halomonas titanicae SOB56 and Its Habitat Adaptation to the Hydrothermal Environment. Front Microbiol 2022; 13:888833. [PMID: 35774465 PMCID: PMC9237845 DOI: 10.3389/fmicb.2022.888833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 05/24/2022] [Indexed: 11/23/2022] Open
Abstract
Halomonas bacteria are ubiquitous in global marine environments, however, their sulfur-oxidizing abilities and survival adaptations in hydrothermal environments are not well understood. In this study, we characterized the sulfur oxidation ability and metabolic mechanisms of Halomonas titanicae SOB56, which was isolated from the sediment of the Tangyin hydrothermal field in the Southern Okinawa Trough. Physiological characterizations showed that it is a heterotrophic sulfur-oxidizing bacterium that can oxidize thiosulfate to tetrathionate, with the Na2S2O3 degradation reaching 94.86%. Two potential thiosulfate dehydrogenase-related genes, tsdA and tsdB, were identified as encoding key catalytic enzymes, and their expression levels in strain SOB56 were significantly upregulated. Nine of fifteen examined Halomonas genomes possess TsdA- and TsdB-homologous proteins, whose amino acid sequences have two typical Cys-X2-Cys-His heme-binding regions. Moreover, the thiosulfate oxidation process in H. titanicae SOB56 might be regulated by quorum sensing, and autoinducer-2 synthesis protein LuxS was identified in its genome. Regarding the mechanisms underlying adaptation to hydrothermal environment, strain SOB56 was capable of forming biofilms and producing EPS. In addition, genes related to complete flagellum assembly system, various signal transduction histidine kinases, heavy metal transporters, anaerobic respiration, and variable osmotic stress regulation were also identified. Our results shed light on the potential functions of heterotrophic Halomonas bacteria in hydrothermal sulfur cycle and revealed possible adaptations for living at deep-sea hydrothermal fields by H. titanicae SOB56.
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Affiliation(s)
- Rui Du
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Di Gao
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
| | - Yiting Wang
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
| | - Lijun Liu
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
| | - Jingguang Cheng
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
| | - Jiwen Liu
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Xiao-Hua Zhang
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Min Yu
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China
- *Correspondence: Min Yu,
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22
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Abosamaha A, Williamson MP, Gilmour DJ. Utilization and accumulation of compatible solutes in Halomonas pacifica: a species of moderately halophilic bacteria isolated from a saline lake in South Libya. Access Microbiol 2022; 4:acmi000359. [PMID: 36003353 PMCID: PMC9394535 DOI: 10.1099/acmi.0.000359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 04/12/2022] [Indexed: 11/23/2022] Open
Abstract
When grown in high salt concentrations, halophilic bacteria often accumulate compatible solutes, which have major applications in biotechnology because they stabilize cells and proteins. Four Gram-negative bacterial strains, belonging to the family Halomonadaceae, were isolated from Qaberoun and Um-Alma lakes in South Libya using high-salinity medium. The strains were identified using 16S rRNA gene sequencing as belonging to Halomonas pacifica (strain ABQ1), Halomonas venusta (ABQ2), Halomonas elongata (ABU1) and Halomonas salifodinae (ABU2). H. pacifica ABQ1 is a moderate halophile (salinity range 0.05 to 2.5 M NaCl), with a broad tolerance to pH (7 to 9) and temperature (25–37 °C). Addition of the compatible solutes glycine betaine (betaine) and ectoine (1,4,5,6-tetrahydro-2-methyl-4-pyrimidine carboxylic acid) to the medium had a positive effect on growth of H. pacifica at 2 M NaCl. In rich LB medium, betaine was the major compatible solute accumulated, with ectoine only being accumulated at salinities in excess of 1 M NaCl. In minimal M9 medium, betaine was not produced, but increasing amounts of ectoine were synthesized with increasing salinity, and hydroxyectoine [(4S,5S)−5-hydroxy-2-methyl-1,4,5,6-tetrahydropyrimidine-4-carboxylic acid] was also synthesized when the cells were grown in very high salt. We have thus identified H. pacifica as a producer of ectoine and hydroxyectoine, with more being produced at higher salinities. As industrial demand for these compatible solutes continues to increase, this system has biotechnological potential.
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Affiliation(s)
- Abdolkader Abosamaha
- School of Science and Technology, Nottingham Trent University, Nottingham NG11 8NS, UK
| | - Mike P. Williamson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
| | - D. James Gilmour
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
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23
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Hobmeier K, Cantone M, Nguyen QA, Pflüger-Grau K, Kremling A, Kunte HJ, Pfeiffer F, Marin-Sanguino A. Adaptation to Varying Salinity in Halomonas elongata: Much More Than Ectoine Accumulation. Front Microbiol 2022; 13:846677. [PMID: 35432243 PMCID: PMC9006882 DOI: 10.3389/fmicb.2022.846677] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 02/21/2022] [Indexed: 11/13/2022] Open
Abstract
The halophilic γ-proteobacterium Halomonas elongata DSM 2581 T thrives at salt concentrations well above 10 % NaCl (1.7 M NaCl). A well-known osmoregulatory mechanism is the accumulation of the compatible solute ectoine within the cell in response to osmotic stress. While ectoine accumulation is central to osmoregulation and promotes resistance to high salinity in halophilic bacteria, ectoine has this effect only to a much lesser extent in non-halophiles. We carried out transcriptome analysis of H. elongata grown on two different carbon sources (acetate or glucose), and low (0.17 M NaCl), medium (1 M), and high salinity (2 M) to identify additional mechanisms for adaptation to high saline environments. To avoid a methodological bias, the transcripts were evaluated by applying two methods, DESeq2 and Transcripts Per Million (TPM). The differentially transcribed genes in response to the available carbon sources and salt stress were then compared to the transcriptome profile of Chromohalobacter salexigens, a closely related moderate halophilic bacterium. Transcriptome profiling supports the notion that glucose is degraded via the cytoplasmic Entner-Doudoroff pathway, whereas the Embden-Meyerhoff-Parnas pathway is employed for gluconeogenesis. The machinery of oxidative phosphorylation in H. elongata and C. salexigens differs greatly from that of non-halophilic organisms, and electron flow can occur from quinone to oxygen along four alternative routes. Two of these pathways via cytochrome bo' and cytochrome bd quinol oxidases seem to be upregulated in salt stressed cells. Among the most highly regulated genes in H. elongata and C. salexigens are those encoding chemotaxis and motility proteins, with genes for chemotaxis and flagellar assembly severely downregulated at low salt concentrations. We also compared transcripts at low and high-salt stress (low growth rate) with transcripts at optimal salt concentration and found that the majority of regulated genes were down-regulated in stressed cells, including many genes involved in carbohydrate metabolism, while ribosome synthesis was up-regulated, which is in contrast to what is known from non-halophiles at slow growth. Finally, comparing the acidity of the cytoplasmic proteomes of non-halophiles, extreme halophiles and moderate halophiles suggests adaptation to an increased cytoplasmic ion concentration of H. elongata. Taken together, these results lead us to propose a model for salt tolerance in H. elongata where ion accumulation plays a greater role in salt tolerance than previously assumed.
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Affiliation(s)
- Karina Hobmeier
- Systems Biotechnology, Technical University of Munich, Garching, Germany
| | - Martina Cantone
- Systems Biotechnology, Technical University of Munich, Garching, Germany
| | - Quynh Anh Nguyen
- Systems Biotechnology, Technical University of Munich, Garching, Germany
| | | | - Andreas Kremling
- Systems Biotechnology, Technical University of Munich, Garching, Germany
| | - Hans Jörg Kunte
- Division Biodeterioration and Reference Organisms, Bundesanstalt für Materialforschung und -prüfung (BAM), Berlin, Germany
| | - Friedhelm Pfeiffer
- Computational Biology Group, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Alberto Marin-Sanguino
- Systems Biotechnology, Technical University of Munich, Garching, Germany.,Departament de Ciències Mèdiques Bàsiques, Universitat de Lleida, Lleida, Spain
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24
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Zhang T, Zhang X, Li Y, Yang N, Qiao L, Miao Z, Xing J, Zhu D. Study of osmoadaptation mechanisms of halophilic Halomonas alkaliphila XH26 under salt stress by transcriptome and ectoine analysis. Extremophiles 2022; 26:14. [PMID: 35229247 DOI: 10.1007/s00792-022-01256-1] [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: 04/07/2021] [Accepted: 01/04/2022] [Indexed: 11/04/2022]
Abstract
Halophilic bacteria such as the genus Halomonas are promising candidates in diverse industrial, agricultural and biomedical applications. Here, we successfully isolated a halophilic Halomonas alkaliphila strain XH26 from Xiaochaidan Salt Lake, and studied its osmoadaptation strategies using transcriptome and ectoine analysis. Divergent mechanisms were involved in osmoadaptation at different salinities in H. alkaliphila XH26. At moderate salinity (6% NaCl), increased transcriptions of ABC transporters related to iron (III), phosphate, phosphonate, monosaccharide and oligosaccharide import were observed. At high salinity (15% NaCl), transcriptions of flagellum assembly and cell motility were significantly inhibited. The transcriptional levels of ABC transporter genes related to iron (III) and iron3+-hydroxamate import, glycine betaine and putrescine uptake, and cytochrome biogenesis and assembly were significantly up-regulated. Ectoine synthesis and accumulation was significantly increased under salt stress, and the increased transcriptional expressions of ectoine synthesis genes ectB and ectC may play a key role in high salinity induced osmoadaptation. At extreme high salinity (18% NaCl), 5-hydroxyectoine and ectoine worked together to maintain cell survival. Together these results give valuable insights into the osmoadaptation mechanisms of H. alkaliphila XH26, and provide useful information for further engineering this specific strain for increased ectoine synthesis and related applications.
