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Demeke MM, Echemendia D, Belo E, Foulquié-Moreno MR, Thevelein JM. Enhancing xylose-fermentation capacity of engineered Saccharomyces cerevisiae by multistep evolutionary engineering in inhibitor-rich lignocellulose hydrolysate. FEMS Yeast Res 2024; 24:foae013. [PMID: 38604750 PMCID: PMC11062418 DOI: 10.1093/femsyr/foae013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 02/19/2024] [Accepted: 04/10/2024] [Indexed: 04/13/2024] Open
Abstract
Major progress in developing Saccharomyces cerevisiae strains that utilize the pentose sugar xylose has been achieved. However, the high inhibitor content of lignocellulose hydrolysates still hinders efficient xylose fermentation, which remains a major obstacle for commercially viable second-generation bioethanol production. Further improvement of xylose utilization in inhibitor-rich lignocellulose hydrolysates remains highly challenging. In this work, we have developed a robust industrial S. cerevisiae strain able to efficiently ferment xylose in concentrated undetoxified lignocellulose hydrolysates. This was accomplished with novel multistep evolutionary engineering. First, a tetraploid strain was generated and evolved in xylose-enriched pretreated spruce biomass. The best evolved strain was sporulated to obtain a genetically diverse diploid population. The diploid strains were then screened in industrially relevant conditions. The best performing strain, MDS130, showed superior fermentation performance in three different lignocellulose hydrolysates. In concentrated corncob hydrolysate, with initial cell density of 1 g DW/l, at 35°C, MDS130 completely coconsumed glucose and xylose, producing ± 7% v/v ethanol with a yield of 91% of the maximum theoretical value and an overall productivity of 1.22 g/l/h. MDS130 has been developed from previous industrial yeast strains without applying external mutagenesis, minimizing the risk of negative side-effects on other commercially important properties and maximizing its potential for industrial application.
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Affiliation(s)
- Mekonnen M Demeke
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Kasteelpark Arenberg 31, B-3001 Leuven-Heverlee, Belgium
- Center for Microbiology, VIB, Kasteelpark Arenberg 31, B-3001 Leuven-Heverlee, Flanders, Belgium
- NovelYeast bv, Bio-incubator BIO4, Gaston Geenslaan 3, 3001 Leuven-Heverlee, Belgium
| | - Dannele Echemendia
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Kasteelpark Arenberg 31, B-3001 Leuven-Heverlee, Belgium
- Center for Microbiology, VIB, Kasteelpark Arenberg 31, B-3001 Leuven-Heverlee, Flanders, Belgium
| | - Edgard Belo
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Kasteelpark Arenberg 31, B-3001 Leuven-Heverlee, Belgium
- Center for Microbiology, VIB, Kasteelpark Arenberg 31, B-3001 Leuven-Heverlee, Flanders, Belgium
| | - María R Foulquié-Moreno
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Kasteelpark Arenberg 31, B-3001 Leuven-Heverlee, Belgium
- Center for Microbiology, VIB, Kasteelpark Arenberg 31, B-3001 Leuven-Heverlee, Flanders, Belgium
| | - Johan M Thevelein
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Kasteelpark Arenberg 31, B-3001 Leuven-Heverlee, Belgium
- Center for Microbiology, VIB, Kasteelpark Arenberg 31, B-3001 Leuven-Heverlee, Flanders, Belgium
- NovelYeast bv, Bio-incubator BIO4, Gaston Geenslaan 3, 3001 Leuven-Heverlee, Belgium
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Jang YS, Yang J, Kim JK, Kim TI, Park YC, Kim IJ, Kim KH. Adaptive laboratory evolution and transcriptomics-guided engineering of Escherichia coli for increased isobutanol tolerance. Biotechnol J 2024; 19:e2300270. [PMID: 37799109 DOI: 10.1002/biot.202300270] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 09/08/2023] [Accepted: 09/26/2023] [Indexed: 10/07/2023]
Abstract
As a renewable energy from biomass, isobutanol is considered as a promising alternative to fossil fuels. To biotechnologically produce isobutanol, strain development using industrial microbial hosts, such as Escherichia coli, has been conducted by introducing a heterologous isobutanol synthetic pathway. However, the toxicity of produced isobutanol inhibits cell growth, thereby restricting improvements in isobutanol titer, yield, and productivity. Therefore, the development of robust microbial strains tolerant to isobutanol is required. In this study, isobutanol-tolerant mutants were isolated from two E. coli parental strains, E. coli BL21(DE3) and MG1655(DE3), through adaptive laboratory evolution (ALE) under high isobutanol concentrations. Subsequently, 16 putative genes responsible for isobutanol tolerance were identified by transcriptomic analysis. When overexpressed in E. coli, four genes (fadB, dppC, acs, and csiD) conferred isobutanol tolerance. A fermentation study with a reverse engineered isobutanol-producing E. coli JK209 strain showed that fadB or dppC overexpression improved isobutanol titers by 1.5 times, compared to the control strain. Through coupling adaptive evolution with transcriptomic analysis, new genetic targets utilizable were identified as the basis for the development of an isobutanol-tolerant strain. Thus, these new findings will be helpful not only for a fundamental understanding of microbial isobutanol tolerance but also for facilitating industrially feasible isobutanol production.
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Affiliation(s)
- Young Seo Jang
- Department of Biotechnology, Graduate School, Korea University, Seoul, Republic of Korea
| | - Jungwoo Yang
- Department of Biotechnology, Graduate School, Korea University, Seoul, Republic of Korea
| | - Jae Kyun Kim
- Department of Biotechnology, Graduate School, Korea University, Seoul, Republic of Korea
| | - Tae In Kim
- Department of Biotechnology, Graduate School, Korea University, Seoul, Republic of Korea
| | - Yong-Cheol Park
- Department of Bio and Fermentation Convergence Technology, Kookmin University, Seoul, Republic of Korea
| | - In Jung Kim
- Department of Food Science and Technology, Institute of Agriculture and Life Science, Gyeongsang National University, Jinju, Republic of Korea
| | - Kyoung Heon Kim
- Department of Biotechnology, Graduate School, Korea University, Seoul, Republic of Korea
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Topaloğlu A, Esen Ö, Turanlı-Yıldız B, Arslan M, Çakar ZP. From Saccharomyces cerevisiae to Ethanol: Unlocking the Power of Evolutionary Engineering in Metabolic Engineering Applications. J Fungi (Basel) 2023; 9:984. [PMID: 37888240 PMCID: PMC10607480 DOI: 10.3390/jof9100984] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 09/25/2023] [Accepted: 09/28/2023] [Indexed: 10/28/2023] Open
Abstract
Increased human population and the rapid decline of fossil fuels resulted in a global tendency to look for alternative fuel sources. Environmental concerns about fossil fuel combustion led to a sharp move towards renewable and environmentally friendly biofuels. Ethanol has been the primary fossil fuel alternative due to its low carbon emission rates, high octane content and comparatively facile microbial production processes. In parallel to the increased use of bioethanol in various fields such as transportation, heating and power generation, improvements in ethanol production processes turned out to be a global hot topic. Ethanol is by far the leading yeast output amongst a broad spectrum of bio-based industries. Thus, as a well-known platform microorganism and native ethanol producer, baker's yeast Saccharomyces cerevisiae has been the primary subject of interest for both academic and industrial perspectives in terms of enhanced ethanol production processes. Metabolic engineering strategies have been primarily adopted for direct manipulation of genes of interest responsible in mainstreams of ethanol metabolism. To overcome limitations of rational metabolic engineering, an alternative bottom-up strategy called inverse metabolic engineering has been widely used. In this context, evolutionary engineering, also known as adaptive laboratory evolution (ALE), which is based on random mutagenesis and systematic selection, is a powerful strategy to improve bioethanol production of S. cerevisiae. In this review, we focus on key examples of metabolic and evolutionary engineering for improved first- and second-generation S. cerevisiae bioethanol production processes. We delve into the current state of the field and show that metabolic and evolutionary engineering strategies are intertwined and many metabolically engineered strains for bioethanol production can be further improved by powerful evolutionary engineering strategies. We also discuss potential future directions that involve recent advancements in directed genome evolution, including CRISPR-Cas9 technology.
