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Asefi S, Nouri H, Pourmohammadi G, Moghimi H. Comprehensive network of stress-induced responses in Zymomonas mobilis during bioethanol production: from physiological and molecular responses to the effects of system metabolic engineering. Microb Cell Fact 2024; 23:180. [PMID: 38890644 PMCID: PMC11186258 DOI: 10.1186/s12934-024-02459-1] [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: 10/05/2023] [Accepted: 06/13/2024] [Indexed: 06/20/2024] Open
Abstract
Nowadays, biofuels, especially bioethanol, are becoming increasingly popular as an alternative to fossil fuels. Zymomonas mobilis is a desirable species for bioethanol production due to its unique characteristics, such as low biomass production and high-rate glucose metabolism. However, several factors can interfere with the fermentation process and hinder microbial activity, including lignocellulosic hydrolysate inhibitors, high temperatures, an osmotic environment, and high ethanol concentration. Overcoming these limitations is critical for effective bioethanol production. In this review, the stress response mechanisms of Z. mobilis are discussed in comparison to other ethanol-producing microbes. The mechanism of stress response is divided into physiological (changes in growth, metabolism, intracellular components, and cell membrane structures) and molecular (up and down-regulation of specific genes and elements of the regulatory system and their role in expression of specific proteins and control of metabolic fluxes) changes. Systemic metabolic engineering approaches, such as gene manipulation, overexpression, and silencing, are successful methods for building new metabolic pathways. Therefore, this review discusses systems metabolic engineering in conjunction with systems biology and synthetic biology as an important method for developing new strains with an effective response mechanism to fermentation stresses during bioethanol production. Overall, understanding the stress response mechanisms of Z. mobilis can lead to more efficient and effective bioethanol production.
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Affiliation(s)
- Shaqayeq Asefi
- Department of Microbial Biotechnology, School of Biology, College of Science, University of Tehran, Tehran, Iran
| | - Hoda Nouri
- Department of Microbial Biotechnology, School of Biology, College of Science, University of Tehran, Tehran, Iran.
| | - Golchehr Pourmohammadi
- Department of Microbial Biotechnology, School of Biology, College of Science, University of Tehran, Tehran, Iran
| | - Hamid Moghimi
- Department of Microbial Biotechnology, School of Biology, College of Science, University of Tehran, Tehran, Iran.
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2
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Yang H, He Y, Zhou S, Deng Y. Dynamic regulation and cofactor engineering of escherichia coli to enhance production of glycolate from corn stover hydrolysate. BIORESOURCE TECHNOLOGY 2024; 398:130531. [PMID: 38447620 DOI: 10.1016/j.biortech.2024.130531] [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: 12/27/2023] [Revised: 02/24/2024] [Accepted: 03/03/2024] [Indexed: 03/08/2024]
Abstract
Glycolic acid is widely employed in chemical cleaning, the production of polyglycolic acid-lactic acid, and polyglycolic acid. Currently, the bottleneck of glycolate biosynthesis lies on the imbalance of metabolic flux and the deficiency of NADPH. In this study, a dynamic regulation system was developed and optimized to enhance the metabolic flux from glucose to glycolate. Additionally, the knockout of transhydrogenase (sthA), along with the overexpression of pyridine nucleotide transhydrogenase (pntAB) and the implementation of the Entner-Doudoroff pathway, were performed to further increase the production of the NADPH, thereby increasing the titer of glycolate to 5.6 g/L. To produce glycolate from corn stover hydrolysate, carbon catabolite repression was alleviated and glucose utilization was accelerated. The final strain, E. coli Mgly10-245, is inducer-free, achieving a glycolate titer of 46.1 g/L using corn stover hydrolysate (77.1 % of theoretical yield). These findings will contribute to the advancement of industrial glycolate production.
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Affiliation(s)
- Haining Yang
- National Engineering Research Center of Cereal Fermentation and Food Biomanufacturing, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China
| | - Yucai He
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, China, 430062
| | - Shenghu Zhou
- National Engineering Research Center of Cereal Fermentation and Food Biomanufacturing, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China.
| | - Yu Deng
- National Engineering Research Center of Cereal Fermentation and Food Biomanufacturing, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China.
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3
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Brück P, Wasser D, Soppa J. One Advantage of Being Polyploid: Prokaryotes of Various Phylogenetic Groups Can Grow in the Absence of an Environmental Phosphate Source at the Expense of Their High Genome Copy Numbers. Microorganisms 2023; 11:2267. [PMID: 37764113 PMCID: PMC10536925 DOI: 10.3390/microorganisms11092267] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 08/30/2023] [Accepted: 09/06/2023] [Indexed: 09/29/2023] Open
Abstract
Genomic DNA has high phosphate content; therefore, monoploid prokaryotes need an external phosphate source or an internal phosphate storage polymer for replication and cell division. For two polyploid prokaryotic species, the halophilic archaeon Haloferax volcanii and the cyanobacterium Synechocystis PCC 6803, it has been reported that they can grow in the absence of an external phosphate source by reducing the genome copy number per cell. To unravel whether this feature might be widespread in and typical for polyploid prokaryotes, three additional polyploid prokaryotic species were analyzed in the present study, i.e., the alphaproteobacterium Zymomonas mobilis, the gammaproteobacterium Azotobacter vinelandii, and the haloarchaeon Halobacterium salinarum. Polyploid cultures were incubated in the presence and in the absence of external phosphate, growth was recorded, and genome copy numbers per cell were quantified. Limited growth in the absence of phosphate was observed for all three species. Phosphate was added to phosphate-starved cultures to verify that the cells were still viable and growth-competent. Remarkably, stationary-phase cells grown in the absence or presence of phosphate did not become monoploid but stayed oligoploid with about five genome copies per cell. As a negative control, it was shown that monoploid Escherichia coli cultures did not exhibit any growth in the absence of phosphate. Taken together, all five polyploid prokaryotic species that have been characterized until now can grow in the absence of environmental phosphate by reducing their genome copy numbers, indicating that cell proliferation outperforms other evolutionary advantages of polyploidy.
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Affiliation(s)
| | | | - Jörg Soppa
- Biocentre, Institute for Molecular Biosciences, Goethe University, Max-von-Laue-Str. 9, D-60438 Frankfurt, Germany (D.W.)
