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Wohlers H, Zentgraf L, van der Sande L, Holtmann D. Metabolic engineering of Shewanella oneidensis to produce glutamate and itaconic acid. Appl Microbiol Biotechnol 2024; 108:36. [PMID: 38183472 PMCID: PMC10771365 DOI: 10.1007/s00253-023-12879-5] [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: 06/20/2023] [Revised: 11/17/2023] [Accepted: 11/24/2023] [Indexed: 01/08/2024]
Abstract
Shewanella oneidensis is a gram-negative bacterium known for its unique respiratory capabilities, which allow it to utilize a wide range of electron acceptors, including solid substrates such as electrodes. For a future combination of chemical production and electro-fermentation, the goal of this study was to expand its product spectrum. S. oneidensis was metabolically engineered to optimize its glutamate production and to enable production of itaconic acid. By deleting the glutamate importer gltS for a reduced glutamate uptake and pckA/ptA to redirect the carbon flux towards the TCA cycle, a ∆3 mutant was created. In combination with the plasmid pG2 carrying the glutamate dehydrogenase gdhA and a specific glutamate exporter NCgl1221 A111V, a 72-fold increase in glutamate concentration compared to the wild type was achieved. Along with overexpression of gdhA and NCgl1221 A111V, the deletion of gltS and pckA/ptA as well as the deletion of all three genes (∆3) was examined for their impact on growth and lactate consumption. This showed that the redirection of the carbon flux towards the TCA cycle is possible. Furthermore, we were able to produce itaconic acid for the first time with a S. oneidensis strain. A titer of 7 mM was achieved after 48 h. This suggests that genetic optimization with an expression vector carrying a cis-aconitate decarboxylase (cadA) and a aconitate hydratase (acnB) along with the proven redirection of the carbon flux to the TCA cycle enabled the production of itaconic acid, a valuable platform chemical used in the production of a variety of products. KEY POINTS: •Heterologous expression of gdhA and NCgl1221_A111V leads to higher glutamate production. •Deletion of ackA/pta redirects carbon flux towards TCA cycle. •Heterologous expression of cadA and acnB enables itaconic acid production.
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Affiliation(s)
- Hannah Wohlers
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen, Wiesenstrasse 14, 35390, Giessen, Germany
- DECHEMA-Forschungsinstitut, Microbial Biotechnology, Theodor-Heuss-Allee 25, 60486, Frankfurt Am Main, Germany
| | - Laura Zentgraf
- DECHEMA-Forschungsinstitut, Microbial Biotechnology, Theodor-Heuss-Allee 25, 60486, Frankfurt Am Main, Germany
| | - Lisa van der Sande
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen, Wiesenstrasse 14, 35390, Giessen, Germany
- Institute of Process Engineering in Life Sciences, Karlsruhe Institute of Technology, Karlsruhe, Fritz-Haber-Weg 4, 76131, Karlsruhe, Germany
| | - Dirk Holtmann
- Institute of Process Engineering in Life Sciences, Karlsruhe Institute of Technology, Karlsruhe, Fritz-Haber-Weg 4, 76131, Karlsruhe, Germany.
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Lin WQ, Cheng ZH, Wu QZ, Liu JQ, Liu DF, Sheng GP. Efficient Enhancement of Extracellular Electron Transfer in Shewanella oneidensis MR-1 via CRISPR-Mediated Transposase Technology. ACS Synth Biol 2024; 13:1941-1951. [PMID: 38780992 DOI: 10.1021/acssynbio.4c00240] [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] [Indexed: 05/25/2024]
Abstract
Electroactive bacteria, exemplified by Shewanella oneidensis MR-1, have garnered significant attention due to their unique extracellular electron-transfer (EET) capabilities, which are crucial for energy recovery and pollutant conversion. However, the practical application of MR-1 is constrained by its EET efficiency, a key limiting factor, due to the complexity of research methodologies and the challenges associated with the practical use of gene editing tools. To address this challenge, a novel gene integration system, INTEGRATE, was developed, utilizing CRISPR-mediated transposase technologies for precise genomic insertion within the S. oneidensis MR-1 genome. This system facilitated the insertion of extensive gene segments at different sites of the Shewanella genome with an efficiency approaching 100%. The inserted cargo genes could be kept stable on the genome after continuous cultivation. The enhancement of the organism's EET efficiency was realized through two primary strategies: the integration of the phenazine-1-carboxylic acid synthesis gene cluster to augment EET efficiency and the targeted disruption of the SO3350 gene to promote anodic biofilm development. Collectively, our findings highlight the potential of utilizing the INTEGRATE system for strategic genomic alterations, presenting a synergistic approach to augment the functionality of electroactive bacteria within bioelectrochemical systems.
