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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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Ehrmann AK, Wronska AK, Perli T, de Hulster EAF, Luttik MAH, van den Broek M, Carqueija Cardoso C, Pronk JT, Daran JM. Engineering Saccharomyces cerevisiae for fast vitamin-independent aerobic growth. Metab Eng 2024; 82:201-215. [PMID: 38364997 DOI: 10.1016/j.ymben.2024.01.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 01/08/2024] [Accepted: 01/26/2024] [Indexed: 02/18/2024]
Abstract
Chemically defined media for cultivation of Saccharomyces cerevisiae strains are commonly supplemented with a mixture of multiple Class-B vitamins, whose omission leads to strongly reduced growth rates. Fast growth without vitamin supplementation is interesting for industrial applications, as it reduces costs and complexity of medium preparation and may decrease susceptibility to contamination by auxotrophic microbes. In this study, suboptimal growth rates of S. cerevisiae CEN.PK113-7D in the absence of pantothenic acid, para-aminobenzoic acid (pABA), pyridoxine, inositol and/or biotin were corrected by single or combined overexpression of ScFMS1, ScABZ1/ScABZ2, ScSNZ1/ScSNO1, ScINO1 and Cyberlindnera fabianii BIO1, respectively. Several strategies were explored to improve growth of S. cerevisiae CEN.PK113-7D in thiamine-free medium. Overexpression of ScTHI4 and/or ScTHI5 enabled thiamine-independent growth at 83% of the maximum specific growth rate of the reference strain in vitamin-supplemented medium. Combined overexpression of seven native S. cerevisiae genes and CfBIO1 enabled a maximum specific growth rate of 0.33 ± 0.01 h-1 in vitamin-free synthetic medium. This growth rate was only 17 % lower than that of a congenic reference strain in vitamin-supplemented medium. Physiological parameters of the engineered vitamin-independent strain in aerobic glucose-limited chemostat cultures (dilution rate 0.10 h-1) grown on vitamin-free synthetic medium were similar to those of similar cultures of the parental strain grown on vitamin-supplemented medium. Transcriptome analysis revealed only few differences in gene expression between these cultures, which primarily involved genes with roles in Class-B vitamin metabolism. These results pave the way for development of fast-growing vitamin-independent industrial strains of S. cerevisiae.
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Affiliation(s)
- Anja K Ehrmann
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet, Building 220, 2800 Kgs, Lyngby, Denmark
| | - Anna K Wronska
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, the Netherlands
| | - Thomas Perli
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, the Netherlands
| | - Erik A F de Hulster
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, the Netherlands
| | - Marijke A H Luttik
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, the Netherlands
| | - Marcel van den Broek
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, the Netherlands
| | - Clara Carqueija Cardoso
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, the Netherlands
| | - Jack T Pronk
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, the Netherlands
| | - Jean-Marc Daran
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, the Netherlands.
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Sonal, Yuan AE, Yang X, Shou W. Collective production of hydrogen sulfide gas enables budding yeast lacking MET17 to overcome their metabolic defect. PLoS Biol 2023; 21:e3002439. [PMID: 38060626 PMCID: PMC10729969 DOI: 10.1371/journal.pbio.3002439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 12/19/2023] [Accepted: 11/20/2023] [Indexed: 12/20/2023] Open
Abstract
Assimilation of sulfur is vital to all organisms. In S. cerevisiae, inorganic sulfate is first reduced to sulfide, which is then affixed to an organic carbon backbone by the Met17 enzyme. The resulting homocysteine can then be converted to all other essential organosulfurs such as methionine, cysteine, and glutathione. This pathway has been known for nearly half a century, and met17 mutants have long been classified as organosulfur auxotrophs, which are unable to grow on sulfate as their sole sulfur source. Surprisingly, we found that met17Δ could grow on sulfate, albeit only at sufficiently high cell densities. We show that the accumulation of hydrogen sulfide gas underpins this density-dependent growth of met17Δ on sulfate and that the locus YLL058W (HSU1) enables met17Δ cells to assimilate hydrogen sulfide. Hsu1 protein is induced during sulfur starvation and under exposure to high sulfide concentrations in wild-type cells, and the gene has a pleiotropic role in sulfur assimilation. In a mathematical model, the low efficiency of sulfide assimilation in met17Δ can explain the observed density-dependent growth of met17Δ on sulfate. Thus, having uncovered and explained the paradoxical growth of a commonly used "auxotroph," our findings may impact the design of future studies in yeast genetics, metabolism, and volatile-mediated microbial interactions.
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Affiliation(s)
- Sonal
- Centre for Life’s Origins and Evolution, Department of Genetics, Evolution and Environment, University College London, London, United Kingdom
| | - Alex E. Yuan
- University of Washington, Seattle, Washington, United States of America
| | - Xueqin Yang
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, China
| | - Wenying Shou
- Centre for Life’s Origins and Evolution, Department of Genetics, Evolution and Environment, University College London, London, United Kingdom
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van Aalst ACA, van der Meulen IS, Jansen MLA, Mans R, Pronk JT. Co-cultivation of Saccharomyces cerevisiae strains combines advantages of different metabolic engineering strategies for improved ethanol yield. Metab Eng 2023; 80:151-162. [PMID: 37751790 DOI: 10.1016/j.ymben.2023.09.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 09/14/2023] [Accepted: 09/15/2023] [Indexed: 09/28/2023]
Abstract
Glycerol is the major organic byproduct of industrial ethanol production with the yeast Saccharomyces cerevisiae. Improved ethanol yields have been achieved with engineered S. cerevisiae strains in which heterologous pathways replace glycerol formation as the predominant mechanism for anaerobic re-oxidation of surplus NADH generated in biosynthetic reactions. Functional expression of heterologous phosphoribulokinase (PRK) and ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) genes enables yeast cells to couple a net oxidation of NADH to the conversion of glucose to ethanol. In another strategy, NADH-dependent reduction of exogenous acetate to ethanol is enabled by introduction of a heterologous acetylating acetaldehyde dehydrogenase (A-ALD). This study explores potential advantages of co-cultivating engineered PRK-RuBisCO-based and A-ALD-based strains in anaerobic bioreactor batch cultures. Co-cultivation of these strains, which in monocultures showed reduced glycerol yields and improved ethanol yields, strongly reduced the formation of acetaldehyde and acetate, two byproducts that were formed in anaerobic monocultures of a PRK-RuBisCO-based strain. In addition, co-cultures on medium with low acetate-to-glucose ratios that mimicked those in industrial feedstocks completely removed acetate from the medium. Kinetics of co-cultivation processes and glycerol production could be optimized by tuning the relative inoculum sizes of the two strains. Co-cultivation of a PRK-RuBisCO strain with a Δgpd1 Δgpd2 A-ALD strain, which was unable to grow in the absence of acetate and evolved for faster anaerobic growth in acetate-supplemented batch cultures, further reduced glycerol formation but led to extended fermentation times. These results demonstrate the potential of using defined consortia of engineered S. cerevisiae strains for high-yield, minimal-waste ethanol production.
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Affiliation(s)
- Aafke C A van Aalst
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629, HZ, Delft, the Netherlands
| | - Igor S van der Meulen
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629, HZ, Delft, the Netherlands
| | - Mickel L A Jansen
- DSM Biotechnology Centre, Alexander Fleminglaan 1, 2613, AX, Delft, the Netherlands
| | - Robert Mans
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629, HZ, Delft, the Netherlands
| | - Jack T Pronk
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629, HZ, Delft, the Netherlands.
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Vijayraghavan S, Kozmin SG, Strope PK, Skelly DA, Magwene PM, Dietrich FS, McCusker JH. RNA viruses, M satellites, chromosomal killer genes, and killer/nonkiller phenotypes in the 100-genomes S. cerevisiae strains. G3 (BETHESDA, MD.) 2023; 13:jkad167. [PMID: 37497616 PMCID: PMC10542562 DOI: 10.1093/g3journal/jkad167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 07/13/2023] [Accepted: 07/14/2023] [Indexed: 07/28/2023]
Abstract
We characterized previously identified RNA viruses (L-A, L-BC, 20S, and 23S), L-A-dependent M satellites (M1, M2, M28, and Mlus), and M satellite-dependent killer phenotypes in the Saccharomyces cerevisiae 100-genomes genetic resource population. L-BC was present in all strains, albeit in 2 distinct levels, L-BChi and L-BClo; the L-BC level is associated with the L-BC genotype. L-BChi, L-A, 20S, 23S, M1, M2, and Mlus (M28 was absent) were in fewer strains than the similarly inherited 2µ plasmid. Novel L-A-dependent phenotypes were identified. Ten M+ strains exhibited M satellite-dependent killing (K+) of at least 1 of the naturally M0 and cured M0 derivatives of the 100-genomes strains; in these M0 strains, sensitivities to K1+, K2+, and K28+ strains varied. Finally, to complement our M satellite-encoded killer toxin analysis, we assembled the chromosomal KHS1 and KHR1 killer genes and used naturally M0 and cured M0 derivatives of the 100-genomes strains to assess and characterize the chromosomal killer phenotypes.
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Affiliation(s)
- Sriram Vijayraghavan
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Stanislav G Kozmin
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Pooja K Strope
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Daniel A Skelly
- Department of Biology, Duke University, Durham, NC 27708, USA
| | - Paul M Magwene
- Department of Biology, Duke University, Durham, NC 27708, USA
| | - Fred S Dietrich
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - John H McCusker
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
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Cachera P, Olsson H, Coumou H, Jensen ML, Sánchez B, Strucko T, van den Broek M, Daran JM, Jensen M, Sonnenschein N, Lisby M, Mortensen U. CRI-SPA: a high-throughput method for systematic genetic editing of yeast libraries. Nucleic Acids Res 2023; 51:e91. [PMID: 37572348 PMCID: PMC10516668 DOI: 10.1093/nar/gkad656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 07/07/2023] [Accepted: 08/10/2023] [Indexed: 08/14/2023] Open
Abstract
Biological functions are orchestrated by intricate networks of interacting genetic elements. Predicting the interaction landscape remains a challenge for systems biology and new research tools allowing simple and rapid mapping of sequence to function are desirable. Here, we describe CRI-SPA, a method allowing the transfer of chromosomal genetic features from a CRI-SPA Donor strain to arrayed strains in large libraries of Saccharomyces cerevisiae. CRI-SPA is based on mating, CRISPR-Cas9-induced gene conversion, and Selective Ploidy Ablation. CRI-SPA can be massively parallelized with automation and can be executed within a week. We demonstrate the power of CRI-SPA by transferring four genes that enable betaxanthin production into each strain of the yeast knockout collection (≈4800 strains). Using this setup, we show that CRI-SPA is highly efficient and reproducible, and even allows marker-free transfer of genetic features. Moreover, we validate a set of CRI-SPA hits by showing that their phenotypes correlate strongly with the phenotypes of the corresponding mutant strains recreated by reverse genetic engineering. Hence, our results provide a genome-wide overview of the genetic requirements for betaxanthin production. We envision that the simplicity, speed, and reliability offered by CRI-SPA will make it a versatile tool to forward systems-level understanding of biological processes.
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Affiliation(s)
- Paul Cachera
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Denmark
| | - Helén Olsson
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Denmark
| | - Hilde Coumou
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Denmark
| | - Mads L Jensen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Denmark
| | - Benjamín J Sánchez
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Denmark
| | - Tomas Strucko
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Denmark
| | - Marcel van den Broek
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - Jean-Marc Daran
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - Michael K Jensen
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Denmark
| | - Nikolaus Sonnenschein
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Denmark
| | - Michael Lisby
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Uffe H Mortensen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Denmark
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Stellner NI, Rerop ZS, Mehlmer N, Masri M, Ringel M, Brück TB. Expanding the genetic toolbox for Cutaneotrichosporon oleaginosus employing newly identified promoters and a novel antibiotic resistance marker. BMC Biotechnol 2023; 23:40. [PMID: 37723521 PMCID: PMC10506223 DOI: 10.1186/s12896-023-00812-7] [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: 06/09/2023] [Accepted: 09/08/2023] [Indexed: 09/20/2023] Open
Abstract
BACKGROUND Cutaneotrichosporon oleaginosus is an oleaginous yeast that can produce up to 80% lipid per dry weight. Its high capacity for the biosynthesis of single cell oil makes it highly interesting for the production of engineered lipids or oleochemicals for industrial applications. However, the genetic toolbox for metabolic engineering of this non-conventional yeast has not yet been systematically expanded. Only three long endogenous promoter sequences have been used for heterologous gene expression, further three dominant and one auxotrophic marker have been established. RESULTS In this study, the structure of putative endogenous promoter sequences was analyzed based on more than 280 highly expressed genes. The identified motifs of regulatory elements and translational initiation sites were used to annotate the four endogenous putative promoter sequences D9FADp, UBIp, PPIp, and 60Sp. The promoter sequences were tested in a construct regulating the known dominant marker hygromycin B phosphotransferase. The four newly described promoters and the previously established GAPDHp successfully initiated expression of the resistance gene and PPIp was selected for further marker development. The geneticin G418 resistance (aminoglycoside 3'-phosphotransferase, APH) and the nourseothricin resistance gene N-acetyl transferase (NAT) were tested for applicability in C. oleaginosus. Both markers showed high transformation efficiency, positive rate, and were compatible for combined use in a successive and simultaneous manner. CONCLUSIONS The implementation of four endogenous promoters and one novel dominant resistance markers for C. oleaginosus opens up new opportunities for genetic engineering and strain development. In combination with recently developed methods for targeted genomic integration, the established toolbox allows a wide spectrum of new strategies for genetic and metabolic engineering of the industrially highly relevant yeast.
