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Duperray M, Delvenne M, François JM, Delvigne F, Capp JP. Genomic and metabolic instability during long-term fermentation of an industrial Saccharomyces cerevisiae strain engineered for C5 sugar utilization. Front Bioeng Biotechnol 2024; 12:1357671. [PMID: 38595997 PMCID: PMC11002265 DOI: 10.3389/fbioe.2024.1357671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 03/07/2024] [Indexed: 04/11/2024] Open
Abstract
The genetic stability and metabolic robustness of production strains is one of the key criteria for the production of bio-based products by microbial fermentation on an industrial scale. These criteria were here explored in an industrial ethanol-producer strain of Saccharomyces cerevisiae able to co-ferment D-xylose and L-arabinose with glucose through the chromosomal integration of several copies of pivotal genes for the use of these pentose (C5) sugars. Using batch sequential cultures in a controlled bioreactor that mimics long-term fermentation in an industrial setting, this strain was found to exhibit significant fluctuations in D-xylose and L-arabinose consumption as early as the 50th generation and beyond. These fluctuations seem not related to the few low-consumption C5 sugar clones that appeared throughout the sequential batch cultures at a frequency lower than 1.5% and that were due to the reduction in the number of copies of transgenes coding for C5 sugar assimilation enzymes. Also, subpopulations enriched with low or high RAD52 expression, whose expression level was reported to be proportional to homologous recombination rate did not exhibit defect in C5-sugar assimilation, arguing that other mechanisms may be responsible for copy number variation of transgenes. Overall, this work highlighted the existence of genetic and metabolic instabilities in an industrial yeast which, although modest in our conditions, could be more deleterious in harsher industrial conditions, leading to reduced production performance.
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Affiliation(s)
- Maëlle Duperray
- Toulouse Biotechnology Institute, INSA/University of Toulouse, CNRS, INRAE, Toulouse, France
| | - Mathéo Delvenne
- TERRA Research and Teaching Centre, Microbial Processes and Interactions (MiPI), Gembloux Agro-Bio Tech, University of Liège, Gembloux, Belgium
| | - Jean Marie François
- Toulouse Biotechnology Institute, INSA/University of Toulouse, CNRS, INRAE, Toulouse, France
- Toulouse White Biotechnology, INSA, INRAE, CNRS, Toulouse, France
| | - Frank Delvigne
- TERRA Research and Teaching Centre, Microbial Processes and Interactions (MiPI), Gembloux Agro-Bio Tech, University of Liège, Gembloux, Belgium
| | - Jean-Pascal Capp
- Toulouse Biotechnology Institute, INSA/University of Toulouse, CNRS, INRAE, Toulouse, France
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2
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Hu KKY, Suri A, Dumsday G, Haritos VS. Cross-feeding promotes heterogeneity within yeast cell populations. Nat Commun 2024; 15:418. [PMID: 38200012 PMCID: PMC10781747 DOI: 10.1038/s41467-023-44623-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Accepted: 12/20/2023] [Indexed: 01/12/2024] Open
Abstract
Cellular heterogeneity in cell populations of isogenic origin is driven by intrinsic factors such as stochastic gene expression, as well as external factors like nutrient availability and interactions with neighbouring cells. Heterogeneity promotes population fitness and thus has important implications in antimicrobial and anticancer treatments, where stress tolerance plays a significant role. Here, we study plasmid retention dynamics within a population of plasmid-complemented ura3∆0 yeast cells, and show that the exchange of complementary metabolites between plasmid-carrying prototrophs and plasmid-free auxotrophs allows the latter to survive and proliferate in selective environments. This process also affects plasmid copy number in plasmid-carrying prototrophs, further promoting cellular functional heterogeneity. Finally, we show that targeted genetic engineering can be used to suppress cross-feeding and reduce the frequency of plasmid-free auxotrophs, or to exploit it for intentional population diversification and division of labour in co-culture systems.
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Affiliation(s)
- Kevin K Y Hu
- Department of Chemical and Biological Engineering, Monash University, Clayton, VIC, 3800, Australia
| | - Ankita Suri
- Department of Chemical and Biological Engineering, Monash University, Clayton, VIC, 3800, Australia
| | - Geoff Dumsday
- Commonwealth Scientific and Industrial Research Organisation, Clayton, VIC, 3169, Australia
| | - Victoria S Haritos
- Department of Chemical and Biological Engineering, Monash University, Clayton, VIC, 3800, Australia.