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Affiliation(s)
- Wei-Qiang Lin
- School of Life Sciences, University of Science and Technology of China, Hefei 230026, China
| | - Zhou-Hua Cheng
- Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China
| | - Qi-Zhong Wu
- School of Life Sciences, University of Science and Technology of China, Hefei 230026, China
| | - Jia-Qi Liu
- Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China
| | - Dong-Feng Liu
- Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China
| | - Guo-Ping Sheng
- Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China
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Wu M, Xu Y, Zhao C, Huang H, Liu C, Duan X, Zhang X, Zhao G, Chen Y. Efficient nitrate and Cr(VI) removal by denitrifier: The mechanism of S. oneidensis MR-1 promoting electron production, transportation and consumption. JOURNAL OF HAZARDOUS MATERIALS 2024; 469:133675. [PMID: 38508109 DOI: 10.1016/j.jhazmat.2024.133675] [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: 12/18/2023] [Revised: 01/21/2024] [Accepted: 01/29/2024] [Indexed: 03/22/2024]
Abstract
When Cr(VI) and nitrate coexist, the efficiency of both bio-denitrification and Cr(VI) bio-reduction is poor because chromate hinders bacterial normal functions (i.e., electron production, transportation and consumption). Moreover, under anaerobic condition, the method about efficient nitrate and Cr(VI) removal remained unclear. In this paper, the addition of Shewanella oneidensis MR-1 to promote the electron production, transportation and consumption of denitrifier and cause an increase in the removal of nitrate and Cr(VI). The efficiency of nitrate and Cr(VI) removal accomplished by P. denitrificans as a used model denitrifier increased respectively from 51.3% to 96.1% and 34.3% to 99.8% after S. oneidensis MR-1 addition. The mechanism investigations revealed that P. denitrificans provided S. oneidensis MR-1 with lactate, which was utilized to secreted riboflavin and phenazine by S. oneidensis MR-1. The riboflavin served as coenzymes of cellular reductants (i.e., thioredoxin and glutathione) in P. denitrificans, which created favorable intracellular microenvironment conditions for electron generation. Meanwhile, phenazine promoted biofilm formation, which increased the adsorption of Cr(VI) on the cell surface and accelerated the Cr(VI) reduction by membrane bound chromate reductases thereby reducing damage to other enzymes respectively. Overall, this strategy reduced the negative effect of chromate, thus improved the generation, transportation, and consumption of electrons. SYNOPSIS: The presence of S. oneidensis MR-1 facilitated nitrate and Cr(VI) removal by P. denitrificans through decreasing the negative effect of chromate due to the metabolites' secretion.
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Affiliation(s)
- Meirou Wu
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Yanan Xu
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Chunxia Zhao
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Haining Huang
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Chao Liu
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Xu Duan
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Xuemeng Zhang
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Guohua Zhao
- School of Chemical Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Yinguang Chen
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China.
