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Weimer A, Pause L, Ries F, Kohlstedt M, Adrian L, Krömer J, Lai B, Wittmann C. Systems biology of electrogenic Pseudomonas putida - multi-omics insights and metabolic engineering for enhanced 2-ketogluconate production. Microb Cell Fact 2024; 23:246. [PMID: 39261865 PMCID: PMC11389600 DOI: 10.1186/s12934-024-02509-8] [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: 06/06/2024] [Accepted: 08/10/2024] [Indexed: 09/13/2024] Open
Abstract
BACKGROUND Pseudomonas putida KT2440 has emerged as a promising host for industrial bioproduction. However, its strictly aerobic nature limits the scope of applications. Remarkably, this microbe exhibits high bioconversion efficiency when cultured in an anoxic bio-electrochemical system (BES), where the anode serves as the terminal electron acceptor instead of oxygen. This environment facilitates the synthesis of commercially attractive chemicals, including 2-ketogluconate (2KG). To better understand this interesting electrogenic phenotype, we studied the BES-cultured strain on a systems level through multi-omics analysis. Inspired by our findings, we constructed novel mutants aimed at improving 2KG production. RESULTS When incubated on glucose, P. putida KT2440 did not grow but produced significant amounts of 2KG, along with minor amounts of gluconate, acetate, pyruvate, succinate, and lactate. 13C tracer studies demonstrated that these products are partially derived from biomass carbon, involving proteins and lipids. Over time, the cells exhibited global changes on both the transcriptomic and proteomic levels, including the shutdown of translation and cell motility, likely to conserve energy. These adaptations enabled the cells to maintain significant metabolic activity for several weeks. Acetate formation was shown to contribute to energy supply. Mutants deficient in acetate production demonstrated superior 2KG production in terms of titer, yield, and productivity. The ∆aldBI ∆aldBII double deletion mutant performed best, accumulating 2KG at twice the rate of the wild type and with an increased yield (0.96 mol/mol). CONCLUSIONS By integrating transcriptomic, proteomic, and metabolomic analyses, this work provides the first systems biology insight into the electrogenic phenotype of P. putida KT2440. Adaptation to anoxic-electrogenic conditions involved coordinated changes in energy metabolism, enabling cells to sustain metabolic activity for extended periods. The metabolically engineered mutants are promising for enhanced 2KG production under these conditions. The attenuation of acetate synthesis represents the first systems biology-informed metabolic engineering strategy for enhanced 2KG production in P. putida. This non-growth anoxic-electrogenic mode expands our understanding of the interplay between growth, glucose phosphorylation, and glucose oxidation into gluconate and 2KG in P. putida.
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Affiliation(s)
- Anna Weimer
- Institute of Systems Biotechnology, Saarland University, Saarbrücken, Germany
| | - Laura Pause
- Systems Biotechnology Group, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany
| | - Fabian Ries
- Institute of Systems Biotechnology, Saarland University, Saarbrücken, Germany
| | - Michael Kohlstedt
- Institute of Systems Biotechnology, Saarland University, Saarbrücken, Germany
| | - Lorenz Adrian
- Department of Molecular Environmental Biotechnology, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany
| | - Jens Krömer
- Systems Biotechnology Group, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany
| | - Bin Lai
- BMBF Junior Research Group Biophotovoltaics, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany
| | - Christoph Wittmann
- Institute of Systems Biotechnology, Saarland University, Saarbrücken, Germany.