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Affiliation(s)
- Tiantian Zhang
- Research Centre of Basic Medical Sciences, Medical College, Qinghai University, Xining, 810016, People's Republic of China
| | - Xin Zhang
- Research Centre of Basic Medical Sciences, Medical College, Qinghai University, Xining, 810016, People's Republic of China
| | - Yongzhen Li
- Research Centre of Basic Medical Sciences, Medical College, Qinghai University, Xining, 810016, People's Republic of China
| | - Ning Yang
- Research Centre of Basic Medical Sciences, Medical College, Qinghai University, Xining, 810016, People's Republic of China
| | - Lijuan Qiao
- Research Centre of Basic Medical Sciences, Medical College, Qinghai University, Xining, 810016, People's Republic of China
| | - Zengqiang Miao
- Research Centre of Basic Medical Sciences, Medical College, Qinghai University, Xining, 810016, People's Republic of China
| | - Jiangwa Xing
- Research Centre of Basic Medical Sciences, Medical College, Qinghai University, Xining, 810016, People's Republic of China.
| | - Derui Zhu
- Research Centre of Basic Medical Sciences, Medical College, Qinghai University, Xining, 810016, People's Republic of China.
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25
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Hermann L, Dempwolff F, Steinchen W, Freibert SA, Smits SHJ, Seubert A, Bremer E. The MocR/GabR Ectoine and Hydroxyectoine Catabolism Regulator EnuR: Inducer and DNA Binding. Front Microbiol 2022; 12:764731. [PMID: 35003002 PMCID: PMC8739950 DOI: 10.3389/fmicb.2021.764731] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 12/01/2021] [Indexed: 11/26/2022] Open
Abstract
The compatible solutes ectoine and 5-hydroxyectoine are widely synthesized by bacteria as osmostress protectants. These nitrogen-rich tetrahydropyrimidines can also be exploited as nutrients by microorganisms. Many ectoine/5-hydroxyectoine catabolic gene clusters are associated with a regulatory gene (enuR: ectoine nutrient utilization regulator) encoding a repressor protein belonging to the MocR/GabR sub-family of GntR-type transcription factors. Focusing on EnuR from the marine bacterium Ruegeria pomeroyi, we show that the dimerization of EnuR is mediated by its aminotransferase domain. This domain can fold independently from its amino-terminal DNA reading head and can incorporate pyridoxal-5′-phosphate (PLP) as cofactor. The covalent attachment of PLP to residue Lys302 of EnuR was proven by mass-spectrometry. PLP interacts with system-specific, ectoine and 5-hydroxyectoine-derived inducers: alpha-acetyldiaminobutyric acid (alpha-ADABA), and hydroxy-alpha-acetyldiaminobutyric acid (hydroxy-alpha-ADABA), respectively. These inducers are generated in cells actively growing with ectoines as sole carbon and nitrogen sources, by the EutD hydrolase and targeted metabolic analysis allowed their detection. EnuR binds these effector molecules with affinities in the low micro-molar range. Studies addressing the evolutionary conservation of EnuR, modelling of the EnuR structure, and docking experiments with the inducers provide an initial view into the cofactor and effector binding cavity. In this cavity, the two high-affinity inducers for EnuR, alpha-ADABA and hydroxy-alpha-ADABA, are positioned such that their respective primary nitrogen group can chemically interact with PLP. Purified EnuR bound with micro-molar affinity to a 48 base pair DNA fragment containing the sigma-70 type substrate-inducible promoter for the ectoine/5-hydroxyectoine importer and catabolic gene cluster. Consistent with the function of EnuR as a repressor, the core elements of the promoter overlap with two predicted EnuR operators. Our data lend themselves to a straightforward regulatory model for the initial encounter of EnuR-possessing ectoine/5-hydroxyectoine consumers with environmental ectoines and for the situation when the external supply of these compounds has been exhausted by catabolism.
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Affiliation(s)
- Lucas Hermann
- Faculty of Biology, Philipps-University Marburg, Marburg, Germany.,Department of Biochemistry and Synthetic Metabolism, Max-Planck-Institute for Terrestrial Microbiology, Marburg, Germany
| | - Felix Dempwolff
- SYNMIKRO Research Center, Philipps-University Marburg, Marburg, Germany
| | - Wieland Steinchen
- SYNMIKRO Research Center, Philipps-University Marburg, Marburg, Germany
| | - Sven-Andreas Freibert
- Department of Medicine, Institute for Cytobiology and Cytopathology, and SYNMIKRO Research Center, Philipps-University Marburg, Marburg, Germany
| | - Sander H J Smits
- Institute of Biochemistry, Heinrich-Heine-University, Düsseldorf, Germany.,Center for Structural Studies (CSS), Faculty of Biochemistry, Heinrich-Heine-University, Düsseldorf, Germany
| | - Andreas Seubert
- Faculty of Chemistry, Philipps-University Marburg, Marburg, Germany
| | - Erhard Bremer
- Faculty of Biology, Philipps-University Marburg, Marburg, Germany.,SYNMIKRO Research Center, Philipps-University Marburg, Marburg, Germany
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26
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Kang JY, Lee B, Kim JA, Kim MS, Kim CH. Identification and characterization of an ectoine biosynthesis gene cluster from Aestuariispira ectoiniformans sp. nov., isolated from seawater. Microbiol Res 2021; 254:126898. [PMID: 34710834 DOI: 10.1016/j.micres.2021.126898] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 09/16/2021] [Accepted: 10/19/2021] [Indexed: 11/26/2022]
Abstract
An ectoine-producing bacterium, designated SWCN16T, was isolated from seawater and could be grown in a medium containing up to 12 % NaCl. A phylogenetic analysis based on 16S rRNA gene sequences revealed that strain SWCN16T belonged to the genus Aestuariispira, class Alphaproteobacteria, and shared the highest 16S rRNA gene sequence similarity of 96.8% with Aestuariispira insulae CECT 8488T. The phenotypic, chemotaxonomic, and genotypic characteristics findings of this study suggested that strain SWCN16T represented a novel species of the genus Aestuariispira. We propose the name Aestuariispira ectoiniformans sp. nov. for this species. Whole-genome sequencing analysis of the isolate revealed a putative ectABC gene cluster for ectoine biosynthesis. These genes were found to be functional using ectoine synthesis testing and S16-ectBAC cells, which were pET21a-ectBAC-transformed E. coli BL21 cells. We found that S16-ectBAC synthesized about 1.67 g/L extracellular ectoine and about 0.59 g/L intracellular ectoine via bioconversion at optimum conditions.
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Affiliation(s)
- Ji Young Kang
- Industrial Microbiology and Bioprocess Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Jeongeup-si, 580-185, Republic of Korea.
| | - Binna Lee
- Industrial Microbiology and Bioprocess Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Jeongeup-si, 580-185, Republic of Korea.
| | - Jeong Ah Kim
- Industrial Microbiology and Bioprocess Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Jeongeup-si, 580-185, Republic of Korea.
| | - Min-Soo Kim
- Industrial Microbiology and Bioprocess Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Jeongeup-si, 580-185, Republic of Korea.
| | - Chul Ho Kim
- Industrial Microbiology and Bioprocess Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Jeongeup-si, 580-185, Republic of Korea.
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27
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Frikha-Dammak D, Ayadi H, Hakim-Rekik I, Belbahri L, Maalej S. Genome analysis of the salt-resistant Paludifilum halophilum DSM 102817 T reveals genes involved in flux-tuning of ectoines and unexplored bioactive secondary metabolites. World J Microbiol Biotechnol 2021; 37:178. [PMID: 34549358 DOI: 10.1007/s11274-021-03147-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 09/14/2021] [Indexed: 10/20/2022]
Abstract
Paludifilum halophilum DSM 102817T is the first member of the genus Paludifilum in the Thermoactinomycetaceae family. The thermohalophilic bacterium was isolated from the solar saltern of Sfax, Tunisia and was shown to be able to produce ectoines with a relatively high-yield and to cope with salt stress conditions. In this study, the whole genome of P. halophilum was sequenced and analysed. Analysis revealed 3,789,765 base pairs with an average GC% content of 51.5%. A total of 3775 genes were predicted of which 3616 were protein-coding genes and 73 were RNA genes. The genes encoding key enzymes for ectoines (ectoine and hydroxyectoine) synthesis (ectABCD) were identified from the bacterial genome next to a gene cluster (ehuABCD) encoding a binding-protein-dependent ABC transport system responsible for ectoines mobility through the cell membrane. With the aid of KEGG analysis, we found that the central catabolic network of P. halophilum comprises the pathways of glycolysis, tricarboxylic acid cycle, and pentose phosphate. In addition, anaplerotic pathways replenishing oxaloacetate and glutamate synthesis from central metabolism needed for high ectoines biosynthetic fluxes were identified through several key enzymes. Furthermore, a total of 18 antiSMASH-predicted putative biosynthetic gene clusters for secondary metabolites with high novelty and diversity were identified in P. halophilum genome, including biosynthesis of colabomycine-A, fusaricidin-E, zwittermycin A, streptomycin, mycosubtilin and meilingmycin. Based on these data, P. halophilum emerged as a promising source for ectoines and antimicrobials with the potential to be scaled up for industrial production, which could benefit the pharmaceutical and cosmetic industries.