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Affiliation(s)
- Alican Topaloğlu
- Department of Molecular Biology and Genetics, Faculty of Science and Letters, Istanbul Technical University, Istanbul 34469, Türkiye; (A.T.); (Ö.E.)
- Dr. Orhan Öcalgiray Molecular Biology, Biotechnology and Genetics Research Center (ITU-MOBGAM), Istanbul Technical University, Istanbul 34469, Türkiye;
| | - Ömer Esen
- Department of Molecular Biology and Genetics, Faculty of Science and Letters, Istanbul Technical University, Istanbul 34469, Türkiye; (A.T.); (Ö.E.)
- Dr. Orhan Öcalgiray Molecular Biology, Biotechnology and Genetics Research Center (ITU-MOBGAM), Istanbul Technical University, Istanbul 34469, Türkiye;
| | - Burcu Turanlı-Yıldız
- Dr. Orhan Öcalgiray Molecular Biology, Biotechnology and Genetics Research Center (ITU-MOBGAM), Istanbul Technical University, Istanbul 34469, Türkiye;
| | - Mevlüt Arslan
- Department of Genetics, Faculty of Veterinary Medicine, Van Yüzüncü Yıl University, Van 65000, Türkiye;
| | - Zeynep Petek Çakar
- Department of Molecular Biology and Genetics, Faculty of Science and Letters, Istanbul Technical University, Istanbul 34469, Türkiye; (A.T.); (Ö.E.)
- Dr. Orhan Öcalgiray Molecular Biology, Biotechnology and Genetics Research Center (ITU-MOBGAM), Istanbul Technical University, Istanbul 34469, Türkiye;
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Basso TP, Procópio DP, Petrin THC, Giacon TG, Jin YS, Basso TO, Basso LC. Engineering xylose fermentation in an industrial yeast: continuous cultivation as a tool for selecting improved strains. Lett Appl Microbiol 2023:ovad077. [PMID: 37410619 DOI: 10.1093/lambio/ovad077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/08/2023]
Abstract
Production of second-generation ethanol from lignocellulosic residues should be fueling the energy matrix in the near future. Lignocellulosic feedstock has received much attention as an alternative energy resource for biorefineries toward reducing the demand for fossil resources, contributing to a future sustainable bio-based economy. Fermentation of lignocellulosic hydrolysates poses many scientific and technological challenges as the drawback of Saccharomyces cerevisiae's inability in fermenting pentose sugars (derived from hemicellulose). To overcome the inability of S. cerevisiae to ferment xylose and increase yeast robustness in the presence of inhibitory compound-containing media, the industrial S. cerevisiae strain SA-1 was engineered using CRISPR-Cas9 with the oxidoreductive xylose pathway from Scheffersomyces stipitis (encoded by XYL1, XYL2, and XYL3). The engineered strain was then cultivated in a xylose-limited chemostat under increasing dilution rates (for 64 days) to improve its xylose consumption kinetics under aerobic conditions. The evolved strain (DPY06) and its parental strain (SA-1 XR/XDH) were evaluated under microaerobic in the hemicellulosic hydrolysate. DPY06 exhibited 35% superior volumetric ethanol productivity compared to its parental strain.
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Affiliation(s)
- Thalita Peixoto Basso
- Department of Genetics, Escola Superior de Agricultura Luiz de Queiroz, University of São Paulo, Piracicaba, SP, Brazil
| | - Dielle Pierotti Procópio
- Department of Chemical Engineering, Escola Politécnica, University of São Paulo, São Paulo, SP, Brazil
| | - Thais Helena Costa Petrin
- Department of Chemical Engineering, Escola Politécnica, University of São Paulo, São Paulo, SP, Brazil
| | - Thamiris Guerra Giacon
- Department of Chemical Engineering, Escola Politécnica, University of São Paulo, São Paulo, SP, Brazil
| | - Yong-Su Jin
- DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Department of Food Science and Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Thiago Olitta Basso
- Department of Chemical Engineering, Escola Politécnica, University of São Paulo, São Paulo, SP, Brazil
| | - Luiz Carlos Basso
- Department of Biological Sciences, Escola Superior de Agricultura Luiz de Queiroz, University of São Paulo, Piracicaba, SP, Brazil
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Holyavkin C, Turanlı-Yıldız B, Yılmaz Ü, Alkım C, Arslan M, Topaloğlu A, Kısakesen Hİ, de Billerbeck G, François JM, Çakar ZP. Genomic, transcriptomic, and metabolic characterization of 2-Phenylethanol-resistant Saccharomyces cerevisiae obtained by evolutionary engineering. Front Microbiol 2023; 14:1148065. [PMID: 37113225 PMCID: PMC10127108 DOI: 10.3389/fmicb.2023.1148065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 03/13/2023] [Indexed: 04/29/2023] Open
Abstract
2-Phenylethanol is an aromatic compound commonly used in the food, cosmetic, and pharmaceutical industries. Due to increasing demand for natural products by consumers, the production of this flavor by microbial fermentation is gaining interest, as a sustainable alternative to chemical synthesis or expensive plant extraction, both processes relying on the use of fossil resources. However, the drawback of the fermentation process is the high toxicity of 2-phenylethanol to the producing microorganism. The aim of this study was to obtain a 2-phenylethanol-resistant Saccharomyces cerevisiae strain by in vivo evolutionary engineering and characterize the adapted yeast at the genomic, transcriptomic and metabolic levels. For this purpose, the tolerance to 2-phenylethanol was developed by gradually increasing the concentration of this flavor compound through successive batch cultivations, leading to an adapted strain that could tolerate 3.4 g/L of 2-phenylethanol, which was about 3-times better than the reference strain. Genome sequencing of the adapted strain identified point mutations in several genes, notably in HOG1 that encodes the Mitogen-Activated Kinase of the high-osmolarity signaling pathway. As this mutation is localized in the phosphorylation lip of this protein, it likely resulted in a hyperactive protein kinase. Transcriptomic analysis of the adapted strain supported this suggestion by revealing a large set of upregulated stress-responsive genes that could be explained in great part by HOG1-dependent activation of the Msn2/Msn4 transcription factor. Another relevant mutation was found in PDE2 encoding the low affinity cAMP phosphodiesterase, the missense mutation of which may lead to hyperactivation of this enzyme and thereby enhance the stressful state of the 2-phenylethanol adapted strain. In addition, the mutation in CRH1 that encodes a chitin transglycosylase implicated in cell wall remodeling could account for the increased resistance of the adapted strain to the cell wall-degrading enzyme lyticase. Finally, the potent upregulation of ALD3 and ALD4 encoding NAD+ -dependent aldehyde dehydrogenase together with the observed phenylacetate resistance of the evolved strain suggest a resistance mechanism involving conversion of 2-phenylethanol into phenylacetaldehyde and phenylacetate implicating these dehydrogenases.