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3
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Tavares LF, Ribeiro NV, Zocca VFB, Corrêa GG, Amorim LAS, Lins MRCR, Pedrolli DB. Preventing Production Escape Using an Engineered Glucose-Inducible Genetic Circuit. ACS Synth Biol 2023; 12:3124-3130. [PMID: 37772403 DOI: 10.1021/acssynbio.3c00134] [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: 09/30/2023]
Abstract
A proper balance of metabolic pathways is crucial for engineering microbial strains that can efficiently produce biochemicals on an industrial scale while maintaining cell fitness. High production loads can negatively impact cell fitness and hinder industrial-scale production. To address this, fine-tuning gene expression using engineered promoters and genetic circuits can promote control over multiple targets in pathways and reduce the burden. We took advantage of the robust carbon catabolite repression system of Bacillus subtilis to engineer a glucose-inducible genetic circuit that supports growth and production. The circuit is resilient, enabling a quick switch in the production status when exposed to the correct carbon source. By performing serial cultivations for 61 generations under repressive conditions, we preserved the production capacity of the cells, which could be fully accessed by switching to glucose in the next cultivation step. Switching to glucose after 61 generations resulted in 34-fold activation and generated 70% higher production in comparison to standard cultivation in glucose. Conversely, serial cultivation under permanent induction resulted in 62% production loss after 67 generations alongside an increase in the culture growth rate. As a pathway-independent circuit activated by the preferred carbon source, our engineered glucose-inducible genetic circuit is broadly useful and imposes no additional cost to traditional production processes.
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Affiliation(s)
- Leonardo F Tavares
- Universidade Estadual Paulista (UNESP), School of Pharmaceutical Sciences, Department of Bioprocess Engineering and Biotechnology, Araraquara, 14800-903, Brazil
| | - Nathan V Ribeiro
- Universidade Estadual Paulista (UNESP), School of Pharmaceutical Sciences, Department of Bioprocess Engineering and Biotechnology, Araraquara, 14800-903, Brazil
| | - Vitória F B Zocca
- Universidade Estadual Paulista (UNESP), School of Pharmaceutical Sciences, Department of Bioprocess Engineering and Biotechnology, Araraquara, 14800-903, Brazil
| | - Graciely G Corrêa
- Universidade Estadual Paulista (UNESP), School of Pharmaceutical Sciences, Department of Bioprocess Engineering and Biotechnology, Araraquara, 14800-903, Brazil
| | - Laura A S Amorim
- Universidade Estadual Paulista (UNESP), School of Pharmaceutical Sciences, Department of Bioprocess Engineering and Biotechnology, Araraquara, 14800-903, Brazil
| | - Milca R C R Lins
- Federal University of ABC (UFABC), Center for Natural and Human Sciences, Campus Santo André, 09210-580, Brazil
| | - Danielle B Pedrolli
- Universidade Estadual Paulista (UNESP), School of Pharmaceutical Sciences, Department of Bioprocess Engineering and Biotechnology, Araraquara, 14800-903, Brazil
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Mu X, Zhang F. Diverse mechanisms of bioproduction heterogeneity in fermentation and their control strategies. J Ind Microbiol Biotechnol 2023; 50:kuad033. [PMID: 37791393 PMCID: PMC10583207 DOI: 10.1093/jimb/kuad033] [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: 06/17/2023] [Accepted: 09/28/2023] [Indexed: 10/05/2023]
Abstract
Microbial bioproduction often faces challenges related to populational heterogeneity, where cells exhibit varying biosynthesis capabilities. Bioproduction heterogeneity can stem from genetic and non-genetic factors, resulting in decreased titer, yield, stability, and reproducibility. Consequently, understanding and controlling bioproduction heterogeneity are crucial for enhancing the economic competitiveness of large-scale biomanufacturing. In this review, we provide a comprehensive overview of current understandings of the various mechanisms underlying bioproduction heterogeneity. Additionally, we examine common strategies for controlling bioproduction heterogeneity based on these mechanisms. By implementing more robust measures to mitigate heterogeneity, we anticipate substantial enhancements in the scalability and stability of bioproduction processes. ONE-SENTENCE SUMMARY This review summarizes current understandings of different mechanisms of bioproduction heterogeneity and common control strategies based on these mechanisms.