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de Rosset A, Tyszkiewicz N, Wiśniewski J, Pudełko-Malik N, Rutkowski P, Młynarz P, Pasternak G. Bioelectrochemical synthesis of rhamnolipids and energy production and its correlation with nitrogen in air-cathode microbial fuel cells. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 365:121514. [PMID: 38908152 DOI: 10.1016/j.jenvman.2024.121514] [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: 02/06/2024] [Revised: 05/17/2024] [Accepted: 06/16/2024] [Indexed: 06/24/2024]
Abstract
Microbial fuel cells (MFCs) have been recently proven to synthesise biosurfactants from waste products. In classic bioreactors, the efficiency of biosynthesis process can be controlled by the concentration of nitrogen content in the electrolyte. However, it was not known whether a similar control mechanism could be applied in current-generating conditions. In this work, the effect of nitrogen concentration on biosurfactant production from waste cooking oil was investigated. The concentration of NH4Cl in the electrolyte ranged from 0 to 1 g L-1. The maximum power density equal to 17.5 W m-3 was achieved at a concentration of 0.5 g L-1 (C/N = 2.32) and was accompanied by the highest surface tension decrease (to 54.6 mN m-1) and an emulsification activity index of 95.4%. Characterisation of the biosurfactants produced by the LC-MS/MS method showed the presence of eleven compounds belonging to the mono- and di-rhamnolipids group, most likely produced by P. aeruginosa, which was the most abundant (19.6%) in the community. Importantly, we have found a strong correlation (R = -0.96) of power and biosurfactant activity in response to C/N ratio. This study shows that nitrogen plays an important role in the current-generating metabolism of waste cooking oil. To the best of our knowledge, this is the first study where the nitrogen optimisation was investigated to improve the synthesis of biosurfactants and power generation in a bioelectrochemical system.
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Affiliation(s)
- Aleksander de Rosset
- Department of Process Engineering and Technology of Polymer and Carbon Materials, Faculty of Chemistry, Wroclaw University of Science and Technology, Wroclaw, 50-370, Poland
| | - Natalia Tyszkiewicz
- Department of Process Engineering and Technology of Polymer and Carbon Materials, Faculty of Chemistry, Wroclaw University of Science and Technology, Wroclaw, 50-370, Poland; Department of Biochemistry, Molecular Biology and Biotechnology, Faculty of Chemistry, Wroclaw University of Science and Technology, Wroclaw, 50-370, Poland
| | - Jerzy Wiśniewski
- Department of Biochemistry, Molecular Biology and Biotechnology, Faculty of Chemistry, Wroclaw University of Science and Technology, Wroclaw, 50-370, Poland
| | - Natalia Pudełko-Malik
- Department of Biochemistry, Molecular Biology and Biotechnology, Faculty of Chemistry, Wroclaw University of Science and Technology, Wroclaw, 50-370, Poland
| | - Piotr Rutkowski
- Department of Process Engineering and Technology of Polymer and Carbon Materials, Faculty of Chemistry, Wroclaw University of Science and Technology, Wroclaw, 50-370, Poland
| | - Piotr Młynarz
- Department of Biochemistry, Molecular Biology and Biotechnology, Faculty of Chemistry, Wroclaw University of Science and Technology, Wroclaw, 50-370, Poland
| | - Grzegorz Pasternak
- Department of Process Engineering and Technology of Polymer and Carbon Materials, Faculty of Chemistry, Wroclaw University of Science and Technology, Wroclaw, 50-370, Poland.
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Harnisch F, Deutzmann JS, Boto ST, Rosenbaum MA. Microbial electrosynthesis: opportunities for microbial pure cultures. Trends Biotechnol 2024; 42:1035-1047. [PMID: 38431514 PMCID: PMC11310912 DOI: 10.1016/j.tibtech.2024.02.004] [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: 12/08/2023] [Revised: 02/05/2024] [Accepted: 02/05/2024] [Indexed: 03/05/2024]
Abstract
Microbial electrosynthesis (MES) is an emerging technology that couples renewable electricity to microbial production processes. Although advances in MES performance have been driven largely by microbial mixed cultures, we see a great limitation in the diversity, and hence value, of products that can be achieved in undefined mixed cultures. By contrast, metabolic control of pure cultures and genetic engineering could greatly expand the scope of MES, and even of broader electrobiotechnology, to include targeted high-value products. To leverage this potential, we advocate for more efforts and activities to develop engineered electroactive microbes for synthesis, and we highlight the need for a standardized electrobioreactor infrastructure that allows the establishment and engineering of electrobioprocesses with these novel biocatalysts.