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Affiliation(s)
- Nikolaus I Stellner
- TUM School of Natural Sciences, Department of Chemistry, Werner Siemens-Chair for Synthetic Biotechnology, Technical University of Munich, Lichtenbergstr. 4, 85748, Garching, Germany
- TUM CREATE Ltd, 1 Create Way, #10-02 CREATE Tower, Singapore, 138602, Singapore
| | - Zora S Rerop
- TUM School of Natural Sciences, Department of Chemistry, Werner Siemens-Chair for Synthetic Biotechnology, Technical University of Munich, Lichtenbergstr. 4, 85748, Garching, Germany
| | - Norbert Mehlmer
- TUM School of Natural Sciences, Department of Chemistry, Werner Siemens-Chair for Synthetic Biotechnology, Technical University of Munich, Lichtenbergstr. 4, 85748, Garching, Germany
| | - Mahmoud Masri
- TUM School of Natural Sciences, Department of Chemistry, Werner Siemens-Chair for Synthetic Biotechnology, Technical University of Munich, Lichtenbergstr. 4, 85748, Garching, Germany
| | - Marion Ringel
- TUM School of Natural Sciences, Department of Chemistry, Werner Siemens-Chair for Synthetic Biotechnology, Technical University of Munich, Lichtenbergstr. 4, 85748, Garching, Germany
| | - Thomas B Brück
- TUM School of Natural Sciences, Department of Chemistry, Werner Siemens-Chair for Synthetic Biotechnology, Technical University of Munich, Lichtenbergstr. 4, 85748, Garching, Germany.
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Stepchenkova EI, Zadorsky SP, Shumega AR, Aksenova AY. Practical Approaches for the Yeast Saccharomyces cerevisiae Genome Modification. Int J Mol Sci 2023; 24:11960. [PMID: 37569333 PMCID: PMC10419131 DOI: 10.3390/ijms241511960] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 07/21/2023] [Accepted: 07/22/2023] [Indexed: 08/13/2023] Open
Abstract
The yeast S. cerevisiae is a unique genetic object for which a wide range of relatively simple, inexpensive, and non-time-consuming methods have been developed that allow the performing of a wide variety of genome modifications. Among the latter, one can mention point mutations, disruptions and deletions of particular genes and regions of chromosomes, insertion of cassettes for the expression of heterologous genes, targeted chromosomal rearrangements such as translocations and inversions, directed changes in the karyotype (loss or duplication of particular chromosomes, changes in the level of ploidy), mating-type changes, etc. Classical yeast genome manipulations have been advanced with CRISPR/Cas9 technology in recent years that allow for the generation of multiple simultaneous changes in the yeast genome. In this review we discuss practical applications of both the classical yeast genome modification methods as well as CRISPR/Cas9 technology. In addition, we review methods for ploidy changes, including aneuploid generation, methods for mating type switching and directed DSB. Combined with a description of useful selective markers and transformation techniques, this work represents a nearly complete guide to yeast genome modification.
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Affiliation(s)
- Elena I. Stepchenkova
- Department of Genetics and Biotechnology, St. Petersburg State University, 199034 St. Petersburg, Russia; (E.I.S.); (S.P.Z.); (A.R.S.)
- Vavilov Institute of General Genetics, St. Petersburg Branch, Russian Academy of Sciences, 199034 St. Petersburg, Russia
| | - Sergey P. Zadorsky
- Department of Genetics and Biotechnology, St. Petersburg State University, 199034 St. Petersburg, Russia; (E.I.S.); (S.P.Z.); (A.R.S.)
- Vavilov Institute of General Genetics, St. Petersburg Branch, Russian Academy of Sciences, 199034 St. Petersburg, Russia
| | - Andrey R. Shumega
- Department of Genetics and Biotechnology, St. Petersburg State University, 199034 St. Petersburg, Russia; (E.I.S.); (S.P.Z.); (A.R.S.)
| | - Anna Y. Aksenova
- Laboratory of Amyloid Biology, St. Petersburg State University, 199034 St. Petersburg, Russia
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Zhang Y, Chen S, Yang L, Zhang Q. Application progress of CRISPR/Cas9 genome-editing technology in edible fungi. Front Microbiol 2023; 14:1169884. [PMID: 37303782 PMCID: PMC10248459 DOI: 10.3389/fmicb.2023.1169884] [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: 02/20/2023] [Accepted: 04/26/2023] [Indexed: 06/13/2023] Open
Abstract
Edible fungi are not only delicious but are also rich in nutritional and medicinal value, which is highly sought after by consumers. As the edible fungi industry continues to rapidly advance worldwide, particularly in China, the cultivation of superior and innovative edible fungi strains has become increasingly pivotal. Nevertheless, conventional breeding techniques for edible fungi can be arduous and time-consuming. CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/CRISPR-associated nuclease 9) is a powerful tool for molecular breeding due to its ability to mediate high-efficiency and high-precision genome modification, which has been successfully applied to many kinds of edible fungi. In this review, we briefly summarized the working mechanism of the CRISPR/Cas9 system and highlighted the application progress of CRISPR/Cas9-mediated genome-editing technology in edible fungi, including Agaricus bisporus, Ganoderma lucidum, Flammulina filiformis, Ustilago maydis, Pleurotus eryngii, Pleurotus ostreatus, Coprinopsis cinerea, Schizophyllum commune, Cordyceps militaris, and Shiraia bambusicola. Additionally, we discussed the limitations and challenges encountered using CRISPR/Cas9 technology in edible fungi and provided potential solutions. Finally, the applications of CRISPR/Cas9 system for molecular breeding of edible fungi in the future are explored.
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10
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van Aalst ACA, Geraats EH, Jansen MLA, Mans R, Pronk JT. Optimizing the balance between heterologous acetate- and CO2-reduction pathways in anaerobic cultures of Saccharomyces cerevisiae strains engineered for low-glycerol production. FEMS Yeast Res 2023; 23:foad048. [PMID: 37942589 PMCID: PMC10647013 DOI: 10.1093/femsyr/foad048] [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: 05/22/2023] [Revised: 10/24/2023] [Accepted: 11/03/2023] [Indexed: 11/10/2023] Open
Abstract
In anaerobic Saccharomyces cerevisiae cultures, NADH (reduced form of nicotinamide adenine dinucleotide)-cofactor balancing by glycerol formation constrains ethanol yields. Introduction of an acetate-to-ethanol reduction pathway based on heterologous acetylating acetaldehyde dehydrogenase (A-ALD) can replace glycerol formation as 'redox-sink' and improve ethanol yields in acetate-containing media. Acetate concentrations in feedstock for first-generation bioethanol production are, however, insufficient to completely replace glycerol formation. An alternative glycerol-reduction strategy bypasses the oxidative reaction in glycolysis by introducing phosphoribulokinase (PRK) and ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO). For optimal performance in industrial settings, yeast strains should ideally first fully convert acetate and, subsequently, continue low-glycerol fermentation via the PRK-RuBisCO pathway. However, anaerobic batch cultures of a strain carrying both pathways showed inferior acetate reduction relative to a strain expressing only the A-ALD pathway. Complete A-ALD-mediated acetate reduction by a dual-pathway strain, grown anaerobically on 50 g L-1 glucose and 5 mmol L-1 acetate, was achieved upon reducing PRK abundance by a C-terminal extension of its amino acid sequence. Yields of glycerol and ethanol on glucose were 55% lower and 6% higher, respectively, than those of a nonengineered reference strain. The negative impact of the PRK-RuBisCO pathway on acetate reduction was attributed to sensitivity of the reversible A-ALD reaction to intracellular acetaldehyde concentrations.
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Affiliation(s)
- Aafke C A van Aalst
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Ellen H Geraats
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Mickel L A Jansen
- DSM Biotechnology Centre, Alexander Fleminglaan 1, 2613 AX Delft, The Netherlands
| | - Robert Mans
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Jack T Pronk
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
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Abstract
Saccharomyces cerevisiae, whose evolutionary past includes a whole-genome duplication event, is characterized by a mosaic genome configuration with substantial apparent genetic redundancy. This apparent redundancy raises questions about the evolutionary driving force for genomic fixation of “minor” paralogs and complicates modular and combinatorial metabolic engineering strategies. While isoenzymes might be important in specific environments, they could be dispensable in controlled laboratory or industrial contexts. The present study explores the extent to which the genetic complexity of the central carbon metabolism (CCM) in S. cerevisiae, here defined as the combination of glycolysis, the pentose phosphate pathway, the tricarboxylic acid cycle, and a limited number of related pathways and reactions, can be reduced by elimination of (iso)enzymes without major negative impacts on strain physiology. Cas9-mediated, groupwise deletion of 35 of the 111 genes yielded a “minimal CCM” strain which, despite the elimination of 32% of CCM-related proteins, showed only a minimal change in phenotype on glucose-containing synthetic medium in controlled bioreactor cultures relative to a congenic reference strain. Analysis under a wide range of other growth and stress conditions revealed remarkably few phenotypic changes from the reduction of genetic complexity. Still, a well-documented context-dependent role of GPD1 in osmotolerance was confirmed. The minimal CCM strain provides a model system for further research into genetic redundancy of yeast genes and a platform for strategies aimed at large-scale, combinatorial remodeling of yeast CCM.
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An Adjuvant-Based Approach Enables the Use of Dominant HYG and KAN Selectable Markers in Candida albicans. mSphere 2022; 7:e0034722. [PMID: 35968963 PMCID: PMC9429937 DOI: 10.1128/msphere.00347-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Candida albicans is a pathobiont fungus that can colonize multiple niches in the human body but is also a frequent cause of both mucosal and systemic disease. Despite its clinical importance, a paucity of dominant selectable markers has hindered the development of tools for genetic manipulation of the species. One factor limiting the utilization of dominant selectable markers is that C. albicans is inherently more resistant to antibiotics used for selection in other species. Here, we showed that the inclusion of suitable adjuvants can enable the use of two aminoglycoside antibiotics, hygromycin B and G418, for positive selection in C. albicans. Combining these antibiotics with an adjuvant, such as quinine or molybdate, substantially suppressed the background growth of C. albicans, thereby enabling transformants expressing CaHygB or CaKan markers to be readily identified. We verified that these adjuvants were not mutagenic to C. albicans and that CaHygB and CaKan markers were orthogonal to the existing marker NAT1/SAT1, and so provide complementary tools for the genetic manipulation of C. albicans strains. Our study also established that adjuvant-based approaches can enable the use of selectable markers that would otherwise be limited by high background growth from susceptible cells. IMPORTANCE Only a single dominant selectable marker has been widely adopted for use in the opportunistic fungal pathogen Candida albicans. This is in stark contrast to model fungi where a repertoire of dominant markers is readily available. A limiting factor for C. albicans has been the high levels of background growth obtained with multiple antibiotics, thereby limiting their use for distinguishing cells that carry an antibiotic-resistance gene from those that do not. Here, we demonstrated that the inclusion of adjuvants can reduce background growth and enable the robust use of both CaHygB and CaKan markers for genetic selection in C. albicans.
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13
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Boonekamp FJ, Knibbe E, Vieira-Lara MA, Wijsman M, Luttik MAH, van Eunen K, Ridder MD, Bron R, Almonacid Suarez AM, van Rijn P, Wolters JC, Pabst M, Daran JM, Bakker BM, Daran-Lapujade P. Full humanization of the glycolytic pathway in Saccharomyces cerevisiae. Cell Rep 2022; 39:111010. [PMID: 35767960 DOI: 10.1016/j.celrep.2022.111010] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 02/03/2022] [Accepted: 06/07/2022] [Indexed: 12/22/2022] Open
Abstract
Although transplantation of single genes in yeast plays a key role in elucidating gene functionality in metazoans, technical challenges hamper humanization of full pathways and processes. Empowered by advances in synthetic biology, this study demonstrates the feasibility and implementation of full humanization of glycolysis in yeast. Single gene and full pathway transplantation revealed the remarkable conservation of glycolytic and moonlighting functions and, combined with evolutionary strategies, brought to light context-dependent responses. Human hexokinase 1 and 2, but not 4, required mutations in their catalytic or allosteric sites for functionality in yeast, whereas hexokinase 3 was unable to complement its yeast ortholog. Comparison with human tissues cultures showed preservation of turnover numbers of human glycolytic enzymes in yeast and human cell cultures. This demonstration of transplantation of an entire essential pathway paves the way for establishment of species-, tissue-, and disease-specific metazoan models.
