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Yan L, Yin M, Miao J, Song X, Jiang J, Zhang S. Removal of nitrate nitrogen by Pseudomonas JI-2 under strong alkaline conditions: Performance and mechanism. BIORESOURCE TECHNOLOGY 2023; 388:129755. [PMID: 37696334 DOI: 10.1016/j.biortech.2023.129755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 08/21/2023] [Accepted: 09/07/2023] [Indexed: 09/13/2023]
Abstract
The nitrate nitrogen removal characteristics of Pseudomonas JI-2 under strong alkaline conditions and the composition and functional groups of extracellular polymeric substance were analyzed. Furthermore, nontargeted metabonomics and bioinformatics technology were used to investigate the alkaline tolerance mechanism. JI-2 removed 11.05 mg N/(L·h) of nitrate with the initial pH, carbon to nitrogen ratio and temperature were 11.0, 8 and 25 °C respectively. Even when the pH was maintained at 11.0, JI-2 could still effectively remove nitrate. JI-2 contains a large number of Na+/H+ antiporters, such as Mrp, Mnh (mnhACDEFG) and Pha (phaACDEFG), which can stabilize the intracellular acid-base environment, and SlpA can enable quick adaptation to alkaline conditions. Moreover, JI-2 responds to the strong alkaline environment by secreting more polysaccharides, acidic functional groups and compatible solutes and regulating key metabolic processes such as pantothenate and CoA biosynthesis and carbapenem biosynthesis. Therefore, JI-2 can survive in strong alkaline environments and remove nitrate efficiently.
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Affiliation(s)
- Lilong Yan
- College of Resource and Environment, Northeast Agricultural University, Harbin 150030 China
| | - Mingyue Yin
- College of Resource and Environment, Northeast Agricultural University, Harbin 150030 China
| | - Jingwen Miao
- College of Resource and Environment, Northeast Agricultural University, Harbin 150030 China
| | - Xu Song
- College of Resource and Environment, Northeast Agricultural University, Harbin 150030 China
| | - Jishuang Jiang
- College of Resource and Environment, Northeast Agricultural University, Harbin 150030 China
| | - Shaoliang Zhang
- College of Resource and Environment, Northeast Agricultural University, Harbin 150030 China.
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Wang Y, Luo CB, Li YQ. Biofuneling lignin-derived compounds into lipids using a newly isolated Citricoccus sp. P2. BIORESOURCE TECHNOLOGY 2023; 387:129669. [PMID: 37573985 DOI: 10.1016/j.biortech.2023.129669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 08/08/2023] [Accepted: 08/09/2023] [Indexed: 08/15/2023]
Abstract
Lignin-derived compounds (LDCs) bioconversion into lipids is a promising yet challenging task. This study focuses on the isolation of the ligninolytic bacterium Citricoccus sp. P2 and investigates its mechanism for producing lipids from LDCs. Although strain P2 exhibits a relatively low lignin degradation rate of 44.63%, it efficiently degrades various concentrations of LDCs. The highest degradation rate is observed when incubated with 0.6 g/L vanillic acid, 0.6 g/L syringic acid, 0.8 g/L p-coumaric acid, and 0.4 g/L phenol, resulting in respective lipid yields of 0.16 g/L, 0.13 g/L, 0.24 g/L, and 0.13 g/L. The genome of strain P2 provides insights into LDCs bioconversion into lipids and stress tolerance. Moreover, Citricoccus sp. P2 has been successfully developed a non-sterilized lipid production using its native alkali-halophilic characteristics, which significantly enhances the lipid yield. This study presents a promising platform for lipids production from LDCs and has potential to promote valorization of lignin.
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Affiliation(s)
- Yan Wang
- College of Life Science, Leshan Normal University, Leshan 614000, China
| | - Chao-Bing Luo
- College of Life Science, Leshan Normal University, Leshan 614000, China
| | - Yuan-Qiu Li
- College of Life Science, Leshan Normal University, Leshan 614000, China.