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Affiliation(s)
- Xinyue Mu
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Fuzhong Zhang
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
- Division of Biological & Biomedical Sciences, Washington University in St. Louis, St. Louis, MO 63130, USA
- Institute of Materials Science & Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
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5
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Allen JR, Torres-Acosta MA, Mohan N, Lye GJ, Ward JM. Segregationally stabilised plasmids improve production of commodity chemicals in glucose-limited continuous fermentation. Microb Cell Fact 2022; 21:229. [PMID: 36329510 PMCID: PMC9632041 DOI: 10.1186/s12934-022-01958-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 10/24/2022] [Indexed: 11/05/2022] Open
Abstract
Background The production of chemicals via bio-based routes is held back by limited easy-to-use stabilisation systems. A wide range of plasmid stabilisation mechanisms can be found in the literature, however, how these mechanisms effect genetic stability and how host strains still revert to non-productive variants is poorly understood at the single-cell level. This phenomenon can generate difficulties in production-scale bioreactors as different populations of productive and non-productive cells can arise. To understand how to prevent non-productive strains from arising, it is vital to understand strain behaviour at a single-cell level. The persistence of genes located on plasmid vectors is dependent on numerous factors but can be broadly separated into structural stability and segregational stability. While structural stability refers to the capability of a cell to resist genetic mutations that bring about a loss of gene function in a production pathway, segregational stability refers to the capability of a cell to correctly distribute plasmids into daughter cells to maintain copy number. A lack of segregational stability can rapidly generate plasmid-free variants during replication, which compromises productivity. Results Citramalate synthase expression was linked in an operon to the expression of a fluorescent reporter to enable rapid screening of the retention of a model chemical synthesis pathway in a continuous fermentation of E. coli. Cells without additional plasmid stabilisation started to lose productivity immediately after entering the continuous phase. Inclusion of a multimer resolution site, cer, enabled a steady-state production period of 58 h before a drop in productivity was detected. Single-cell fluorescence measurements showed that plasmid-free variants arose rapidly without cer stabilisation and that this was likely due to unequal distribution of plasmid into daughter cells during cell division. The addition of cer increased total chemical yield by more than 50%. Conclusions This study shows the potential remains high for plasmids to be used as pathway vectors in industrial bio-based chemicals production, providing they are correctly stabilised. We demonstrate the need for accessible bacterial ‘toolkits’ to enable rapid production of known, stabilised bacterial production strains to enable continuous fermentation at scale for the chemicals industry. Supplementary Information The online version contains supplementary material available at 10.1186/s12934-022-01958-3.
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Muratovska N, Silva P, Pozdniakova T, Pereira H, Grey C, Johansson B, Carlquist M. Towards engineered yeast as production platform for capsaicinoids. Biotechnol Adv 2022; 59:107989. [PMID: 35623491 DOI: 10.1016/j.biotechadv.2022.107989] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 05/17/2022] [Accepted: 05/18/2022] [Indexed: 12/23/2022]
Abstract
Capsaicinoids are bioactive alkaloids produced by the chili pepper fruit and are known to be the most potent agonists of the human pain receptor TRPV1 (Transient Receptor Potential Cation Channel Subfamily V Member 1). They are currently produced by extraction from chili pepper fruit or by chemical synthesis. Transfer of the biosynthetic route to a microbial host could enable more efficient capsaicinoid production by fermentation and may also enable the use of synthetic biology to create a diversity of new compounds with potentially improved properties. This review summarises the current state of the art on the biosynthesis of capsaicinoid precursors in baker's yeast, Saccharomyces cerevisiae, and discusses bioengineering strategies for achieving total synthesis from sugar.