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4
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Grausa K, Siddiqui SA, Lameyer N, Wiesotzki K, Smetana S, Pentjuss A. Metabolic Modeling of Hermetia illucens Larvae Resource Allocation for High-Value Fatty Acid Production. Metabolites 2023; 13:724. [PMID: 37367882 DOI: 10.3390/metabo13060724] [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: 03/21/2023] [Revised: 05/31/2023] [Accepted: 06/01/2023] [Indexed: 06/28/2023] Open
Abstract
All plant and animal kingdom organisms use highly connected biochemical networks to facilitate sustaining, proliferation, and growth functions. While the biochemical network details are well known, the understanding of the intense regulation principles is still limited. We chose to investigate the Hermetia illucens fly at the larval stage because this stage is a crucial period for the successful accumulation and allocation of resources for the subsequent organism's developmental stages. We combined iterative wet lab experiments and innovative metabolic modeling design approaches to simulate and explain the H. illucens larval stage resource allocation processes and biotechnology potential. We performed time-based growth and high-value chemical compound accumulation wet lab chemical analysis experiments on larvae and the Gainesville diet composition. We built and validated the first H. illucens medium-size, stoichiometric metabolic model to predict the effects of diet-based alterations on fatty acid allocation potential. Using optimization methods such as flux balance and flux variability analysis on the novel insect metabolic model, we predicted that doubled essential amino acid consumption increased the growth rate by 32%, but pure glucose consumption had no positive impact on growth. In the case of doubled pure valine consumption, the model predicted a 2% higher growth rate. In this study, we describe a new framework for researching the impact of dietary alterations on the metabolism of multi-cellular organisms at different developmental stages for improved, sustainable, and directed high-value chemicals.
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Affiliation(s)
- Kristina Grausa
- Department of Computer Systems, Latvia University of Life Sciences and Technologies, LV-3001 Jelgava, Latvia
- Institute of Microbiology and Biotechnology, University of Latvia, LV-1050 Riga, Latvia
| | - Shahida A Siddiqui
- Campus Straubing for Biotechnology and Sustainability, Technical University of Munich, Essigberg 3, D-94315 Straubing, Germany
- German Institute of Food Technologies (DIL e.V.), 49610 Quakenbrück, Germany
| | - Norbert Lameyer
- German Institute of Food Technologies (DIL e.V.), 49610 Quakenbrück, Germany
| | - Karin Wiesotzki
- German Institute of Food Technologies (DIL e.V.), 49610 Quakenbrück, Germany
| | - Sergiy Smetana
- German Institute of Food Technologies (DIL e.V.), 49610 Quakenbrück, Germany
| | - Agris Pentjuss
- Department of Computer Systems, Latvia University of Life Sciences and Technologies, LV-3001 Jelgava, Latvia
- Institute of Microbiology and Biotechnology, University of Latvia, LV-1050 Riga, Latvia
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5
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Grausa K, Mozga I, Pleiko K, Pentjuss A. Integrative Gene Expression and Metabolic Analysis Tool IgemRNA. Biomolecules 2022; 12:biom12040586. [PMID: 35454176 PMCID: PMC9029533 DOI: 10.3390/biom12040586] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 04/11/2022] [Accepted: 04/14/2022] [Indexed: 01/27/2023] Open
Abstract
Genome-scale metabolic modeling is widely used to study the impact of metabolism on the phenotype of different organisms. While substrate modeling reflects the potential distribution of carbon and other chemical elements within the model, the additional use of omics data, e.g., transcriptome, has implications when researching the genotype–phenotype responses to environmental changes. Several algorithms for transcriptome analysis using genome-scale metabolic modeling have been proposed. Still, they are restricted to specific objectives and conditions and lack flexibility, have software compatibility issues, and require advanced user skills. We classified previously published algorithms, summarized transcriptome pre-processing, integration, and analysis methods, and implemented them in the newly developed transcriptome analysis tool IgemRNA, which (1) has a user-friendly graphical interface, (2) tackles compatibility issues by combining previous data input and pre-processing algorithms in MATLAB, and (3) introduces novel algorithms for the automatic comparison of different transcriptome datasets with or without Cobra Toolbox 3.0 optimization algorithms. We used publicly available transcriptome datasets from Saccharomyces cerevisiae BY4741 and H4-S47D strains for validation. We found that IgemRNA provides a means for transcriptome and environmental data validation on biochemical network topology since the biomass function varies for different phenotypes. Our tool can detect problematic reaction constraints.
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Affiliation(s)
- Kristina Grausa
- Department of Computer Systems, Latvia University of Life Sciences and Technologies, Liela Street 2, LV-3001 Jelgava, Latvia; (K.G.); (I.M.)
| | - Ivars Mozga
- Department of Computer Systems, Latvia University of Life Sciences and Technologies, Liela Street 2, LV-3001 Jelgava, Latvia; (K.G.); (I.M.)
| | - Karlis Pleiko
- Laboratory of Precision and Nanomedicine, Institute of Biomedicine and Translational Medicine, University of Tartu, 50411 Tartu, Estonia;
- Faculty of Medicine, University of Latvia, LV-1586 Riga, Latvia
| | - Agris Pentjuss
- Institute of Microbiology and Biotechnology, University of Latvia, Jelgavas Street 1, LV-1004 Riga, Latvia
- Correspondence:
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6
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Berzins K, Muiznieks R, Baumanis MR, Strazdina I, Shvirksts K, Prikule S, Galvanauskas V, Pleissner D, Pentjuss A, Grube M, Kalnenieks U, Stalidzans E. Kinetic and Stoichiometric Modeling-Based Analysis of Docosahexaenoic Acid (DHA) Production Potential by C. cohnii from Glycerol, Glucose and Ethanol. Mar Drugs 2022; 20:md20020115. [PMID: 35200644 PMCID: PMC8879253 DOI: 10.3390/md20020115] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 01/26/2022] [Accepted: 01/28/2022] [Indexed: 11/16/2022] Open
Abstract
Docosahexaenoic acid (DHA) is one of the most important long-chain polyunsaturated fatty acids (LC-PUFAs), with numerous health benefits. Crypthecodinium cohnii, a marine heterotrophic dinoflagellate, is successfully used for the industrial production of DHA because it can accumulate DHA at high concentrations within the cells. Glycerol is an interesting renewable substrate for DHA production since it is a by-product of biodiesel production and other industries, and is globally generated in large quantities. The DHA production potential from glycerol, ethanol and glucose is compared by combining fermentation experiments with the pathway-scale kinetic modeling and constraint-based stoichiometric modeling of C. cohnii metabolism. Glycerol has the slowest biomass growth rate among the tested substrates. This is partially compensated by the highest PUFAs fraction, where DHA is dominant. Mathematical modeling reveals that glycerol has the best experimentally observed carbon transformation rate into biomass, reaching the closest values to the theoretical upper limit. In addition to our observations, the published experimental evidence indicates that crude glycerol is readily consumed by C. cohnii, making glycerol an attractive substrate for DHA production.