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3
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Tang H, Wang MJ, Gan XF, Li YQ. Funneling lignin-derived compounds into polyhydroxyalkanoate by Halomonas sp. Y3. BIORESOURCE TECHNOLOGY 2022; 362:127837. [PMID: 36031122 DOI: 10.1016/j.biortech.2022.127837] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 08/21/2022] [Accepted: 08/22/2022] [Indexed: 06/15/2023]
Abstract
Lignin-derived compounds (LDCs) biological funneling for polyhydroxyalkanoate (PHA) synthesis has been attractive but elusive. Herein, the Halomonas sp. Y3 is isolated and developed for PHA production from LDCs. Of the tested 13 LDCs, 4-hydroxybenzoic acid (4-HBA), protocatechuate (PA), catechol (CAT), and vanillic acid (VA) exhibit a hyper-degradation and production with 87.2 %, 85.8 %, 84.7 %, and 83.4 % TOC removal rate and 535.2 mg/L, 506.5 mg/L, 435.6 mg/L, and 440.8 mg/L PHA concentration, respectively. The Halomonas sp. Y3 genome is sequenced by identifying numerous genes responsible for LDCs funneling, stress response, and PHA biosynthesis. An open unsterilized fermentation with optimal conditions of pH 9.0 and NaCl 60 g/L is investigated, achieving a completely aseptic effect and significantly improved PHA production from LDCs. Overall, the results indicate that the Halomonas sp. Y3 is an ideal candidate for LDC bioconversion and exhibits a great potential to realize black liquor valorization.
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Affiliation(s)
- Hao Tang
- Bamboo Diseases and Pests Control and Resources Development Key Laboratory of Sichuan Province, Leshan Normal University, Leshan 614000, China
| | - Ming-Jun Wang
- Bamboo Diseases and Pests Control and Resources Development Key Laboratory of Sichuan Province, Leshan Normal University, Leshan 614000, China
| | - Xiao-Feng Gan
- Bamboo Diseases and Pests Control and Resources Development Key Laboratory of Sichuan Province, Leshan Normal University, Leshan 614000, China
| | - Yuan-Qiu Li
- Bamboo Diseases and Pests Control and Resources Development Key Laboratory of Sichuan Province, Leshan Normal University, Leshan 614000, China; College of Life Sciences, Capital Normal University, Beijing 100048, China.
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Somayaji A, Dhanjal CR, Lingamsetty R, Vinayagam R, Selvaraj R, Varadavenkatesan T, Govarthanan M. An insight into the mechanisms of homeostasis in extremophiles. Microbiol Res 2022; 263:127115. [PMID: 35868258 DOI: 10.1016/j.micres.2022.127115] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 07/07/2022] [Accepted: 07/07/2022] [Indexed: 01/10/2023]
Abstract
The homeostasis of extremophiles is one that is a diamond hidden in the rough. The way extremophiles adapt to their extreme environments gives a clue into the true extent of what is possible when it comes to life. The discovery of new extremophiles is ever-expanding and an explosion of knowledge surrounding their successful existence in extreme environments is obviously perceived in scientific literature. The present review paper aims to provide a comprehensive view on the different mechanisms governing the extreme adaptations of extremophiles, along with insights and discussions on what the limits of life can possibly be. The membrane adaptations that are vital for survival are discussed in detail. It was found that there are many alterations in the genetic makeup of such extremophiles when compared to their mesophilic counterparts. Apart from the several proteins involved, the significance of chaperones, efflux systems, DNA repair proteins and a host of other enzymes that adapt to maintain functionality, are enlisted, and explained. A deeper understanding of the underlying mechanisms could have a plethora of applications in the industry. There are cases when certain microbes can withstand extreme doses of antibiotics. Such microbes accumulate numerous genetic elements (or plasmids) that possess genes for multiple drug resistance (MDR). A deeper understanding of such mechanisms helps in the development of potential approaches and therapeutic schemes for treating pathogen-mediated outbreaks. An in-depth analysis of the parameters - radiation, pressure, temperature, pH value and metal resistance - are discussed in this review, and the key to survival in these precarious niches is described.