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Affiliation(s)
- Nina Muratovska
- Division of Applied Microbiology, Lund University, Box 124, 221 00 Lund, Sweden
| | - Paulo Silva
- CBMA - Center of Molecular and Environmental Biology Engineering, University of Minho, Campus de Gualtar, Braga 4710-057, Portugal
| | - Tatiana Pozdniakova
- CBMA - Center of Molecular and Environmental Biology Engineering, University of Minho, Campus de Gualtar, Braga 4710-057, Portugal
| | - Humberto Pereira
- CBMA - Center of Molecular and Environmental Biology Engineering, University of Minho, Campus de Gualtar, Braga 4710-057, Portugal
| | - Carl Grey
- Division of Biotechnology, Lund University, Box 118, SE-221 00 Lund, Sweden
| | - Björn Johansson
- CBMA - Center of Molecular and Environmental Biology Engineering, University of Minho, Campus de Gualtar, Braga 4710-057, Portugal.
| | - Magnus Carlquist
- Division of Applied Microbiology, Lund University, Box 124, 221 00 Lund, Sweden.
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7
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Kastberg LLB, Ard R, Jensen MK, Workman CT. Burden Imposed by Heterologous Protein Production in Two Major Industrial Yeast Cell Factories: Identifying Sources and Mitigation Strategies. FRONTIERS IN FUNGAL BIOLOGY 2022; 3:827704. [PMID: 37746199 PMCID: PMC10512257 DOI: 10.3389/ffunb.2022.827704] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 01/10/2022] [Indexed: 09/26/2023]
Abstract
Production of heterologous proteins, especially biopharmaceuticals and industrial enzymes, in living cell factories consumes cellular resources. Such resources are reallocated from normal cellular processes toward production of the heterologous protein that is often of no benefit to the host cell. This competition for resources is a burden to host cells, has a negative impact on cell fitness, and may consequently trigger stress responses. Importantly, this often causes a reduction in final protein titers. Engineering strategies to generate more burden resilient production strains offer sustainable opportunities to increase production and profitability for this growing billion-dollar global industry. We review recently reported impacts of burden derived from resource competition in two commonly used protein-producing yeast cell factories: Saccharomyces cerevisiae and Komagataella phaffii (syn. Pichia pastoris). We dissect possible sources of burden in these organisms, from aspects related to genetic engineering to protein translation and export of soluble protein. We also summarize advances as well as challenges for cell factory design to mitigate burden and increase overall heterologous protein production from metabolic engineering, systems biology, and synthetic biology perspectives. Lastly, future profiling and engineering strategies are highlighted that may lead to constructing robust burden-resistant cell factories. This includes incorporation of systems-level data into mathematical models for rational design and engineering dynamical regulation circuits in production strains.
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Affiliation(s)
| | - Ryan Ard
- Department of Biology, University of British Columbia, Kelowna, BC, Canada
| | - Michael Krogh Jensen
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, Denmark
| | - Christopher T. Workman
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
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8
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Ma Q, Liu L, Zhao S, Huang Z, Li C, Jiang S, Li Q, Gu P. Biosynthesis of vanillin by different microorganisms: a review. World J Microbiol Biotechnol 2022; 38:40. [PMID: 35018518 DOI: 10.1007/s11274-022-03228-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 01/02/2022] [Indexed: 02/06/2023]
Abstract
Vanillin is a popular flavoring agent widely used around the world. Vanillin is generated by natural extraction, chemical synthesis, or tissue culture technology, but these production methods no longer meet the increasing worldwide demand for vanillin. Accordingly, a biotechnological approach may provide an effective replacement route to obtaining vanillin. Processes for environmentally friendly production of vanillin in microorganisms from different carbon sources, such as eugenol, isoeugenol, lignin, ferulic acid, sugars, and waste residues, with high productivity and yield have been developed. However, challenges remain for optimizing the vanillin biosynthesis process and further improving production titer and yield. In this review, successful and applicable strategies for increasing vanillin titer and yield in different microorganisms are summarized. Additionally, perspectives for further optimizing the production of vanillin are discussed.
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Affiliation(s)
- Qianqian Ma
- School of Biological Science and Technology, University of Jinan, Jinan, 250022, People's Republic of China
| | - Liwen Liu
- School of Biological Science and Technology, University of Jinan, Jinan, 250022, People's Republic of China
| | - Shuo Zhao
- School of Biological Science and Technology, University of Jinan, Jinan, 250022, People's Republic of China
| | - Zhaosong Huang
- School of Biological Science and Technology, University of Jinan, Jinan, 250022, People's Republic of China
| | - Changtao Li
- RZBC GROUP CO., LTD., Rizhao, 276800, Shandong, People's Republic of China
| | - Shuixing Jiang
- RZBC GROUP CO., LTD., Rizhao, 276800, Shandong, People's Republic of China
| | - Qiang Li
- School of Biological Science and Technology, University of Jinan, Jinan, 250022, People's Republic of China
| | - Pengfei Gu
- School of Biological Science and Technology, University of Jinan, Jinan, 250022, People's Republic of China.