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Jia B, Wan J, Liu H, Yan B, Zhang L, Su X. DIET-like and MIET-like mutualism of S. oneidensis MR-1 and metal-reducing function microflora boosts Cr(VI) reduction. JOURNAL OF HAZARDOUS MATERIALS 2024; 465:133401. [PMID: 38171202 DOI: 10.1016/j.jhazmat.2023.133401] [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: 11/15/2023] [Revised: 12/18/2023] [Accepted: 12/27/2023] [Indexed: 01/05/2024]
Abstract
Microbial treatment of Cr(VI) is an environmentally friendly and low-cost approach. However, the mechanism of mutualism and the role of interspecies electron transfer in Cr(VI) reducing microflora are unclear. Herein, we constructed an intersymbiotic microbial association flora to augment interspecies electron transfer via functionalizing electroactive Shewanella oneidensis MR-1 with metal-reducing microflora, and thus the efficiency of Cr(VI) reduction. The findings suggest that the metal-reducing active microflora could converts glucose into lactic acid and riboflavin for S. oneidensis MR-1 to act as a carbon source and electron mediator. Thus, when adding initial 25 mg/L Cr (VI), this microflora exhibited an outstanding Cr (VI) removal efficiency (100%) at 12 h and elevated Cr (III) immobilization efficiency (80%) at 60 h with the assistance of 25 mg/L Cu(II). A series of electrochemical experiments proved this remarkable removal efficiency were ascribed to the improved interspecies electron transfer efficiency through direct interspecies electron transfer and riboflavin through mediated interspecies electron transfer. Furthermore, the metagenomic analysis revealed the expression level of the electron transport pathway was promoted. Intriguing high abundance of genes participating in the bio-reduction and biotransformation of Cr(VI) was also observed in functional microflora. These outcomes give a novel strategy for enhancing the reduction and fixation of harmful heavy metals by coculturing function microflora with electrogenic microorganisms.
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Affiliation(s)
- Boyu Jia
- School of Environment and Energy, Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling, South China University of Technology, Guangzhou, Guangdong 510006, China
| | - Juanjuan Wan
- School of Environment and Energy, Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling, South China University of Technology, Guangzhou, Guangdong 510006, China
| | - Hui Liu
- Huadian Coal Industry Group Co., Ltd, Beijing 100035, China
| | - Bo Yan
- SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, China; School of Environment, South China Normal University, University Town, Guangzhou 510006, China
| | - Lijuan Zhang
- SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, China; School of Environment, South China Normal University, University Town, Guangzhou 510006, China.
| | - Xintai Su
- School of Environment and Energy, Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling, South China University of Technology, Guangzhou, Guangdong 510006, China.
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Verma M, Singh V, Mishra V. Moving towards the enhancement of extracellular electron transfer in electrogens. World J Microbiol Biotechnol 2023; 39:130. [PMID: 36959310 DOI: 10.1007/s11274-023-03582-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 03/15/2023] [Indexed: 03/25/2023]
Abstract
Electrogens are very common in nature and becoming a contemporary theme for research as they can be exploited for extracellular electron transfer. Extracellular electron transfer is the key mechanism behind bioelectricity generation and bioremediation of pollutants via microbes. Extracellular electron transfer mechanisms for electrogens other than Shewanella and Geobacter are less explored. An efficient extracellular electron transfer system is crucial for the sustainable future of bioelectrochemical systems. At present, the poor extracellular electron transfer efficiency remains a decisive factor in limiting the development of efficient bioelectrochemical systems. In this review article, the EET mechanisms in different electrogens (bacteria and yeast) have been focused. Apart from the well-known electron transfer mechanisms of Shewanella oneidensis and Geobacter metallireducens, a brief introduction of the EET pathway in Rhodopseudomonas palustris TIE-1, Sideroxydans lithotrophicus ES-1, Thermincola potens JR, Lysinibacillus varians GY32, Carboxydothermus ferrireducens, Enterococcus faecalis and Saccharomyces cerevisiae have been included. In addition to this, the article discusses the several approaches to anode modification and genetic engineering that may be used in order to increase the rate of extracellular electron transfer. In the side lines, this review includes the engagement of the electrogens for different applications followed by the future perspective of efficient extracellular electron transfer.
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Affiliation(s)
- Manisha Verma
- School of Biochemical Engineering, IIT (BHU), 221005, Varanasi, India
| | - Vishal Singh
- School of Biochemical Engineering, IIT (BHU), 221005, Varanasi, India
| | - Vishal Mishra
- School of Biochemical Engineering, IIT (BHU), 221005, Varanasi, India.
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