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Affiliation(s)
- Adithi Somayaji
- Department of Biotechnology, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India; Manipal Biomachines, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India
| | - Chetan Roger Dhanjal
- Department of Biotechnology, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India; Manipal Biomachines, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India
| | - Rathnamegha Lingamsetty
- Department of Biotechnology, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India; Manipal Biomachines, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India
| | - Ramesh Vinayagam
- Department of Chemical Engineering, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India
| | - Raja Selvaraj
- Department of Chemical Engineering, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India
| | - Thivaharan Varadavenkatesan
- Department of Biotechnology, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India.
| | - Muthusamy Govarthanan
- Department of Environmental Engineering, Kyungpook National University, Daegu, South Korea; Department of Biomaterials, Saveetha Dental College and Hospital, Saveetha Institute of Medical and Technical Sciences, Chennai 600077, India.
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Yan L, Wang C, Jiang J, Liu S, Zheng Y, Yang M, Zhang Y. Nitrate removal by alkali-resistant Pseudomonas sp. XS-18 under aerobic conditions: Performance and mechanism. BIORESOURCE TECHNOLOGY 2022; 344:126175. [PMID: 34678448 DOI: 10.1016/j.biortech.2021.126175] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 10/13/2021] [Accepted: 10/17/2021] [Indexed: 06/13/2023]
Abstract
To improve poor nitrate removal by microorganisms under strong alkaline conditions, a new type of aerobic nitrification-reducing bacteria was isolated in this study. Using nitrogen balance and genome information, the capacity of Pseudomonas XS-18 to remove nitrate and the mechanism of alkali tolerance were analyzed. At pH 11.0, XS-18 could remove 12.17 mg N/(L·h) nitrate. At C/N ratios of 13.0 and 25 °C, nitrite and ammonia nitrogen were barely enriched. XS-18 could reduce nitrate through dissimilation and assimilation, and 21.74% and 77.39% of nitrate was converted into cellular components and organic nitrogen, respectively. Meanwhile, functional genes (nirBD, nasAB, gdhA, glnA, and gltBD) associated with nitrogen metabolism were determined. In addition, Na+/H+ antiporters (MnhACDEFG, PhaACDEFG, NhaCD and TrkAH) and a cell surface protein (SlpA) from the XS-18 genome, as well as compatible solutes that help stabilize intracellular pH, were also characterized. XS-18 possessed significant potential in alkaline wastewater treatment.
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Affiliation(s)
- Lilong Yan
- College of Resource and Environment, Northeast Agricultural University, Harbin 150030 PR China.
| | - Caixu Wang
- College of Resource and Environment, Northeast Agricultural University, Harbin 150030 PR China
| | - Jishuang Jiang
- College of Resource and Environment, Northeast Agricultural University, Harbin 150030 PR China
| | - Shuang Liu
- College of Resource and Environment, Northeast Agricultural University, Harbin 150030 PR China
| | - Yaoqi Zheng
- College of Resource and Environment, Northeast Agricultural University, Harbin 150030 PR China
| | - Mengya Yang
- College of Resource and Environment, Northeast Agricultural University, Harbin 150030 PR China
| | - Ying Zhang
- College of Resource and Environment, Northeast Agricultural University, Harbin 150030 PR China.
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Transcriptomic responses of haloalkalitolerant bacterium Egicoccus halophilus EGI 80432 T to highly alkaline stress. Extremophiles 2021; 25:459-470. [PMID: 34402982 DOI: 10.1007/s00792-021-01239-8] [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: 06/15/2021] [Accepted: 08/05/2021] [Indexed: 10/20/2022]
Abstract
The haloalkalitolerant bacterium Egicoccus halophilus EGI 80432T exhibits high adaptability to saline-alkaline environment. The salinity adaptation mechanism of E. halophilus EGI 80432T was fully understood based on transcriptome analyses and physiological responses; however, the alkaline response mechanism has not yet been investigated. Here, we investigated the alkaline response mechanism of E. halophilus EGI 80432T by a transcriptomic comparison. In this study, the genes involved in the glycolysis, TCA cycle, starch, and trehalose metabolism for energy production and storage, were up-regulated under highly alkaline condition. Furthermore, genes responsible for the production of acidic and neutral metabolites, i.e., acetate, pyruvate, formate, glutamate, threonine, and ectoine, showed increased expression under highly alkaline condition, compared with the control pH condition. In contrast, the opposite results were observed in proton capture or retention gene expression profiles, i.e., cation/proton antiporters and ATP synthases. The above results revealed that E. halophilus EGI 80432T likely tended to adopt an "acidic metabolites production" strategy in response to a highly alkaline condition. These findings would pave the way for further studies in the saline-alkaline adaptation mechanisms of E. halophilus EGI 80432T, and hopefully provide a new insight into the foundational theory and application in ecological restoration with saline-alkaline strains.