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Affiliation(s)
- Falk Harnisch
- Department of Microbial Biotechnology, Helmholtz Centre for Environmental Research GmbH, Permoserstrasse 15, 04318 Leipzig, Germany
| | - Jörg S Deutzmann
- Department of Civil and Environmental Engineering, Stanford University, Stanford, CA, USA
| | - Santiago T Boto
- Leibniz Institute for Natural Product Research and Infection Biology, Hans-Knöll-Institute, Adolf Reichwein Strasse 23, 07745 Jena, Germany; Institute of Microbiology, Faculty for Biological Sciences, Friedrich-Schiller-University Jena, Neugasse 23, 07743 Jena, Germany
| | - Miriam A Rosenbaum
- Leibniz Institute for Natural Product Research and Infection Biology, Hans-Knöll-Institute, Adolf Reichwein Strasse 23, 07745 Jena, Germany; Institute of Microbiology, Faculty for Biological Sciences, Friedrich-Schiller-University Jena, Neugasse 23, 07743 Jena, Germany.
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4
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Qi X, Gao X, Wang X, Xu P. Harnessing Pseudomonas putida in bioelectrochemical systems. Trends Biotechnol 2024; 42:877-894. [PMID: 38184440 DOI: 10.1016/j.tibtech.2023.12.002] [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: 10/24/2023] [Revised: 12/02/2023] [Accepted: 12/04/2023] [Indexed: 01/08/2024]
Abstract
Bioelectrochemical systems (BESs), a group of promising integrated systems that combine the advantages of biotechnology and electrochemical techniques, offer new opportunities to address environmental and energy challenges. Exoelectrogens capable of extracellular electron transfer (EET) are the critical factor enabling electrocatalytic activity in BESs. Pseudomonas putida, an aerobe widely used in environmental bioremediation, the biosynthesis of valuable chemicals, and energy bioproduction, has attracted much attention due to its unique application potential in BESs. This review provides a comprehensive understanding of the working principles, key factors, and applications of BESs using P. putida as the exoelectrogen. The challenges and perspectives for the development of BESs with P. putida as the exoelectrogen are also proposed and discussed.
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Affiliation(s)
- Xiaoyan Qi
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, PR China
| | - Xinyu Gao
- College of Arts and Science, University of North Carolina at Chapel Hill, Chapel Hill, NC 27514, USA
| | - Xia Wang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, PR China.
| | - Ping Xu
- State Key Laboratory of Microbial Metabolism and School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, PR China.
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Martínez-García E, de Lorenzo V. Pseudomonas putida as a synthetic biology chassis and a metabolic engineering platform. Curr Opin Biotechnol 2024; 85:103025. [PMID: 38061264 DOI: 10.1016/j.copbio.2023.103025] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 11/14/2023] [Accepted: 11/14/2023] [Indexed: 02/09/2024]
Abstract
The soil bacterium Pseudomonas putida, especially the KT2440 strain, is increasingly being utilized as a host for biotransformations of both industrial and environmental interest. The foundations of such performance include its robust redox metabolism, ability to tolerate a wide range of physicochemical stresses, rapid growth, versatile metabolism, nonpathogenic nature, and the availability of molecular tools for advanced genetic programming. These attributes have been leveraged for hosting engineered pathways for production of valuable chemicals or degradation/valorization of environmental pollutants. This has in turn pushed the boundaries of conventional enzymology toward previously unexplored reactions in nature. Furthermore, modifications to the physical properties of the cells have been made to enhance their catalytic performance. These advancements establish P. putida as bona fide chassis for synthetic biology, on par with more traditional metabolic engineering platforms.
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Affiliation(s)
- Esteban Martínez-García
- Systems Biology Department, Centro Nacional de Biotecnología (CNB-CSIC), Campus Universidad Autónoma de Madrid, Calle Darwin 3, 28049 Madrid, Spain
| | - Víctor de Lorenzo
- Systems Biology Department, Centro Nacional de Biotecnología (CNB-CSIC), Campus Universidad Autónoma de Madrid, Calle Darwin 3, 28049 Madrid, Spain.