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Affiliation(s)
- Kristaps Berzins
- Institute of Microbiology and Biotechnology, University of Latvia, Jelgavas Street 1, LV-1004 Riga, Latvia; (K.B.); (R.M.); (M.R.B.); (I.S.); (K.S.); (S.P.); (A.P.); (M.G.); (U.K.)
| | - Reinis Muiznieks
- Institute of Microbiology and Biotechnology, University of Latvia, Jelgavas Street 1, LV-1004 Riga, Latvia; (K.B.); (R.M.); (M.R.B.); (I.S.); (K.S.); (S.P.); (A.P.); (M.G.); (U.K.)
| | - Matiss R. Baumanis
- Institute of Microbiology and Biotechnology, University of Latvia, Jelgavas Street 1, LV-1004 Riga, Latvia; (K.B.); (R.M.); (M.R.B.); (I.S.); (K.S.); (S.P.); (A.P.); (M.G.); (U.K.)
| | - Inese Strazdina
- Institute of Microbiology and Biotechnology, University of Latvia, Jelgavas Street 1, LV-1004 Riga, Latvia; (K.B.); (R.M.); (M.R.B.); (I.S.); (K.S.); (S.P.); (A.P.); (M.G.); (U.K.)
| | - Karlis Shvirksts
- Institute of Microbiology and Biotechnology, University of Latvia, Jelgavas Street 1, LV-1004 Riga, Latvia; (K.B.); (R.M.); (M.R.B.); (I.S.); (K.S.); (S.P.); (A.P.); (M.G.); (U.K.)
| | - Santa Prikule
- Institute of Microbiology and Biotechnology, University of Latvia, Jelgavas Street 1, LV-1004 Riga, Latvia; (K.B.); (R.M.); (M.R.B.); (I.S.); (K.S.); (S.P.); (A.P.); (M.G.); (U.K.)
| | - Vytautas Galvanauskas
- Biotehniskais Centrs AS, Dzerbenes Street 27, LV-1006 Riga, Latvia;
- Department of Automation, Kaunas University of Technology, LT-51367 Kaunas, Lithuania
| | - Daniel Pleissner
- Sustainable Chemistry (Resource Efciency), Institute of Sustainable and Environmental Chemistry, Leuphana University of Lüneburg, Universitätsallee 1, C13.203, 21335 Luneburg, Germany;
- Institute for Food and Environmental Research (ILU), Papendorfer Weg 3, 14806 Bad Belzig, Germany
| | - Agris Pentjuss
- Institute of Microbiology and Biotechnology, University of Latvia, Jelgavas Street 1, LV-1004 Riga, Latvia; (K.B.); (R.M.); (M.R.B.); (I.S.); (K.S.); (S.P.); (A.P.); (M.G.); (U.K.)
| | - Mara Grube
- Institute of Microbiology and Biotechnology, University of Latvia, Jelgavas Street 1, LV-1004 Riga, Latvia; (K.B.); (R.M.); (M.R.B.); (I.S.); (K.S.); (S.P.); (A.P.); (M.G.); (U.K.)
| | - Uldis Kalnenieks
- Institute of Microbiology and Biotechnology, University of Latvia, Jelgavas Street 1, LV-1004 Riga, Latvia; (K.B.); (R.M.); (M.R.B.); (I.S.); (K.S.); (S.P.); (A.P.); (M.G.); (U.K.)
| | - Egils Stalidzans
- Institute of Microbiology and Biotechnology, University of Latvia, Jelgavas Street 1, LV-1004 Riga, Latvia; (K.B.); (R.M.); (M.R.B.); (I.S.); (K.S.); (S.P.); (A.P.); (M.G.); (U.K.)
- Biotehniskais Centrs AS, Dzerbenes Street 27, LV-1006 Riga, Latvia;
- Correspondence: ; Tel.: +371-29575510
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7
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Petrovs R, Stalidzans E, Pentjuss A. IMFLer: A Web Application for Interactive Metabolic Flux Analysis and Visualization. J Comput Biol 2021; 28:1021-1032. [PMID: 34424732 DOI: 10.1089/cmb.2021.0056] [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] [Indexed: 12/15/2022] Open
Abstract
Increasing genome-wide data in biological sciences and medicine has contributed to the development of a variety of visualization tools. Several automatic, semiautomatic, and manual visualization tools have already been developed. Some even have integrated flux balance analysis (FBA), but in most cases, it depends on separately installed third party software that is proprietary and does not allow customization of its functionality and has many restrictions for easy data distribution and analysis. In this study, we present an interactive metabolic flux analyzer and visualizer (IMFLer)-a static single-page web application that enables the reading and management of metabolic model layout maps, as well as immediate visualization of results from both FBA and flux variability analysis (FVA). IMFLer uses the Escher Builder tool to load, show, edit, and save metabolic pathway maps. This makes IMFLer an attractive and easily applicable tool with a user-friendly interface. Moreover, it allows to faster interpret results from FBA and FVA and improves data interoperability by using a standardized file format for the genome-scale metabolic model. IMFLer is a fully open-source tool that enables the rapid visualization and interpretation of the results of FBA and FVA with no time setup and no programming skills required, available at https://lv-csbg.github.io/IMFLer/.
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Affiliation(s)
- Rudolfs Petrovs
- Computational Systems Biology Group, Institute of Microbiology and Biotechnology, University of Latvia, Riga, Latvia
| | - Egils Stalidzans
- Computational Systems Biology Group, Institute of Microbiology and Biotechnology, University of Latvia, Riga, Latvia.,Biosystems Group, Department of Computer Systems, Latvia University of Life Sciences and Technologies, Jelgava, Latvia
| | - Agris Pentjuss
- Computational Systems Biology Group, Institute of Microbiology and Biotechnology, University of Latvia, Riga, Latvia
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8
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Wu C, Spiller R, Dowe N, Bomble YJ, St John PC. Thermodynamic and Kinetic Modeling of Co-utilization of Glucose and Xylose for 2,3-BDO Production by Zymomonas mobilis. Front Bioeng Biotechnol 2021; 9:707749. [PMID: 34381766 PMCID: PMC8350737 DOI: 10.3389/fbioe.2021.707749] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 06/30/2021] [Indexed: 11/20/2022] Open
Abstract
Prior engineering of the ethanologen Zymomonas mobilis has enabled it to metabolize xylose and to produce 2,3-butanediol (2,3-BDO) as a dominant fermentation product. When co-fermenting with xylose, glucose is preferentially utilized, even though xylose metabolism generates ATP more efficiently during 2,3-BDO production on a BDO-mol basis. To gain a deeper understanding of Z. mobilis metabolism, we first estimated the kinetic parameters of the glucose facilitator protein of Z. mobilis by fitting a kinetic uptake model, which shows that the maximum transport capacity of glucose is seven times higher than that of xylose, and glucose is six times more affinitive to the transporter than xylose. With these estimated kinetic parameters, we further compared the thermodynamic driving force and enzyme protein cost of glucose and xylose metabolism. It is found that, although 20% more ATP can be yielded stoichiometrically during xylose utilization, glucose metabolism is thermodynamically more favorable with 6% greater cumulative Gibbs free energy change, more economical with 37% less enzyme cost required at the initial stage and sustains the advantage of the thermodynamic driving force and protein cost through the fermentation process until glucose is exhausted. Glucose-6-phosphate dehydrogenase (g6pdh), glyceraldehyde-3-phosphate dehydrogenase (gapdh) and phosphoglycerate mutase (pgm) are identified as thermodynamic bottlenecks in glucose utilization pathway, as well as two more enzymes of xylose isomerase and ribulose-5-phosphate epimerase in xylose metabolism. Acetolactate synthase is found as potential engineering target for optimized protein cost supporting unit metabolic flux. Pathway analysis was then extended to the core stoichiometric matrix of Z. mobilis metabolism. Growth was simulated by dynamic flux balance analysis and the model was validated showing good agreement with experimental data. Dynamic FBA simulations suggest that a high agitation is preferable to increase 2,3-BDO productivity while a moderate agitation will benefit the 2,3-BDO titer. Taken together, this work provides thermodynamic and kinetic insights of Z. mobilis metabolism on dual substrates, and guidance of bioengineering efforts to increase hydrocarbon fuel production.