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Affiliation(s)
- Can Holyavkin
- Department of Molecular Biology & Genetics, Faculty of Science & Letters, Istanbul Technical University, Istanbul, Turkey
- Dr. Orhan Öcalgiray Molecular Biology, Biotechnology and Genetics Research Center (ITU-MOBGAM), Istanbul Technical University, Istanbul, Turkey
| | - Burcu Turanlı-Yıldız
- Department of Molecular Biology & Genetics, Faculty of Science & Letters, Istanbul Technical University, Istanbul, Turkey
- Dr. Orhan Öcalgiray Molecular Biology, Biotechnology and Genetics Research Center (ITU-MOBGAM), Istanbul Technical University, Istanbul, Turkey
| | - Ülkü Yılmaz
- Department of Molecular Biology & Genetics, Faculty of Science & Letters, Istanbul Technical University, Istanbul, Turkey
- Dr. Orhan Öcalgiray Molecular Biology, Biotechnology and Genetics Research Center (ITU-MOBGAM), Istanbul Technical University, Istanbul, Turkey
| | - Ceren Alkım
- Department of Molecular Biology & Genetics, Faculty of Science & Letters, Istanbul Technical University, Istanbul, Turkey
- Dr. Orhan Öcalgiray Molecular Biology, Biotechnology and Genetics Research Center (ITU-MOBGAM), Istanbul Technical University, Istanbul, Turkey
| | - Mevlüt Arslan
- Department of Molecular Biology & Genetics, Faculty of Science & Letters, Istanbul Technical University, Istanbul, Turkey
- Dr. Orhan Öcalgiray Molecular Biology, Biotechnology and Genetics Research Center (ITU-MOBGAM), Istanbul Technical University, Istanbul, Turkey
| | - Alican Topaloğlu
- Department of Molecular Biology & Genetics, Faculty of Science & Letters, Istanbul Technical University, Istanbul, Turkey
- Dr. Orhan Öcalgiray Molecular Biology, Biotechnology and Genetics Research Center (ITU-MOBGAM), Istanbul Technical University, Istanbul, Turkey
| | - Halil İbrahim Kısakesen
- Department of Molecular Biology & Genetics, Faculty of Science & Letters, Istanbul Technical University, Istanbul, Turkey
- Dr. Orhan Öcalgiray Molecular Biology, Biotechnology and Genetics Research Center (ITU-MOBGAM), Istanbul Technical University, Istanbul, Turkey
| | | | - Jean Marie François
- Toulouse Biotechnology Institute (TBI), CNRS, INRA, INSA, Université de Toulouse, Toulouse, France
- *Correspondence: Jean Marie François,
| | - Z. Petek Çakar
- Department of Molecular Biology & Genetics, Faculty of Science & Letters, Istanbul Technical University, Istanbul, Turkey
- Dr. Orhan Öcalgiray Molecular Biology, Biotechnology and Genetics Research Center (ITU-MOBGAM), Istanbul Technical University, Istanbul, Turkey
- Z. Petek Çakar,
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Alkim C, Farias D, Fredonnet J, Serrano-Bataille H, Herviou P, Picot M, Slama N, Dejean S, Morin N, Enjalbert B, François JM. Toxic effect and inability of L-homoserine to be a nitrogen source for growth of Escherichia coli resolved by a combination of in vivo evolution engineering and omics analyses. Front Microbiol 2022; 13:1051425. [PMID: 36583047 PMCID: PMC9792984 DOI: 10.3389/fmicb.2022.1051425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 11/17/2022] [Indexed: 12/14/2022] Open
Abstract
L-homoserine is a pivotal intermediate in the carbon and nitrogen metabolism of E. coli. However, this non-canonical amino acid cannot be used as a nitrogen source for growth. Furthermore, growth of this bacterium in a synthetic media is potently inhibited by L-homoserine. To understand this dual effect, an adapted laboratory evolution (ALE) was applied, which allowed the isolation of a strain able to grow with L-homoserine as the nitrogen source and was, at the same time, desensitized to growth inhibition by this amino acid. Sequencing of this evolved strain identified only four genomic modifications, including a 49 bp truncation starting from the stop codon of thrL. This mutation resulted in a modified thrL locus carrying a thrL* allele encoding a polypeptide 9 amino acids longer than the thrL encoded leader peptide. Remarkably, the replacement of thrL with thrL* in the original strain MG1655 alleviated L-homoserine inhibition to the same extent as strain 4E, but did not allow growth with this amino acid as a nitrogen source. The loss of L-homoserine toxic effect could be explained by the rapid conversion of L-homoserine into threonine via the thrL*-dependent transcriptional activation of the threonine operon thrABC. On the other hand, the growth of E. coli on a mineral medium with L-homoserine required an activation of the threonine degradation pathway II and glycine cleavage system, resulting in the release of ammonium ions that were likely recaptured by NAD(P)-dependent glutamate dehydrogenase. To infer about the direct molecular targets of L-homoserine toxicity, a transcriptomic analysis of wild-type MG1655 in the presence of 10 mM L-homoserine was performed, which notably identified a potent repression of locomotion-motility-chemotaxis process and of branched-chain amino acids synthesis. Since the magnitude of these effects was lower in a ΔthrL mutant, concomitant with a twofold lower sensitivity of this mutant to L-homoserine, it could be argued that growth inhibition by L-homoserine is due to the repression of these biological processes. In addition, L-homoserine induced a strong upregulation of genes in the sulfate reductive assimilation pathway, including those encoding its transport. How this non-canonical amino acid triggers these transcriptomic changes is discussed.
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Affiliation(s)
- Ceren Alkim
- Toulouse Biotechnology Institute (TBI), Université de Toulouse, CNRS, INRA, INSA, Toulouse, France,Toulouse White Biotechnology Center (TWB), UMS-INSA-INRA-CNRS, Toulouse, France
| | - Daniele Farias
- Toulouse Biotechnology Institute (TBI), Université de Toulouse, CNRS, INRA, INSA, Toulouse, France
| | - Julie Fredonnet
- Toulouse White Biotechnology Center (TWB), UMS-INSA-INRA-CNRS, Toulouse, France
| | | | - Pauline Herviou
- Toulouse White Biotechnology Center (TWB), UMS-INSA-INRA-CNRS, Toulouse, France
| | - Marc Picot
- Toulouse White Biotechnology Center (TWB), UMS-INSA-INRA-CNRS, Toulouse, France
| | - Nawel Slama
- Toulouse White Biotechnology Center (TWB), UMS-INSA-INRA-CNRS, Toulouse, France
| | | | - Nicolas Morin
- Toulouse White Biotechnology Center (TWB), UMS-INSA-INRA-CNRS, Toulouse, France
| | - Brice Enjalbert
- Toulouse Biotechnology Institute (TBI), Université de Toulouse, CNRS, INRA, INSA, Toulouse, France
| | - Jean M. François
- Toulouse Biotechnology Institute (TBI), Université de Toulouse, CNRS, INRA, INSA, Toulouse, France,Toulouse White Biotechnology Center (TWB), UMS-INSA-INRA-CNRS, Toulouse, France,*Correspondence: Jean M. François,
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Yao Z, Wang Q, Dai Z. Recent Advances in Directed Yeast Genome Evolution. J Fungi (Basel) 2022; 8:jof8060635. [PMID: 35736118 PMCID: PMC9225242 DOI: 10.3390/jof8060635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 06/09/2022] [Accepted: 06/13/2022] [Indexed: 11/16/2022] Open
Abstract
Saccharomyces cerevisiae, as a Generally Recognized as Safe (GRAS) fungus, has become one of the most widely used chassis cells for industrial applications and basic research. However, owing to its complex genetic background and intertwined metabolic networks, there are still many obstacles that need to be overcome in order to improve desired traits and to successfully link genotypes to phenotypes. In this context, genome editing and evolutionary technology have rapidly progressed over the last few decades to facilitate the rapid generation of tailor-made properties as well as for the precise determination of relevant gene targets that regulate physiological functions, including stress resistance, metabolic-pathway optimization and organismal adaptation. Directed genome evolution has emerged as a versatile tool to enable researchers to access desired traits and to study increasingly complicated phenomena. Here, the development of directed genome evolutions in S. cerevisiae is reviewed, with a focus on different techniques driving evolutionary engineering.