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6
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Pause L, Weimer A, Wirth NT, Nguyen AV, Lenz C, Kohlstedt M, Wittmann C, Nikel PI, Lai B, Krömer JO. Anaerobic glucose uptake in Pseudomonas putida KT2440 in a bioelectrochemical system. Microb Biotechnol 2024; 17:e14375. [PMID: 37990843 PMCID: PMC10832537 DOI: 10.1111/1751-7915.14375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Revised: 11/01/2023] [Accepted: 11/07/2023] [Indexed: 11/23/2023] Open
Abstract
Providing an anodic potential in a bio-electrochemical system to the obligate aerobe Pseudomonas putida enables anaerobic survival and allows the cells to overcome redox imbalances. In this setup, the bacteria could be exploited to produce chemicals via oxidative pathways at high yield. However, the absence of anaerobic growth and low carbon turnover rates remain as obstacles for the application of such an electro-fermentation technology. Growth and carbon turnover start with carbon uptake into the periplasm and cytosol. P. putida KT2440 has three native transporting systems for glucose, each differing in energy and redox demand. This architecture previously led to the hypothesis that internal redox and energy constraints ultimately limit cytoplasmic carbon utilization in a bio-electrochemical system. However, it remains largely unclear which uptake route is predominantly used by P. putida under electro-fermentative conditions. To elucidate this, we created three gene deletion mutants of P. putida KT2440, forcing the cells to exclusively utilize one of the routes. When grown in a bio-electrochemical system, the pathway mutants were heavily affected in terms of sugar consumption, current output and product formation. Surprisingly, however, we found that about half of the acetate formed in the cytoplasm originated from carbon that was put into the system via the inoculation biomass, while the other half came from the consumption of substrate. The deletion of individual sugar uptake routes did not alter significantly the secreted acetate concentrations among different strains even with different carbon sources. This means that the stoichiometry of the sugar uptake routes is not a limiting factor during electro-fermentation and that the low rates might be caused by other reasons, for example energy limitations or a yet-to-be-identified oxygen-dependent regulatory mechanism.
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Affiliation(s)
- Laura Pause
- Systems Biotechnology groupHelmholtz Centre for Environmental Research – UFZLeipzigGermany
| | - Anna Weimer
- Institute of Systems BiotechnologySaarland UniversitySaarbrückenGermany
| | - Nicolas T. Wirth
- Systems Environmental Microbiology Group, The Novo Nordisk Foundation Center for BiosustainabilityTechnical University of DenmarkLyngbyDenmark
| | - Anh Vu Nguyen
- Systems Biotechnology groupHelmholtz Centre for Environmental Research – UFZLeipzigGermany
| | - Claudius Lenz
- Systems Biotechnology groupHelmholtz Centre for Environmental Research – UFZLeipzigGermany
| | - Michael Kohlstedt
- Institute of Systems BiotechnologySaarland UniversitySaarbrückenGermany
| | | | - Pablo I. Nikel
- Systems Environmental Microbiology Group, The Novo Nordisk Foundation Center for BiosustainabilityTechnical University of DenmarkLyngbyDenmark
| | - Bin Lai
- BMBF Junior Research Group BiophotovoltaicsHelmholtz Centre for Environmental Research – UFZLeipzigGermany
| | - Jens O. Krömer
- Systems Biotechnology groupHelmholtz Centre for Environmental Research – UFZLeipzigGermany
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7
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Pous N, Bañeras L, Corvini PFX, Liu SJ, Puig S. Direct ammonium oxidation to nitrogen gas (Dirammox) in Alcaligenes strain HO-1: The electrode role. ENVIRONMENTAL SCIENCE AND ECOTECHNOLOGY 2023; 15:100253. [PMID: 36896143 PMCID: PMC9988695 DOI: 10.1016/j.ese.2023.100253] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 02/07/2023] [Accepted: 02/13/2023] [Indexed: 05/14/2023]
Abstract
It has been recently suggested that Alcaligenes use a previously unknown pathway to convert ammonium into dinitrogen gas (Dirammox) via hydroxylamine (NH2OH). This fact alone already implies a significant decrease in the aeration requirements for the process, but the process would still be dependent on external aeration. This work studied the potential use of a polarised electrode as an electron acceptor for ammonium oxidation using the recently described Alcaligenes strain HO-1 as a model heterotrophic nitrifier. Results indicated that Alcaligenes strain HO-1 requires aeration for metabolism, a requirement that cannot be replaced for a polarised electrode alone. However, concomitant elimination of succinate and ammonium was observed when operating a previously grown Alcaligenes strain HO-1 culture in the presence of a polarised electrode and without aeration. The usage of a polarised electrode together with aeration did not increase the succinate nor the nitrogen removal rates observed with aeration alone. However, current density generation was observed along a feeding batch test representing an electron share of 3% of the ammonium removed in the presence of aeration and 16% without aeration. Additional tests suggested that hydroxylamine oxidation to dinitrogen gas could have a relevant role in the electron discharge onto the anode. Therefore, the presence of a polarised electrode supported the metabolic functions of Alcaligenes strain HO-1 on the simultaneous oxidation of succinate and ammonium.