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Affiliation(s)
- Francine J Boonekamp
- Department of Biotechnology, Delft University of Technology, Van Der Maasweg 9, 2629 Delft, the Netherlands
| | - Ewout Knibbe
- Department of Biotechnology, Delft University of Technology, Van Der Maasweg 9, 2629 Delft, the Netherlands
| | - Marcel A Vieira-Lara
- Laboratory of Pediatrics, Section Systems Medicine and Metabolic Signalling, Center for Liver, Digestive and Metabolic Disease, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Melanie Wijsman
- Department of Biotechnology, Delft University of Technology, Van Der Maasweg 9, 2629 Delft, the Netherlands
| | - Marijke A H Luttik
- Department of Biotechnology, Delft University of Technology, Van Der Maasweg 9, 2629 Delft, the Netherlands
| | - Karen van Eunen
- Laboratory of Pediatrics, Section Systems Medicine and Metabolic Signalling, Center for Liver, Digestive and Metabolic Disease, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Maxime den Ridder
- Department of Biotechnology, Delft University of Technology, Van Der Maasweg 9, 2629 Delft, the Netherlands
| | - Reinier Bron
- Department of Biomedical Engineering-FB40, W.J. Kolff Institute for Biomedical Engineering and Materials Science-FB41, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Ana Maria Almonacid Suarez
- Department of Pathology and Medical Biology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Patrick van Rijn
- Department of Biomedical Engineering-FB40, W.J. Kolff Institute for Biomedical Engineering and Materials Science-FB41, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Justina C Wolters
- Laboratory of Pediatrics, Section Systems Medicine and Metabolic Signalling, Center for Liver, Digestive and Metabolic Disease, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Martin Pabst
- Department of Biotechnology, Delft University of Technology, Van Der Maasweg 9, 2629 Delft, the Netherlands
| | - Jean-Marc Daran
- Department of Biotechnology, Delft University of Technology, Van Der Maasweg 9, 2629 Delft, the Netherlands
| | - Barbara M Bakker
- Laboratory of Pediatrics, Section Systems Medicine and Metabolic Signalling, Center for Liver, Digestive and Metabolic Disease, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Pascale Daran-Lapujade
- Department of Biotechnology, Delft University of Technology, Van Der Maasweg 9, 2629 Delft, the Netherlands.
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14
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The microprotein Nrs1 rewires the G1/S transcriptional machinery during nitrogen limitation in budding yeast. PLoS Biol 2022; 20:e3001548. [PMID: 35239649 PMCID: PMC8893695 DOI: 10.1371/journal.pbio.3001548] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 01/19/2022] [Indexed: 12/01/2022] Open
Abstract
Commitment to cell division at the end of G1 phase, termed Start in the budding yeast Saccharomyces cerevisiae, is strongly influenced by nutrient availability. To identify new dominant activators of Start that might operate under different nutrient conditions, we screened a genome-wide ORF overexpression library for genes that bypass a Start arrest caused by absence of the G1 cyclin Cln3 and the transcriptional activator Bck2. We recovered a hypothetical gene YLR053c, renamed NRS1 for Nitrogen-Responsive Start regulator 1, which encodes a poorly characterized 108 amino acid microprotein. Endogenous Nrs1 was nuclear-localized, restricted to poor nitrogen conditions, induced upon TORC1 inhibition, and cell cycle-regulated with a peak at Start. NRS1 interacted genetically with SWI4 and SWI6, which encode subunits of the main G1/S transcription factor complex SBF. Correspondingly, Nrs1 physically interacted with Swi4 and Swi6 and was localized to G1/S promoter DNA. Nrs1 exhibited inherent transactivation activity, and fusion of Nrs1 to the SBF inhibitor Whi5 was sufficient to suppress other Start defects. Nrs1 appears to be a recently evolved microprotein that rewires the G1/S transcriptional machinery under poor nitrogen conditions. Commitment to cell division at the end of G1 phase in the budding yeast Saccharomyces cerevisiae is strongly influenced by nutrient availability. This study identifies a micro-protein that promotes G1/S transcription activation and cell cycle entry in yeast under nitrogen-limited conditions.
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15
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Zhang T, Sun Y, Ma Z, Zhang J, Lv B, Li C. Developing iterative and quantified transgenic manipulations of non-conventional filamentous fungus Talaromyces pinophilus Li-93. Biochem Eng J 2022. [DOI: 10.1016/j.bej.2021.108317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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16
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Siewers V. An Overview on Selection Marker Genes for Transformation of Saccharomyces cerevisiae. Methods Mol Biol 2022; 2513:1-13. [PMID: 35781196 DOI: 10.1007/978-1-0716-2399-2_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] [Indexed: 06/15/2023]
Abstract
For genetic manipulation of yeast, numerous selection marker genes have been employed. These include prototrophic markers, markers conferring drug resistance, autoselection markers, and counterselectable markers. This chapter describes the different classes of selection markers and provides a number of examples for different applications.
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Affiliation(s)
- Verena Siewers
- Division of Systems and Synthetic Biology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden.
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17
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den Haan R, Rose SH, Cripwell RA, Trollope KM, Myburgh MW, Viljoen-Bloom M, van Zyl WH. Heterologous production of cellulose- and starch-degrading hydrolases to expand Saccharomyces cerevisiae substrate utilization: Lessons learnt. Biotechnol Adv 2021; 53:107859. [PMID: 34678441 DOI: 10.1016/j.biotechadv.2021.107859] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 10/14/2021] [Accepted: 10/15/2021] [Indexed: 12/28/2022]
Abstract
Selected strains of Saccharomyces cerevisiae are used for commercial bioethanol production from cellulose and starch, but the high cost of exogenous enzymes for substrate hydrolysis remains a challenge. This can be addressed through consolidated bioprocessing (CBP) where S. cerevisiae strains are engineered to express recombinant glycoside hydrolases during fermentation. Looking back at numerous strategies undertaken over the past four decades to improve recombinant protein production in S. cerevisiae, it is evident that various steps in the protein production "pipeline" can be manipulated depending on the protein of interest and its anticipated application. In this review, we briefly introduce some of the strategies and highlight lessons learned with regards to improved transcription, translation, post-translational modification and protein secretion of heterologous hydrolases. We examine how host strain selection and modification, as well as enzyme compatibility, are crucial determinants for overall success. Finally, we discuss how lessons from heterologous hydrolase expression can inform modern synthetic biology and genome editing tools to provide process-ready yeast strains in future. However, it is clear that the successful expression of any particular enzyme is still unpredictable and requires a trial-and-error approach.
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Affiliation(s)
- Riaan den Haan
- Department of Biotechnology, University of the Western Cape, Bellville, South Africa
| | - Shaunita H Rose
- Department of Microbiology, Stellenbosch University, Stellenbosch, South Africa
| | - Rosemary A Cripwell
- Department of Microbiology, Stellenbosch University, Stellenbosch, South Africa
| | - Kim M Trollope
- Department of Microbiology, Stellenbosch University, Stellenbosch, South Africa
| | - Marthinus W Myburgh
- Department of Microbiology, Stellenbosch University, Stellenbosch, South Africa
| | | | - Willem H van Zyl
- Department of Microbiology, Stellenbosch University, Stellenbosch, South Africa.
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18
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Perli T, Borodina I, Daran JM. Engineering of molybdenum-cofactor-dependent nitrate assimilation in Yarrowia lipolytica. FEMS Yeast Res 2021; 21:6370176. [PMID: 34519821 PMCID: PMC8456426 DOI: 10.1093/femsyr/foab050] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 09/01/2021] [Indexed: 12/13/2022] Open
Abstract
Engineering a new metabolic function in a microbial host can be limited by the availability of the relevant cofactor. For instance, in Yarrowia lipolytica, the expression of a functional nitrate reductase is precluded by the absence of molybdenum cofactor (Moco) biosynthesis. In this study, we demonstrated that the Ogataea parapolymorpha Moco biosynthesis pathway combined with the expression of a high affinity molybdate transporter could lead to the synthesis of Moco in Y. lipolytica. The functionality of Moco was demonstrated by expression of an active Moco-dependent nitrate assimilation pathway from the same yeast donor, O. parapolymorpha. In addition to 11 heterologous genes, fast growth on nitrate required adaptive laboratory evolution which, resulted in up to 100-fold increase in nitrate reductase activity and in up to 4-fold increase in growth rate, reaching 0.13h-1. Genome sequencing of evolved isolates revealed the presence of a limited number of non-synonymous mutations or small insertions/deletions in annotated coding sequences. This study that builds up on a previous work establishing Moco synthesis in S. cerevisiae demonstrated that the Moco pathway could be successfully transferred in very distant yeasts and, potentially, to any other genera, which would enable the expression of new enzyme families and expand the nutrient range used by industrial yeasts.
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Affiliation(s)
- Thomas Perli
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, The Netherlands
| | - Irina Borodina
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet, Building 220, 2800 Kgs. Lyngby, Denmark
| | - Jean-Marc Daran
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, The Netherlands
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19
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Bouyx C, Schiavone M, Teste MA, Dague E, Sieczkowski N, Julien A, François JM. The dual role of amyloid-β-sheet sequences in the cell surface properties of FLO11-encoded flocculins in Saccharomyces cerevisiae. eLife 2021; 10:e68592. [PMID: 34467855 PMCID: PMC8457840 DOI: 10.7554/elife.68592] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 08/29/2021] [Indexed: 11/21/2022] Open
Abstract
Fungal adhesins (Als) or flocculins are family of cell surface proteins that mediate adhesion to diverse biotic and abiotic surfaces. A striking characteristic of Als proteins originally identified in the pathogenic Candida albicans is to form functional amyloids that mediate cis-interaction leading to the formation of adhesin nanodomains and trans-interaction between amyloid sequences of opposing cells. In this report, we show that flocculins encoded by FLO11 in Saccharomyces cerevisiae behave like adhesins in C. albicans. To do so, we show that the formation of nanodomains under an external physical force requires a threshold number of amyloid-forming sequences in the Flo11 protein. Then, using a genome editing approach, we constructed strains expressing variants of the Flo11 protein under the endogenous FLO11 promoter, leading to the demonstration that the loss of amyloid-forming sequences strongly reduces cell-cell interaction but has no effect on either plastic adherence or invasive growth in agar, both phenotypes being dependent on the N- and C-terminal ends of Flo11p. Finally, we show that the location of Flo11 is not altered either by the absence of amyloid-forming sequences or by the removal of the N- or C-terminus of the protein.
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Affiliation(s)
- Clara Bouyx
- Toulouse Biotechnology Institute, INSAToulouseFrance
| | - Marion Schiavone
- Toulouse Biotechnology Institute, INSAToulouseFrance
- Lallemand, Lallemand SASBlagnacFrance
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20
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A squalene-hopene cyclase in Schizosaccharomyces japonicus represents a eukaryotic adaptation to sterol-limited anaerobic environments. Proc Natl Acad Sci U S A 2021; 118:2105225118. [PMID: 34353908 PMCID: PMC8364164 DOI: 10.1073/pnas.2105225118] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Biosynthesis of sterols requires oxygen. This study identifies a previously unknown evolutionary adaptation in a eukaryote, which enables anaerobic growth in absence of exogenous sterols. A squalene–hopene cyclase, proposed to have been acquired by horizontal gene transfer from an acetic acid bacterium, is implicated in a unique ability of the yeast Schizosaccharomyces japonicus to synthesize hopanoids and grow in anaerobic, sterol-free media. Expression of this cyclase in Saccharomyces cerevisiae confirmed that at least one of its hopanoid products acts as sterol surrogate. These observations provide leads for research into the structure and function of eukaryotic membranes and into the development of sterol-independent yeast cell factories for application in anaerobic processes. Biosynthesis of sterols, which are key constituents of canonical eukaryotic membranes, requires molecular oxygen. Anaerobic protists and deep-branching anaerobic fungi are the only eukaryotes in which a mechanism for sterol-independent growth has been elucidated. In these organisms, tetrahymanol, formed through oxygen-independent cyclization of squalene by a squalene–tetrahymanol cyclase, acts as a sterol surrogate. This study confirms an early report [C. J. E. A. Bulder, Antonie Van Leeuwenhoek, 37, 353–358 (1971)] that Schizosaccharomyces japonicus is exceptional among yeasts in growing anaerobically on synthetic media lacking sterols and unsaturated fatty acids. Mass spectrometry of lipid fractions of anaerobically grown Sch. japonicus showed the presence of hopanoids, a class of cyclic triterpenoids not previously detected in yeasts, including hop-22(29)-ene, hop-17(21)-ene, hop-21(22)-ene, and hopan-22-ol. A putative gene in Sch. japonicus showed high similarity to bacterial squalene–hopene cyclase (SHC) genes and in particular to those of Acetobacter species. No orthologs of the putative Sch. japonicus SHC were found in other yeast species. Expression of the Sch. japonicus SHC gene (Sjshc1) in Saccharomyces cerevisiae enabled hopanoid synthesis and stimulated anaerobic growth in sterol-free media, thus indicating that one or more of the hopanoids produced by SjShc1 could at least partially replace sterols. Use of hopanoids as sterol surrogates represents a previously unknown adaptation of eukaryotic cells to anaerobic growth. The fast anaerobic growth of Sch. japonicus in sterol-free media is an interesting trait for developing robust fungal cell factories for application in anaerobic industrial processes.