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Khalikova E, Somersalo S, Korpela T. Metabolites Produced by Alkaliphiles with Potential Biotechnological Applications. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2019; 172:157-193. [PMID: 31240347 DOI: 10.1007/10_2019_96] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Alkaliphiles are a diverse group of relatively less known microorganisms living in alkaline environments. To thrive in alkaline environments, alkaliphiles require special adaptations. This adaptation may have evolved metabolites which can be useful for biotechnological processes or other applications. In fact, certain metabolites are found unique to alkaliphiles or are effectively produced by alkaliphiles. This probably aroused the interest in metabolites of alkaliphiles. During recent years, many alkaliphilic microbes have been isolated, especially in countries having alkaline environments, like soda lakes. Even if the number of such isolated alkaliphiles is large, their metabolites have not yet been extensively analyzed and exploited. This is expected to come in the years ahead. So far, the focus of interests in metabolites from alkaliphiles falls into categories such as organic acids, ingredients for foodstuffs and cosmetics, antibiotics, and substances which modify properties of other materials used in industry. This chapter deals with biotechnologically important metabolites of alkaliphiles including compatible solutes, biosurfactants, siderophores, carotenoids, exopolysaccharides, and antimicrobial agents. It also covers the promising potential of alkaliphiles as sources of bioplastic raw materials. Moreover, an overview of the patent literature related to alkaliphiles is highlighted. Graphical Abstract.
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Affiliation(s)
- Elvira Khalikova
- Joint Biotechnology Laboratory, University of Turku, Turku, Finland
| | | | - Timo Korpela
- Department of Future Technologies, University of Turku, Turku, Finland.
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Lebre PH, Cowan DA. Genomics of Alkaliphiles. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2019; 172:135-155. [PMID: 30796503 DOI: 10.1007/10_2018_83] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Alkalinicity presents a challenge for life due to a "reversed" proton gradient that is unfavourable to many bioenergetic processes across the membranes of microorganisms. Despite this, many bacteria, archaea, and eukaryotes, collectively termed alkaliphiles, are adapted to life in alkaline ecosystems and are of great scientific and biotechnological interest due to their niche specialization and ability to produce highly stable enzymes. Advances in next-generation sequencing technologies have propelled not only the genomic characterization of many alkaliphilic microorganisms that have been isolated from nature alkaline sources but also our understanding of the functional relationships between different taxa in microbial communities living in these ecosystems. In this review, we discuss the genetics and molecular biology of alkaliphiles from an "omics" point of view, focusing on how metagenomics and transcriptomics have contributed to our understanding of these extremophiles. Graphical Abstract.
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Affiliation(s)
- Pedro H Lebre
- Centre for Microbial Ecology and Genomics, Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
| | - Don A Cowan
- Centre for Microbial Ecology and Genomics, Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa.