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Affiliation(s)
- Narcís Pous
- Laboratory of Chemical and Environmental Engineering (LEQUiA), Institute of the Environment, University of Girona, Carrer Maria Aurèlia Capmany, 69, E-17003, Girona, Spain
| | - Lluis Bañeras
- Group of Environmental Microbial Ecology, Institute of Aquatic Ecology, University of Girona, C/Maria Aurèlia Capmany, 40, E-17003, Girona, Spain
| | - Philippe F.-X. Corvini
- School of Life Sciences, University of Applied Sciences and Arts Northwestern Switzerland, Muttenz, 4132, Switzerland
| | - Shuang-Jiang Liu
- State Key Laboratory of Microbial Resource at Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Sebastià Puig
- Laboratory of Chemical and Environmental Engineering (LEQUiA), Institute of the Environment, University of Girona, Carrer Maria Aurèlia Capmany, 69, E-17003, Girona, Spain
- Corresponding author.
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8
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Franco A, Elbahnasy M, Rosenbaum MA. Screening of natural phenazine producers for electroactivity in bioelectrochemical systems. Microb Biotechnol 2023; 16:579-594. [PMID: 36571174 PMCID: PMC9948232 DOI: 10.1111/1751-7915.14199] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 12/05/2022] [Accepted: 12/07/2022] [Indexed: 12/27/2022] Open
Abstract
Mediated extracellular electron transfer (EET) might be a great vehicle to connect microbial bioprocesses with electrochemical control in stirred-tank bioreactors. However, mediated electron transfer to date is not only much less efficient but also much less studied than microbial direct electron transfer to an anode. For example, despite the widespread capacity of pseudomonads to produce phenazine natural products, only Pseudomonas aeruginosa has been studied for its use of phenazines in bioelectrochemical applications. To provide a deeper understanding of the ecological potential for the bioelectrochemical exploitation of phenazines, we here investigated the potential electroactivity of over 100 putative diverse native phenazine producers and the performance within bioelectrochemical systems. Five species from the genera Pseudomonas, Streptomyces, Nocardiopsis, Brevibacterium and Burkholderia were identified as new electroactive bacteria. Electron discharge to the anode and electric current production correlated with the phenazine synthesis of Pseudomonas chlororaphis subsp. aurantiaca. Phenazine-1-carboxylic acid was the dominant molecule with a concentration of 86.1 μg/ml mediating an anodic current of 15.1 μA/cm2 . On the other hand, Nocardiopsis chromatogenes used a wider range of phenazines at low concentrations and likely yet-unknown redox compounds to mediate EET, achieving an anodic current of 9.5 μA/cm2 . Elucidating the energetic and metabolic usage of phenazines in these and other species might contribute to improving electron discharge and respiration. In the long run, this may enhance oxygen-limited bioproduction of value-added compounds based on mediated EET mechanisms.