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Affiliation(s)
- Donyez Frikha-Dammak
- Laboratoire de Biodiversité Marine et Environnement (LR18ES30), Faculté des Sciences de Sfax, Université de Sfax, BP 1171, 3000, Sfax, Tunisia
| | - Houda Ayadi
- Laboratoire de Biodiversité Marine et Environnement (LR18ES30), Faculté des Sciences de Sfax, Université de Sfax, BP 1171, 3000, Sfax, Tunisia
| | - Imen Hakim-Rekik
- Unité de Génomique Fonctionnelle et Physiologie des Plantes, Université de Sfax, Institut Supérieur de Biotechnologie de Sfax, BP 1175, 3000, Sfax, Tunisia
| | - Lassaad Belbahri
- Laboratory of Soil Biology, University of Neuchatel, 11 Rue Emile Argand, 2000, Neuchâtel, Switzerland
| | - Sami Maalej
- Laboratoire de Biodiversité Marine et Environnement (LR18ES30), Faculté des Sciences de Sfax, Université de Sfax, BP 1171, 3000, Sfax, Tunisia.
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28
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Hermann L, Mais CN, Czech L, Smits SHJ, Bange G, Bremer E. The ups and downs of ectoine: structural enzymology of a major microbial stress protectant and versatile nutrient. Biol Chem 2021; 401:1443-1468. [PMID: 32755967 DOI: 10.1515/hsz-2020-0223] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 07/22/2020] [Indexed: 12/13/2022]
Abstract
Ectoine and its derivative 5-hydroxyectoine are compatible solutes and chemical chaperones widely synthesized by Bacteria and some Archaea as cytoprotectants during osmotic stress and high- or low-growth temperature extremes. The function-preserving attributes of ectoines led to numerous biotechnological and biomedical applications and fostered the development of an industrial scale production process. Synthesis of ectoines requires the expenditure of considerable energetic and biosynthetic resources. Hence, microorganisms have developed ways to exploit ectoines as nutrients when they are no longer needed as stress protectants. Here, we summarize our current knowledge on the phylogenomic distribution of ectoine producing and consuming microorganisms. We emphasize the structural enzymology of the pathways underlying ectoine biosynthesis and consumption, an understanding that has been achieved only recently. The synthesis and degradation pathways critically differ in the isomeric form of the key metabolite N-acetyldiaminobutyric acid (ADABA). γ-ADABA serves as preferred substrate for the ectoine synthase, while the α-ADABA isomer is produced by the ectoine hydrolase as an intermediate in catabolism. It can serve as internal inducer for the genetic control of ectoine catabolic genes via the GabR/MocR-type regulator EnuR. Our review highlights the importance of structural enzymology to inspire the mechanistic understanding of metabolic networks at the biological scale.
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Affiliation(s)
- Lucas Hermann
- Department of Biology, Laboratory for Microbiology, Philipps-University Marburg, Karl-von Frisch Str. 8, D-35043 Marburg, Germany.,Biochemistry and Synthetic Biology of Microbial Metabolism Group, Max Planck Institute for Terrestrial Microbiology, Karl-von Frisch Str. 10, D-35043 Marburg, Germany
| | - Christopher-Nils Mais
- Center for Synthetic Microbiology (SYNMIKRO) & Faculty of Chemistry, Philipps-University Marburg, Hans-Meerwein Str. 6, D-35043 Marburg, Germany
| | - Laura Czech
- Department of Biology, Laboratory for Microbiology, Philipps-University Marburg, Karl-von Frisch Str. 8, D-35043 Marburg, Germany.,Center for Synthetic Microbiology (SYNMIKRO) & Faculty of Chemistry, Philipps-University Marburg, Hans-Meerwein Str. 6, D-35043 Marburg, Germany
| | - Sander H J Smits
- Center for Structural Studies, Heinrich Heine University Düsseldorf, Universitätsstr. 1, D-40225 Düsseldorf, Germany.,Institute of Biochemistry, Heinrich Heine University Düsseldorf, Universitätsstr. 1, D-40225 Düsseldorf, Germany
| | - Gert Bange
- Center for Synthetic Microbiology (SYNMIKRO) & Faculty of Chemistry, Philipps-University Marburg, Hans-Meerwein Str. 6, D-35043 Marburg, Germany
| | - Erhard Bremer
- Department of Biology, Laboratory for Microbiology, Philipps-University Marburg, Karl-von Frisch Str. 8, D-35043 Marburg, Germany.,Center for Synthetic Microbiology (SYNMIKRO), Philipps University Marburg, Hans-Meerwein Str. 6, D-35043 Marburg, Germany
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29
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Qiu X, Cao X, Xu G, Wu H, Tang X. Halomonas maris sp. nov., a moderately halophilic bacterium isolated from sediment in the southwest Indian Ocean. Arch Microbiol 2021; 203:3279-3285. [PMID: 33860341 DOI: 10.1007/s00203-021-02317-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 03/14/2021] [Accepted: 03/30/2021] [Indexed: 11/30/2022]
Abstract
A halophilic, Gram-staining-negative, rod-shaped, flagellated and motile bacterium, strain QX-1 T, was isolated from deep-sea sediment at a depth of 3332 m in the southwestern Indian Ocean. Strain QX-1 T growth was observed at 4-50 °C (optimum 37 °C), pH 5.0-11.0 (optimum pH 7.0), 3-25% NaCl (w/v; optimum 7%), and it did not grow without NaCl. A phylogenetic analysis based on the 16S rRNA gene placed strain QX-1 T in the genus Halomonas and most closely related to Halomonas sulfidaeris (97.9%), Halomonas zhaodongensis (97.8%), Halomonas songnenensis (97.6%), Halomonas hydrothermalis (97.4%), Halomonas subterranea (97.3%), Halomonas salicampi (97.1%), and Halomonas arcis (97.0%). DNA-DNA hybridization (< 26.5%) and average nucleotide identity values (< 83.5%) between strain QX-1 T and the related type strains meet the accepted criteria for a new species. The principal fatty acids (> 10%) of strain QX-1 T are C16:0 (25.5%), C17:0 cyclo (14.0%), C19:0 cyclo ω8c (18.7%), and summed feature 8 (C18:1 ω7c and/or C18:1 ω6c, 18.1%). The polar lipids of strain QX-1 T are mainly diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, unidentified phospholipid, unidentified aminophospholipid, and five unidentified lipids. The main respiratory quinone is Q-9. The G + C content of its chromosomal DNA is 54.4 mol%. Its fatty acid profile, respiratory quinones, and G + C content also support the placement of QX-1 T in the genus Halomonas. These phylogenetic, phenotypic, and chemotaxonomic analyses indicate that QX-1 T is a novel species, for which the name Halomonas maris is proposed. The type strain is QX-1 T (= MCCC 1A17875T = KCTC 82198 T = NBRC 114670 T).
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Affiliation(s)
- Xu Qiu
- Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China.,School of Ocean Sciences, China University of Geosciences (Beijing), Beijing, 100083, China
| | - Xiaorong Cao
- Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China
| | - Guangxin Xu
- Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China
| | - Huangming Wu
- Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China
| | - Xixiang Tang
- Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China.
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30
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Frank C, Hoffmann T, Zelder O, Felle MF, Bremer E. Enhanced Glutamate Synthesis and Export by the Thermotolerant Emerging Industrial Workhorse Bacillus methanolicus in Response to High Osmolarity. Front Microbiol 2021; 12:640980. [PMID: 33897645 PMCID: PMC8060640 DOI: 10.3389/fmicb.2021.640980] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Accepted: 03/01/2021] [Indexed: 11/13/2022] Open
Abstract
The thermotolerant methylotroph Bacillus methanolicus MGA3 was originally isolated from freshwater marsh soil. Due to its ability to use methanol as sole carbon and energy source, B. methanolicus is increasingly explored as a cell factory for the production of amino acids, fine chemicals, and proteins of biotechnological interest. During high cell density fermentation in industrial settings with the membrane-permeable methanol as the feed, the excretion of low molecular weight products synthesized from it will increase the osmotic pressure of the medium. This in turn will impair cell growth and productivity of the overall biotechnological production process. With this in mind, we have analyzed the core of the physiological adjustment process of B. methanolicus MGA3 to sustained high osmolarity surroundings. Through growth assays, we found that B. methanolicus MGA3 possesses only a restricted ability to cope with sustained osmotic stress. This finding is consistent with the ecophysiological conditions in the habitat from which it was originally isolated. None of the externally provided compatible solutes and proline-containing peptides affording osmostress protection for Bacillus subtilis were able to stimulate growth of B. methanolicus MGA3 at high salinity. B. methanolicus MGA3 synthesized the moderately effective compatible solute L-glutamate in a pattern such that the cellular pool increased concomitantly with increases in the external osmolarity. Counterintuitively, a large portion of the newly synthesized L-glutamate was excreted. The expression of the genes (gltAB and gltA2) for two L-glutamate synthases were upregulated in response to high salinity along with that of the gltC regulatory gene. Such a regulatory pattern of the system(s) for L-glutamate synthesis in Bacilli is new. Our findings might thus be generally relevant to understand the production of the osmostress protectant L-glutamate by those Bacilli that exclusively rely on this compatible solute for their physiological adjustment to high osmolarity surroundings.