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Affiliation(s)
- Zhen Yao
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China;
- National Center of Technology Innovation for Synthetic Biology, Tianjin 300308, China
| | - Qinhong Wang
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China;
- National Center of Technology Innovation for Synthetic Biology, Tianjin 300308, China
- Correspondence: (Q.W.); (Z.D.)
| | - Zongjie Dai
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China;
- National Center of Technology Innovation for Synthetic Biology, Tianjin 300308, China
- Correspondence: (Q.W.); (Z.D.)
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Zhang L, Gao J, Liu C, Deng L. [Tolerance engineering regulates stress resistance of microbial cell factory]. Sheng Wu Gong Cheng Xue Bao 2022; 38:1373-1389. [PMID: 35470613 DOI: 10.13345/j.cjb.210726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The production efficiency of microbial cell factory is determined by the growth performance, product synthetic capacity, and stress resistance of the strain. Strengthening the stress resistance is the key point to improve the production efficiency of microbial cell factory. Tolerance engineering is based on the response mechanism of microbial cell factory to resist stress. Specifically, it consolidates the cell wall-cell membrane barrier to enhance the defense against stress, accelerates the stress response to improve the damage repair, and creates tolerance evolutionary tools to screen industrial microorganisms with enhanced robustness. We summarize the regulation strategies and forecast the prospects of tolerance engineering, which plays an important role in the microbial cell factories for sustainable production of natural products and bulk chemicals.
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Affiliation(s)
- Li Zhang
- College of Marine and Bioengineering, Yancheng Institute of Technology, Yancheng 224051, Jiangsu, China
| | - Jian Gao
- College of Marine and Bioengineering, Yancheng Institute of Technology, Yancheng 224051, Jiangsu, China
| | - Changqing Liu
- College of Marine and Bioengineering, Yancheng Institute of Technology, Yancheng 224051, Jiangsu, China
| | - Lina Deng
- College of Marine and Bioengineering, Yancheng Institute of Technology, Yancheng 224051, Jiangsu, China
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9
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Kocaefe-Özşen N, Yilmaz B, Alkım C, Arslan M, Topaloğlu A, Kısakesen HLB, Gülsev E, Çakar ZP. Physiological and Molecular Characterization of an Oxidative Stress-Resistant Saccharomyces cerevisiae Strain Obtained by Evolutionary Engineering. Front Microbiol 2022; 13:822864. [PMID: 35283819 PMCID: PMC8911705 DOI: 10.3389/fmicb.2022.822864] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 02/02/2022] [Indexed: 12/14/2022] Open
Abstract
Oxidative stress is a major stress type observed in yeast bioprocesses, resulting in a decrease in yeast growth, viability, and productivity. Thus, robust yeast strains with increased resistance to oxidative stress are in highly demand by the industry. In addition, oxidative stress is also associated with aging and age-related complex conditions such as cancer and neurodegenerative diseases. Saccharomyces cerevisiae, as a model eukaryote, has been used to study these complex eukaryotic processes. However, the molecular mechanisms underlying oxidative stress responses and resistance are unclear. In this study, we have employed evolutionary engineering (also known as adaptive laboratory evolution – ALE) strategies to obtain an oxidative stress-resistant and genetically stable S. cerevisiae strain. Comparative physiological, transcriptomic, and genomic analyses of the evolved strain were then performed with respect to the reference strain. The results show that the oxidative stress-resistant evolved strain was also cross-resistant against other types of stressors, including heat, freeze-thaw, ethanol, cobalt, iron, and salt. It was also found to have higher levels of trehalose and glycogen production. Further, comparative transcriptomic analysis showed an upregulation of many genes associated with the stress response, transport, carbohydrate, lipid and cofactor metabolic processes, protein phosphorylation, cell wall organization, and biogenesis. Genes that were downregulated included those related to ribosome and RNA processing, nuclear transport, tRNA, and cell cycle. Whole genome re-sequencing analysis of the evolved strain identified mutations in genes related to the stress response, cell wall organization, carbohydrate metabolism/transport, which are in line with the physiological and transcriptomic results, and may give insight toward the complex molecular mechanisms of oxidative stress resistance.
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Affiliation(s)
- Nazlı Kocaefe-Özşen
- Department of Molecular Biology and Genetics, Istanbul Technical University, Istanbul, Turkey.,Dr. Orhan Öcalgiray Molecular Biology, Biotechnology and Genetics Research Center (ITU-MOBGAM), Istanbul Technical University, Istanbul, Turkey
| | - Bahtiyar Yilmaz
- Department of Molecular Biology and Genetics, Istanbul Technical University, Istanbul, Turkey.,Dr. Orhan Öcalgiray Molecular Biology, Biotechnology and Genetics Research Center (ITU-MOBGAM), Istanbul Technical University, Istanbul, Turkey
| | - Ceren Alkım
- Department of Molecular Biology and Genetics, Istanbul Technical University, Istanbul, Turkey.,Dr. Orhan Öcalgiray Molecular Biology, Biotechnology and Genetics Research Center (ITU-MOBGAM), Istanbul Technical University, Istanbul, Turkey
| | - Mevlüt Arslan
- Department of Molecular Biology and Genetics, Istanbul Technical University, Istanbul, Turkey.,Dr. Orhan Öcalgiray Molecular Biology, Biotechnology and Genetics Research Center (ITU-MOBGAM), Istanbul Technical University, Istanbul, Turkey
| | - Alican Topaloğlu
- Department of Molecular Biology and Genetics, Istanbul Technical University, Istanbul, Turkey.,Dr. Orhan Öcalgiray Molecular Biology, Biotechnology and Genetics Research Center (ITU-MOBGAM), Istanbul Technical University, Istanbul, Turkey
| | - Halil L Brahim Kısakesen
- Department of Molecular Biology and Genetics, Istanbul Technical University, Istanbul, Turkey.,Dr. Orhan Öcalgiray Molecular Biology, Biotechnology and Genetics Research Center (ITU-MOBGAM), Istanbul Technical University, Istanbul, Turkey
| | - Erdinç Gülsev
- Department of Molecular Biology and Genetics, Istanbul Technical University, Istanbul, Turkey.,Dr. Orhan Öcalgiray Molecular Biology, Biotechnology and Genetics Research Center (ITU-MOBGAM), Istanbul Technical University, Istanbul, Turkey
| | - Z Petek Çakar
- Department of Molecular Biology and Genetics, Istanbul Technical University, Istanbul, Turkey.,Dr. Orhan Öcalgiray Molecular Biology, Biotechnology and Genetics Research Center (ITU-MOBGAM), Istanbul Technical University, Istanbul, Turkey
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10
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Ishii-Hyakutake M, Sakurai T, Tsuge T. Screening Method for Polyhydroxyalkanoate Synthase Mutants Based on Polyester Degree of Polymerization Using High-Performance Liquid Chromatography. Microorganisms 2021; 9:1949. [PMID: 34576844 DOI: 10.3390/microorganisms9091949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 09/08/2021] [Accepted: 09/08/2021] [Indexed: 11/29/2022] Open
Abstract
A high-throughput screening method based on the degree of polymerization (DP) of polyhydroxyalkanoate (PHA) was developed using high-performance liquid chromatography (HPLC). In this method, PHA production was achieved using recombinant Escherichia coli supplemented with benzyl alcohol as a chain terminal compound. The cultured cells containing benzyl alcohol-capped PHA were decomposed by alkaline treatment, and the peaks of the decomposed monomer and benzyl alcohol were detected using HPLC. The DP of PHA could be determined from the peak ratio of the decomposed monomer to terminal benzyl alcohol. The measured DP was validated by other instrumental analyses using purified PHA samples. Using this system, mutants of PHA synthase from Bacillus cereus YB-4 (PhaRCYB4) were screened, and some enzymes capable of producing PHA with higher DP than the wild-type enzyme were obtained. The PHA yields of two of these enzymes were equivalent to the yield of the wild-type enzyme. Therefore, this screening method is suitable for the selection of beneficial mutants that can produce high molecular weight PHAs.