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21
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Dekker WJC, Ortiz-Merino RA, Kaljouw A, Battjes J, Wiering FW, Mooiman C, Torre PDL, Pronk JT. Engineering the thermotolerant industrial yeast Kluyveromyces marxianus for anaerobic growth. Metab Eng 2021; 67:347-364. [PMID: 34303845 DOI: 10.1016/j.ymben.2021.07.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 07/06/2021] [Accepted: 07/13/2021] [Indexed: 10/20/2022]
Abstract
Current large-scale, anaerobic industrial processes for ethanol production from renewable carbohydrates predominantly rely on the mesophilic yeast Saccharomyces cerevisiae. Use of thermotolerant, facultatively fermentative yeasts such as Kluyveromyces marxianus could confer significant economic benefits. However, in contrast to S. cerevisiae, these yeasts cannot grow in the absence of oxygen. Responses of K. marxianus and S. cerevisiae to different oxygen-limitation regimes were analyzed in chemostats. Genome and transcriptome analysis, physiological responses to sterol supplementation and sterol-uptake measurements identified absence of a functional sterol-uptake mechanism as a key factor underlying the oxygen requirement of K. marxianus. Heterologous expression of a squalene-tetrahymanol cyclase enabled oxygen-independent synthesis of the sterol surrogate tetrahymanol in K. marxianus. After a brief adaptation under oxygen-limited conditions, tetrahymanol-expressing K. marxianus strains grew anaerobically on glucose at temperatures of up to 45 °C. These results open up new directions in the development of thermotolerant yeast strains for anaerobic industrial applications.
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Affiliation(s)
- Wijbrand J C Dekker
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629, HZ Delft, the Netherlands
| | - Raúl A Ortiz-Merino
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629, HZ Delft, the Netherlands
| | - Astrid Kaljouw
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629, HZ Delft, the Netherlands
| | - Julius Battjes
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629, HZ Delft, the Netherlands
| | - Frank W Wiering
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629, HZ Delft, the Netherlands
| | - Christiaan Mooiman
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629, HZ Delft, the Netherlands
| | - Pilar de la Torre
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629, HZ Delft, the Netherlands
| | - Jack T Pronk
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629, HZ Delft, the Netherlands.
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22
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Wang Y, Li X, Chen X, Nielsen J, Petranovic D, Siewers V. Expression of antibody fragments in Saccharomyces cerevisiae strains evolved for enhanced protein secretion. Microb Cell Fact 2021; 20:134. [PMID: 34261490 PMCID: PMC8278646 DOI: 10.1186/s12934-021-01624-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 07/01/2021] [Indexed: 11/10/2022] Open
Abstract
Monoclonal antibodies, antibody fragments and fusion proteins derived thereof have revolutionized the practice of medicine. Major challenges faced by the biopharmaceutical industry are however high production costs, long processing times and low productivities associated with their production in mammalian cell lines. The yeast Saccharomyces cerevisiae, a well-characterized eukaryotic cell factory possessing the capacity of post-translational modifications, has been industrially exploited as a secretion host for production of a range of products, including pharmaceuticals. However, due to the incompatible surface glycosylation, few antibody molecules have been functionally expressed in S. cerevisiae. Here, three non-glycosylated antibody fragments from human and the Camelidae family were chosen for expression in a S. cerevisiae strain (HA) previously evolved for high α-amylase secretion. These included the Fab fragment Ranibizumab (Ran), the scFv peptide Pexelizumab (Pex), and a nanobody consisting of a single V-type domain (Nan). Both secretion and biological activities of the antibody fragments were confirmed. In addition, the secretion level of each protein was compared in the wild type (LA) and two evolved strains (HA and MA) with different secretory capacities. We found that the secretion of Ran and Nan was positively correlated with the strains' secretory capacity, while Pex was most efficiently secreted in the parental strain. To investigate the mechanisms for different secretion abilities in these selected yeast strains for the different antibody fragments, RNA-seq analysis was performed. The results showed that several bioprocesses were significantly enriched for differentially expressed genes when comparing the enriched terms between HA.Nan vs. LA.Nan and HA.Pex vs. LA.Pex, including amino acid metabolism, protein synthesis, cell cycle and others, which indicates that there are unique physiological needs for each antibody fragment secretion.
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Affiliation(s)
- Yanyan Wang
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Xiaowei Li
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Xin Chen
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Jens Nielsen
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
- Novo Nordisk Foundation Center for Biosustainability, Chalmers University of Technology, Gothenburg, Sweden
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, Denmark
| | - Dina Petranovic
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
- Novo Nordisk Foundation Center for Biosustainability, Chalmers University of Technology, Gothenburg, Sweden
| | - Verena Siewers
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden.
- Novo Nordisk Foundation Center for Biosustainability, Chalmers University of Technology, Gothenburg, Sweden.
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23
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Identification of Oxygen-Independent Pathways for Pyridine Nucleotide and Coenzyme A Synthesis in Anaerobic Fungi by Expression of Candidate Genes in Yeast. mBio 2021; 12:e0096721. [PMID: 34154398 PMCID: PMC8262920 DOI: 10.1128/mbio.00967-21] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Neocallimastigomycetes are unique examples of strictly anaerobic eukaryotes. This study investigates how these anaerobic fungi bypass reactions involved in synthesis of pyridine nucleotide cofactors and coenzyme A that, in canonical fungal pathways, require molecular oxygen. Analysis of Neocallimastigomycetes proteomes identified a candidate l-aspartate-decarboxylase (AdcA) and l-aspartate oxidase (NadB) and quinolinate synthase (NadA), constituting putative oxygen-independent bypasses for coenzyme A synthesis and pyridine nucleotide cofactor synthesis. The corresponding gene sequences indicated acquisition by ancient horizontal gene transfer (HGT) events involving bacterial donors. To test whether these enzymes suffice to bypass corresponding oxygen-requiring reactions, they were introduced into fms1Δ and bna2Δ Saccharomyces cerevisiae strains. Expression of nadA and nadB from Piromyces finnis and adcA from Neocallimastix californiae conferred cofactor prototrophy under aerobic and anaerobic conditions. This study simulates how HGT can drive eukaryotic adaptation to anaerobiosis and provides a basis for elimination of auxotrophic requirements in anaerobic industrial applications of yeasts and fungi. IMPORTANCE NAD (NAD+) and coenzyme A (CoA) are central metabolic cofactors whose canonical biosynthesis pathways in fungi require oxygen. Anaerobic gut fungi of the Neocallimastigomycota phylum are unique eukaryotic organisms that adapted to anoxic environments. Analysis of Neocallimastigomycota genomes revealed that these fungi might have developed oxygen-independent biosynthetic pathways for NAD+ and CoA biosynthesis, likely acquired through horizontal gene transfer (HGT) from prokaryotic donors. We confirmed functionality of these putative pathways under anaerobic conditions by heterologous expression in the yeast Saccharomyces cerevisiae. This approach, combined with sequence comparison, offers experimental insight on whether HGT events were required and/or sufficient for acquiring new traits. Moreover, our results demonstrate an engineering strategy for enabling S. cerevisiae to grow anaerobically in the absence of the precursor molecules pantothenate and nicotinate, thereby contributing to alleviate oxygen requirements and to move closer to prototrophic anaerobic growth of this industrially relevant yeast.
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24
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Wronska AK, van den Broek M, Perli T, de Hulster E, Pronk JT, Daran JM. Engineering oxygen-independent biotin biosynthesis in Saccharomyces cerevisiae. Metab Eng 2021; 67:88-103. [PMID: 34052444 DOI: 10.1016/j.ymben.2021.05.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 05/17/2021] [Accepted: 05/23/2021] [Indexed: 01/10/2023]
Abstract
An oxygen requirement for de novo biotin synthesis in Saccharomyces cerevisiae precludes the application of biotin-prototrophic strains in anoxic processes that use biotin-free media. To overcome this issue, this study explores introduction of the oxygen-independent Escherichia coli biotin-biosynthesis pathway in S. cerevisiae. Implementation of this pathway required expression of seven E. coli genes involved in fatty-acid synthesis and three E. coli genes essential for the formation of a pimelate thioester, key precursor of biotin synthesis. A yeast strain expressing these genes readily grew in biotin-free medium, irrespective of the presence of oxygen. However, the engineered strain exhibited specific growth rates 25% lower in biotin-free media than in biotin-supplemented media. Following adaptive laboratory evolution in anoxic cultures, evolved cell lines that no longer showed this growth difference in controlled bioreactors, were characterized by genome sequencing and proteome analyses. The evolved isolates exhibited a whole-genome duplication accompanied with an alteration in the relative gene dosages of biosynthetic pathway genes. These alterations resulted in a reduced abundance of the enzymes catalyzing the first three steps of the E. coli biotin pathway. The evolved pathway configuration was reverse engineered in the diploid industrial S. cerevisiae strain Ethanol Red. The resulting strain grew at nearly the same rate in biotin-supplemented and biotin-free media non-controlled batches performed in an anaerobic chamber. This study established an unique genetic engineering strategy to enable biotin-independent anoxic growth of S. cerevisiae and demonstrated its portability in industrial strain backgrounds.
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Affiliation(s)
- Anna K Wronska
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629, HZ, Delft, the Netherlands.
| | - Marcel van den Broek
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629, HZ, Delft, the Netherlands.
| | - Thomas Perli
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629, HZ, Delft, the Netherlands.
| | - Erik de Hulster
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629, HZ, Delft, the Netherlands.
| | - Jack T Pronk
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629, HZ, Delft, the Netherlands.
| | - Jean-Marc Daran
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629, HZ, Delft, the Netherlands.
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Solieri L. The revenge of Zygosaccharomyces yeasts in food biotechnology and applied microbiology. World J Microbiol Biotechnol 2021; 37:96. [PMID: 33969449 DOI: 10.1007/s11274-021-03066-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 04/28/2021] [Indexed: 12/01/2022]
Abstract
Non-conventional yeasts refer to a huge and still poorly explored group of species alternative to the well-known model organism Saccharomyces cerevisiae. Among them, Zygosaccharomyces rouxii and the sister species Zygosaccharomyces bailii are infamous for spoiling food and beverages even in presence of several food preservatives. On the other hand, their capability to cope with a wide range of process conditions makes these yeasts very attractive factories (the so-called "ZygoFactories") for bio-converting substrates poorly permissive for the growth of other species. In balsamic vinegar Z. rouxii is the main yeast responsible for converting highly concentrated sugars into ethanol, with a preference for fructose over glucose (a trait called fructophily). Z. rouxii has also attracted much attention for the ability to release important flavor compounds, such as fusel alcohols and the derivatives of 4-hydroxyfuranone, which markedly contribute to fragrant and smoky aroma in soy sauce. While Z. rouxii was successfully proposed in brewing for producing low ethanol beer, Z. bailii is promising for lactic acid and bioethanol production. Recently, several research efforts exploited omics tools to pinpoint the genetic bases of distinctive traits in "ZygoFactories", like fructophily, tolerance to high concentrations of sugars, lactic acid and salt. Here, I provided an overview of Zygosaccharomyces industrially relevant phenotypes and summarized the most recent findings in disclosing their genetic bases. I suggest that the increasing number of genomes available for Z. rouxii and other Zygosaccharomyces relatives, combined with recently developed genetic engineering toolkits, will boost the applications of these yeasts in biotechnology and applied microbiology.
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Affiliation(s)
- L Solieri
- Department of Life Sciences, University of Modena and Reggio Emilia, Via Amendola 2, 42122, Reggio Emilia, Italy.
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Randazzo P, Bennis NX, Daran JM, Daran-Lapujade P. gEL DNA: A Cloning- and Polymerase Chain Reaction-Free Method for CRISPR-Based Multiplexed Genome Editing. CRISPR J 2021; 4:896-913. [PMID: 33900846 DOI: 10.1089/crispr.2020.0028] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Even for the genetically accessible yeast Saccharomyces cerevisiae, the CRISPR-Cas DNA editing technology has strongly accelerated and facilitated strain construction. Several methods have been validated for fast and highly efficient single editing events, and diverse approaches for multiplex genome editing have been described in the literature by means of SpCas9 or FnCas12a endonucleases and their associated guide RNAs (gRNAs). The gRNAs used to guide the Cas endonuclease to the editing site are typically expressed from plasmids using native Pol II or Pol III RNA polymerases. These gRNA expression plasmids require laborious, time-consuming cloning steps, which hampers their implementation for academic and applied purposes. In this study, we explore the potential of expressing gRNA from linear DNA fragments using the T7 RNA polymerase (T7RNAP) for single and multiplex genome editing in Saccharomyces cerevisiae. Using FnCas12a, this work demonstrates that transforming short, linear DNA fragments encoding gRNAs in yeast strains expressing T7RNAP promotes highly efficient single and duplex DNA editing. These DNA fragments can be custom ordered, which makes this approach highly suitable for high-throughput strain construction. This work expands the CRISPR toolbox for large-scale strain construction programs in S. cerevisiae and promises to be relevant for other less genetically accessible yeast species.