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Affiliation(s)
- Chao Wu
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Ryan Spiller
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Nancy Dowe
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, United States.,National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Yannick J Bomble
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Peter C St John
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, United States
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9
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Banta AB, Enright AL, Siletti C, Peters JM. A High-Efficacy CRISPR Interference System for Gene Function Discovery in Zymomonas mobilis. Appl Environ Microbiol 2020; 86:e01621-20. [PMID: 32978126 PMCID: PMC7657623 DOI: 10.1128/aem.01621-20] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 09/20/2020] [Indexed: 01/23/2023] Open
Abstract
Zymomonas mobilis is a promising biofuel producer due to its high alcohol tolerance and streamlined metabolism that efficiently converts sugar to ethanol. Z. mobilis genes are poorly characterized relative to those of model bacteria, hampering our ability to rationally engineer the genome with pathways capable of converting sugars from plant hydrolysates into valuable biofuels and bioproducts. Many of the unique properties that make Z. mobilis an attractive biofuel producer are controlled by essential genes; however, these genes cannot be manipulated using traditional genetic approaches (e.g., deletion or transposon insertion) because they are required for viability. CRISPR interference (CRISPRi) is a programmable gene knockdown system that can precisely control the timing and extent of gene repression, thus enabling targeting of essential genes. Here, we establish a stable, high-efficacy CRISPRi system in Z. mobilis that is capable of perturbing all genes-including essential genes. We show that Z. mobilis CRISPRi causes either strong knockdowns (>100-fold) using single guide RNA (sgRNA) spacers that perfectly match target genes or partial knockdowns using spacers with mismatches. We demonstrate the efficacy of Z. mobilis CRISPRi by targeting essential genes that are universally conserved in bacteria, are key to the efficient metabolism of Z. mobilis, or underlie alcohol tolerance. Our Z. mobilis CRISPRi system will enable comprehensive gene function discovery, opening a path to rational design of biofuel production strains with improved yields.IMPORTANCE Biofuels produced by microbial fermentation of plant feedstocks provide renewable and sustainable energy sources that have the potential to mitigate climate change and improve energy security. Engineered strains of the bacterium Z. mobilis can convert sugars extracted from plant feedstocks into next-generation biofuels like isobutanol; however, conversion by these strains remains inefficient due to key gaps in our knowledge about genes involved in metabolism and stress responses such as alcohol tolerance. Here, we develop CRISPRi as a tool to explore gene function in Z. mobilis We characterize genes that are essential for growth, required to ferment sugar to ethanol, and involved in resistance to isobutanol. Our Z. mobilis CRISPRi system makes it straightforward to define gene function and can be applied to improve strain engineering and increase biofuel yields.
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Affiliation(s)
- Amy B Banta
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Great Lakes Bioenergy Research Center, Wisconsin Energy Institute, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Amy L Enright
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Great Lakes Bioenergy Research Center, Wisconsin Energy Institute, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Cheta Siletti
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Jason M Peters
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Great Lakes Bioenergy Research Center, Wisconsin Energy Institute, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
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10
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Abstract
Metabolic engineering is crucial in the development of production strains for platform chemicals, pharmaceuticals and biomaterials from renewable resources. The central carbon metabolism (CCM) of heterotrophs plays an essential role in the conversion of biomass to the cellular building blocks required for growth. Yet, engineering the CCM ultimately aims toward a maximization of flux toward products of interest. The most abundant dissimilative carbohydrate pathways amongst prokaryotes (and eukaryotes) are the Embden-Meyerhof-Parnas (EMP) and the Entner-Doudoroff (ED) pathways, which build the basics for heterotrophic metabolic chassis strains. Although the EMP is regarded as the textbook example of a carbohydrate pathway owing to its central role in production strains like Escherichia coli, Saccharomyces cerevisiae and Bacillus subtilis, it is either modified, complemented or even replaced by alternative carbohydrate pathways in different organisms. The ED pathway also plays key roles in biotechnological relevant bacteria, like Zymomonas mobilis and Pseudomonas putida, and its importance was recently discovered in photoautotrophs and marine microorganisms. In contrast to the EMP, the ED pathway and its variations are not evolutionary optimized for high ATP production and it differs in key principles such as protein cost, energetics and thermodynamics, which can be exploited in the construction of unique metabolic designs. Single ED pathway enzymes and complete ED pathway modules have been used to rewire carbon metabolisms in production strains and for the construction of cell-free enzymatic pathways. This review focuses on the differences of the ED and EMP pathways including their variations and discusses the use of alternative pathway strategies for in vivo and cell-free metabolic engineering.