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11
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Baldi N, de Valk SC, Sousa-Silva M, Casal M, Soares-Silva I, Mans R. Evolutionary engineering reveals amino acid substitutions in Ato2 and Ato3 that allow improved growth of Saccharomyces cerevisiae on lactic acid. FEMS Yeast Res 2021; 21:6286924. [PMID: 34042971 DOI: 10.1093/femsyr/foab033] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 05/25/2021] [Indexed: 12/11/2022] Open
Abstract
In Saccharomyces cerevisiae, the complete set of proteins involved in transport of lactic acid across the cell membrane has not been determined. In this study, we aimed to identify transport proteins not previously described to be involved in lactic acid transport via a combination of directed evolution, whole-genome resequencing and reverse engineering. Evolution of a strain lacking all known lactic acid transporters on lactate led to the discovery of mutated Ato2 and Ato3 as two novel lactic acid transport proteins. When compared to previously identified S. cerevisiae genes involved in lactic acid transport, expression of ATO3T284C was able to facilitate the highest growth rate (0.15 ± 0.01 h-1) on this carbon source. A comparison between (evolved) sequences and 3D models of the transport proteins showed that most of the identified mutations resulted in a widening of the narrowest hydrophobic constriction of the anion channel. We hypothesize that this observation, sometimes in combination with an increased binding affinity of lactic acid to the sites adjacent to this constriction, are responsible for the improved lactic acid transport in the evolved proteins.
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Affiliation(s)
- Nicolò Baldi
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629HZ Delft, The Netherlands
| | - Sophie Claire de Valk
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629HZ Delft, The Netherlands
| | - Maria Sousa-Silva
- Centre of Molecular and Environmental Biology (CBMA), University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.,Institute of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Margarida Casal
- Centre of Molecular and Environmental Biology (CBMA), University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.,Institute of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Isabel Soares-Silva
- Centre of Molecular and Environmental Biology (CBMA), University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.,Institute of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Robert Mans
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629HZ Delft, The Netherlands
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12
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Li J, Zhu K, Miao L, Rong L, Zhao Y, Li S, Ma L, Li J, Zhang C, Xiao D, Foo JL, Yu A. Simultaneous Improvement of Limonene Production and Tolerance in Yarrowia lipolytica through Tolerance Engineering and Evolutionary Engineering. ACS Synth Biol 2021; 10:884-896. [PMID: 33715363 DOI: 10.1021/acssynbio.1c00052] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Limonene is an important plant natural product widely used in food and cosmetics production as well as in the pharmaceutical and chemical industries. However, low efficiency of plant extraction and high energy consumption in chemical synthesis limit the sustainability of industrial limonene production. Recently, the advancement of metabolic engineering and synthetic biology has facilitated the engineering of microbes into microbial cell factories for producing limonene. However, the deleterious effects on cellular activity by the toxicity of limonene is the major obstacle in achieving high-titer production of limonene in engineered microbes. In this study, by using transcriptomics, we identified 82 genes from the nonconventional yeast Yarrowia lipolytica that were up-regulated when exposed to limonene. When overexpressed, 8 of the gene candidates improved tolerance of this yeast to exogenously added limonene. To determine whether overexpression of these genes could also improve limonene production, we individually coexpressed the tolerance-enhancing genes with a limonene synthase gene. Indeed, expression of 5 of the 8 candidate genes enhanced limonene production in Y. lipolytica. Particularly, overexpressing YALI0F19492p led to an 8-fold improvement in product titer. Furthermore, through short-term adaptive laboratory evolution strategy, in combination with morphological and cytoplasmic membrane integrity analysis, we shed light on the underlying mechanism of limonene cytotoxicity to Y. lipolytica. This study demonstrated an effective strategy for improving limonene tolerance of Y. lipolytica and limonene titer in the host strain through the combinatorial use of tolerance engineering and evolutionary engineering.
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Affiliation(s)
- Jian Li
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of Industrial Fermentation Microbiology of the Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, No. 29 13th Street TEDA, Tianjin 300457, PR China
| | - Kun Zhu
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of Industrial Fermentation Microbiology of the Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, No. 29 13th Street TEDA, Tianjin 300457, PR China
| | - Lin Miao
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of Industrial Fermentation Microbiology of the Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, No. 29 13th Street TEDA, Tianjin 300457, PR China
| | - Lanxin Rong
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of Industrial Fermentation Microbiology of the Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, No. 29 13th Street TEDA, Tianjin 300457, PR China
| | - Yu Zhao
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of Industrial Fermentation Microbiology of the Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, No. 29 13th Street TEDA, Tianjin 300457, PR China
| | - Shenglong Li
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of Industrial Fermentation Microbiology of the Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, No. 29 13th Street TEDA, Tianjin 300457, PR China
| | - Lijuan Ma
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of Industrial Fermentation Microbiology of the Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, No. 29 13th Street TEDA, Tianjin 300457, PR China
| | - Jianxun Li
- Agricultural Processing Institute, Chinese Academy of Agricultural Sciences, Beijing 100193, PR China
| | - Cuiying Zhang
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of Industrial Fermentation Microbiology of the Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, No. 29 13th Street TEDA, Tianjin 300457, PR China
| | - Dongguang Xiao
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of Industrial Fermentation Microbiology of the Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, No. 29 13th Street TEDA, Tianjin 300457, PR China
| | - Jee Loon Foo
- Synthetic Biology Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, 119228 Singapore
- NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), National University of Singapore, 117456 Singapore
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, 117597 Singapore
| | - Aiqun Yu
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of Industrial Fermentation Microbiology of the Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, No. 29 13th Street TEDA, Tianjin 300457, PR China
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13
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Liu T, Zhao Q, Li Y, Zhu L, Jiang L, Huang H. Transcriptomics and Proteomics Analyses of the Responses of Propionibacterium acidipropionici to Metabolic and Evolutionary Manipulation. Front Microbiol 2020; 11:1564. [PMID: 32903527 PMCID: PMC7438477 DOI: 10.3389/fmicb.2020.01564] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 06/16/2020] [Indexed: 01/12/2023] Open
Abstract
We first performed a combination of metabolic engineering (deletion of ldh and poxB and overexpression of mmc) with evolutionary engineering (selection under oxygen stress, acid stress and osmotic stress) in Propionibacterium acidipropionici. The results indicated that the mutants had superior physiological activity, especially the mutant III obtained from P. acidipropionici-Δldh-ΔpoxB+mmc by evolutionary engineering, with 1.5-3.5 times higher growth rates, as well as a 37.1% increase of propionic acid (PA) titer and a 37.8% increase PA productivity compared to the wild type. Moreover, the integrative transcriptomics and proteomics analyses revealed that the differentially expressed genes (DEGs) and proteins (DEPs) in the mutant III were involved in energy metabolism, including the glycolysis pathway and tricarboxylic acid cycle (TCA cycle). These genes were up-regulated to supply increased amounts of energy and precursors for PA synthesis compared to the wild type. In addition, the down-regulation of fatty acid biosynthesis and fatty acid metabolism may indicate that the repressed metabolic flux was related to the production of PA. Quantitative reverse-transcription polymerase chain reaction (qRT-PCR) was performed to verify the differential expression levels of 16 selected key genes. The results offer deep insights into the mechanism of high PA production, which provides the theoretical foundation for the construction of advanced microbial cell factories.