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Affiliation(s)
- Christine Frank
- Laboratory for Microbiology, Department of Biology, Philipps-University Marburg, Marburg, Germany
| | - Tamara Hoffmann
- Laboratory for Microbiology, Department of Biology, Philipps-University Marburg, Marburg, Germany.,Center for Synthetic Microbiology (SYNMIKRO), Philipps-University Marburg, Marburg, Germany
| | - Oskar Zelder
- BASF SE, RWB/EC - A030 - L3/10, Ludwigshafen, Germany
| | - Max F Felle
- BASF SE, RWB/EC - A030 - L3/10, Ludwigshafen, Germany
| | - Erhard Bremer
- Laboratory for Microbiology, Department of Biology, Philipps-University Marburg, Marburg, Germany.,Center for Synthetic Microbiology (SYNMIKRO), Philipps-University Marburg, Marburg, Germany
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31
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Liu M, Liu H, Shi M, Jiang M, Li L, Zheng Y. Microbial production of ectoine and hydroxyectoine as high-value chemicals. Microb Cell Fact 2021; 20:76. [PMID: 33771157 PMCID: PMC7995798 DOI: 10.1186/s12934-021-01567-6] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Accepted: 03/16/2021] [Indexed: 12/20/2022] Open
Abstract
Ectoine and hydroxyectoine as typical representatives of compatible solutes are not only essential for extremophiles to survive in extreme environments, but also widely used in cosmetic and medical industries. Ectoine was traditionally produced by Halomonas elongata through a "bacterial milking" process, of which the marked feature is using a high-salt medium to stimulate ectoine biosynthesis and then excreting ectoine into a low-salt medium by osmotic shock. The optimal hydroxyectoine production was achieved by optimizing the fermentation process of Halomonas salina. However, high-salinity broth exacerbates the corrosion to fermenters, and more importantly, brings a big challenge to the subsequent wastewater treatment. Therefore, increasing attention has been paid to reducing the salinity of the fermentation broth but without a sacrifice of ectoine/hydroxyectoine production. With the fast development of functional genomics and synthetic biology, quite a lot of progress on the bioproduction of ectoine/hydroxyectoine has been achieved in recent years. The importation and expression of an ectoine producing pathway in a non-halophilic chassis has so far achieved the highest titer of ectoine (~ 65 g/L), while rational flux-tuning of halophilic chassis represents a promising strategy for the next-generation of ectoine industrial production. However, efficient conversion of ectoine to hydroxyectoine, which could benefit from a clearer understanding of the ectoine hydroxylase, is still a challenge to date.
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Affiliation(s)
- Mengshuang Liu
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, No. 1 Beichen West Road, Chaoyang District, Beijing, 100101, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Hui Liu
- CAS Key Laboratory of Bio-Based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
| | - Meng Shi
- Department of Microbiology, University of Washington, Seattle, USA
| | - Mingyue Jiang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, No. 1 Beichen West Road, Chaoyang District, Beijing, 100101, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Lingling Li
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, No. 1 Beichen West Road, Chaoyang District, Beijing, 100101, China
| | - Yanning Zheng
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, No. 1 Beichen West Road, Chaoyang District, Beijing, 100101, China.
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Dong Y, Zhang H, Wang X, Ma J, Lei P, Xu H, Li S. Enhancing ectoine production by recombinant Escherichia coli through step-wise fermentation optimization strategy based on kinetic analysis. Bioprocess Biosyst Eng 2021; 44:1557-1566. [PMID: 33751211 DOI: 10.1007/s00449-021-02541-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 02/16/2021] [Indexed: 12/29/2022]
Abstract
In this study, the recombinant ectoine-producing Escherichia coli ET01 was constructed by introducing the ectABC operon from Halomonas venusta ZH. To further improve ectoine production, the regulation of the fermentation process was systematically investigated. First, the effects of the initial glucose concentrations and glucose feeding mode on ectoine production were analyzed. Using a combination of pH-feedback feeding and glucose-controlled feeding, the ectoine titer reached 25.5 g/L, representing an 8.8-fold increase over standard batch culture. Then, the effects of dissolved oxygen (DO) levels (50, 40, 30, or 20%) on ectoine production were studied, and a DO control strategy was developed based on the fermentation kinetics. When the final optimized two-stage fermentation strategy was used, the ectoine titer reached 47.8 g/L, which was the highest level of ectoine produced by E. coli fermentation. The fermentation regulation strategy developed in this study might be useful for scaling up the commercial production of ectoine.
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Affiliation(s)
- Yingsheng Dong
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing, 211816, People's Republic of China
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, 211816, People's Republic of China
| | - Hao Zhang
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing, 211816, People's Republic of China
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, 211816, People's Republic of China
| | - XinYi Wang
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, 211816, People's Republic of China
| | - JunJie Ma
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, 211816, People's Republic of China
| | - Peng Lei
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, 211816, People's Republic of China
| | - Hong Xu
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing, 211816, People's Republic of China
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, 211816, People's Republic of China
- Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, Nanjing, People's Republic of China
| | - Sha Li
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing, 211816, People's Republic of China.
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, 211816, People's Republic of China.
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33
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Qiu X, Yu L, Cao X, Wu H, Xu G, Tang X. Halomonas sedimenti sp. nov., a Halotolerant Bacterium Isolated from Deep-Sea Sediment of the Southwest Indian Ocean. Curr Microbiol 2021; 78:1662-1669. [PMID: 33651187 DOI: 10.1007/s00284-021-02425-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 02/10/2021] [Indexed: 10/22/2022]
Abstract
A Gram-staining-negative, aerobic, flagellated, motile, rod-shaped, halophilic bacterium QX-2T was isolated from the deep-sea sediment of the Southwest Indian Ocean at a depth of 2699 m. Growth of the QX-2T bacteria was observed at 4-50 °C (optimum 30 °C), pH 5.0-12.0 (optimum pH 6.0) and 0%-30% NaCl (w/v) [optimum 4% (w/v)]. 16S rRNA gene sequencing revealed that strain QX-2T has the closest relationship with Halomonas titanicae DSM 22872T (98.2%). Phylogeny analysis classified the strain QX-2T into the genus Halomonas. The average nucleotide identity and DNA-DNA hybridization values between strain QX-2T and related type strains were lower than the currently accepted new species definition standards. Principal fatty acids (> 10%) determined were C16:0 (12.41%), C12:0-3OH (25.15%), summed feature 3 (C16:1 ω7c and/or C16:1 ω6c, 11.55%) and summed feature 8 (C18:1 ω7c and/or C18:1 ω6c, 16.06%). Identified polar lipids in strain QX-2T were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, unidentified phospholipid, unidentified aminophospholipid and five unidentified lipids (L1-L5). The main respiratory quinone was Q-9. The content of DNA G+C was determined to be 54.34 mol%. The results of phylogenetic analysis, phenotypic analysis and chemotaxonomic studies showed that strain QX-2T represents a novel species within the genus Halomonas, for which the name Halomonas sedimenti sp. nov. is proposed, with the type strain QX-2T (MCCC 1A17876T = KCTC 82199T).
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Affiliation(s)
- Xu Qiu
- Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China.,School of Ocean Sciences, China University of Geosciences (Beijing), Beijing, 100083, China
| | - Libo Yu
- Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China
| | - Xiaorong Cao
- Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China
| | - Huangming Wu
- Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China
| | - Guangxin Xu
- Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China
| | - Xixiang Tang
- Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China.
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Gregory GJ, Boyd EF. Stressed out: Bacterial response to high salinity using compatible solute biosynthesis and uptake systems, lessons from Vibrionaceae. Comput Struct Biotechnol J 2021; 19:1014-1027. [PMID: 33613867 PMCID: PMC7876524 DOI: 10.1016/j.csbj.2021.01.030] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 01/18/2021] [Accepted: 01/20/2021] [Indexed: 12/19/2022] Open
Abstract
Bacteria have evolved mechanisms that allow them to adapt to changes in osmolarity and some species have adapted to live optimally in high salinity environments such as in the marine ecosystem. Most bacteria that live in high salinity do so by the biosynthesis and/or uptake of compatible solutes, small organic molecules that maintain the turgor pressure of the cell. Osmotic stress response mechanisms and their regulation among marine heterotrophic bacteria are poorly understood. In this review, we discuss what is known about compatible solute metabolism and transport and new insights gained from studying marine bacteria belonging to the family Vibrionaceae.