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Affiliation(s)
- Angel Franco
- Bio Pilot Plant, Leibniz Institute for Natural Product Research and Infection Biology - Hans-Knöll-Institute (HKI), Jena, Germany
| | - Mahmoud Elbahnasy
- Bio Pilot Plant, Leibniz Institute for Natural Product Research and Infection Biology - Hans-Knöll-Institute (HKI), Jena, Germany.,Faculty of Biological Sciences, Friedrich Schiller University (FSU), Jena, Germany
| | - Miriam A Rosenbaum
- Bio Pilot Plant, Leibniz Institute for Natural Product Research and Infection Biology - Hans-Knöll-Institute (HKI), Jena, Germany.,Faculty of Biological Sciences, Friedrich Schiller University (FSU), Jena, Germany
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9
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Sun Y, Kokko M, Vassilev I. Anode-assisted electro-fermentation with Bacillus subtilis under oxygen-limited conditions. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:6. [PMID: 36627716 PMCID: PMC9832610 DOI: 10.1186/s13068-022-02253-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 12/20/2022] [Indexed: 01/12/2023]
Abstract
BACKGROUND Bacillus subtilis is generally regarded as a ubiquitous facultative anaerobe. Oxygen is the major electron acceptor of B. subtilis, and when oxygen is absent, B. subtilis can donate electrons to nitrate or perform fermentation. An anode electrode can also be used by microorganisms as the electron sink in systems called anodic electro-fermentation. The facultative anaerobic character of B. subtilis makes it an excellent candidate to explore with different electron acceptors, such as an anode. This study aimed to optimise industrial aerobic bioprocesses using alternative electron acceptors. In particular, different end product spectrum of B. subtilis with various electron acceptors, including anode from the electro-fermentation system, was investigated. RESULTS B. subtilis was grown using three electron acceptors, i.e. oxygen, nitrate and anode (poised at a potential of 0.7 V vs. standard hydrogen electrode). The results showed oxygen had a crucial role for cells to remain metabolically active. When nitrate or anode was applied as the sole electron acceptor anaerobically, immediate cell lysis and limited glucose consumption were observed. In anode-assisted electro-fermentation with a limited aeration rate, acetoin, as the main end product showed the highest yield of 0.78 ± 0.04 molproduct/molglucose, two-fold higher than without poised potential (0.39 ± 0.08 molproduct/molglucose). CONCLUSIONS Oxygen controls B. subtilis biomass growth, alternative electron acceptors utilisation and metabolites formation. Limited oxygen/air supply enabled the bacteria to donate excess electrons to nitrate or anode, leading to steered product spectrum. The anode-assisted electro-fermentation showed its potential to boost acetoin production for future industrial biotechnology applications.
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Affiliation(s)
- Yu Sun
- grid.502801.e0000 0001 2314 6254Faculty of Engineering and Natural Sciences, Tampere University, Korkeakoulunkatu 8, 33720 Tampere, Finland
| | - Marika Kokko
- grid.502801.e0000 0001 2314 6254Faculty of Engineering and Natural Sciences, Tampere University, Korkeakoulunkatu 8, 33720 Tampere, Finland
| | - Igor Vassilev
- grid.502801.e0000 0001 2314 6254Faculty of Engineering and Natural Sciences, Tampere University, Korkeakoulunkatu 8, 33720 Tampere, Finland
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10
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Virdis B, Hoelzle R, Marchetti A, Boto ST, Rosenbaum MA, Blasco-Gómez R, Puig S, Freguia S, Villano M. Electro-fermentation: Sustainable bioproductions steered by electricity. Biotechnol Adv 2022; 59:107950. [PMID: 35364226 DOI: 10.1016/j.biotechadv.2022.107950] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Revised: 02/22/2022] [Accepted: 03/24/2022] [Indexed: 01/06/2023]
Abstract
The market of biobased products obtainable via fermentation processes is steadily increasing over the past few years, driven by the need to create a decarbonized economy. To date, industrial fermentation (IF) employs either pure or mixed microbial cultures (MMC) whereby the type of the microbial catalysts and the used feedstock affect metabolic pathways and, in turn, the type of product(s) generated. In many cases, especially when dealing with MMC, the economic viability of IF is hindered by factors such as the low attained product titer and selectivity, which ultimately challenge the downstream recovery and purification steps. In this context, electro-fermentation (EF) represents an innovative approach, based on the use of a polarized electrode interface to trigger changes in the rate, yield, titer or product distribution deriving from traditional fermentation processes. In principle, the electrode in EF can act as an electron acceptor (i.e., anodic electro-fermentation, AEF) or donor (i.e., cathodic electro-fermentation, CEF), or simply as a mean to control the oxidation-reduction potential of the fermentation broth. However, the molecular and biochemical basis underlying the EF process are still largely unknown. This review paper provides a comprehensive overview of recent literature studies including both AEF and CEF examples with either pure or mixed microbial cultures. A critical analysis of biochemical, microbiological, and engineering aspects which presently hamper the transition of the EF technology from the laboratory to the market is also presented.