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Affiliation(s)
- Paola Randazzo
- Department of Biotechnology, Delft University of Biotechnology, Delft, Netherlands
| | - Nicole Xanthe Bennis
- Department of Biotechnology, Delft University of Biotechnology, Delft, Netherlands
| | - Jean-Marc Daran
- Department of Biotechnology, Delft University of Biotechnology, Delft, Netherlands
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Perli T, van der Vorm DNA, Wassink M, van den Broek M, Pronk JT, Daran JM. Engineering heterologous molybdenum-cofactor-biosynthesis and nitrate-assimilation pathways enables nitrate utilization by Saccharomyces cerevisiae. Metab Eng 2021; 65:11-29. [PMID: 33617956 DOI: 10.1016/j.ymben.2021.02.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 01/28/2021] [Accepted: 02/15/2021] [Indexed: 02/06/2023]
Abstract
Metabolic capabilities of cells are not only defined by their repertoire of enzymes and metabolites, but also by availability of enzyme cofactors. The molybdenum cofactor (Moco) is widespread among eukaryotes but absent from the industrial yeast Saccharomyces cerevisiae. No less than 50 Moco-dependent enzymes covering over 30 catalytic activities have been described to date, introduction of a functional Moco synthesis pathway offers interesting options to further broaden the biocatalytic repertoire of S. cerevisiae. In this study, we identified seven Moco biosynthesis genes in the non-conventional yeast Ogataea parapolymorpha by SpyCas9-mediated mutational analysis and expressed them in S. cerevisiae. Functionality of the heterologously expressed Moco biosynthesis pathway in S. cerevisiae was assessed by co-expressing O. parapolymorpha nitrate-assimilation enzymes, including the Moco-dependent nitrate reductase. Following two-weeks of incubation, growth of the engineered S. cerevisiae strain was observed on nitrate as sole nitrogen source. Relative to the rationally engineered strain, the evolved derivatives showed increased copy numbers of the heterologous genes, increased levels of the encoded proteins and a 5-fold higher nitrate-reductase activity in cell extracts. Growth at nM molybdate concentrations was enabled by co-expression of a Chlamydomonas reinhardtii high-affinity molybdate transporter. In serial batch cultures on nitrate-containing medium, a non-engineered S. cerevisiae strain was rapidly outcompeted by the spoilage yeast Brettanomyces bruxellensis. In contrast, an engineered and evolved nitrate-assimilating S. cerevisiae strain persisted during 35 generations of co-cultivation. This result indicates that the ability of engineered strains to use nitrate may be applicable to improve competitiveness of baker's yeast in industrial processes upon contamination with spoilage yeasts.
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Affiliation(s)
- Thomas Perli
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629, HZ, Delft, the Netherlands.
| | - Daan N A van der Vorm
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629, HZ, Delft, the Netherlands.
| | - Mats Wassink
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629, HZ, Delft, the Netherlands.
| | - Marcel van den Broek
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629, HZ, Delft, the Netherlands.
| | - Jack T Pronk
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629, HZ, Delft, the Netherlands.
| | - Jean-Marc Daran
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629, HZ, Delft, the Netherlands.
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Abstract
The production of biofuels from plant biomass is dependent on the availability of enzymes that can hydrolyze the plant cell wall polysaccharides to their monosaccharides. These enzyme mixtures are formed by microorganisms but their native compositions and properties are often not ideal for application. Genetic engineering of these microorganisms is therefore necessary, in which introduction of DNA is an essential precondition. The filamentous fungus Trichoderma reesei-the main producer of plant-cell-wall-degrading enzymes for biofuels and other industries-has been subjected to intensive genetic engineering toward this goal and has become one of the iconic examples of the successful genetic improvement of fungi. However, the genetic manipulation of other enzyme-producing Trichoderma species is frequently less efficient and, therefore, rarely managed. In this chapter, we therefore describe the two potent methods of Trichoderma transformation mediated by either (a) polyethylene glycol (PEG) or (b) Agrobacterium. The methods are optimized for T. reesei but can also be applied for such transformation-resilient species as T. harzianum and T. guizhouense, which are putative upcoming alternatives for T. reesei in this field. The protocols are simple, do not require extensive training or special equipment, and can be further adjusted for T. reesei mutants with particular properties.
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Affiliation(s)
- Feng Cai
- Institute of Chemical, Environmental and Bioscience Engineering (ICEBE), TU Wien, Vienna, Austria.,FungiG, Fungal Genomics Laboratory, Nanjing Agricultural University, Nanjing, People's Republic of China
| | - Christian P Kubicek
- Institute of Chemical, Environmental and Bioscience Engineering (ICEBE), TU Wien, Vienna, Austria
| | - Irina S Druzhinina
- Institute of Chemical, Environmental and Bioscience Engineering (ICEBE), TU Wien, Vienna, Austria. .,FungiG, Fungal Genomics Laboratory, Nanjing Agricultural University, Nanjing, People's Republic of China.
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Scarless Genomic Protein Labeling in Saccharomyces cerevisiae. Methods Mol Biol 2021; 2196:63-75. [PMID: 32889713 DOI: 10.1007/978-1-0716-0868-5_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Labeling a protein of interest is widely used to examine its quantity, modification, localization, and dynamics in the budding yeast Saccharomyces cerevisiae. Fluorescent proteins and epitope tags are often used as protein fusion tags to study target proteins. One prevailing technique is to fuse these tags to a target gene at the precise chromosomal location via homologous recombination. Here we describe a protein labeling strategy based on the URA3 pop-in/pop-out and counterselection system to fuse a fluorescent protein or epitope tag scarlessly to a target protein at its native locus in S. cerevisiae.
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Abstract
DNA break lesions pose a serious threat to the integrity of the genome. Eukaryotic cells can repair these lesions using the homologous recombination pathway that guides the repair reaction by using a homologous DNA template. The budding yeast Saccharomyces cerevisiae is an excellent model system with which to study this repair mechanism and the resulting patterns of genomic change resulting from it. In this chapter, we describe an approach that utilizes whole-genome sequencing data to support the analysis of tracts of loss-of-heterozygosity (LOH) that can arise from mitotic recombination in the context of the entire diploid yeast genome. The workflow and the discussion in this chapter are intended to enable classically trained molecular biologists and geneticists with limited experience in computational methods to conceptually understand and execute the steps of genome-wide LOH analysis as well as to adapt and apply them to their own specific studies and experimental models.
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Affiliation(s)
- Lydia R Heasley
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, USA
| | - Nadia M V Sampaio
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, USA
- Cell and Molecular Biology Graduate Program, Colorado State University, Fort Collins, CO, USA
| | - Juan Lucas Argueso
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, USA.
- Cell and Molecular Biology Graduate Program, Colorado State University, Fort Collins, CO, USA.
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Squalene-Tetrahymanol Cyclase Expression Enables Sterol-Independent Growth of Saccharomyces cerevisiae. Appl Environ Microbiol 2020; 86:AEM.00672-20. [PMID: 32561581 PMCID: PMC7440791 DOI: 10.1128/aem.00672-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 06/14/2020] [Indexed: 02/08/2023] Open
Abstract
The laboratory experiments described in this report simulate a proposed horizontal gene transfer event during the evolution of strictly anaerobic fungi. The demonstration that expression of a single heterologous gene sufficed to eliminate anaerobic sterol requirements in the model eukaryote Saccharomyces cerevisiae therefore contributes to our understanding of how sterol-independent eukaryotes evolved in anoxic environments. This report provides a proof of principle for a metabolic engineering strategy to eliminate sterol requirements in yeast strains that are applied in large-scale anaerobic industrial processes. The sterol-independent yeast strains described in this report provide a valuable platform for further studies on the physiological roles and impacts of sterols and sterol surrogates in eukaryotic cells. Biosynthesis of sterols, which are considered essential components of virtually all eukaryotic membranes, requires molecular oxygen. Anaerobic growth of the yeast Saccharomyces cerevisiae therefore strictly depends on sterol supplementation of synthetic growth media. Neocallimastigomycota are a group of strictly anaerobic fungi which, instead of containing sterols, contain the pentacyclic triterpenoid “sterol surrogate” tetrahymanol, which is formed by cyclization of squalene. Here, we demonstrate that expression of the squalene-tetrahymanol cyclase gene TtTHC1 from the ciliate Tetrahymena thermophila enables synthesis of tetrahymanol by S. cerevisiae. Moreover, expression of TtTHC1 enabled exponential growth of anaerobic S. cerevisiae cultures in sterol-free synthetic media. After deletion of the ERG1 gene from a TtTHC1-expressing S. cerevisiae strain, native sterol synthesis was abolished and sustained sterol-free growth was demonstrated under anaerobic as well as aerobic conditions. Anaerobic cultures of TtTHC1-expressing S. cerevisiae on sterol-free medium showed lower specific growth rates and biomass yields than ergosterol-supplemented cultures, while their ethanol yield was higher. This study demonstrated that acquisition of a functional squalene-tetrahymanol cyclase gene offers an immediate growth advantage to S. cerevisiae under anaerobic, sterol-limited conditions and provides the basis for a metabolic engineering strategy to eliminate the oxygen requirements associated with sterol synthesis in yeasts. IMPORTANCE The laboratory experiments described in this report simulate a proposed horizontal gene transfer event during the evolution of strictly anaerobic fungi. The demonstration that expression of a single heterologous gene sufficed to eliminate anaerobic sterol requirements in the model eukaryote Saccharomyces cerevisiae therefore contributes to our understanding of how sterol-independent eukaryotes evolved in anoxic environments. This report provides a proof of principle for a metabolic engineering strategy to eliminate sterol requirements in yeast strains that are applied in large-scale anaerobic industrial processes. The sterol-independent yeast strains described in this report provide a valuable platform for further studies on the physiological roles and impacts of sterols and sterol surrogates in eukaryotic cells.
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Dekker WJC, Wiersma SJ, Bouwknegt J, Mooiman C, Pronk JT. Anaerobic growth of Saccharomyces cerevisiae CEN.PK113-7D does not depend on synthesis or supplementation of unsaturated fatty acids. FEMS Yeast Res 2020; 19:5551482. [PMID: 31425603 PMCID: PMC6750169 DOI: 10.1093/femsyr/foz060] [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: 06/25/2019] [Accepted: 08/15/2019] [Indexed: 12/20/2022] Open
Abstract
In Saccharomyces cerevisiae, acyl-coenzyme A desaturation by Ole1 requires molecular oxygen. Tween 80, a poly-ethoxylated sorbitan-oleate ester, is therefore routinely included in anaerobic growth media as a source of unsaturated fatty acids (UFAs). During optimization of protocols for anaerobic bioreactor cultivation of this yeast, we consistently observed growth of the laboratory strain S. cerevisiae CEN.PK113-7D in media that contained the anaerobic growth factor ergosterol, but lacked UFAs. To minimize oxygen contamination, additional experiments were performed in an anaerobic chamber. After anaerobic precultivation without ergosterol and Tween 80, strain CEN.PK113-7D and a congenic ole1Δ strain both grew during three consecutive batch-cultivation cycles on medium that contained ergosterol, but not Tween 80. During these three cycles, no UFAs were detected in biomass of cultures grown without Tween 80, while contents of C10 to C14 saturated fatty acids were higher than in biomass from Tween 80-supplemented cultures. In contrast to its UFA-independent anaerobic growth, aerobic growth of the ole1Δ strain strictly depended on Tween 80 supplementation. This study shows that the requirement of anaerobic cultures of S. cerevisiae for UFA supplementation is not absolute and provides a basis for further research on the effects of lipid composition on yeast viability and robustness.
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Affiliation(s)
- Wijb J C Dekker
- Delft University of Technology, Department of Biotechnology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Sanne J Wiersma
- Delft University of Technology, Department of Biotechnology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Jonna Bouwknegt
- Delft University of Technology, Department of Biotechnology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Christiaan Mooiman
- Delft University of Technology, Department of Biotechnology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Jack T Pronk
- Delft University of Technology, Department of Biotechnology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
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Boonekamp FJ, Dashko S, Duiker D, Gehrmann T, van den Broek M, den Ridder M, Pabst M, Robert V, Abeel T, Postma ED, Daran JM, Daran-Lapujade P. Design and Experimental Evaluation of a Minimal, Innocuous Watermarking Strategy to Distinguish Near-Identical DNA and RNA Sequences. ACS Synth Biol 2020; 9:1361-1375. [PMID: 32413257 PMCID: PMC7309318 DOI: 10.1021/acssynbio.0c00045] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The construction of powerful cell factories requires intensive and extensive remodelling of microbial genomes. Considering the rapidly increasing number of these synthetic biology endeavors, there is an increasing need for DNA watermarking strategies that enable the discrimination between synthetic and native gene copies. While it is well documented that codon usage can affect translation, and most likely mRNA stability in eukaryotes, remarkably few quantitative studies explore the impact of watermarking on transcription, protein expression, and physiology in the popular model and industrial yeast Saccharomyces cerevisiae. The present study, using S. cerevisiae as eukaryotic paradigm, designed, implemented, and experimentally validated a systematic strategy to watermark DNA with minimal alteration of yeast physiology. The 13 genes encoding proteins involved in the major pathway for sugar utilization (i.e., glycolysis and alcoholic fermentation) were simultaneously watermarked in a yeast strain using the previously published pathway swapping strategy. Carefully swapping codons of these naturally codon optimized, highly expressed genes, did not affect yeast physiology and did not alter transcript abundance, protein abundance, and protein activity besides a mild effect on Gpm1. The markerQuant bioinformatics method could reliably discriminate native from watermarked genes and transcripts. Furthermore, presence of watermarks enabled selective CRISPR/Cas genome editing, specifically targeting the native gene copy while leaving the synthetic, watermarked variant intact. This study offers a validated strategy to simply watermark genes in S. cerevisiae.