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Affiliation(s)
| | - E. Fidelma Boyd
- Corresponding author at: Department of Biological Sciences, 341 Wolf Hall, University of Delaware, Newark, DE 19716, United States.
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Sunita K, Mishra I, Mishra J, Prakash J, Arora NK. Secondary Metabolites From Halotolerant Plant Growth Promoting Rhizobacteria for Ameliorating Salinity Stress in Plants. Front Microbiol 2020; 11:567768. [PMID: 33193157 PMCID: PMC7641974 DOI: 10.3389/fmicb.2020.567768] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 09/29/2020] [Indexed: 12/23/2022] Open
Abstract
Soil salinization has emerged as one of the prime environmental constraints endangering soil quality and agricultural productivity. Anthropogenic activities coupled with rapid pace of climate change are the key drivers of soil salinity resulting in degradation of agricultural lands. Increasing levels of salt not only impair structure of soil and its microbial activity but also restrict plant growth by causing harmful imbalance and metabolic disorders. Potential of secondary metabolites synthesized by halotolerant plant growth promoting rhizobacteria (HT-PGPR) in the management of salinity stress in crops is gaining importance. A wide array of secondary metabolites such as osmoprotectants/compatible solutes, exopolysaccharides (EPS) and volatile organic compounds (VOCs) from HT-PGPR have been reported to play crucial roles in ameliorating salinity stress in plants and their symbiotic partners. In addition, HT-PGPR and their metabolites also help in prompt buffering of the salt stress and act as biological engineers enhancing the quality and productivity of saline soils. The review documents prominent secondary metabolites from HT-PGPR and their role in modulating responses of plants to salinity stress. The review also highlights the mechanisms involved in the production of secondary metabolites by HT-PGPR in saline conditions. Utilizing the HT-PGPR and their secondary metabolites for the development of novel bioinoculants for the management of saline agro-ecosystems can be an important strategy in the future.
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Affiliation(s)
- Kumari Sunita
- Department of Botany, Deen Dayal Upadhyay Gorakhpur University, Gorakhpur, India
| | - Isha Mishra
- Department of Microbiology, School for Environmental Sciences, Babasaheb Bhimrao Ambedkar University, Lucknow, India
| | - Jitendra Mishra
- DST-Center for Policy Research, Babasaheb Bhimrao Ambedkar University, Lucknow, India
| | - Jai Prakash
- Department of Microbiology, School for Environmental Sciences, Babasaheb Bhimrao Ambedkar University, Lucknow, India
| | - Naveen Kumar Arora
- Department of Environmental Science, School for Environmental Sciences, Babasaheb Bhimrao Ambedkar University, Lucknow, India
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36
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Yan M, Treu L, Zhu X, Tian H, Basile A, Fotidis IA, Campanaro S, Angelidaki I. Insights into Ammonia Adaptation and Methanogenic Precursor Oxidation by Genome-Centric Analysis. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:12568-12582. [PMID: 32852203 PMCID: PMC8154354 DOI: 10.1021/acs.est.0c01945] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 08/22/2020] [Accepted: 08/27/2020] [Indexed: 05/04/2023]
Abstract
Ammonia released from the degradation of protein and/or urea usually leads to suboptimal anaerobic digestion (AD) when N-rich organic waste is used. However, the insights behind the differential ammonia tolerance of anaerobic microbiomes remain an enigma. In this study, the cultivation in synthetic medium with different carbon sources (acetate, methanol, formate, and H2/CO2) shaped a common initial inoculum into four unique ammonia-tolerant syntrophic populations. Specifically, various levels of ammonia tolerance were observed: consortia fed with methanol and H2/CO2 could grow at ammonia levels up to 7.25 g NH+-N/L, whereas the other two groups (formate and acetate) only thrived at 5.25 and 4.25 g NH+-N/L, respectively. Metabolic reconstruction highlighted that this divergent microbiome might be achieved by complementary metabolisms to maximize biomethane recovery from carbon sources, thus indicating the importance of the syntrophic community in the AD of N-rich substrates. Besides, sodium/proton antiporter operon, osmoprotectant/K+ regulator, and osmoprotectant synthesis operon may function as the main drivers of adaptation to the ammonia stress. Moreover, energy from the substrate-level phosphorylation and multiple energy-converting hydrogenases (e.g., Ech and Eha) could aid methanogens to balance the energy request for anabolic activities and contribute to thriving when exposed to high ammonia levels.
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Affiliation(s)
- Miao Yan
- Department of Environmental
Engineering, Technical University of Denmark, Bygningstorvet Bygning 115, DK-2800 Kongens Lyngby, Denmark
| | - Laura Treu
- Department of Biology, University
of Padova, Via U. Bassi
58/b, 35121 Padova, Italy
| | - Xinyu Zhu
- Department of Environmental
Engineering, Technical University of Denmark, Bygningstorvet Bygning 115, DK-2800 Kongens Lyngby, Denmark
| | - Hailin Tian
- Department of Environmental
Engineering, Technical University of Denmark, Bygningstorvet Bygning 115, DK-2800 Kongens Lyngby, Denmark
- NUS Environmental Research Institute, National
University of Singapore, 1 Create Way, 138602, Singapore
| | - Arianna Basile
- Department of Biology, University
of Padova, Via U. Bassi
58/b, 35121 Padova, Italy
| | - Ioannis A. Fotidis
- Department of Environmental
Engineering, Technical University of Denmark, Bygningstorvet Bygning 115, DK-2800 Kongens Lyngby, Denmark
- School of Civil Engineering, Southeast University, 210096 Nanjing, China
| | - Stefano Campanaro
- Department of Biology, University
of Padova, Via U. Bassi
58/b, 35121 Padova, Italy
- CRIBI Biotechnology Center, University of Padua, 35131 Padua, Italy
| | - Irini Angelidaki
- Department of Environmental
Engineering, Technical University of Denmark, Bygningstorvet Bygning 115, DK-2800 Kongens Lyngby, Denmark
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37
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Van Thuoc D, Loan TT, Trung TA, Van Quyen N, Tung QN, Tien PQ, Sudesh K. Genome Mining Reveals the Biosynthetic Pathways of Polyhydroxyalkanoate and Ectoines of the Halophilic Strain Salinivibrio proteolyticus M318 Isolated from Fermented Shrimp Paste. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2020; 22:651-660. [PMID: 32827070 DOI: 10.1007/s10126-020-09986-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 08/03/2020] [Indexed: 06/11/2023]
Abstract
Salinivibrio proteolyticus M318, a halophilic bacterium isolated from fermented shrimp paste, is able to produce polyhydroxyalkanoate (PHA) from different carbon sources. In this study, we report the whole-genome sequence of strain M138, which comprises 2 separated chromosomes and 2 plasmids, and the complete genome contains 3,605,935 bp with an average GC content of 49.9%. The genome of strain M318 contains 3341 genes, 98 tRNA genes, and 28 rRNA genes. The 16S rRNA gene sequence and average nucleotide identity analysis associated with morphological and biochemical tests showed that this strain has high homology to the reference strain Salinivibrio proteolyticus DSM 8285. The genes encoding key enzymes for PHA and ectoine synthesis were identified from the bacterial genome. In addition, the TeaABC transporter responsible for ectoine uptake from the environment and the operon doeABXCD responsible for the degradation of ectoine were also detected. Strain M318 was able to produce poly(3-hydroxybutyrate) [P(3HB)] from different carbon sources such as glycerol, maltose, glucose, fructose, and starch. The ability to produce ectoines at different NaCl concentrations was investigated. High ectoine content of 26.2% of cell dry weight was obtained by this strain at 18% NaCl. This report provides genetic information regarding adaptive mechanisms of strain M318 to stress conditions, as well as new knowledge to facilitate the application of this strain as a bacterial cell factory for the production of PHA and ectoine.
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Affiliation(s)
- Doan Van Thuoc
- Faculty of Biology, Hanoi National University of Education, 136 Xuan Thuy, Cau Giay, Hanoi, Vietnam.
| | - Tran Thi Loan
- Faculty of Biology, Hanoi National University of Education, 136 Xuan Thuy, Cau Giay, Hanoi, Vietnam
| | - Trieu Anh Trung
- Faculty of Biology, Hanoi National University of Education, 136 Xuan Thuy, Cau Giay, Hanoi, Vietnam
| | - Nguyen Van Quyen
- Faculty of Biology, Hanoi National University of Education, 136 Xuan Thuy, Cau Giay, Hanoi, Vietnam
| | - Quach Ngoc Tung
- Institute of Biotechnology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Caugiay, Hanoi, Vietnam
| | - Phi Quyet Tien
- Institute of Biotechnology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Caugiay, Hanoi, Vietnam
| | - Kumar Sudesh
- School of Biological Sciences, Universiti Sains Malaysia, 11800, Penang, Malaysia
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38
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Kumar S, Paul D, Bhushan B, Wakchaure GC, Meena KK, Shouche Y. Traversing the "Omic" landscape of microbial halotolerance for key molecular processes and new insights. Crit Rev Microbiol 2020; 46:631-653. [PMID: 32991226 DOI: 10.1080/1040841x.2020.1819770] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Post-2005, the biology of the salt afflicted habitats is predominantly studied employing high throughput "Omic" approaches comprising metagenomics, transcriptomics, metatranscriptomics, metabolomics, and proteomics. Such "Omic-based" studies have deciphered the unfamiliar details about microbial salt-stress biology. The MAGs (Metagenome-assembled genomes) of uncultured halophilic microbial lineages such as Nanohaloarchaea and haloalkaliphilic members within CPR (Candidate Phyla Radiation) have been reconstructed from diverse hypersaline habitats. The study of MAGs of such uncultured halophilic microbial lineages has unveiled the genomic basis of salt stress tolerance in "yet to culture" microbial lineages. Furthermore, functional metagenomic approaches have been used to decipher the novel genes from uncultured microbes and their possible role in microbial salt-stress tolerance. The present review focuses on the new insights into microbial salt-stress biology gained through different "Omic" approaches. This review also summarizes the key molecular processes that underlie microbial salt-stress response, and their role in microbial salt-stress tolerance has been confirmed at more than one "Omic" levels.