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9
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Lee SW, Rugbjerg P, Sommer MOA. Exploring Selective Pressure Trade-Offs for Synthetic Addiction to Extend Metabolite Productive Lifetimes in Yeast. ACS Synth Biol 2021; 10:2842-2849. [PMID: 34699715 DOI: 10.1021/acssynbio.1c00240] [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: 11/28/2022]
Abstract
Engineered microbes often suffer from reduced fitness resulting from metabolic burden and various stresses. The productive lifetime of a bioreactor with engineered microbes is therefore susceptible to the rise of nonproductive mutants with better fitness. Synthetic addiction is emerging as a concept to artificially couple the growth rate of the microbe to production to tackle this problem. However, only a few successful cases of synthetic addiction systems have been reported to date. To understand the limitations and design constraints in long-term cultivations, we designed and studied conditional synthetic addiction circuits in Saccharomyces cerevisiae. This allowed us to probe a range of selective pressure strengths and identify the optimal balance between circuit stability and production-to-growth coupling. In the optimal balance, the productive lifetime was greatly extended compared with suboptimal circuit tuning. With a too-high or -low pressure, we found that production declines mainly through homologous recombination. These principles of trade-off in the design of synthetic addition systems should lead to the better control of bioprocess performance.
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Affiliation(s)
- Sang-Woo Lee
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Peter Rugbjerg
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
- Enduro Genetics ApS, 2200 Copenhagen, Denmark
| | - Morten Otto Alexander Sommer
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
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10
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Jensen ED, Ambri F, Bendtsen MB, Javanpour AA, Liu CC, Jensen MK, Keasling JD. Integrating continuous hypermutation with high-throughput screening for optimization of cis,cis-muconic acid production in yeast. Microb Biotechnol 2021; 14:2617-2626. [PMID: 33645919 PMCID: PMC8601171 DOI: 10.1111/1751-7915.13774] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 01/31/2021] [Accepted: 02/02/2021] [Indexed: 12/16/2022] Open
Abstract
Directed evolution is a powerful method to optimize proteins and metabolic reactions towards user-defined goals. It usually involves subjecting genes or pathways to iterative rounds of mutagenesis, selection and amplification. While powerful, systematic searches through large sequence-spaces is a labour-intensive task, and can be further limited by a priori knowledge about the optimal initial search space, and/or limits in terms of screening throughput. Here, we demonstrate an integrated directed evolution workflow for metabolic pathway enzymes that continuously generate enzyme variants using the recently developed orthogonal replication system, OrthoRep and screens for optimal performance in high-throughput using a transcription factor-based biosensor. We demonstrate the strengths of this workflow by evolving a rate-limiting enzymatic reaction of the biosynthetic pathway for cis,cis-muconic acid (CCM), a precursor used for bioplastic and coatings, in Saccharomyces cerevisiae. After two weeks of simply iterating between passaging of cells to generate variant enzymes via OrthoRep and high-throughput sorting of best-performing variants using a transcription factor-based biosensor for CCM, we ultimately identified variant enzymes improving CCM titers > 13-fold compared with reference enzymes. Taken together, the combination of synthetic biology tools as adopted in this study is an efficient approach to debottleneck repetitive workflows associated with directed evolution of metabolic enzymes.