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Affiliation(s)
- Francine J. Boonekamp
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629HZ Delft, The Netherlands
| | - Sofia Dashko
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629HZ Delft, The Netherlands
| | - Donna Duiker
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629HZ Delft, The Netherlands
| | - Thies Gehrmann
- Westerdijk Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Marcel van den Broek
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629HZ Delft, The Netherlands
| | - Maxime den Ridder
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629HZ Delft, The Netherlands
| | - Martin Pabst
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629HZ Delft, The Netherlands
| | - Vincent Robert
- Westerdijk Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Thomas Abeel
- Intelligent Systems − Delft Bioinformatics Lab, Delft University of Technology, Van Mourik Broekmanweg 6, 2628XE Delft, The Netherlands
| | - Eline D. Postma
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629HZ Delft, The Netherlands
| | - Jean-Marc Daran
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629HZ Delft, The Netherlands
| | - Pascale Daran-Lapujade
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629HZ Delft, The Netherlands
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Gorter de Vries AR, Knibbe E, van Roosmalen R, van den Broek M, de la Torre Cortés P, O'Herne SF, Vijverberg PA, El Masoudi A, Brouwers N, Pronk JT, Daran JMG. Improving Industrially Relevant Phenotypic Traits by Engineering Chromosome Copy Number in Saccharomyces pastorianus. Front Genet 2020; 11:518. [PMID: 32582279 PMCID: PMC7283523 DOI: 10.3389/fgene.2020.00518] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 04/28/2020] [Indexed: 11/13/2022] Open
Abstract
The lager-brewing yeast Saccharomyces pastorianus is a hybrid between S. cerevisiae and S. eubayanus with an exceptional degree of aneuploidy. While chromosome copy number variation (CCNV) is present in many industrial Saccharomyces strains and has been linked to various industrially-relevant traits, its impact on the brewing performance of S. pastorianus remains elusive. Here we attempt to delete single copies of chromosomes which are relevant for the production of off-flavor compound diacetyl by centromere silencing. However, the engineered strains display CNV of multiple non-targeted chromosomes. We attribute this unintended CCNV to inherent instability and to a mutagenic effect of electroporation and of centromere-silencing. Regardless, the resulting strains displayed large phenotypic diversity. By growing centromere-silenced cells in repeated sequential batches in medium containing 10% ethanol, mutants with increased ethanol tolerance were obtained. By using CCNV mutagenesis by exposure to the mitotic inhibitor MBC, selection in the same set-up yielded even more tolerant mutants that would not classify as genetically modified organisms. These results show that CCNV of alloaneuploid S. pastorianus genomes is highly unstable, and that CCNV mutagenesis can generate broad diversity. Coupled to effective selection or screening, CCNV mutagenesis presents a potent tool for strain improvement.
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Affiliation(s)
| | - Ewout Knibbe
- Department of Biotechnology, Delft University of Technology, Delft, Netherlands
| | | | | | | | - Stephanie F O'Herne
- Department of Biotechnology, Delft University of Technology, Delft, Netherlands
| | - Pascal A Vijverberg
- Department of Biotechnology, Delft University of Technology, Delft, Netherlands
| | - Anissa El Masoudi
- Department of Biotechnology, Delft University of Technology, Delft, Netherlands
| | - Nick Brouwers
- Department of Biotechnology, Delft University of Technology, Delft, Netherlands
| | - Jack T Pronk
- Department of Biotechnology, Delft University of Technology, Delft, Netherlands
| | - Jean-Marc G Daran
- Department of Biotechnology, Delft University of Technology, Delft, Netherlands
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Wang G, Øzmerih S, Guerreiro R, Meireles AC, Carolas A, Milne N, Jensen MK, Ferreira BS, Borodina I. Improvement of cis, cis-Muconic Acid Production in Saccharomyces cerevisiae through Biosensor-Aided Genome Engineering. ACS Synth Biol 2020; 9:634-646. [PMID: 32058699 PMCID: PMC8457548 DOI: 10.1021/acssynbio.9b00477] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Muconic acid is a potential platform chemical for the production of nylon, polyurethanes, and terephthalic acid. It is also an attractive functional copolymer in plastics due to its two double bonds. At this time, no economically viable process for the production of muconic acid exists. To harness novel genetic targets for improved production of cis,cis-muconic acid (CCM) in the yeast Saccharomyces cerevisiae, we employed a CCM-biosensor coupled to GFP expression with a broad dynamic response to screen UV-mutagenesis libraries of CCM-producing yeast. Via fluorescence activated cell sorting we identified a clone Mut131 with a 49.7% higher CCM titer and 164% higher titer of biosynthetic intermediate-protocatechuic acid (PCA). Genome resequencing of the Mut131 and reverse engineering identified seven causal missense mutations of the native genes (PWP2, EST2, ATG1, DIT1, CDC15, CTS2, and MNE1) and a duplication of two CCM biosynthetic genes, encoding dehydroshikimate dehydratase and catechol 1,2-dioxygenase, which were not recognized as flux controlling before. The Mut131 strain was further rationally engineered by overexpression of the genes encoding for PCA decarboxylase and AROM protein without shikimate dehydrogenase domain (Aro1pΔE), and by restoring URA3 prototrophy. The resulting engineered strain produced 20.8 g/L CCM in controlled fed-batch fermentation, with a yield of 66.2 mg/g glucose and a productivity of 139 mg/L/h, representing the highest reported performance metrics in a yeast for de novo CCM production to date and the highest production of an aromatic compound in yeast. The study illustrates the benefit of biosensor-based selection and brings closer the prospect of biobased muconic acid.
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Affiliation(s)
- Guokun Wang
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, DK-2800 Kgs, Denmark
| | - Süleyman Øzmerih
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, DK-2800 Kgs, Denmark
| | - Rogério Guerreiro
- Biotrend-Inovação e Engenharia em Biotecnologia SA, Cantanhede, 3060-197, Portugal
| | - Ana C. Meireles
- Biotrend-Inovação e Engenharia em Biotecnologia SA, Cantanhede, 3060-197, Portugal
| | - Ana Carolas
- Biotrend-Inovação e Engenharia em Biotecnologia SA, Cantanhede, 3060-197, Portugal
| | - Nicholas Milne
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, DK-2800 Kgs, Denmark
| | - Michael K. Jensen
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, DK-2800 Kgs, Denmark
| | - Bruno S. Ferreira
- Biotrend-Inovação e Engenharia em Biotecnologia SA, Cantanhede, 3060-197, Portugal
| | - Irina Borodina
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, DK-2800 Kgs, Denmark
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Yang S, Cao X, Yu W, Li S, Zhou YJ. Efficient targeted mutation of genomic essential genes in yeast Saccharomyces cerevisiae. Appl Microbiol Biotechnol 2020; 104:3037-3047. [PMID: 32043190 DOI: 10.1007/s00253-020-10405-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Revised: 01/13/2020] [Accepted: 01/23/2020] [Indexed: 02/06/2023]
Abstract
Targeted gene mutation by allelic replacement is important for functional genomic analysis and metabolic engineering. However, it is challenging in mutating the essential genes with the traditional method by using a selection marker, since the first step of essential gene knockout will result in a lethal phenotype. Here, we developed a two-end selection marker (Two-ESM) method for site-directed mutation of essential genes in Saccharomyces cerevisiae with the aid of the CRISPR/Cas9 system. With this method, single and double mutations of the essential gene ERG20 (encoding farnesyl diphosphate synthase) in S. cerevisiae were successfully constructed with high efficiencies of 100%. In addition, the Two-ESM method significantly improved the mutation efficiency and simplified the genetic manipulation procedure compared with traditional methods. The genome integration and mutation efficiencies were further improved by dynamic regulation of mutant gene expression and optimization of the integration modules. This Two-ESM method will facilitate the construction of genomic mutations of essential genes for functional genomic analysis and metabolic flux regulation in yeasts. KEY POINTS: • A Two-ESM strategy achieves mutations of essential genes with high efficiency of 100%. • The optimized three-module method improves the integration efficiency by more than three times. • This method will facilitate the functional genomic analysis and metabolic flux regulation.
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Affiliation(s)
- Shan Yang
- Division of Biotechnology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, 116023, China
- Dalian Key Laboratory of Energy Biotechnology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xuan Cao
- Division of Biotechnology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, 116023, China
| | - Wei Yu
- Division of Biotechnology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, 116023, China
| | - Shengying Li
- Shandong Provincial Key Laboratory of Synthetic Biology, CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, 266101, Shandong, China
| | - Yongjin J Zhou
- Division of Biotechnology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, 116023, China.
- Dalian Key Laboratory of Energy Biotechnology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China.
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China.
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Hamilton M, Consiglio AL, MacEwen K, Shaw AJ, Tsakraklides V. Identification of a Yarrowia lipolytica acetamidase and its use as a yeast genetic marker. Microb Cell Fact 2020; 19:22. [PMID: 32024536 PMCID: PMC7003347 DOI: 10.1186/s12934-020-1292-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 01/22/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Yarrowia lipolytica is an oleaginous yeast that can be genetically engineered to produce lipid and non-lipid biochemicals from a variety of feedstocks. Metabolic engineering of this organism usually requires genetic markers in order to select for modified cells. The potential to combine multiple genetic manipulations depends on the availability of multiple or recyclable selectable markers. RESULTS We found that Y. lipolytica has the ability to utilize acetamide as the sole nitrogen source suggesting that the genome contains an acetamidase gene. Two potential Y. lipolytica acetamidase gene candidates were identified by homology to the A. nidulans acetamidase amdS. These genes were deleted in the wild-type Y. lipolytica strain YB-392, and deletion strains were evaluated for acetamide utilization. One deletion strain was unable to grow on acetamide and a putative acetamidase gene YlAMD1 was identified. Transformation of YlAMD1 followed by selection on acetamide media and counterselection on fluoroacetamide media showed that YlAMD1 can be used as a recyclable genetic marker in Saccharomyces cerevisiae and Ylamd1Δ Y. lipolytica. CONCLUSIONS These findings add to our understanding of Y. lipolytica nitrogen utilization and expand the set of genetic tools available for engineering this organism, as well as S. cerevisiae.
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Affiliation(s)
| | | | - Kyle MacEwen
- Novogy, Inc., 85 Bolton Street, Cambridge, MA, 02140, USA
| | - A Joe Shaw
- Novogy, Inc., 85 Bolton Street, Cambridge, MA, 02140, USA
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Functional expression of a bacterial α-ketoglutarate dehydrogenase in the cytosol of Saccharomyces cerevisiae. Metab Eng 2019; 56:190-197. [DOI: 10.1016/j.ymben.2019.10.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 09/20/2019] [Accepted: 10/01/2019] [Indexed: 11/23/2022]
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Pereira R, Wei Y, Mohamed E, Radi M, Malina C, Herrgård MJ, Feist AM, Nielsen J, Chen Y. Adaptive laboratory evolution of tolerance to dicarboxylic acids in Saccharomyces cerevisiae. Metab Eng 2019; 56:130-141. [DOI: 10.1016/j.ymben.2019.09.008] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 09/19/2019] [Accepted: 09/19/2019] [Indexed: 11/16/2022]
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Brouwers N, Brickwedde A, Gorter de Vries AR, van den Broek M, Weening SM, van den Eijnden L, Diderich JA, Bai FY, Pronk JT, Daran JMG. Himalayan Saccharomyces eubayanus Genome Sequences Reveal Genetic Markers Explaining Heterotic Maltotriose Consumption by Saccharomyces pastorianus Hybrids. Appl Environ Microbiol 2019; 85:e01516-19. [PMID: 31519660 PMCID: PMC6821976 DOI: 10.1128/aem.01516-19] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 09/04/2019] [Indexed: 12/27/2022] Open
Abstract
Saccharomyces pastorianus strains are hybrids of Saccharomyces cerevisiae and Saccharomyces eubayanus that have been domesticated for centuries in lager beer brewing environments. As sequences and structures of S. pastorianus genomes are being resolved, molecular mechanisms and evolutionary origins of several industrially relevant phenotypes remain unknown. This study investigates how maltotriose metabolism, a key feature in brewing, may have arisen in early S. eubayanus × S. cerevisiae hybrids. To address this question, we generated a nearly complete genome assembly of Himalayan S. eubayanus strains of the Holarctic subclade. This group of strains has been proposed to be the S. eubayanus subgenome origin of current S. pastorianus strains. The Himalayan S. eubayanus genomes harbored several copies of an S. eubayanusAGT1 (SeAGT1) α-oligoglucoside transporter gene with high sequence identity to genes encountered in S. pastorianus Although Himalayan S. eubayanus strains cannot grow on maltose and maltotriose, their maltose-hydrolase and SeMALT1 and SeAGT1 maltose transporter genes complemented the corresponding null mutants of S. cerevisiae Expression, in Himalayan S. eubayanus of a functional S. cerevisiae maltose metabolism regulator gene (MALx3) enabled growth on oligoglucosides. The hypothesis that the maltotriose-positive phenotype in S. pastorianus is a result of heterosis was experimentally tested by constructing an S. cerevisiae × S. eubayanus laboratory hybrid with a complement of maltose metabolism genes that resembles that of current S. pastorianus strains. The ability of this hybrid to consume maltotriose in brewer's wort demonstrated regulatory cross talk between subgenomes and thereby validated this hypothesis. These results support experimentally the new postulated hypothesis on the evolutionary origin of an essential phenotype of lager brewing strains and valuable knowledge for industrial exploitation of laboratory-made S. pastorianus-like hybrids.IMPORTANCES. pastorianus, an S. cerevisiae × S. eubayanus hybrid, is used for production of lager beer, the most produced alcoholic beverage worldwide. It emerged by spontaneous hybridization and colonized early lager brewing processes. Despite accumulation and analysis of genome sequencing data of S. pastorianus parental genomes, the genetic blueprint of industrially relevant phenotypes remains unresolved. Assimilation of maltotriose, an abundant sugar in wort, has been postulated to be inherited from the S. cerevisiae parent. Here, we demonstrate that although Asian S. eubayanus isolates harbor a functional maltotriose transporter SeAGT1 gene, they are unable to grow on α-oligoglucosides, but expression of S. cerevisiae regulator MAL13 (ScMAL13) was sufficient to restore growth on trisaccharides. We hypothesized that the S. pastorianus maltotriose phenotype results from regulatory interaction between S. cerevisiae maltose transcription activator and the promoter of SeAGT1 We experimentally confirmed the heterotic nature of the phenotype, and thus these results provide experimental evidence of the evolutionary origin of an essential phenotype of lager brewing strains.