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Affiliation(s)
- Tingting Liu
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, China
| | - Qianru Zhao
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China
| | - Yang Li
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China
| | - Liying Zhu
- College of Chemical and Molecular Engineering, Nanjing Tech University, Nanjing, China
| | - Ling Jiang
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, China
| | - He Huang
- College of Pharmaceutical Science, Nanjing Tech University, Nanjing, China
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14
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Terzioğlu E, Alkım C, Arslan M, Balaban BG, Holyavkin C, Kısakesen Hİ, Topaloğlu A, Yılmaz Şahin Ü, Gündüz Işık S, Akman S, Çakar ZP. Genomic, transcriptomic and physiological analyses of silver-resistant Saccharomyces cerevisiae obtained by evolutionary engineering. Yeast 2020; 37:413-426. [PMID: 33464648 DOI: 10.1002/yea.3514] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Revised: 06/12/2020] [Accepted: 07/15/2020] [Indexed: 12/24/2022] Open
Abstract
Silver is a non-essential metal used in medical applications as an antimicrobial agent, but it is also toxic for biological systems. To investigate the molecular basis of silver resistance in yeast, we employed evolutionary engineering using successive batch cultures at gradually increased silver stress levels up to 0.25-mM AgNO3 in 29 populations and obtained highly silver-resistant and genetically stable Saccharomyces cerevisiae strains. Cross-resistance analysis results indicated that the silver-resistant mutants also gained resistance against copper and oxidative stress. Growth physiological analysis results revealed that the highly silver-resistant evolved strain 2E was not significantly inhibited by silver stress, unlike the reference strain. Genomic and transcriptomic analysis results revealed that there were mutations and/or significant changes in the expression levels of the genes involved in cell wall integrity, cellular respiration, oxidative metabolism, copper homeostasis, endocytosis and vesicular transport activities. Particularly the missense mutation in the RLM1 gene encoding a transcription factor involved in the maintenance of cell wall integrity and with 707 potential gene targets might have a key role in the high silver resistance of 2E, along with its improved cell wall integrity, as confirmed by the lyticase sensitivity assay results. In conclusion, the comparative physiological, transcriptomic and genomic analysis results of the silver-resistant S. cerevisiae strain revealed potential key factors that will help understand the complex molecular mechanisms of silver resistance in yeast.
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Affiliation(s)
- Ergi Terzioğlu
- Department of Molecular Biology and Genetics, Faculty of Science and Letters, Istanbul Technical University, Istanbul, Turkey.,Dr. Orhan Öcalgiray Molecular Biology, Biotechnology and Genetics Research Center (ITU-MOBGAM), Istanbul Technical University, Istanbul, Turkey
| | - Ceren Alkım
- Department of Molecular Biology and Genetics, Faculty of Science and Letters, Istanbul Technical University, Istanbul, Turkey.,Dr. Orhan Öcalgiray Molecular Biology, Biotechnology and Genetics Research Center (ITU-MOBGAM), Istanbul Technical University, Istanbul, Turkey
| | - Mevlüt Arslan
- Department of Genetics, Faculty of Veterinary Medicine, Van Yüzüncü Yıl University, Van, Turkey
| | - Berrak Gülçin Balaban
- Department of Molecular Biology and Genetics, Faculty of Science and Letters, Istanbul Technical University, Istanbul, Turkey.,Dr. Orhan Öcalgiray Molecular Biology, Biotechnology and Genetics Research Center (ITU-MOBGAM), Istanbul Technical University, Istanbul, Turkey
| | - Can Holyavkin
- Department of Molecular Biology and Genetics, Faculty of Science and Letters, Istanbul Technical University, Istanbul, Turkey.,Dr. Orhan Öcalgiray Molecular Biology, Biotechnology and Genetics Research Center (ITU-MOBGAM), Istanbul Technical University, Istanbul, Turkey
| | - Halil İbrahim Kısakesen
- Department of Molecular Biology and Genetics, Faculty of Science and Letters, Istanbul Technical University, Istanbul, Turkey.,Dr. Orhan Öcalgiray Molecular Biology, Biotechnology and Genetics Research Center (ITU-MOBGAM), Istanbul Technical University, Istanbul, Turkey
| | - Alican Topaloğlu
- Department of Molecular Biology and Genetics, Faculty of Science and Letters, Istanbul Technical University, Istanbul, Turkey.,Dr. Orhan Öcalgiray Molecular Biology, Biotechnology and Genetics Research Center (ITU-MOBGAM), Istanbul Technical University, Istanbul, Turkey
| | - Ülkü Yılmaz Şahin
- Department of Molecular Biology and Genetics, Faculty of Science and Letters, Istanbul Technical University, Istanbul, Turkey.,Dr. Orhan Öcalgiray Molecular Biology, Biotechnology and Genetics Research Center (ITU-MOBGAM), Istanbul Technical University, Istanbul, Turkey
| | - Sema Gündüz Işık
- Department of Chemistry, Faculty of Science and Letters, Istanbul Technical University, Istanbul, Turkey
| | - Süleyman Akman
- Department of Chemistry, Faculty of Science and Letters, Istanbul Technical University, Istanbul, Turkey
| | - Zeynep Petek Çakar
- Department of Molecular Biology and Genetics, Faculty of Science and Letters, Istanbul Technical University, Istanbul, Turkey.,Dr. Orhan Öcalgiray Molecular Biology, Biotechnology and Genetics Research Center (ITU-MOBGAM), Istanbul Technical University, Istanbul, Turkey
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15
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Perli T, Moonen DPI, van den Broek M, Pronk JT, Daran JM. Adaptive Laboratory Evolution and Reverse Engineering of Single-Vitamin Prototrophies in Saccharomyces cerevisiae. Appl Environ Microbiol 2020; 86:e00388-20. [PMID: 32303542 DOI: 10.1128/AEM.00388-20] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 04/11/2020] [Indexed: 01/28/2023] Open
Abstract
Many strains of Saccharomyces cerevisiae, a popular platform organism in industrial biotechnology, carry the genetic information required for synthesis of biotin, thiamine, pyridoxine, para-aminobenzoic acid, pantothenic acid, nicotinic acid, and inositol. However, omission of these B vitamins typically leads to suboptimal growth. This study demonstrates that, for each individual B vitamin, it is possible to achieve fast vitamin-independent growth by adaptive laboratory evolution (ALE). Identification of mutations responsible for these fast-growing phenotypes by whole-genome sequencing and reverse engineering showed that, for each compound, a small number of mutations sufficed to achieve fast growth in its absence. These results form an important first step toward development of S. cerevisiae strains that exhibit fast growth on inexpensive, fully supplemented mineral media that only require complementation with a carbon source, thereby reducing costs, complexity, and contamination risks in industrial yeast fermentation processes. Quantitative physiological studies on Saccharomyces cerevisiae commonly use synthetic media (SM) that contain a set of water-soluble growth factors that, based on their roles in human nutrition, are referred to as B vitamins. Previous work demonstrated that in S. cerevisiae CEN.PK113-7D, requirements for biotin were eliminated by laboratory evolution. In the present study, this laboratory strain was shown to exhibit suboptimal specific growth rates when either inositol, nicotinic acid, pyridoxine, pantothenic acid, para-aminobenzoic acid (pABA), or thiamine was omitted from SM. Subsequently, this strain was evolved in parallel serial-transfer experiments for fast aerobic growth on glucose