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Challenges and Adaptations of Life in Alkaline Habitats. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2019; 172:85-133. [DOI: 10.1007/10_2019_97] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Orellana R, Macaya C, Bravo G, Dorochesi F, Cumsille A, Valencia R, Rojas C, Seeger M. Living at the Frontiers of Life: Extremophiles in Chile and Their Potential for Bioremediation. Front Microbiol 2018; 9:2309. [PMID: 30425685 PMCID: PMC6218600 DOI: 10.3389/fmicb.2018.02309] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 09/10/2018] [Indexed: 11/19/2022] Open
Abstract
Extremophiles are organisms capable of adjust, survive or thrive in hostile habitats that were previously thought to be adverse or lethal for life. Chile gathers a wide range of extreme environments: salars, geothermal springs, and geysers located at Altiplano and Atacama Desert, salars and cold mountains in Central Chile, and ice fields, cold lakes and fjords, and geothermal sites in Patagonia and Antarctica. The aims of this review are to describe extremophiles that inhabit main extreme biotopes in Chile, and their molecular and physiological capabilities that may be advantageous for bioremediation processes. After briefly describing the main ecological niches of extremophiles along Chilean territory, this review is focused on the microbial diversity and composition of these biotopes microbiomes. Extremophiles have been isolated in diverse zones in Chile that possess extreme conditions such as Altiplano, Atacama Desert, Central Chile, Patagonia, and Antarctica. Interesting extremophiles from Chile with potential biotechnological applications include thermophiles (e.g., Methanofollis tationis from Tatio Geyser), acidophiles (e.g., Acidithiobacillus ferrooxidans, Leptospirillum ferriphilum from Atacama Desert and Central Chile copper ores), halophiles (e.g., Shewanella sp. Asc-3 from Altiplano, Streptomyces sp. HKF-8 from Patagonia), alkaliphiles (Exiguobacterium sp. SH31 from Altiplano), xerotolerant bacteria (S. atacamensis from Atacama Desert), UV- and Gamma-resistant bacteria (Deinococcus peraridilitoris from Atacama Desert) and psychrophiles (e.g., Pseudomonas putida ATH-43 from Antarctica). The molecular and physiological properties of diverse extremophiles from Chile and their application in bioremediation or waste treatments are further discussed. Interestingly, the remarkable adaptative capabilities of extremophiles convert them into an attractive source of catalysts for bioremediation and industrial processes.
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Affiliation(s)
- Roberto Orellana
- Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química and Centro de Biotecnología Daniel Alkalay Lowitt, Universidad Técnica Federico Santa María, Valparaíso, Chile
- Departamento de Biología, Facultad de Ciencias Naturales y Exactas, Universidad de Playa Ancha, Valparaíso, Chile
| | - Constanza Macaya
- Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química and Centro de Biotecnología Daniel Alkalay Lowitt, Universidad Técnica Federico Santa María, Valparaíso, Chile
| | - Guillermo Bravo
- Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química and Centro de Biotecnología Daniel Alkalay Lowitt, Universidad Técnica Federico Santa María, Valparaíso, Chile
| | - Flavia Dorochesi
- Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química and Centro de Biotecnología Daniel Alkalay Lowitt, Universidad Técnica Federico Santa María, Valparaíso, Chile
| | - Andrés Cumsille
- Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química and Centro de Biotecnología Daniel Alkalay Lowitt, Universidad Técnica Federico Santa María, Valparaíso, Chile
| | - Ricardo Valencia
- Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química and Centro de Biotecnología Daniel Alkalay Lowitt, Universidad Técnica Federico Santa María, Valparaíso, Chile
| | - Claudia Rojas
- Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química and Centro de Biotecnología Daniel Alkalay Lowitt, Universidad Técnica Federico Santa María, Valparaíso, Chile
| | - Michael Seeger
- Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química and Centro de Biotecnología Daniel Alkalay Lowitt, Universidad Técnica Federico Santa María, Valparaíso, Chile
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Matsuno T, Goto T, Ogami S, Morimoto H, Yamazaki K, Inoue N, Matsuyama H, Yoshimune K, Yumoto I. Formation of Proton Motive Force Under Low-Aeration Alkaline Conditions in Alkaliphilic Bacteria. Front Microbiol 2018; 9:2331. [PMID: 30333809 PMCID: PMC6176047 DOI: 10.3389/fmicb.2018.02331] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 09/11/2018] [Indexed: 11/22/2022] Open
Abstract