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Affiliation(s)
- Dominik Kopp
- Department of Molecular Sciences, Macquarie University, Sydney, Australia
| | - Anwar Sunna
- Department of Molecular Sciences, Macquarie University, Sydney, Australia.,Biomolecular Discovery Research Centre, Macquarie University, Sydney, Australia
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11
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Zymomonas mobilis metabolism: Novel tools and targets for its rational engineering. Adv Microb Physiol 2020; 77:37-88. [PMID: 34756211 DOI: 10.1016/bs.ampbs.2020.08.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Zymomonas mobilis is an α-proteobacterium that interests the biofuel industry due to its perfect ethanol fermentation yields. From its first description as a bacterial isolate in fermented alcoholic beverages to date, Z. mobilis has been rigorously studied in directions basic and applied. The Z. mobilis powerful Entner-Doudoroff glycolytic pathway has been the center of rigorous biochemical studies and, aside from ethanol, it has attracted interest in terms of high-added-value chemical manufacturing. Energetic balances and the effects of respiration have been explored in fundamental directions as also in applications pursuing strain enhancement and the utilization of alternative carbon sources. Metabolic modeling has addressed the optimization of the biochemical circuitry at various conditions of growth and/or substrate utilization; it has been also critical in predicting desirable end-product yields via flux redirection. Lastly, stress tolerance has received particular attention, since it directly determines biocatalytical performance at challenging bioreactor conditions. At a genetic level, advances in the genetic engineering of the organism have brought forth beneficial manipulations in the Z. mobilis gene pool, e.g., knock-outs, knock-ins and gene stacking, aiming to broaden the metabolic repertoire and increase robustness. Recent omic and expressional studies shed light on the genomic content of the most applied strains and reveal landscapes of activity manifested at ambient or reactor-based conditions. Studies such as those reviewed in this work, contribute to the understanding of the biology of Z. mobilis, enable insightful strain development, and pave the way for the transformation of Z. mobilis into a consummate organism for biomass conversion.
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12
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Genome comparison of different Zymomonas mobilis strains provides insights on conservation of the evolution. PLoS One 2018; 13:e0195994. [PMID: 29694430 PMCID: PMC5919020 DOI: 10.1371/journal.pone.0195994] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 04/04/2018] [Indexed: 11/19/2022] Open
Abstract
Zymomonas mobilis has the special Entner-Doudoroff (ED) pathway and it has excellent industrial characteristics, including low cell mass formation, high-specific productivity,ethanol yield, notable ethanol tolerance and wide pH range, a relatively small genome size. In this study, the genome sequences of NRRL B-14023 and NRRL B-12526 were sequenced and compared with other strains to explore their evolutionary relationships and the genetic basis of Z. mobilis. The comparative genomic analyses revealed that the 8 strains share a conserved core chromosomal backbone. ZM4, NRRL B-12526, NRRL B-14023, NCIMB 11163 and NRRL B-1960 share 98% sequence identity across the whole genome sequences. Highly similar plasmids and CRISPR repeats were detected in these strains. A whole-genome phylogenetic tree of the 8 strains indicated that NRRL B-12526, NRRL B-14023 and ATCC 10988 had a close evolutionary relationship with the strain ZM4. Furthermore, strains ATCC29191 and ATCC29192 had distinctive CRISPR with a far distant relationship. The size of the pan-genome was 1945 genes, including 1428 core genes and 517 accessory genes. The genomes of Z. mobilis were highly conserved; particularly strains ZM4, NRRL B-12526, NRRL B-14023, NCIMB 11163 and NRRL B-1960 had a close genomic relationship. This comparative study of Z. mobilis presents a foundation for future functional analyses and applications.
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Stalidzans E, Seiman A, Peebo K, Komasilovs V, Pentjuss A. Model-based metabolism design: constraints for kinetic and stoichiometric models. Biochem Soc Trans 2018; 46:261-267. [PMID: 29472367 PMCID: PMC5906704 DOI: 10.1042/bst20170263] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 12/19/2017] [Accepted: 01/01/2018] [Indexed: 02/06/2023]
Abstract
The implementation of model-based designs in metabolic engineering and synthetic biology may fail. One of the reasons for this failure is that only a part of the real-world complexity is included in models. Still, some knowledge can be simplified and taken into account in the form of optimization constraints to improve the feasibility of model-based designs of metabolic pathways in organisms. Some constraints (mass balance, energy balance, and steady-state assumption) serve as a basis for many modelling approaches. There are others (total enzyme activity constraint and homeostatic constraint) proposed decades ago, but which are frequently ignored in design development. Several new approaches of cellular analysis have made possible the application of constraints like cell size, surface, and resource balance. Constraints for kinetic and stoichiometric models are grouped according to their applicability preconditions in (1) general constraints, (2) organism-level constraints, and (3) experiment-level constraints. General constraints are universal and are applicable for any system. Organism-level constraints are applicable for biological systems and usually are organism-specific, but these constraints can be applied without information about experimental conditions. To apply experimental-level constraints, peculiarities of the organism and the experimental set-up have to be taken into account to calculate the values of constraints. The limitations of applicability of particular constraints for kinetic and stoichiometric models are addressed.
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Affiliation(s)
- Egils Stalidzans
- Biosystems Group, Latvia University of Agriculture, Liela Iela 2, LV 3001 Jelgava, Latvia
| | - Andrus Seiman
- Center of Food and Fermentation Technologies, Akadeemia tee 15A, 12618 Tallinn, Estonia
| | - Karl Peebo
- Center of Food and Fermentation Technologies, Akadeemia tee 15A, 12618 Tallinn, Estonia
| | - Vitalijs Komasilovs
- Biosystems Group, Latvia University of Agriculture, Liela Iela 2, LV 3001 Jelgava, Latvia
| | - Agris Pentjuss
- Biosystems Group, Latvia University of Agriculture, Liela Iela 2, LV 3001 Jelgava, Latvia
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Wang X, He Q, Yang Y, Wang J, Haning K, Hu Y, Wu B, He M, Zhang Y, Bao J, Contreras LM, Yang S. Advances and prospects in metabolic engineering of Zymomonas mobilis. Metab Eng 2018; 50:57-73. [PMID: 29627506 DOI: 10.1016/j.ymben.2018.04.001] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 03/31/2018] [Accepted: 04/01/2018] [Indexed: 12/22/2022]
Abstract
Biorefinery of biomass-based biofuels and biochemicals by microorganisms is a competitive alternative of traditional petroleum refineries. Zymomonas mobilis is a natural ethanologen with many desirable characteristics, which makes it an ideal industrial microbial biocatalyst for commercial production of desirable bioproducts through metabolic engineering. In this review, we summarize the metabolic engineering progress achieved in Z. mobilis to expand its substrate and product ranges as well as to enhance its robustness against stressful conditions such as inhibitory compounds within the lignocellulosic hydrolysates and slurries. We also discuss a few metabolic engineering strategies that can be applied in Z. mobilis to further develop it as a robust workhorse for economic lignocellulosic bioproducts. In addition, we briefly review the progress of metabolic engineering in Z. mobilis related to the classical synthetic biology cycle of "Design-Build-Test-Learn", as well as the progress and potential to develop Z. mobilis as a model chassis for biorefinery practices in the synthetic biology era.