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Affiliation(s)
- Emil D. Jensen
- Novo Nordisk Foundation Center for BiosustainabilityTechnical University of DenmarkKgs. LyngbyDenmark
| | - Francesca Ambri
- Novo Nordisk Foundation Center for BiosustainabilityTechnical University of DenmarkKgs. LyngbyDenmark
| | - Marie B. Bendtsen
- Novo Nordisk Foundation Center for BiosustainabilityTechnical University of DenmarkKgs. LyngbyDenmark
| | - Alex A. Javanpour
- Department of Biomedical EngineeringUniversity of California, IrvineIrvineCA92697USA
| | - Chang C. Liu
- Department of Biomedical EngineeringUniversity of California, IrvineIrvineCA92697USA
- Department of ChemistryUniversity of California, IrvineIrvineCA92697USA
- Department of Molecular Biology and BiochemistryUniversity of California, IrvineIrvineCA92697USA
| | - Michael K. Jensen
- Novo Nordisk Foundation Center for BiosustainabilityTechnical University of DenmarkKgs. LyngbyDenmark
| | - Jay D. Keasling
- Novo Nordisk Foundation Center for BiosustainabilityTechnical University of DenmarkKgs. LyngbyDenmark
- Joint BioEnergy InstituteEmeryvilleCAUSA
- Biological Systems and Engineering DivisionLawrence Berkeley National LaboratoryBerkeleyCAUSA
- Department of Chemical and Biomolecular EngineeringDepartment of BioengineeringUniversity of CaliforniaBerkeleyCAUSA
- Center for Synthetic BiochemistryInstitute for Synthetic BiologyShenzhen Institutes of Advanced TechnologiesShenzhenChina
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11
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Stella RG, Gertzen CGW, Smits SHJ, Gätgens C, Polen T, Noack S, Frunzke J. Biosensor-based growth-coupling and spatial separation as an evolution strategy to improve small molecule production of Corynebacterium glutamicum. Metab Eng 2021; 68:162-173. [PMID: 34628038 DOI: 10.1016/j.ymben.2021.10.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 09/27/2021] [Accepted: 10/03/2021] [Indexed: 12/13/2022]
Abstract
Evolutionary engineering is a powerful method to improve the performance of microbial cell factories, but can typically not be applied to enhance the production of chemicals due to the lack of an appropriate selection regime. We report here on a new strategy based on transcription factor-based biosensors, which directly couple production to growth. The growth of Corynebacterium glutamicum was coupled to the intracellular concentration of branched-chain amino acids, by integrating a synthetic circuit based on the Lrp biosensor upstream of two growth-regulating genes, pfkA and hisD. Modelling and experimental data highlight spatial separation as key strategy to limit the selection of 'cheater' strains that escaped the evolutionary pressure. This approach facilitated the isolation of strains featuring specific causal mutations enhancing amino acid production. We envision that this strategy can be applied with the plethora of known biosensors in various microbes, unlocking evolution as a feasible strategy to improve production of chemicals.
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Affiliation(s)
- Roberto G Stella
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Straße, Jülich D-52425, Germany
| | - Christoph G W Gertzen
- Center for Structural Studies (CSS), Heinrich Heine University Düsseldorf, Universitätsstr. 1, 40225, Düsseldorf, Germany; Institute for Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, Universitätsstr. 1, 40225, Düsseldorf, Germany
| | - Sander H J Smits
- Center for Structural Studies (CSS), Heinrich Heine University Düsseldorf, Universitätsstr. 1, 40225, Düsseldorf, Germany; Institute of Biochemistry, Heinrich Heine University Düsseldorf, Universitätsstr. 1, 40225, Düsseldorf, Germany
| | - Cornelia Gätgens
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Straße, Jülich D-52425, Germany
| | - Tino Polen
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Straße, Jülich D-52425, Germany
| | - Stephan Noack
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Straße, Jülich D-52425, Germany; Bioeconomy Science Center (BioSC), Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Straße, Jülich D-52425, Germany
| | - Julia Frunzke
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Straße, Jülich D-52425, Germany.
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12
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Harnessing the yeast Saccharomyces cerevisiae for the production of fungal secondary metabolites. Essays Biochem 2021; 65:277-291. [PMID: 34061167 PMCID: PMC8314005 DOI: 10.1042/ebc20200137] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 04/09/2021] [Accepted: 04/14/2021] [Indexed: 12/17/2022]
Abstract
Fungal secondary metabolites (FSMs) represent a remarkable array of bioactive compounds, with potential applications as pharmaceuticals, nutraceuticals, and agrochemicals. However, these molecules are typically produced only in limited amounts by their native hosts. The native organisms may also be difficult to cultivate and genetically engineer, and some can produce undesirable toxic side-products. Alternatively, recombinant production of fungal bioactives can be engineered into industrial cell factories, such as aspergilli or yeasts, which are well amenable for large-scale manufacturing in submerged fermentations. In this review, we summarize the development of baker's yeast Saccharomyces cerevisiae to produce compounds derived from filamentous fungi and mushrooms. These compounds mainly include polyketides, terpenoids, and amino acid derivatives. We also describe how native biosynthetic pathways can be combined or expanded to produce novel derivatives and new-to-nature compounds. We describe some new approaches for cell factory engineering, such as genome-scale engineering, biosensor-based high-throughput screening, and machine learning, and how these tools have been applied for S. cerevisiae strain improvement. Finally, we prospect the challenges and solutions in further development of yeast cell factories to more efficiently produce FSMs.