in the absence of individual B vitamins. In all evolution lines, specific growth rates reached at least 90% of the growth rate observed in SM supplemented with a complete B vitamin mixture. Fast growth was already observed after a few transfers on SM without myo-inositol, nicotinic acid, or pABA. Reaching similar results in SM lacking thiamine, pyridoxine, or pantothenate required more than 300 generations of selective growth. The genomes of evolved single-colony isolates were resequenced, and for each B vitamin, a subset of non-synonymous mutations associated with fast vitamin-independent growth was selected. These mutations were introduced in a non-evolved reference strain using CRISPR/Cas9-based genome editing. For each B vitamin, the introduction of a small number of mutations sufficed to achieve a substantially increased specific growth rate in non-supplemented SM that represented at least 87% of the specific growth rate observed in fully supplemented complete SM. IMPORTANCE Many strains of Saccharomyces cerevisiae, a popular platform organism in industrial biotechnology, carry the genetic information required for synthesis of biotin, thiamine, pyridoxine, para-aminobenzoic acid, pantothenic acid, nicotinic acid, and inositol. However, omission of these B vitamins typically leads to suboptimal growth. This study demonstrates that, for each individual B vitamin, it is possible to achieve fast vitamin-independent growth by adaptive laboratory evolution (ALE). Identification of mutations responsible for these fast-growing phenotypes by whole-genome sequencing and reverse engineering showed that, for each compound, a small number of mutations sufficed to achieve fast growth in its absence. These results form an important first step toward development of S. cerevisiae strains that exhibit fast growth on inexpensive, fully supplemented mineral media that only require complementation with a carbon source, thereby reducing costs, complexity, and contamination risks in industrial yeast fermentation processes.
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16
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Balaban BG, Yılmaz Ü, Alkım C, Topaloğlu A, Kısakesen Hİ, Holyavkin C, Çakar ZP. Evolutionary Engineering of an Iron-Resistant Saccharomyces cerevisiae Mutant and Its Physiological and Molecular Characterization. Microorganisms 2019; 8:E43. [PMID: 31878309 DOI: 10.3390/microorganisms8010043] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 12/18/2019] [Accepted: 12/20/2019] [Indexed: 12/31/2022] Open
Abstract
Iron plays an essential role in all organisms and is involved in the structure of many biomolecules. It also regulates the Fenton reaction where highly reactive hydroxyl radicals occur. Iron is also important for microbial biodiversity, health and nutrition. Excessive iron levels can cause oxidative damage in cells. Saccharomyces cerevisiae evolved mechanisms to regulate its iron levels. To study the iron stress resistance in S. cerevisiae, evolutionary engineering was employed. The evolved iron stress-resistant mutant “M8FE” was analysed physiologically, transcriptomically and by whole genome re-sequencing. M8FE showed cross-resistance to other transition metals: cobalt, chromium and nickel and seemed to cope with the iron stress by both avoidance and sequestration strategies. PHO84, encoding the high-affinity phosphate transporter, was the most down-regulated gene in the mutant, and may be crucial in iron-resistance. M8FE had upregulated many oxidative stress response, reserve carbohydrate metabolism and mitophagy genes, while ribosome biogenesis genes were downregulated. As a possible result of the induced oxidative stress response genes, lower intracellular oxidation levels were observed. M8FE also had high trehalose and glycerol production levels. Genome re-sequencing analyses revealed several mutations associated with diverse cellular and metabolic processes, like cell division, phosphate-mediated signalling, cell wall integrity and multidrug transporters.
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17
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Pattharaprachayakul N, Lee HJ, Incharoensakdi A, Woo HM. Evolutionary Engineering of Cyanobacteria to Enhance the Production of α-Farnesene from CO 2. J Agric Food Chem 2019; 67:13658-13664. [PMID: 31755253 DOI: 10.1021/acs.jafc.9b06254] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Photosynthetic cyanobacteria can fix CO2 and utilize it as the sole carbon source for cell growth and production of biochemicals. Here, we metabolically engineered Synechococcus elongatus PCC 7942 for an enhanced production of α-farnesene by optimizing the ribosome-binding site (RBS) of the codon-optimized farnesene synthase gene. The production of α-farnesene was found to be enhanced in strains with a low translation initiation rate, resulting in α-farnesene production (0.57 mg/(L day)). Using the RBS variants and random mutations, we performed fluorescence-based analysis of cells grown in 96-well culture plates to screen the α-farnesene-producing strains but could not improve the titers of the RBS-optimized strains. However, evolutionary engineering of the RBS-optimized strains resulted in a twofold increase in α-farnesene production (1.2 mg/(L day)) compared to the previous study. Therefore, combining metabolic and evolutionary engineering might be helpful for enhancing the cellular fitness of cyanobacteria for the production of target chemicals.
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Affiliation(s)
- Napisa Pattharaprachayakul
- Department of Food Science and Biotechnology , Sungkyunkwan University (SKKU) , 2066 Seobu-ro , Jangan-gu, Suwon 16419 , Republic of Korea
- Laboratory of Cyanobacterial Biotechnology, Department of Biochemistry, Faculty of Science , Chulalongkorn University , 254 Phayathai Road , Pathumwan, Bangkok 10330 , Thailand
| | - Hyun Jeong Lee
- Department of Food Science and Biotechnology , Sungkyunkwan University (SKKU) , 2066 Seobu-ro , Jangan-gu, Suwon 16419 , Republic of Korea
| | - Aran Incharoensakdi
- Laboratory of Cyanobacterial Biotechnology, Department of Biochemistry, Faculty of Science , Chulalongkorn University , 254 Phayathai Road , Pathumwan, Bangkok 10330 , Thailand
| | - Han Min Woo
- Department of Food Science and Biotechnology , Sungkyunkwan University (SKKU) , 2066 Seobu-ro , Jangan-gu, Suwon 16419 , Republic of Korea
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18
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Lv Z, Zhou J, Zhang Y, Zhou X, Xu N, Xin F, Ma J, Jiang M, Dong W. Techniques for enhancing the tolerance of industrial microbes to abiotic stresses: A review. Biotechnol Appl Biochem 2019; 67:73-81. [PMID: 31206805 DOI: 10.1002/bab.1794] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 06/05/2019] [Indexed: 12/20/2022]
Abstract
The diversity of stress responses and survival strategies evolved by microorganism enables them to survive and reproduce in a multitude of harsh environments, whereas the discovery of the underlying resistance genes or mechanisms laid the foundation for the directional enhancement of microbial tolerance to abiotic stresses encountered in industrial applications. Many biological techniques have been developed for improving the stress resistance of industrial microorganisms, which greatly benefited the bacteria on which industrial production is based. This review introduces the main techniques for enhancing the resistance of microorganisms to abiotic stresses, including evolutionary engineering, metabolic engineering, and process engineering, developed in recent years. In addition, we also discuss problems that are still present in this area and offer directions for future research.