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Affiliation(s)
- Xia Wang
- Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Environmental Microbial Technology Center of Hubei Province, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan 430062, China.
| | - Qiaoning He
- Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Environmental Microbial Technology Center of Hubei Province, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan 430062, China.
| | - Yongfu Yang
- Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Environmental Microbial Technology Center of Hubei Province, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan 430062, China.
| | - Jingwen Wang
- Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Environmental Microbial Technology Center of Hubei Province, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan 430062, China.
| | - Katie Haning
- Institute for Cellular and Molecular Biology, Department of Chemical Engineering, Cockrell School of Engineering, University of Texas at Austin, Austin, TX, United States.
| | - Yun Hu
- Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Environmental Microbial Technology Center of Hubei Province, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan 430062, China.
| | - Bo Wu
- Key Laboratory of Development and Application of Rural Renewable Energy, Biomass Energy Technology Research Centre, Biogas Institute of Ministry of Agriculture, South Renmin Road, Chengdu 610041, China.
| | - Mingxiong He
- Key Laboratory of Development and Application of Rural Renewable Energy, Biomass Energy Technology Research Centre, Biogas Institute of Ministry of Agriculture, South Renmin Road, Chengdu 610041, China.
| | - Yaoping Zhang
- DOE-Great Lakes Bioenergy Research Center (GLBRC), University of Wisconsin-Madison, Madison, WI, United States.
| | - Jie Bao
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China.
| | - Lydia M Contreras
- Institute for Cellular and Molecular Biology, Department of Chemical Engineering, Cockrell School of Engineering, University of Texas at Austin, Austin, TX, United States.
| | - Shihui Yang
- Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Environmental Microbial Technology Center of Hubei Province, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan 430062, China.
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de Araújo LCA, de Cássia Dias Mendes T, Dos Santos BS, da Mota Silveira Filho V, de Souza Lima GM, de Araújo JM, Dos Santos Correia MT, de Oliveira MBM, Morais Júnior MA, da Silva MV. Molecular identification and physiological characterization of Zymomonas mobilis strains from fuel-ethanol production plants in north-east Brazil. Lett Appl Microbiol 2018; 67:54-63. [PMID: 29603295 DOI: 10.1111/lam.12888] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 03/15/2018] [Accepted: 03/16/2018] [Indexed: 11/28/2022]
Abstract
Zymomonas mobilis has long attracted attention owing to its capacity to ferment hexose to ethanol. From a taxonomic viewpoint, Z. mobilis is a unique species of the genus Zymomonas, separated into three subspecies, Z. mobilis subsp. mobilis, Z. mobilis subsp. pomaceae and Z. mobilis subsp. francensis on the basis of physiological tests, which are often unreliable owing to the genetic proximity among these species. Currently, the use of molecular techniques is more appropriate for identification of these bacterial subspecies. In this study, the 32 strains of Z. mobilis present in the UFPEDA bacterial collection were characterized using molecular techniques, such as sequencing of the 16S rDNA gene and its theoretical restriction profile, classifying them as members of the subspecies, Z. mobilis subsp. mobilis. In addition, anaerobic cultivations were performed, which showed the biological diversity of the strains in terms of growth, sugar consumption and ethanol production. From these results, it was possible to identify the strain Z-2-80 as a promising bacterium for use in the fermentation process. SIGNIFICANCE AND IMPACT OF THE STUDY Zymomonas mobilis is a bacterium of great relevance to biotechnology, owing to its capacity to ferment hexose to ethanol. On a molecular basis, 32 isolates were identified as Z. mobilis subsp. mobilis. However, intraspecific diversity was identified when these were grown under strictly anaerobic conditions. The results obtained from this study suggest a strain of Z. mobilis as an alternative for use in the fermentation process.
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Affiliation(s)
- L C A de Araújo
- Department of Biochemistry, Federal University of Pernambuco, Recife, Brazil
| | | | - B S Dos Santos
- Department of Biochemistry, Federal University of Pernambuco, Recife, Brazil
| | | | - G M de Souza Lima
- Department of Antibiotics, Federal University of Pernambuco, Recife, Brazil
| | - J M de Araújo
- Department of Antibiotics, Federal University of Pernambuco, Recife, Brazil
| | | | - M B M de Oliveira
- Department of Biochemistry, Federal University of Pernambuco, Recife, Brazil
| | - M A Morais Júnior
- Department of Genetics, Federal University of Pernambuco, Recife, Brazil
| | - M V da Silva
- Department of Biochemistry, Federal University of Pernambuco, Recife, Brazil
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Yang Y, Hu M, Tang Y, Geng B, Qiu M, He Q, Chen S, Wang X, Yang S. Progress and perspective on lignocellulosic hydrolysate inhibitor tolerance improvement in Zymomonas mobilis. BIORESOUR BIOPROCESS 2018. [DOI: 10.1186/s40643-018-0193-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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17
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Komasilovs V, Pentjuss A, Elsts A, Stalidzans E. Total enzyme activity constraint and homeostatic constraint impact on the optimization potential of a kinetic model. Biosystems 2017; 162:128-134. [PMID: 28965873 DOI: 10.1016/j.biosystems.2017.09.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 09/11/2017] [Accepted: 09/26/2017] [Indexed: 12/26/2022]
Abstract
The application of biologically and biochemically relevant constraints during the optimization of kinetic models reduces the impact of suggested changes in processes not included in the scope of the model. This increases the probability that the design suggested by model optimization can be carried out by an organism after implementation of design in vivo. A case study was carried out to determine the impact of total enzyme activity and homeostatic constraints on the objective function values and the following ranking of adjustable parameter combinations. The application of constraints on the model of sugar cane metabolism revealed that a homeostatic constraint caused heavier limitations of the objective function than a total enzyme activity constraint. Both constraints changed the ranking of adjustable parameter combinations: no "universal" constraint-independent top-ranked combinations were found. Therefore, when searching for the best subset of adjustable parameters, a full scan of their combinations is suggested for a small number of adjustable parameters, and evolutionary search strategies are suggested for a large number. Simultaneous application of both constraints is suggested.
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Affiliation(s)
- Vitalijs Komasilovs
- Biosystems Group, Department of Computer Systems, Latvia University of Agriculture, Liela iela 2, LV-3001 Jelgava, Latvia.
| | - Agris Pentjuss
- Biosystems Group, Department of Computer Systems, Latvia University of Agriculture, Liela iela 2, LV-3001 Jelgava, Latvia
| | - Atis Elsts
- Department of Electrical and Electronic Engineering, University of Bristol, Bristol, BS8 1UB, UK
| | - Egils Stalidzans
- Biosystems Group, Department of Computer Systems, Latvia University of Agriculture, Liela iela 2, LV-3001 Jelgava, Latvia
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18
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Pentjuss A, Stalidzans E, Liepins J, Kokina A, Martynova J, Zikmanis P, Mozga I, Scherbaka R, Hartman H, Poolman MG, Fell DA, Vigants A. Model-based biotechnological potential analysis of Kluyveromyces marxianus central metabolism. J Ind Microbiol Biotechnol 2017; 44:1177-1190. [PMID: 28444480 DOI: 10.1007/s10295-017-1946-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Accepted: 04/16/2017] [Indexed: 12/11/2022]
Abstract
The non-conventional yeast Kluyveromyces marxianus is an emerging industrial producer for many biotechnological processes. Here, we show the application of a biomass-linked stoichiometric model of central metabolism that is experimentally validated, and mass and charge balanced for assessing the carbon conversion efficiency of wild type and modified K. marxianus. Pairs of substrates (lactose, glucose, inulin, xylose) and products (ethanol, acetate, lactate, glycerol, ethyl acetate, succinate, glutamate, phenylethanol and phenylalanine) are examined by various modelling and optimisation methods. Our model reveals the organism's potential for industrial application and metabolic engineering. Modelling results imply that the aeration regime can be used as a tool to optimise product yield and flux distribution in K. marxianus. Also rebalancing NADH and NADPH utilisation can be used to improve the efficiency of substrate conversion. Xylose is identified as a biotechnologically promising substrate for K. marxianus.