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Affiliation(s)
- Satish Kumar
- National Centre for Microbial Resource, National Centre for Cell Science, Pune, India.,ICAR-National Institute of Abiotic Stress Management, Baramati, Pune, India
| | - Dhiraj Paul
- National Centre for Microbial Resource, National Centre for Cell Science, Pune, India
| | - Bharat Bhushan
- ICAR-National Bureau of Plant Genetic Resources, New Delhi, India
| | - G C Wakchaure
- ICAR-National Institute of Abiotic Stress Management, Baramati, Pune, India
| | - Kamlesh K Meena
- ICAR-National Institute of Abiotic Stress Management, Baramati, Pune, India
| | - Yogesh Shouche
- National Centre for Microbial Resource, National Centre for Cell Science, Pune, India
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39
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Yin Y, Mimura H. Mitigation of Hyper KCl Stress at 42ºC with Externally Existing Sodium Glutamate to a Halotolerant Brevibacterium sp. JCM 6894. Biocontrol Sci 2020; 25:139-147. [PMID: 32938843 DOI: 10.4265/bio.25.139] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
Halotolerant Brevibacterium sp. JCM 6894 grew at 37ºC in the presence of 2.3 M KCl, while the growth was repressed with the same concentration of NaCl. When resting cells, 107.4 ± 0.1 (CFU·mL-1), prepared from cells grown in the absence of salts at 30ºC, were exposed to 3.3 M NaCl for 36 h at 42ºC, reduction of the number of resting cells was maintained within a 1-log cycle in the presence of proline, betaine, or ectoine (50 mM). In the presence of 3.3 M KCl, the most functional osmoprotectant was sodium glutamate (50 mM), and the value was 107.2 ± 0.1 (CFU·mL-1) when exposed for 72 h at 42ºC. In the absence of osmoprotectants, the value was reduced to four orders of magnitude in each experimental condition. The number of resting cells, 106.8 ± 0.1 (CFU·mL-1), prepared from grown cells pre-adapted to 2.3 M KCl at 37ºC, was hardly reduced when exposed to 3.3 M KCl in the presence of sodium glutamate more than 50 mM for 72 h at 42ºC. Those results indicate that the isolate can sense the difference in hyper KCl stress as opposed to hyper NaCl stress, and different kinds of osmoadaptation systems can function to cope with each hyper salt stress.
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Affiliation(s)
- Yue Yin
- Graduate School of Maritime Sciences, Kobe University
| | - Haruo Mimura
- Graduate School of Maritime Sciences, Kobe University
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40
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Mais CN, Hermann L, Altegoer F, Seubert A, Richter AA, Wernersbach I, Czech L, Bremer E, Bange G. Degradation of the microbial stress protectants and chemical chaperones ectoine and hydroxyectoine by a bacterial hydrolase-deacetylase complex. J Biol Chem 2020; 295:9087-9104. [PMID: 32404365 PMCID: PMC7335791 DOI: 10.1074/jbc.ra120.012722] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Revised: 05/06/2020] [Indexed: 12/12/2022] Open
Abstract
When faced with increased osmolarity in the environment, many bacterial cells accumulate the compatible solute ectoine and its derivative 5-hydroxyectoine. Both compounds are not only potent osmostress protectants, but also serve as effective chemical chaperones stabilizing protein functionality. Ectoines are energy-rich nitrogen and carbon sources that have an ecological impact that shapes microbial communities. Although the biochemistry of ectoine and 5-hydroxyectoine biosynthesis is well understood, our understanding of their catabolism is only rudimentary. Here, we combined biochemical and structural approaches to unravel the core of ectoine and 5-hydroxy-ectoine catabolisms. We show that a conserved enzyme bimodule consisting of the EutD ectoine/5-hydroxyectoine hydrolase and the EutE deacetylase degrades both ectoines. We determined the high-resolution crystal structures of both enzymes, derived from the salt-tolerant bacteria Ruegeria pomeroyi and Halomonas elongata These structures, either in their apo-forms or in forms capturing substrates or intermediates, provided detailed insights into the catalytic cores of the EutD and EutE enzymes. The combined biochemical and structural results indicate that the EutD homodimer opens the pyrimidine ring of ectoine through an unusual covalent intermediate, N-α-2 acetyl-l-2,4-diaminobutyrate (α-ADABA). We found that α-ADABA is then deacetylated by the zinc-dependent EutE monomer into diaminobutyric acid (DABA), which is further catabolized to l-aspartate. We observed that the EutD-EutE bimodule synthesizes exclusively the α-, but not the γ-isomers of ADABA or hydroxy-ADABA. Of note, α-ADABA is known to induce the MocR/GabR-type repressor EnuR, which controls the expression of many ectoine catabolic genes clusters. We conclude that hydroxy-α-ADABA might serve a similar function.
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Affiliation(s)
- Christopher-Nils Mais
- Philipps-University Marburg, Center for Synthetic Microbiology (SYNMIKRO) & Faculty of Chemistry, Marburg, Germany
| | - Lucas Hermann
- Philipps-University Marburg, Center for Synthetic Microbiology (SYNMIKRO) & Faculty of Biology, Marburg, Germany
| | - Florian Altegoer
- Philipps-University Marburg, Center for Synthetic Microbiology (SYNMIKRO) & Faculty of Chemistry, Marburg, Germany
| | - Andreas Seubert
- Philipps-University Marburg, Faculty of Chemistry, Marburg, Germany
| | - Alexandra A Richter
- Philipps-University Marburg, Center for Synthetic Microbiology (SYNMIKRO) & Faculty of Biology, Marburg, Germany
| | - Isa Wernersbach
- Philipps-University Marburg, Center for Synthetic Microbiology (SYNMIKRO) & Faculty of Chemistry, Marburg, Germany
| | - Laura Czech
- Philipps-University Marburg, Center for Synthetic Microbiology (SYNMIKRO) & Faculty of Biology, Marburg, Germany
| | - Erhard Bremer
- Philipps-University Marburg, Center for Synthetic Microbiology (SYNMIKRO) & Faculty of Biology, Marburg, Germany.
| | - Gert Bange
- Philipps-University Marburg, Center for Synthetic Microbiology (SYNMIKRO) & Faculty of Chemistry, Marburg, Germany.
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41
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Rational flux-tuning of Halomonas bluephagenesis for co-production of bioplastic PHB and ectoine. Nat Commun 2020; 11:3313. [PMID: 32620759 PMCID: PMC7334215 DOI: 10.1038/s41467-020-17223-3] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 06/16/2020] [Indexed: 11/21/2022] Open
Abstract
Ectoine, a compatible solute synthesized by many halophiles for hypersalinity resistance, has been successfully produced by metabolically engineered Halomonas bluephagenesis, which is a bioplastic poly(3-hydroxybutyrate) producer allowing open unsterile and continuous conditions. Here we report a de novo synthesis pathway for ectoine constructed into the chromosome of H. bluephagenesis utilizing two inducible systems, which serve to fine-tune the transcription levels of three clusters related to ectoine synthesis, including ectABC, lysC and asd based on a GFP-mediated transcriptional tuning approach. Combined with bypasses deletion, the resulting recombinant H. bluephagenesis TD-ADEL-58 is able to produce 28 g L−1 ectoine during a 28 h fed-batch growth process. Co-production of ectoine and PHB is achieved to 8 g L−1 ectoine and 32 g L−1 dry cell mass containing 75% PHB after a 44 h growth. H. bluephagenesis demonstrates to be a suitable co-production chassis for polyhydroxyalkanoates and non-polymer chemicals such as ectoine. Halomonas bluephagenesis is a halophilic platform bacterium for next generation industrial biotechnology. Here, the authors employ a stimulus response-based flux-tuning method for coproduction of bioplastic PHB and ectoine under open unsterile and continuous growth conditions.