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Affiliation(s)
- Nick Brouwers
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - Anja Brickwedde
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | | | - Marcel van den Broek
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - Susan M Weening
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | | | - Jasper A Diderich
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - Feng-Yan Bai
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Jack T Pronk
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - Jean-Marc G Daran
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
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Sampaio NMV, Watson RA, Argueso JL. Controlled Reduction of Genomic Heterozygosity in an Industrial Yeast Strain Reveals Wide Cryptic Phenotypic Variation. Front Genet 2019; 10:782. [PMID: 31572430 PMCID: PMC6749062 DOI: 10.3389/fgene.2019.00782] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 07/24/2019] [Indexed: 01/12/2023] Open
Abstract
Abundant genomic heterozygosity can be found in wild strains of the budding yeast Saccharomyces cerevisiae isolated from industrial and clinical environments. The extent to which heterozygosity influences the phenotypes of these isolates is not fully understood. One such case is the PE-2/JAY270 strain, a natural hybrid widely adopted by sugarcane bioethanol distilleries for its ability to thrive under harsh biotic and abiotic stresses during industrial scale fermentation, however, it is not known whether or how the heterozygous configuration of the JAY270 genome contributes to its many desirable traits. In this study, we took a step toward exploring this question by conducting an initial functional characterization of JAY270’s heteroalleles. We manipulated the abundance and distribution of heterozygous alleles through inbreeding and targeted uniparental disomy (UPD). Unique combinations of homozygous alleles in each inbred strain revealed wide phenotypic variation for at least two important industrial traits: Heat stress tolerance and competitive growth. Quantitative trait loci analyses allowed the identification of broad genomic regions where genetic polymorphisms potentially impacted these traits, and there was no overlap between the loci associated with each. In addition, we adapted an approach to induce bidirectional UPD of three targeted pairs of chromosomes (IV, XIV, and XV), while heterozygosity was maintained elsewhere in the genome. In most cases UPD led to detectable phenotypic alterations, often in opposite directions between the two homozygous haplotypes in each UPD pair. Our results showed that both widespread and regional homozygosity could uncover cryptic phenotypic variation supported by the heteroalleles residing in the JAY270 genome. Interestingly, we characterized multiple examples of inbred and UPD strains that displayed heat tolerance or competitive growth phenotypes that were superior to their heterozygous parent. However, we propose that homozygosity for those regions may be associated with a decrease in overall fitness in the complex and dynamic distillery environment, and that may have contributed to slowing down the erosion of heterozygosity from the JAY270 genome. This study also laid a foundation for approaches that can be expanded to the identification of specific alleles of interest for industrial applications in this and other hybrid yeast strains.
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Affiliation(s)
- Nadia M V Sampaio
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, United States.,Cell and Molecular Biology Graduate Program, Colorado State University, Fort Collins, CO, United States
| | - Ruth A Watson
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, United States
| | - Juan Lucas Argueso
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, United States.,Cell and Molecular Biology Graduate Program, Colorado State University, Fort Collins, CO, United States
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Gorter de Vries AR, Couwenberg LGF, van den Broek M, de la Torre Cortés P, Ter Horst J, Pronk JT, Daran JMG. Allele-specific genome editing using CRISPR-Cas9 is associated with loss of heterozygosity in diploid yeast. Nucleic Acids Res 2019; 47:1362-1372. [PMID: 30517747 PMCID: PMC6379674 DOI: 10.1093/nar/gky1216] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Revised: 11/20/2018] [Accepted: 11/22/2018] [Indexed: 12/13/2022] Open
Abstract
Targeted DNA double-strand breaks (DSBs) with CRISPR–Cas9 have revolutionized genetic modification by enabling efficient genome editing in a broad range of eukaryotic systems. Accurate gene editing is possible with near-perfect efficiency in haploid or (predominantly) homozygous genomes. However, genomes exhibiting polyploidy and/or high degrees of heterozygosity are less amenable to genetic modification. Here, we report an up to 99-fold lower gene editing efficiency when editing individual heterozygous loci in the yeast genome. Moreover, Cas9-mediated introduction of a DSB resulted in large scale loss of heterozygosity affecting DNA regions up to 360 kb and up to 1700 heterozygous nucleotides, due to replacement of sequences on the targeted chromosome by corresponding sequences from its non-targeted homolog. The observed patterns of loss of heterozygosity were consistent with homology directed repair. The extent and frequency of loss of heterozygosity represent a novel mutagenic side-effect of Cas9-mediated genome editing, which would have to be taken into account in eukaryotic gene editing. In addition to contributing to the limited genetic amenability of heterozygous yeasts, Cas9-mediated loss of heterozygosity could be particularly deleterious for human gene therapy, as loss of heterozygous functional copies of anti-proliferative and pro-apoptotic genes is a known path to cancer.
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Affiliation(s)
| | - Lucas G F Couwenberg
- Department of Biotechnology, Delft University of Technology, Delft 2629HZ, The Netherlands
| | - Marcel van den Broek
- Department of Biotechnology, Delft University of Technology, Delft 2629HZ, The Netherlands
| | | | - Jolanda Ter Horst
- Department of Biotechnology, Delft University of Technology, Delft 2629HZ, The Netherlands
| | - Jack T Pronk
- Department of Biotechnology, Delft University of Technology, Delft 2629HZ, The Netherlands
| | - Jean-Marc G Daran
- Department of Biotechnology, Delft University of Technology, Delft 2629HZ, The Netherlands
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43
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Bracher JM, Martinez-Rodriguez OA, Dekker WJC, Verhoeven MD, van Maris AJA, Pronk JT. Reassessment of requirements for anaerobic xylose fermentation by engineered, non-evolved Saccharomyces cerevisiae strains. FEMS Yeast Res 2019; 19:5106349. [PMID: 30252062 PMCID: PMC6240133 DOI: 10.1093/femsyr/foy104] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 09/21/2018] [Indexed: 01/03/2023] Open
Abstract
Expression of a heterologous xylose isomerase, deletion of the GRE3 aldose-reductase gene and overexpression of genes encoding xylulokinase (XKS1) and non-oxidative pentose-phosphate-pathway enzymes (RKI1, RPE1, TAL1, TKL1) enables aerobic growth of Saccharomyces cerevisiae on d-xylose. However, literature reports differ on whether anaerobic growth on d-xylose requires additional mutations. Here, CRISPR-Cas9-assisted reconstruction and physiological analysis confirmed an early report that this basic set of genetic modifications suffices to enable anaerobic growth on d-xylose in the CEN.PK genetic background. Strains that additionally carried overexpression cassettes for the transaldolase and transketolase paralogs NQM1 and TKL2 only exhibited anaerobic growth on d-xylose after a 7–10 day lag phase. This extended lag phase was eliminated by increasing inoculum concentrations from 0.02 to 0.2 g biomass L−1. Alternatively, a long lag phase could be prevented by sparging low-inoculum-density bioreactor cultures with a CO2/N2-mixture, thus mimicking initial CO2 concentrations in high-inoculum-density, nitrogen-sparged cultures, or by using l-aspartate instead of ammonium as nitrogen source. This study resolves apparent contradictions in the literature on the genetic interventions required for anaerobic growth of CEN.PK-derived strains on d-xylose. Additionally, it indicates the potential relevance of CO2 availability and anaplerotic carboxylation reactions for anaerobic growth of engineered S. cerevisiae strains on d-xylose.
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Affiliation(s)
- Jasmine M Bracher
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | | | - Wijb J C Dekker
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Maarten D Verhoeven
- DSM Biotechnology Centre, Alexander Fleminglaan 1, 2613 AX Delft, The Netherlands
| | - Antonius J A van Maris
- Department of Industrial Biotechnology, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, AlbaNova University Center, SE 106 91, Stockholm, Sweden
| | - Jack T Pronk
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
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amdS as a dominant recyclable marker in Cryptococcus neoformans. Fungal Genet Biol 2019; 131:103241. [PMID: 31220607 DOI: 10.1016/j.fgb.2019.103241] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 06/13/2019] [Accepted: 06/13/2019] [Indexed: 02/04/2023]
Abstract
While the fungal pathogen Cryptoccocus neoformans is a leading cause of death in immunocompromised individuals, the molecular toolkit currently available to study this important pathogen is extremely limited. To enable an unprecedented level of control over manipulation of the genome, we have developed a dominant recyclable marker by expanding on the classic studies of the amdS gene by Michael J. Hynes and John Pateman. The ascomycete Aspergillus nidulans employs the acetamidase AmdS to hydrolyse acetamide to ammonium and acetate, which serve as a nitrogen and carbon source, respectively. Acetamidase activity has never been reported in the Basidiomycota. Here we have successfully demonstrated that acetamide can be utilized as a good nitrogen source in C. neoformans heterologously expressing amdS and that this activity does not influence virulence, enabling it to be used as a basic dominant selectable marker. The expression of this gene in C. neoformans also causes sensitivity to fluoroacetamide, permitting counterselection. Taking advantage of this toxicity we have modified our basic marker to create a comprehensive series of powerful and reliable tools to successfully delete multiple genes in the one strain, generate markerless strains with modifications such as fluorescent protein fusions at native genomic loci, and establish whether a gene is essential in C. neoformans.
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45
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Borgström C, Wasserstrom L, Almqvist H, Broberg K, Klein B, Noack S, Lidén G, Gorwa-Grauslund MF. Identification of modifications procuring growth on xylose in recombinant Saccharomyces cerevisiae strains carrying the Weimberg pathway. Metab Eng 2019; 55:1-11. [PMID: 31150803 DOI: 10.1016/j.ymben.2019.05.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 05/14/2019] [Accepted: 05/27/2019] [Indexed: 11/29/2022]
Abstract
The most prevalent xylose-assimilating pathways in recombinant Saccharomyces cerevisiae, i.e. the xylose isomerase (XI) and the xylose reductase/xylitol dehydrogenase (XR/XDH) pathways, channel the carbon flux through the pentose phosphate pathway and further into glycolysis. In contrast, the oxidative and non-phosphorylative bacterial Weimberg pathway channels the xylose carbon through five steps into the metabolic node α-ketoglutarate (αKG) that can be utilized for growth or diverted into production of various metabolites. In the present study, steps preventing the establishment of a functional Weimberg pathway in S. cerevisiae were identified. Using an original design where a S. cerevisiae strain was expressing the essential four genes of the Caulobacter crescentus pathway (xylB, xylD, xylX, xylA) together with a deletion of FRA2 gene to upregulate the iron-sulfur metabolism, it was shown that the C. crescentus αKG semialdehyde dehydrogenase, XylA was not functional in S. cerevisiae. When replaced by the recently described analog from Corynebacterium glutamicum, KsaD, significantly higher in vitro activity was observed but the strain did not grow on xylose. Adaptive laboratory evolution (ALE) on a xylose/glucose medium on this strain led to a loss of XylB, the first step of the Weimberg pathway, suggesting that ALE favored minimizing the inhibiting xylonate accumulation by restricting the upper part of the pathway. Therefore three additional gene copies of the lower Weimberg pathway (XylD, XylX and KsaD) were introduced. The resulting S. cerevisiae strain (ΔΔfra2, xylB, 4x (xylD-xylX-ksaD)) was able to generate biomass from xylose and Weimberg pathway intermediates were detected. To our knowledge this is the first report of a functional complete Weimberg pathway expressed in fungi. When optimized this pathway has the potential to channel xylose towards value-added specialty chemicals such as dicarboxylic acids and diols.
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Affiliation(s)
- Celina Borgström
- Division of Applied Microbiology, Department of Chemistry, Lund University, PO Box 124, 221 00, Lund, Sweden
| | - Lisa Wasserstrom
- Division of Applied Microbiology, Department of Chemistry, Lund University, PO Box 124, 221 00, Lund, Sweden
| | - Henrik Almqvist
- Department of Chemical Engineering, Lund University, PO Box 124, 221 00, Lund, Sweden
| | - Kristina Broberg
- Department of Chemical Engineering, Lund University, PO Box 124, 221 00, Lund, Sweden
| | - Bianca Klein
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, Jülich, D-52425, Germany
| | - Stephan Noack
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, Jülich, D-52425, Germany; Bioeconomy Science Center (BioSC), Forschungszentrum Jülich GmbH, Jülich, D-52425, Germany
| | - Gunnar Lidén
- Department of Chemical Engineering, Lund University, PO Box 124, 221 00, Lund, Sweden
| | - Marie F Gorwa-Grauslund
- Division of Applied Microbiology, Department of Chemistry, Lund University, PO Box 124, 221 00, Lund, Sweden.