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Affiliation(s)
- A Pentjuss
- Institute of Microbiology and Biotechnology, University of Latvia, Jelgavas str. 1, Riga, 1004, Latvia
| | - E Stalidzans
- Institute of Microbiology and Biotechnology, University of Latvia, Jelgavas str. 1, Riga, 1004, Latvia.
| | - J Liepins
- Institute of Microbiology and Biotechnology, University of Latvia, Jelgavas str. 1, Riga, 1004, Latvia
| | - A Kokina
- Institute of Microbiology and Biotechnology, University of Latvia, Jelgavas str. 1, Riga, 1004, Latvia
| | - J Martynova
- Institute of Microbiology and Biotechnology, University of Latvia, Jelgavas str. 1, Riga, 1004, Latvia
| | - P Zikmanis
- Institute of Microbiology and Biotechnology, University of Latvia, Jelgavas str. 1, Riga, 1004, Latvia
| | - I Mozga
- Institute of Microbiology and Biotechnology, University of Latvia, Jelgavas str. 1, Riga, 1004, Latvia
| | - R Scherbaka
- Institute of Microbiology and Biotechnology, University of Latvia, Jelgavas str. 1, Riga, 1004, Latvia
| | - H Hartman
- Department of Biological and Medical Sciences, Oxford Brookes University, Headington, OX, OX3 0BP, UK
| | - M G Poolman
- Department of Biological and Medical Sciences, Oxford Brookes University, Headington, OX, OX3 0BP, UK
| | - D A Fell
- Department of Biological and Medical Sciences, Oxford Brookes University, Headington, OX, OX3 0BP, UK
| | - A Vigants
- Institute of Microbiology and Biotechnology, University of Latvia, Jelgavas str. 1, Riga, 1004, Latvia
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19
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Ajit A, Sulaiman AZ, Chisti Y. Production of bioethanol by Zymomonas mobilis in high-gravity extractive fermentations. FOOD AND BIOPRODUCTS PROCESSING 2017. [DOI: 10.1016/j.fbp.2016.12.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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20
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Duwe A, Tippkötter N, Ulber R. Lignocellulose-Biorefinery: Ethanol-Focused. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2017; 166:177-215. [PMID: 29071401 DOI: 10.1007/10_2016_72] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The development prospects of the world markets for petroleum and other liquid fuels are diverse and partly contradictory. However, comprehensive changes for the energy supply of the future are essential. Notwithstanding the fact that there are still very large deposits of energy resources from a geological point of view, the finite nature of conventional oil reserves is indisputable. To reduce our dependence on oil, the EU, the USA, and other major economic zones rely on energy diversification. For this purpose, alternative materials and technologies are being sought, and is most obvious in the transport sector. The objective is to progressively replace fossil fuels with renewable and more sustainable fuels. In this respect, biofuels have a pre-eminent position in terms of their capability of blending with fossil fuels and being usable in existing cars without substantial modification. Ethanol can be considered as the primary renewable liquid fuel. In this chapter enzymes, micro-organisms, and processes for ethanol production based on renewable resources are described.
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Affiliation(s)
- A Duwe
- Institute of Bioprocess Engineering, University of Kaiserslautern, Gottlieb-Daimler-Str. 49, 67663, Kaiserslautern, Germany.
| | - N Tippkötter
- Institute of Bioprocess Engineering, University of Kaiserslautern, Gottlieb-Daimler-Str. 49, 67663, Kaiserslautern, Germany
| | - R Ulber
- Institute of Bioprocess Engineering, University of Kaiserslautern, Gottlieb-Daimler-Str. 49, 67663, Kaiserslautern, Germany
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21
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Yang S, Fei Q, Zhang Y, Contreras LM, Utturkar SM, Brown SD, Himmel ME, Zhang M. Zymomonas mobilis as a model system for production of biofuels and biochemicals. Microb Biotechnol 2016; 9:699-717. [PMID: 27629544 PMCID: PMC5072187 DOI: 10.1111/1751-7915.12408] [Citation(s) in RCA: 98] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 08/03/2016] [Accepted: 08/05/2016] [Indexed: 12/04/2022] Open
Abstract
Zymomonas mobilis is a natural ethanologen with many desirable industrial biocatalyst characteristics. In this review, we will discuss work to develop Z. mobilis as a model system for biofuel production from the perspectives of substrate utilization, development for industrial robustness, potential product spectrum, strain evaluation and fermentation strategies. This review also encompasses perspectives related to classical genetic tools and emerging technologies in this context.
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Affiliation(s)
- Shihui Yang
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA. .,Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan, 430062, China.
| | - Qiang Fei
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA.,School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Yaoping Zhang
- Great Lakes Bioenergy Research Center, Wisconsin Energy Institute, University of Wisconsin, Madison, WI, 53726, USA
| | - Lydia M Contreras
- McKetta Department of Chemical Engineering, University of Texas, Austin, TX, 78712, USA
| | - Sagar M Utturkar
- Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, TN, 37919, USA
| | - Steven D Brown
- Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, TN, 37919, USA.,BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.,Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Michael E Himmel
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Min Zhang
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA.