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42
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Contribution of mechanosensitive channels to osmoadaptation and ectoine excretion in Halomonas elongata. Extremophiles 2020; 24:421-432. [PMID: 32266565 PMCID: PMC7174268 DOI: 10.1007/s00792-020-01168-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 03/24/2020] [Indexed: 12/05/2022]
Abstract
For osmoadaptation the halophilic bacterium Halomonas elongata synthesizes as its main compatible solute the aspartate derivative ectoine. H. elongata does not rely entirely on synthesis but can accumulate ectoine by uptake from the surrounding environment with the help of the osmoregulated transporter TeaABC. Disruption of the TeaABC-mediated ectoine uptake creates a strain that is constantly losing ectoine to the medium. However, the efflux mechanism of ectoine in H. elongata is not yet understood. H. elongata possesses four genes encoding mechanosensitive channels all of which belong to the small conductance type (MscS). Analysis by qRT-PCR revealed a reduction in transcription of the mscS genes with increasing salinity. The response of H. elongata to hypo- and hyperosmotic shock never resulted in up-regulation but rather in down-regulation of mscS transcription. Deletion of all four mscS genes created a mutant that was unable to cope with hypoosmotic shock. However, the knockout mutant grew significantly faster than the wildtype at high salinity of 2 M NaCl, and most importantly, still exported 80% of the ectoine compared to the wildtype. We thus conclude that a yet unknown system, which is independent of mechanosensitive channels, is the major export route for ectoine in H. elongata.
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Chen J, Liu P, Chu X, Chen J, Zhang H, Rowley DC, Wang H. Metabolic Pathway Construction and Optimization of Escherichia coli for High-Level Ectoine Production. Curr Microbiol 2020; 77:1412-1418. [DOI: 10.1007/s00284-020-01888-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 01/14/2020] [Indexed: 01/05/2023]
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Gaffney EM, Grattieri M, Beaver K, Pham J, McCartney C, Minteer SD. Unveiling salinity effects on photo-bioelectrocatalysis through combination of bioinformatics and electrochemistry. Electrochim Acta 2020; 337. [PMID: 32308212 DOI: 10.1016/j.electacta.2020.135731] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Little is known about the adaptation strategies utilized by photosynthetic microorganisms to cope with salinity changes happening in the environment, and the effects on microbial electrochemical technologies. Herein, bioinformatics analysis revealed a metabolism shift in Rhodobacter capsulatus resulting from salt stress, with changes in gene expression allowing accumulation of compatible solutes to balance osmotic pressure, together with the up-regulation of the nitrogen fixation cycle, an electron sink of the photosynthetic electron transfer chain. Using the transcriptome evidence of hindered electron transfer in the photosynthetic electron transport chain induced by adaption to salinity, increased understanding of photo-bioelectrocatalysis under salt stress is achieved. Accumulation of glycine-betaine allows immediate tuning of salinity tolerance but does not provide cell stabilization, with a 40 ± 20% loss of photo-bioelectrocatalysis in a 60 min time scale. Conversely, exposure to or inducing the expression of the Rhodobacter capsulatus gene transfer agent tunes salinity tolerance and increases cell stability. This work provides a proof of concept for the combination of bioinformatics and electrochemical tools to investigate microbial electrochemical systems, opening exciting future research opportunities.
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Affiliation(s)
- Erin M Gaffney
- Department of Chemistry, University of Utah, 315 S 1400 E Room 2020, Salt Lake City, 84112, Utah, USA
| | - Matteo Grattieri
- Department of Chemistry, University of Utah, 315 S 1400 E Room 2020, Salt Lake City, 84112, Utah, USA
| | - Kevin Beaver
- Department of Chemistry, University of Utah, 315 S 1400 E Room 2020, Salt Lake City, 84112, Utah, USA
| | - Jennie Pham
- Department of Chemistry, University of Utah, 315 S 1400 E Room 2020, Salt Lake City, 84112, Utah, USA
| | - Caitlin McCartney
- Department of Chemistry, University of Utah, 315 S 1400 E Room 2020, Salt Lake City, 84112, Utah, USA.,Departments of Chemistry, Brown University, 324 Brook Street Box H, Providence, 02912, Rhode Island, USA
| | - Shelley D Minteer
- Department of Chemistry, University of Utah, 315 S 1400 E Room 2020, Salt Lake City, 84112, Utah, USA
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Fenizia S, Thume K, Wirgenings M, Pohnert G. Ectoine from Bacterial and Algal Origin Is a Compatible Solute in Microalgae. Mar Drugs 2020; 18:E42. [PMID: 31935955 PMCID: PMC7024275 DOI: 10.3390/md18010042] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Revised: 12/20/2019] [Accepted: 12/23/2019] [Indexed: 02/03/2023] Open
Abstract
Osmoregulation in phytoplankton is attributed to several highly polar low-molecular-weight metabolites. A widely accepted model considers dimethylsulfoniopropionate (DMSP) as the most important and abundant osmotically active metabolite. Using an optimized procedure for the extraction and detection of highly polar metabolites, we expand the group of phytoplankton osmolytes by identifying ectoine in several microalgae. Ectoine is known as a bacterial compatible solute, but, to the best of our knowledge, was never considered as a phytoplankton-derived product. Given the ability of microalgae to take up zwitterions, such as DMSP, we tested the hypothesis that the algal ectoine is derived from associated bacteria. We therefore analyzed methanol extracts of xenic and axenic cultures of two different species of microalgae and could detect elevated concentrations of ectoine in those that harbor associated bacteria. However, also microalgae without an associated microbiome contain ectoine in smaller amounts, pointing towards a dual origin of this metabolite in the algae from their own biosynthesis as well as from uptake. We also tested the role of ectoine in the osmoadaptation of microalgae. In the model diatoms Thalassiosira weissflogii and Phaeodactylum tricornutum, elevated amounts of ectoine were found when cultivated in seawater with salinities of 50 PSU compared to the standard culture conditions of 35 PSU. Therefore, we add ectoine to the family of osmoadaptive metabolites in phytoplankton and prove a new, potentially synergistic metabolic interplay of bacteria and algae.
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Affiliation(s)
- Simona Fenizia
- Institute for Inorganic and Analytical Chemistry, Bioorganic Analytics, Friedrich Schiller University, Lessingstrasse 8, D-07743 Jena, Germany; (S.F.); (K.T.); (M.W.)
- Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, D-07745 Jena, Germany
| | - Kathleen Thume
- Institute for Inorganic and Analytical Chemistry, Bioorganic Analytics, Friedrich Schiller University, Lessingstrasse 8, D-07743 Jena, Germany; (S.F.); (K.T.); (M.W.)
| | - Marino Wirgenings
- Institute for Inorganic and Analytical Chemistry, Bioorganic Analytics, Friedrich Schiller University, Lessingstrasse 8, D-07743 Jena, Germany; (S.F.); (K.T.); (M.W.)
| | - Georg Pohnert
- Institute for Inorganic and Analytical Chemistry, Bioorganic Analytics, Friedrich Schiller University, Lessingstrasse 8, D-07743 Jena, Germany; (S.F.); (K.T.); (M.W.)
- Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, D-07745 Jena, Germany
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46
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Anhydrobiotic engineering for the endophyte bacterium Kosakonia radicincitans by osmoadaptation and providing exogenously hydroxyectoine. World J Microbiol Biotechnol 2019; 36:6. [DOI: 10.1007/s11274-019-2780-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 11/30/2019] [Indexed: 10/25/2022]
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Richter AA, Mais CN, Czech L, Geyer K, Hoeppner A, Smits SHJ, Erb TJ, Bange G, Bremer E. Biosynthesis of the Stress-Protectant and Chemical Chaperon Ectoine: Biochemistry of the Transaminase EctB. Front Microbiol 2019; 10:2811. [PMID: 31921013 PMCID: PMC6915088 DOI: 10.3389/fmicb.2019.02811] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 11/20/2019] [Indexed: 12/20/2022] Open
Abstract
Bacteria frequently adapt to high osmolarity surroundings through the accumulation of compatible solutes. Ectoine is a prominent member of these types of stress protectants and is produced via an evolutionarily conserved biosynthetic pathway beginning with the L-2,4-diaminobutyrate (DAB) transaminase (TA) EctB. Here, we studied EctB from the thermo-tolerant Gram-positive bacterium Paenibacillus lautus (Pl) and show that this tetrameric enzyme is highly tolerant to salt, pH, and temperature. During ectoine biosynthesis, EctB converts L-glutamate and L-aspartate-beta-semialdehyde into 2-oxoglutarate and DAB, but it also catalyzes the reverse reaction. Our analysis unravels that EctB enzymes are mechanistically identical to the PLP-dependent gamma-aminobutyrate TAs (GABA-TAs) and only differ with respect to substrate binding. Inspection of the genomic context of the ectB gene in P. lautus identifies an unusual arrangement of juxtapositioned genes for ectoine biosynthesis and import via an Ehu-type binding-protein-dependent ABC transporter. This operon-like structure suggests the operation of a highly coordinated system for ectoine synthesis and import to maintain physiologically adequate cellular ectoine pools under osmotic stress conditions in a resource-efficient manner. Taken together, our study provides an in-depth mechanistic and physiological description of EctB, the first enzyme of the ectoine biosynthetic pathway.