In Mitchell’s chemiosmotic theory, a proton (H+) motive force across the membrane (Δp), generated by the respiratory chain, drives F1Fo-ATPase for ATP production in various organisms. The bulk-base chemiosmotic theory cannot account for ATP production in alkaliphilic bacteria. However, alkaliphiles thrive in environments with a H+ concentrations that are one-thousandth (ca. pH 10) the concentration required by neutralophiles. This situation is similar to the production of electricity by hydroelectric turbines under conditions of very limited water. Alkaliphiles manage their metabolism via various strategies involving the cell wall structure, solute transport systems and molecular mechanisms on the outer surface membrane. Our experimental results indicate that efficient ATP production in alkaliphilic Bacillus spp. is attributable to a high membrane electrical potential (ΔΨ) generated for an attractive force for H+ on the outer surface membrane. In addition, the enhanced F1Fo-ATPase driving force per H+ is derived from the high ΔΨ. However, it is difficult to explain the reasons for high ΔΨ formation based on the respiratory rate. The Donnan effect (which is observed when charged particles that are unable to pass through a semipermeable membrane create an uneven electrical charge) likely contributes to the formation of the high ΔΨ because the intracellular negative ion capacities of alkaliphiles are much higher than those of neutralophiles. There are several variations in the adaptation to alkaline environments by bacteria. However, it could be difficult to utilize high ΔΨ in the low aeration condition due to the low activity of respiration. To explain the efficient ATP production occurring in H+-less and air-limited environments in alkaliphilic bacteria, we propose a cytochrome c-associated “H+ capacitor mechanism” as an alkaline adaptation strategy. As an outer surface protein, cytochrome c-550 from Bacillusclarkii possesses an extra Asn-rich segment between the region anchored to the membrane and the main body of the cytochrome c. This structure may contribute to the formation of the proton-binding network to transfer H+ at the outer surface membrane in obligate alkaliphiles. The H+ capacitor mechanism is further enhanced under low-aeration conditions in both alkaliphilic Bacillus spp. and the Gram-negative alkaliphile Pseudomonas alcaliphila.
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Affiliation(s)
- Toshihide Matsuno
- Department of Chemistry and Biology, National Institute of Technology, Fukui College, Sabae, Japan
| | - Toshitaka Goto
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Sapporo, Japan.,Graduate School of Agriculture, Hokkaido University, Sapporo, Japan
| | - Shinichi Ogami
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Sapporo, Japan.,Graduate School of Agriculture, Hokkaido University, Sapporo, Japan
| | - Hajime Morimoto
- Department of Chemistry and Biology, National Institute of Technology, Fukui College, Sabae, Japan.,Department of Bioscience and Technology, School of Biological Sciences and Engineering, Tokai University, Sapporo, Japan
| | - Koji Yamazaki
- Division of Marine Life Science, Faculty of Fisheries Sciences, Hokkaido University, Hakodate, Japan
| | | | - Hidetoshi Matsuyama
- Department of Bioscience and Technology, School of Biological Sciences and Engineering, Tokai University, Sapporo, Japan
| | - Kazuaki Yoshimune
- College of Industrial Technology, Nihon University, Narashino, Japan
| | - Isao Yumoto
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Sapporo, Japan.,Graduate School of Agriculture, Hokkaido University, Sapporo, Japan
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Banciu HL, Muntyan MS. Adaptive strategies in the double-extremophilic prokaryotes inhabiting soda lakes. Curr Opin Microbiol 2015; 25:73-9. [PMID: 26025020 DOI: 10.1016/j.mib.2015.05.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Revised: 04/27/2015] [Accepted: 05/01/2015] [Indexed: 10/23/2022]
Abstract
Haloalkaliphiles are double extremophilic organisms thriving both at high salinity and alkaline pH. Although numerous haloalkaliphilic representatives have been identified among Archaea and Bacteria over the past 15 years, the adaptations underlying their prosperity at haloalkaline conditions are scarcely known. A multi-level adaptive strategy was proposed to occur in haloalkaliphilic organisms isolated from saline alkaline and soda environments including adjustments in the cell wall structure, plasma membrane lipid composition, membrane transport systems, bioenergetics, and osmoregulation. Isolation of chemolithoautotrophic sulfur-oxidizing γ-Proteobacteria from soda lakes allowed the elucidation of the structural and physiological differences between haloalkaliphilic (prefer NaCl) and natronophilic (prefer NaHCO3/Na2CO3, i.e. soda) microbes.
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Affiliation(s)
- Horia Leonard Banciu
- Institute for Interdisciplinary Research in Bio-Nano-Sciences, Molecular Biology Center, Babeş-Bolyai University, 400271 Cluj-Napoca, Romania; Department of Molecular Biology and Biotechnology, Faculty of Biology and Geology, Babeş-Bolyai University, 400006 Cluj-Napoca, Romania.
| | - Maria S Muntyan
- Lomonosov Moscow State University, Belozersky Institute of Physico-Chemical Biology, Moscow 119991, Russia
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