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22
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Yang S, Mohagheghi A, Franden MA, Chou YC, Chen X, Dowe N, Himmel ME, Zhang M. Metabolic engineering of Zymomonas mobilis for 2,3-butanediol production from lignocellulosic biomass sugars. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:189. [PMID: 27594916 PMCID: PMC5010730 DOI: 10.1186/s13068-016-0606-y] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 08/26/2016] [Indexed: 05/18/2023]
Abstract
BACKGROUND To develop pathways for advanced biofuel production, and to understand the impact of host metabolism and environmental conditions on heterologous pathway engineering for economic advanced biofuels production from biomass, we seek to redirect the carbon flow of the model ethanologen Zymomonas mobilis to produce desirable hydrocarbon intermediate 2,3-butanediol (2,3-BDO). 2,3-BDO is a bulk chemical building block, and can be upgraded in high yields to gasoline, diesel, and jet fuel. RESULTS 2,3-BDO biosynthesis pathways from various bacterial species were examined, which include three genes encoding acetolactate synthase, acetolactate decarboxylase, and butanediol dehydrogenase. Bioinformatics analysis was carried out to pinpoint potential bottlenecks for high 2,3-BDO production. Different combinations of 2,3-BDO biosynthesis metabolic pathways using genes from different bacterial species have been constructed. Our results demonstrated that carbon flux can be deviated from ethanol production into 2,3-BDO biosynthesis, and all three heterologous genes are essential to efficiently redirect pyruvate from ethanol production for high 2,3-BDO production in Z. mobilis. The down-selection of best gene combinations up to now enabled Z. mobilis to reach the 2,3-BDO production of more than 10 g/L from glucose and xylose, as well as mixed C6/C5 sugar streams derived from the deacetylation and mechanical refining process. CONCLUSIONS This study confirms the value of integrating bioinformatics analysis and systems biology data during metabolic engineering endeavors, provides guidance for value-added chemical production in Z. mobilis, and reveals the interactions between host metabolism, oxygen levels, and a heterologous 2,3-BDO biosynthesis pathway. Taken together, this work provides guidance for future metabolic engineering efforts aimed at boosting 2,3-BDO titer anaerobically.
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Affiliation(s)
- Shihui Yang
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, 80401 USA
- Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Ali Mohagheghi
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, 80401 USA
| | - Mary Ann Franden
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, 80401 USA
| | - Yat-Chen Chou
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, 80401 USA
| | - Xiaowen Chen
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, 80401 USA
| | - Nancy Dowe
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, 80401 USA
| | - Michael E. Himmel
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Min Zhang
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, 80401 USA
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23
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Motamedian E, Saeidi M, Shojaosadati SA. Reconstruction of a charge balanced genome-scale metabolic model to study the energy-uncoupled growth of Zymomonas mobilis ZM1. MOLECULAR BIOSYSTEMS 2016; 12:1241-9. [DOI: 10.1039/c5mb00588d] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Zymomonas mobilisis an ethanologenic bacterium and is known to be an example microorganism with energy-uncoupled growth. The reconstructed metabolic model indicate that resistance to intracellular pH reduction could be the main reason for uncoupled growth.
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Affiliation(s)
- E. Motamedian
- Biotechnology Group
- Chemical Engineering Department
- Tarbiat Modares University
- Tehran
- Iran
| | - M. Saeidi
- Biotechnology Group
- Chemical Engineering Department
- Tarbiat Modares University
- Tehran
- Iran
| | - S. A. Shojaosadati
- Biotechnology Group
- Chemical Engineering Department
- Tarbiat Modares University
- Tehran
- Iran
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24
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Simas-Rodrigues C, Villela HDM, Martins AP, Marques LG, Colepicolo P, Tonon AP. Microalgae for economic applications: advantages and perspectives for bioethanol. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:4097-108. [PMID: 25873683 DOI: 10.1093/jxb/erv130] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Renewable energy has attracted significant interest in recent years as a result of sustainability, environmental impact, and socio-economic considerations. Given existing technological knowledge and based on projections relating to biofuels derived from microalgae, microalgal feedstock is considered to be one of the most important renewable energy sources potentially available for industrial production. Therefore, this review examines microalgal bioethanol technology, which converts biomass from microalgae to fuel, the chemical processes involved, and possible ways of increasing the bioethanol yield, such as abiotic factors and genetic manipulation of fermenting organisms.
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Affiliation(s)
- Cíntia Simas-Rodrigues
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, Av. Professor Lineu Prestes, 748, 05508-000, São Paulo, Brazil
| | - Helena D M Villela
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, Av. Professor Lineu Prestes, 748, 05508-000, São Paulo, Brazil
| | - Aline P Martins
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, Av. Professor Lineu Prestes, 748, 05508-000, São Paulo, Brazil
| | - Luiza G Marques
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, Av. Professor Lineu Prestes, 748, 05508-000, São Paulo, Brazil
| | - Pio Colepicolo
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, Av. Professor Lineu Prestes, 748, 05508-000, São Paulo, Brazil
| | - Angela P Tonon
- Los Alamos National Laboratory, Bioscience Division, PO Box M888, Los Alamos, NM 87545, USA
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Ng CY, Farasat I, Maranas CD, Salis HM. Rational design of a synthetic Entner-Doudoroff pathway for improved and controllable NADPH regeneration. Metab Eng 2015; 29:86-96. [PMID: 25769287 DOI: 10.1016/j.ymben.2015.03.001] [Citation(s) in RCA: 118] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Revised: 02/06/2015] [Accepted: 03/02/2015] [Indexed: 01/15/2023]
Abstract
NADPH is an essential cofactor for the biosynthesis of several high-value chemicals, including isoprenoids, fatty acid-based fuels, and biopolymers. Tunable control over all potentially rate-limiting steps, including the NADPH regeneration rate, is crucial to maximizing production titers. We have rationally engineered a synthetic version of the Entner-Doudoroff pathway from Zymomonas mobilis that increased the NADPH regeneration rate in Escherichia coli MG1655 by 25-fold. To do this, we combined systematic design rules, biophysical models, and computational optimization to design synthetic bacterial operons expressing the 5-enzyme pathway, while eliminating undesired genetic elements for maximum expression control. NADPH regeneration rates from genome-integrated pathways were estimated using a NADPH-binding fluorescent reporter and by the productivity of a NADPH-dependent terpenoid biosynthesis pathway. We designed and constructed improved pathway variants by employing the RBS Library Calculator to efficiently search the 5-dimensional enzyme expression space and by performing 40 cycles of MAGE for site-directed genome mutagenesis. 624 pathway variants were screened using a NADPH-dependent blue fluorescent protein, and 22 were further characterized to determine the relationship between enzyme expression levels and NADPH regeneration rates. The best variant exhibited 25-fold higher normalized mBFP levels when compared to wild-type strain. Combining the synthetic Entner-Doudoroff pathway with an optimized terpenoid pathway further increased the terpenoid titer by 97%.
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Affiliation(s)
- Chiam Yu Ng
- Department of Chemical Engineering, Pennsylvania State University, University Park, PA 16802, United States
| | - Iman Farasat
- Department of Chemical Engineering, Pennsylvania State University, University Park, PA 16802, United States
| | - Costas D Maranas
- Department of Chemical Engineering, Pennsylvania State University, University Park, PA 16802, United States
| | - Howard M Salis
- Department of Chemical Engineering, Pennsylvania State University, University Park, PA 16802, United States; Department of Biological Engineering, Pennsylvania State University, University Park, PA 16802, United States.
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