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Osiro KO, Borgström C, Brink DP, Fjölnisdóttir BL, Gorwa-Grauslund MF. Exploring the xylose paradox in Saccharomyces cerevisiae through in vivo sugar signalomics of targeted deletants. Microb Cell Fact 2019; 18:88. [PMID: 31122246 PMCID: PMC6532234 DOI: 10.1186/s12934-019-1141-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Accepted: 05/17/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND There have been many successful strategies to implement xylose metabolism in Saccharomyces cerevisiae, but no effort has so far enabled xylose utilization at rates comparable to that of glucose (the preferred sugar of this yeast). Many studies have pointed towards the engineered yeast not sensing that xylose is a fermentable carbon source despite growing and fermenting on it, which is paradoxical. We have previously used fluorescent biosensor strains to in vivo monitor the sugar signalome in yeast engineered with xylose reductase and xylitol dehydrogenase (XR/XDH) and have established that S. cerevisiae senses high concentrations of xylose with the same signal as low concentration of glucose, which may explain the poor utilization. RESULTS In the present study, we evaluated the effects of three deletions (ira2∆, isu1∆ and hog1∆) that have recently been shown to display epistatic effects on a xylose isomerase (XI) strain. Through aerobic and anaerobic characterization, we showed that the proposed effects in XI strains were for the most part also applicable in the XR/XDH background. The ira2∆isu1∆ double deletion led to strains with the highest specific xylose consumption- and ethanol production rates but also the lowest biomass titre. The signalling response revealed that ira2∆isu1∆ changed the low glucose-signal in the background strain to a simultaneous signalling of high and low glucose, suggesting that engineering of the signalome can improve xylose utilization. CONCLUSIONS The study was able to correlate the previously proposed beneficial effects of ira2∆, isu1∆ and hog1∆ on S. cerevisiae xylose uptake, with a change in the sugar signalome. This is in line with our previous hypothesis that the key to resolve the xylose paradox lies in the sugar sensing and signalling networks. These results indicate that the future engineering targets for improved xylose utilization should probably be sought not in the metabolic networks, but in the signalling ones.
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Affiliation(s)
- Karen O Osiro
- Applied Microbiology, Department of Chemistry, Lund University, Lund, Sweden
| | - Celina Borgström
- Applied Microbiology, Department of Chemistry, Lund University, Lund, Sweden
| | - Daniel P Brink
- Applied Microbiology, Department of Chemistry, Lund University, Lund, Sweden
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Verhoeven MD, Bracher JM, Nijland JG, Bouwknegt J, Daran JMG, Driessen AJM, van Maris AJA, Pronk JT. Laboratory evolution of a glucose-phosphorylation-deficient, arabinose-fermenting S. cerevisiae strain reveals mutations in GAL2 that enable glucose-insensitive l-arabinose uptake. FEMS Yeast Res 2019; 18:5026172. [PMID: 29860442 PMCID: PMC6044391 DOI: 10.1093/femsyr/foy062] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 05/30/2018] [Indexed: 12/28/2022] Open
Abstract
Cas9-assisted genome editing was used to construct an engineered glucose-phosphorylation-negative S. cerevisiae strain, expressing the Lactobacillus plantaruml-arabinose pathway and the Penicillium chrysogenum transporter PcAraT. This strain, which showed a growth rate of 0.26 h−1 on l-arabinose in aerobic batch cultures, was subsequently evolved for anaerobic growth on l-arabinose in the presence of d-glucose and d-xylose. In four strains isolated from two independent evolution experiments the galactose-transporter gene GAL2 had been duplicated, with all alleles encoding Gal2N376T or Gal2N376I substitutions. In one strain, a single GAL2 allele additionally encoded a Gal2T89I substitution, which was subsequently also detected in the independently evolved strain IMS0010. In 14C-sugar-transport assays, Gal2N376S, Gal2N376T and Gal2N376I substitutions showed a much lower glucose sensitivity of l-arabinose transport and a much higher Km for d-glucose transport than wild-type Gal2. Introduction of the Gal2N376I substitution in a non-evolved strain enabled growth on l-arabinose in the presence of d-glucose. Gal2N376T, T89I and Gal2T89I variants showed a lower Km for l-arabinose and a higher Km for d-glucose than wild-type Gal2, while reverting Gal2N376T, T89I to Gal2N376 in an evolved strain negatively affected anaerobic growth on l-arabinose. This study indicates that optimal conversion of mixed-sugar feedstocks may require complex ‘transporter landscapes’, consisting of sugar transporters with complementary kinetic and regulatory properties.
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Affiliation(s)
- Maarten D Verhoeven
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Jasmine M Bracher
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Jeroen G Nijland
- Department of Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Jonna Bouwknegt
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Jean-Marc G Daran
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Arnold J M Driessen
- Department of Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Antonius J A van Maris
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Jack T Pronk
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
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48
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Brouwers N, Gorter de Vries AR, van den Broek M, Weening SM, Elink Schuurman TD, Kuijpers NGA, Pronk JT, Daran JMG. In vivo recombination of Saccharomyces eubayanus maltose-transporter genes yields a chimeric transporter that enables maltotriose fermentation. PLoS Genet 2019; 15:e1007853. [PMID: 30946741 PMCID: PMC6448828 DOI: 10.1371/journal.pgen.1007853] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 11/26/2018] [Indexed: 11/18/2022] Open
Abstract
Saccharomyces eubayanus is the non-S. cerevisiae parent of the lager-brewing hybrid S. pastorianus. In contrast to most S. cerevisiae and Frohberg-type S. pastorianus strains, S. eubayanus cannot utilize the α-tri-glucoside maltotriose, a major carbohydrate in brewer’s wort. In Saccharomyces yeasts, utilization of maltotriose is encoded by the subtelomeric MAL gene family, and requires transporters for maltotriose uptake. While S. eubayanus strain CBS 12357T harbors four SeMALT genes which enable uptake of the α-di-glucoside maltose, it lacks maltotriose transporter genes. In S. cerevisiae, sequence identity indicates that maltotriose and maltose transporters likely evolved from a shared ancestral gene. To study the evolvability of maltotriose utilization in S. eubayanus CBS 12357T, maltotriose-assimilating mutants obtained after UV mutagenesis were subjected to laboratory evolution in carbon-limited chemostat cultures on maltotriose-enriched wort. An evolved strain showed improved maltose and maltotriose fermentation in 7 L fermenter experiments on industrial wort. Whole-genome sequencing revealed a novel mosaic SeMALT413 gene, resulting from repeated gene introgressions by non-reciprocal translocation of at least three SeMALT genes. The predicted tertiary structure of SeMalT413 was comparable to the original SeMalT transporters, but overexpression of SeMALT413 sufficed to enable growth on maltotriose, indicating gene neofunctionalization had occurred. The mosaic structure of SeMALT413 resembles the structure of S. pastorianus maltotriose-transporter gene SpMTY1, which has high sequences identity to alternatingly S. cerevisiae MALx1, S. paradoxus MALx1 and S. eubayanus SeMALT3. Evolution of the maltotriose transporter landscape in hybrid S. pastorianus lager-brewing strains is therefore likely to have involved mechanisms similar to those observed in the present study. Fermentation of the wort sugar maltotriose is critical for the flavor profile obtained during beer brewing. The recently discovered yeast Saccharomyces eubayanus is gaining popularity as an alternative to S. pastorianus and S. cerevisiae for brewing, however it is unable to utilize maltotriose. Here, a combination of non-GMO mutagenesis and laboratory evolution of the S. eubayanus type strain CBS 12357T was used to enable maltotriose fermentation and improve brewing performance. The improved strain expressed a novel transporter gene, SeMALT413, which was formed by recombination between three different SeMALT maltose-transporter genes. Overexpression of SeMALT413 in CBS 12357T confirmed its neofunctionalization as a maltotriose transporter. As the S. pastorianus maltotriose transporter SpMty1 has a mosaic structure similar to SeMalT413, maltotriose utilization likely involved similar recombination events during the domestication of current lager brewing strains. Based on a posteriori sequence analysis, the emergence of gene functions has been attributed to gene neofunctionalization in a broad range of organisms. The real-time observation of neofunctionalization during laboratory evolution constitutes an important validation of the relevance and importance of this mechanism for Darwinian evolution.
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Affiliation(s)
- Nick Brouwers
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629HZ Delft, The Netherlands
| | - Arthur R. Gorter de Vries
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629HZ Delft, The Netherlands
| | - Marcel van den Broek
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629HZ Delft, The Netherlands
| | - Susan M. Weening
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629HZ Delft, The Netherlands
| | | | - Niels G. A. Kuijpers
- HEINEKEN Supply Chain B.V., Global Innovation and Research, Zoeterwoude, Netherlands
| | - Jack T. Pronk
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629HZ Delft, The Netherlands
| | - Jean-Marc G. Daran
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629HZ Delft, The Netherlands
- * E-mail:
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Gorter de Vries AR, Voskamp MA, van Aalst ACA, Kristensen LH, Jansen L, van den Broek M, Salazar AN, Brouwers N, Abeel T, Pronk JT, Daran JMG. Laboratory Evolution of a Saccharomyces cerevisiae × S. eubayanus Hybrid Under Simulated Lager-Brewing Conditions. Front Genet 2019; 10:242. [PMID: 31001314 PMCID: PMC6455053 DOI: 10.3389/fgene.2019.00242] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 03/04/2019] [Indexed: 11/23/2022] Open
Abstract
Saccharomyces pastorianus lager-brewing yeasts are domesticated hybrids of S. cerevisiae x S. eubayanus that display extensive inter-strain chromosome copy number variation and chromosomal recombinations. It is unclear to what extent such genome rearrangements are intrinsic to the domestication of hybrid brewing yeasts and whether they contribute to their industrial performance. Here, an allodiploid laboratory hybrid of S. cerevisiae and S. eubayanus was evolved for up to 418 generations on wort under simulated lager-brewing conditions in six independent sequential batch bioreactors. Characterization of 55 single-cell isolates from the evolved cultures showed large phenotypic diversity and whole-genome sequencing revealed a large array of mutations. Frequent loss of heterozygosity involved diverse, strain-specific chromosomal translocations, which differed from those observed in domesticated, aneuploid S. pastorianus brewing strains. In contrast to the extensive aneuploidy of domesticated S. pastorianus strains, the evolved isolates only showed limited (segmental) aneuploidy. Specific mutations could be linked to calcium-dependent flocculation, loss of maltotriose utilization and loss of mitochondrial activity, three industrially relevant traits that also occur in domesticated S. pastorianus strains. This study indicates that fast acquisition of extensive aneuploidy is not required for genetic adaptation of S. cerevisiae × S. eubayanus hybrids to brewing environments. In addition, this work demonstrates that, consistent with the diversity of brewing strains for maltotriose utilization, domestication under brewing conditions can result in loss of this industrially relevant trait. These observations have important implications for the design of strategies to improve industrial performance of novel laboratory-made hybrids.
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Affiliation(s)
- Arthur R. Gorter de Vries
- Industrial Microbiology, Department of Biotechnology Delft, Delft University of Technology, Delft, Netherlands
| | - Maaike A. Voskamp
- Industrial Microbiology, Department of Biotechnology Delft, Delft University of Technology, Delft, Netherlands
| | - Aafke C. A. van Aalst
- Industrial Microbiology, Department of Biotechnology Delft, Delft University of Technology, Delft, Netherlands
| | - Line H. Kristensen
- Industrial Microbiology, Department of Biotechnology Delft, Delft University of Technology, Delft, Netherlands
| | - Liset Jansen
- Industrial Microbiology, Department of Biotechnology Delft, Delft University of Technology, Delft, Netherlands
| | - Marcel van den Broek
- Industrial Microbiology, Department of Biotechnology Delft, Delft University of Technology, Delft, Netherlands
| | - Alex N. Salazar
- Delft Bioinformatics Lab, Department of Intelligent Systems, Delft University of Technology, Delft, Netherlands
| | - Nick Brouwers
- Industrial Microbiology, Department of Biotechnology Delft, Delft University of Technology, Delft, Netherlands
| | - Thomas Abeel
- Delft Bioinformatics Lab, Department of Intelligent Systems, Delft University of Technology, Delft, Netherlands
- Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, Boston, MA, United States
| | - Jack T. Pronk
- Industrial Microbiology, Department of Biotechnology Delft, Delft University of Technology, Delft, Netherlands
| | - Jean-Marc G. Daran
- Industrial Microbiology, Department of Biotechnology Delft, Delft University of Technology, Delft, Netherlands
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Abstract
Microbial synthesis represents an alternative approach for the sustainable production of chemicals, fuels, and medicines. However, construction of biosynthetic pathways always suffers from side reactions, toxicity of intermediates, or low efficiency of substrate channeling. Subcellular compartmentalization may contribute to a more efficient production of target products by reducing side reactions and toxic effects within a compact insular space. The peroxisome, a type of organelle that is involved in catabolism of fatty acids and reactive oxygen species, has attracted a great deal of attention in the construction of eukaryotic cell factories with little impact on essential cellular function. In this chapter, we will systematically review recent advances in peroxisomal compartmentalization for microbial production of valuable biomolecules. Additionally, detailed experimental designs and protocols are also described. We hope a comprehensive understanding of peroxisomes will promote their application in metabolic engineering and synthetic biology.
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Affiliation(s)
- Jiaoqi Gao
- Division of Biotechnology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China
| | - Yongjin J Zhou
- Division of Biotechnology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China.
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