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13
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Short and long-read ultra-deep sequencing profiles emerging heterogeneity across five platform Escherichia coli strains. Metab Eng 2020; 65:197-206. [PMID: 33242648 DOI: 10.1016/j.ymben.2020.11.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 10/26/2020] [Accepted: 11/12/2020] [Indexed: 11/24/2022]
Abstract
Reprogramming organisms for large-scale bioproduction counters their evolutionary objectives of fast growth and often leads to mutational collapse of the engineered production pathways during cultivation. Yet, the mutational susceptibility of academic and industrial Escherichia coli bioproduction host strains are poorly understood. In this study, we apply 2nd and 3rd generation deep sequencing to profile simultaneous modes of genetic heterogeneity that decimate engineered biosynthetic production in five popular E. coli hosts BL21(DE3), TOP10, MG1655, W, and W3110 producing 2,3-butanediol and mevalonic acid. Combining short-read and long-read sequencing, we detect strain and sequence-specific mutational modes including single nucleotide polymorphism, inversion, and mobile element transposition, as well as complex structural variations that disrupt the integrity of the engineered biosynthetic pathway. Our analysis suggests that organism engineers should avoid chassis strains hosting active insertion sequence (IS) subfamilies such as IS1 and IS10 present in popular E. coli TOP10. We also recommend monitoring for increased mutagenicity in the pathway transcription initiation regions and recombinogenic repeats. Together, short and long sequencing reads identified latent low-frequency mutation events such as a short detrimental inversion within a pathway gene, driven by 8-bp short inverted repeats. This demonstrates the power of combining ultra-deep DNA sequencing technologies to profile genetic heterogeneities of engineered constructs and explore the markedly different mutational landscapes of common E. coli host strains. The observed multitude of evolving variants underlines the usefulness of early mutational profiling for new synthetic pathways designed to sustain in organisms over long cultivation scales.
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Rugbjerg P, Olsson L. The future of self-selecting and stable fermentations. J Ind Microbiol Biotechnol 2020; 47:993-1004. [PMID: 33136197 PMCID: PMC7695646 DOI: 10.1007/s10295-020-02325-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 10/17/2020] [Indexed: 02/08/2023]
Abstract
Unfavorable cell heterogeneity is a frequent risk during bioprocess scale-up and characterized by rising frequencies of low-producing cells. Low-producing cells emerge by both non-genetic and genetic variation and will enrich due to their higher specific growth rate during the extended number of cell divisions of large-scale bioproduction. Here, we discuss recent strategies for synthetic stabilization of fermentation populations and argue for their application to make cell factory designs that better suit industrial needs. Genotype-directed strategies leverage DNA-sequencing data to inform strain design. Self-selecting phenotype-directed strategies couple high production with cell proliferation, either by redirected metabolic pathways or synthetic product biosensing to enrich for high-performing cell variants. Evaluating production stability early in new cell factory projects will guide heterogeneity-reducing design choices. As good initial metrics, we propose production half-life from standardized serial-passage stability screens and production load, quantified as production-associated percent-wise growth rate reduction. Incorporating more stable genetic designs will greatly increase scalability of future cell factories through sustaining a high-production phenotype and enabling stable long-term production.
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Affiliation(s)
- Peter Rugbjerg
- Enduro Genetics ApS, Copenhagen, Denmark. .,Department of Biology and Biological Engineering, Industrial Biotechnology, Chalmers University of Technology, Gothenburg, Sweden.
| | - Lisbeth Olsson
- Department of Biology and Biological Engineering, Industrial Biotechnology, Chalmers University of Technology, Gothenburg, Sweden
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