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Affiliation(s)
- Alexandra A Richter
- Laboratory for Microbiology, Department of Biology, Philipps-University Marburg, Marburg, Germany.,SYNMIKRO Research Center, Philipps-University Marburg, Marburg, Germany
| | - Christopher-Nils Mais
- SYNMIKRO Research Center, Philipps-University Marburg, Marburg, Germany.,Department of Chemistry, Philipps-University Marburg, Marburg, Germany
| | - Laura Czech
- Laboratory for Microbiology, Department of Biology, Philipps-University Marburg, Marburg, Germany.,SYNMIKRO Research Center, Philipps-University Marburg, Marburg, Germany
| | - Kyra Geyer
- Department of Biochemistry and Synthetic Metabolism, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Astrid Hoeppner
- Center for Structural Studies, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Sander H J Smits
- Center for Structural Studies, Heinrich Heine University Düsseldorf, Düsseldorf, Germany.,Institute of Biochemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Tobias J Erb
- SYNMIKRO Research Center, Philipps-University Marburg, Marburg, Germany.,Department of Biochemistry and Synthetic Metabolism, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Gert Bange
- SYNMIKRO Research Center, Philipps-University Marburg, Marburg, Germany.,Department of Chemistry, Philipps-University Marburg, Marburg, Germany
| | - Erhard Bremer
- Laboratory for Microbiology, Department of Biology, Philipps-University Marburg, Marburg, Germany.,SYNMIKRO Research Center, Philipps-University Marburg, Marburg, Germany
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48
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High ectoine production by an engineered Halomonas hydrothermalis Y2 in a reduced salinity medium. Microb Cell Fact 2019; 18:184. [PMID: 31655591 PMCID: PMC6815383 DOI: 10.1186/s12934-019-1230-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 10/11/2019] [Indexed: 12/02/2022] Open
Abstract
Background As an attracted compatible solute, 1,4,5,6-tetrahydro-2-methyl-4-pyrimidinecarboxylic acid (ectoine) showed great potentials in various field. However, lower productivity and high saline medium seriously hinder its wide applications. Results The entire ectoine metabolism, including pathways for ectoine synthesis and catabolism, was identified in the genome of an ectoine-excreting strain Halomonas hydrothermalis Y2. By in-frame deletion of genes encoding ectoine hydroxylase (EctD) and (or) ectoine hydrolase (DoeA) that responsible for ectoine catabolism, the pathways for ectoine utilization were disrupted and resulted in an obviously enhanced productivity. Using an optimized medium containing 100 g L−1 NaCl in a 500-mL flask, the double mutant of Y2/ΔectD/ΔdoeA synthesized 3.13 g L−1 ectoine after 30 h cultivation. This is much higher than that of the wild type strain (1.91 g L−1), and also exceeds the production of Y2/ΔectD (2.21 g L−1). The remarkably enhanced accumulation of ectoine by Y2/ΔectD/ΔdoeA implied a critical function of Doe pathway in the ectoine catabolism. Furthermore, to reduce the salinity of fermentation medium and overcome the wastewater treatment difficulty, mutants that lacking key Na+/H+ antiporter, Mrp and (or) NhaD2, were constructed based on strain Y2/ΔectD/ΔdoeA. As a result, the Mrp-deficient strain could synthesize equal amount of ectoine (around 7 g L−1 or 500 mg (g DCW) −1) in the medium containing lower concentration of NaCl. During a fed-batch fermentation process with 60 g L−1 NaCl stress, a maximum 10.5 g L−1 ectoine was accumulated by the Mrp-deficient strain, with a specific production of 765 mg (g DCW)−1 and a yield of 0.21 g g−1 monosodium glutamate. Conclusion The remarkably enhanced production of ectoine by Y2/ΔectD/ΔdoeA implied the critical function of Doe pathway in the ectoine catabolism. Moreover, the reduced salinity requirement of Mrp-deficient strain implied a feasible protocol for many compatible solute biosynthesis, i.e., by silencing some Na+/H+ antiporters in their halophilic producers and thus lowering the medium salinity.![]()
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de la Haba RR, López-Hermoso C, Sánchez-Porro C, Konstantinidis KT, Ventosa A. Comparative Genomics and Phylogenomic Analysis of the Genus Salinivibrio. Front Microbiol 2019; 10:2104. [PMID: 31572321 PMCID: PMC6749099 DOI: 10.3389/fmicb.2019.02104] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 08/27/2019] [Indexed: 12/02/2022] Open
Abstract
In the genomic era phylogenetic relationship among prokaryotes can be inferred from the core orthologous genes (OGs) or proteins in order to elucidate their evolutionary history and current taxonomy should benefits of that. The genus Salinivibrio belongs to the family Vibrionaceae and currently includes only five halophilic species, in spite the fact that new strains are very frequently isolated from hypersaline environments. Species belonging to this genus have undergone several reclassifications and, moreover, there are many strains of Salinivibrio with available genomes which have not been affiliated to the existing species or have been wrongly designated. Therefore, a phylogenetic study using the available genomic information is necessary to clarify the relationships of existing strains within this genus and to review their taxonomic affiliation. For that purpose, we have also sequenced the first complete genome of a Salinivibrio species, Salinivibrio kushneri AL184T, which was employed as a reference to order the contigs of the draft genomes of the type strains of the current species of this genus, as well as to perform a comparative analysis with all the other available Salinivibrio sp. genomes. The genome of S. kushneri AL184T was assembled in two circular chromosomes (with sizes of 2.84 Mb and 0.60 Mb, respectively), as typically occurs in members of the family Vibrionaceae, with nine complete ribosomal operons, which might explain the fast growing rate of salinivibrios cultured under laboratory conditions. Synteny analysis among the type strains of the genus revealed a high level of genomic conservation in both chromosomes, which allow us to hypothesize a slow speciation process or homogenization events taking place in this group of microorganisms to be tested experimentally in the future. Phylogenomic and orthologous average nucleotide identity (OrthoANI)/average amino acid identity (AAI) analyses also evidenced the elevated level of genetic relatedness within members of this genus and allowed to group all the Salinivibrio strains with available genomes in seven separated species. Genome-scale attribute study of the salinivibrios identified traits related to polar flagellum, facultatively anaerobic growth and osmotic response, in accordance to the phenotypic features described for species of this genus.
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Affiliation(s)
- Rafael R. de la Haba
- Department of Microbiology and Parasitology, Faculty of Pharmacy, University of Seville, Seville, Spain
| | - Clara López-Hermoso
- Department of Microbiology and Parasitology, Faculty of Pharmacy, University of Seville, Seville, Spain
| | - Cristina Sánchez-Porro
- Department of Microbiology and Parasitology, Faculty of Pharmacy, University of Seville, Seville, Spain
| | | | - Antonio Ventosa
- Department of Microbiology and Parasitology, Faculty of Pharmacy, University of Seville, Seville, Spain
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50
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Gießelmann G, Dietrich D, Jungmann L, Kohlstedt M, Jeon EJ, Yim SS, Sommer F, Zimmer D, Mühlhaus T, Schroda M, Jeong KJ, Becker J, Wittmann C. Metabolic Engineering of
Corynebacterium glutamicum
for High‐Level Ectoine Production: Design, Combinatorial Assembly, and Implementation of a Transcriptionally Balanced Heterologous Ectoine Pathway. Biotechnol J 2019; 14:e1800417. [DOI: 10.1002/biot.201800417] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Revised: 05/03/2019] [Indexed: 12/27/2022]
Affiliation(s)
- Gideon Gießelmann
- Institute of Systems BiotechnologySaarland University 66123 Saarbrücken Germany
| | - Demian Dietrich
- Institute of Systems BiotechnologySaarland University 66123 Saarbrücken Germany
| | - Lukas Jungmann
- Institute of Systems BiotechnologySaarland University 66123 Saarbrücken Germany
| | - Michael Kohlstedt
- Institute of Systems BiotechnologySaarland University 66123 Saarbrücken Germany
| | - Eun J. Jeon
- Department of Chemical and Biomolecular EngineeringKAIST 335 Gwahagno Yuseong‐gu Daejeon 305‐701 Republic of Korea
| | - Sung S. Yim
- Department of Chemical and Biomolecular EngineeringKAIST 335 Gwahagno Yuseong‐gu Daejeon 305‐701 Republic of Korea
| | - Frederik Sommer
- Department of Molecular Biotechnology and Systems BiologyTU Kaiserslautern Kaiserslautern 67663 Germany
| | - David Zimmer
- Department of Molecular Biotechnology and Systems BiologyTU Kaiserslautern Kaiserslautern 67663 Germany
| | - Timo Mühlhaus
- Department of Molecular Biotechnology and Systems BiologyTU Kaiserslautern Kaiserslautern 67663 Germany
| | - Michael Schroda
- Department of Molecular Biotechnology and Systems BiologyTU Kaiserslautern Kaiserslautern 67663 Germany
| | - Ki J. Jeong
- Department of Chemical and Biomolecular EngineeringKAIST 335 Gwahagno Yuseong‐gu Daejeon 305‐701 Republic of Korea
| | - Judith Becker
- Institute of Systems BiotechnologySaarland University 66123 Saarbrücken Germany
| | - Christoph Wittmann
- Institute of Systems BiotechnologySaarland University 66123 Saarbrücken Germany
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