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Affiliation(s)
- Bernardino Virdis
- Australian Centre for Water and Environmental Biotechnology (ACWEB, formerly AWMC), The University of Queensland, Brisbane, QLD 4072, Australia
| | - Robert Hoelzle
- School of Earth and Environmental Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Angela Marchetti
- Department of Chemistry, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy
| | - Santiago T Boto
- Bio Pilot Plant, Leibniz Institute for Natural Product Research and Infection Biology - Hans-Knöll-Institute (HKI), 07745 Jena, Germany; Faculty of Biological Sciences, Friedrich Schiller University (FSU), 07743 Jena, Germany
| | - Miriam A Rosenbaum
- Bio Pilot Plant, Leibniz Institute for Natural Product Research and Infection Biology - Hans-Knöll-Institute (HKI), 07745 Jena, Germany; Faculty of Biological Sciences, Friedrich Schiller University (FSU), 07743 Jena, Germany
| | - Ramiro Blasco-Gómez
- LEQUIA, Institute of the Environment, University of Girona, Maria Aurèlia Capmany 69, 17003 Girona, Spain
| | - Sebastià Puig
- LEQUIA, Institute of the Environment, University of Girona, Maria Aurèlia Capmany 69, 17003 Girona, Spain
| | - Stefano Freguia
- Department of Chemical Engineering, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Marianna Villano
- Department of Chemistry, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy.
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11
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Demling P, Ankenbauer A, Klein B, Noack S, Tiso T, Takors R, Blank LM. Pseudomonas putida KT2440 endures temporary oxygen limitations. Biotechnol Bioeng 2021; 118:4735-4750. [PMID: 34506651 DOI: 10.1002/bit.27938] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 08/31/2021] [Accepted: 09/01/2021] [Indexed: 01/26/2023]
Abstract
The obligate aerobic nature of Pseudomonas putida, one of the most prominent whole-cell biocatalysts emerging for industrial bioprocesses, questions its ability to be cultivated in large-scale bioreactors, which exhibit zones of low dissolved oxygen tension. P. putida KT2440 was repeatedly subjected to temporary oxygen limitations in scale-down approaches to assess the effect on growth and an exemplary production of rhamnolipids. At those conditions, the growth and production of P. putida KT2440 were decelerated compared to well-aerated reference cultivations, but remarkably, final biomass and rhamnolipid titers were similar. The robust growth behavior was confirmed across different cultivation systems, media compositions, and laboratories, even when P. putida KT2440 was repeatedly exposed to dual carbon and oxygen starvation. Quantification of the nucleotides ATP, ADP, and AMP revealed a decrease of intracellular ATP concentrations with increasing duration of oxygen starvation, which can, however, be restored when re-supplied with oxygen. Only small changes in the proteome were detected when cells encountered oscillations in dissolved oxygen tensions. Concluding, P. putida KT2440 appears to be able to cope with repeated oxygen limitations as they occur in large-scale bioreactors, affirming its outstanding suitability as a whole-cell biocatalyst for industrial-scale bioprocesses.
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Affiliation(s)
- Philipp Demling
- Institute of Applied Microbiology (iAMB), Aachen Biology and Biotechnology (ABBt), RWTH Aachen University, Aachen, Germany
| | - Andreas Ankenbauer
- Institute of Biochemical Engineering, University of Stuttgart, Stuttgart, Germany
| | - Bianca Klein
- Institute of Bio- and Geosciences (IBG-1): Biotechnology, Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Stephan Noack
- Institute of Bio- and Geosciences (IBG-1): Biotechnology, Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Till Tiso
- Institute of Applied Microbiology (iAMB), Aachen Biology and Biotechnology (ABBt), RWTH Aachen University, Aachen, Germany
| | - Ralf Takors
- Institute of Biochemical Engineering, University of Stuttgart, Stuttgart, Germany
| | - Lars M Blank
- Institute of Applied Microbiology (iAMB), Aachen Biology and Biotechnology (ABBt), RWTH Aachen University, Aachen, Germany
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