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Affiliation(s)
- Ziyao Lv
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, 211800, Peoples' Republic of China
| | - Jie Zhou
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, 211800, Peoples' Republic of China.,Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing, 211800, Peoples' Republic of China
| | - Yue Zhang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, 211800, Peoples' Republic of China
| | - Xinhai Zhou
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, 211800, Peoples' Republic of China
| | - Ning Xu
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, 211800, Peoples' Republic of China
| | - Fengxue Xin
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, 211800, Peoples' Republic of China.,Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing, 211800, Peoples' Republic of China
| | - Jiangfeng Ma
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, 211800, Peoples' Republic of China.,Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing, 211800, Peoples' Republic of China
| | - Min Jiang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, 211800, Peoples' Republic of China.,Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing, 211800, Peoples' Republic of China
| | - Weiliang Dong
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, 211800, Peoples' Republic of China.,Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing, 211800, Peoples' Republic of China
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Shepelin D, Hansen ASL, Lennen R, Luo H, Herrgård MJ. Selecting the Best: Evolutionary Engineering of Chemical Production in Microbes. Genes (Basel) 2018; 9:E249. [PMID: 29751691 PMCID: PMC5977189 DOI: 10.3390/genes9050249] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Revised: 05/02/2018] [Accepted: 05/02/2018] [Indexed: 01/10/2023] Open
Abstract
Microbial cell factories have proven to be an economical means of production for many bulk, specialty, and fine chemical products. However, we still lack both a holistic understanding of organism physiology and the ability to predictively tune enzyme activities in vivo, thus slowing down rational engineering of industrially relevant strains. An alternative concept to rational engineering is to use evolution as the driving force to select for desired changes, an approach often described as evolutionary engineering. In evolutionary engineering, in vivo selections for a desired phenotype are combined with either generation of spontaneous mutations or some form of targeted or random mutagenesis. Evolutionary engineering has been used to successfully engineer easily selectable phenotypes, such as utilization of a suboptimal nutrient source or tolerance to inhibitory substrates or products. In this review, we focus primarily on a more challenging problem-the use of evolutionary engineering for improving the production of chemicals in microbes directly. We describe recent developments in evolutionary engineering strategies, in general, and discuss, in detail, case studies where production of a chemical has been successfully achieved through evolutionary engineering by coupling production to cellular growth.
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Affiliation(s)
- Denis Shepelin
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Kongens Lyngby, Denmark.
| | - Anne Sofie Lærke Hansen
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Kongens Lyngby, Denmark.
| | - Rebecca Lennen
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Kongens Lyngby, Denmark.
| | - Hao Luo
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Kongens Lyngby, Denmark.
| | - Markus J Herrgård
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Kongens Lyngby, Denmark.
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Tekarslan-Sahin SH, Alkim C, Sezgin T. Physiological and transcriptomic analysis of a salt-resistant Saccharomyces cerevisiae mutant obtained by evolutionary engineering. Bosn J Basic Med Sci 2018; 18:55-65. [PMID: 28954203 PMCID: PMC5826675 DOI: 10.17305/bjbms.2017.2250] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 08/07/2017] [Accepted: 08/08/2017] [Indexed: 12/19/2022] Open
Abstract
Salt-resistant yeast strains are highly demanded by industry due to the exposure of yeast cells to high concentrations of salt, in various industrial bioprocesses. The aim of this study was to perform a physiological and transcriptomic analysis of a salt-resistant Saccharomyces cerevisiae (S. cerevisiae) mutant generated by evolutionary engineering. NaCl-resistant S. cerevisiae strains were obtained by ethyl methanesulfonate (EMS) mutagenesis followed by successive batch cultivations in the presence of gradually increasing NaCl concentrations, up to 8.5% w/v of NaCl (1.45 M). The most probable number (MPN) method, high-performance liquid chromatography (HPLC), and glucose oxidase/peroxidase method were used for physiological analysis, while Agilent yeast DNA microarray systems were used for transcriptome analysis. NaCl-resistant mutant strain T8 was highly cross-resistant to LiCl and highly sensitive to AlCl3. In the absence of NaCl stress, T8 strain had significantly higher trehalose and glycogen levels compared to the reference strain. Global transcriptome analysis by means of DNA microarrays showed that the genes related to stress response, carbohydrate transport, glycogen and trehalose biosynthesis, as well as biofilm formation, were upregulated. According to gene set enrichment analysis, 548 genes were upregulated and 22 downregulated in T8 strain, compared to the reference strain. Among the 548 upregulated genes, the highest upregulation was observed for the FLO11 (MUC1) gene (92-fold that of the reference strain). Overall, evolutionary engineering by chemical mutagenesis and increasing NaCl concentrations is a promising approach in developing industrial strains for biotechnological applications.
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Affiliation(s)
- Seyma Hande Tekarslan-Sahin
- Department of Molecular Biology and Genetics, Faculty of Science and Letters, Istanbul Technical University, Istanbul, Turkey; Dr. Orhan Öcalgiray Molecular Biology, Biotechnology and Genetics Research Center (ITU-MOBGAM), Istanbul Technical University, Istanbul, Turkey; Department of Pharmaceutical Technology, Faculty of Pharmacy, Istanbul University, Istanbul, Turkey.
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Brickwedde A, van den Broek M, Geertman JMA, Magalhães F, Kuijpers NGA, Gibson B, Pronk JT, Daran JMG. Evolutionary Engineering in Chemostat Cultures for Improved Maltotriose Fermentation Kinetics in Saccharomyces pastorianus Lager Brewing Yeast. Front Microbiol 2017; 8:1690. [PMID: 28943864 PMCID: PMC5596070 DOI: 10.3389/fmicb.2017.01690] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 08/21/2017] [Indexed: 01/01/2023] Open
Abstract
The lager brewing yeast Saccharomyces pastorianus, an interspecies hybrid of S. eubayanus and S. cerevisiae, ferments maltotriose, maltose, sucrose, glucose and fructose in wort to ethanol and carbon dioxide. Complete and timely conversion ("attenuation") of maltotriose by industrial S. pastorianus strains is a key requirement for process intensification. This study explores a new evolutionary engineering strategy for improving maltotriose fermentation kinetics. Prolonged carbon-limited, anaerobic chemostat cultivation of the reference strain S. pastorianus CBS1483 on a maltotriose-enriched sugar mixture was used to select for spontaneous mutants with improved affinity for maltotriose. Evolved populations exhibited an up to 5-fold lower residual maltotriose concentration and a higher ethanol concentration than the parental strain. Uptake studies with 14C-labeled sugars revealed an up to 4.75-fold higher transport capacity for maltotriose in evolved strains. In laboratory batch cultures on wort, evolved strains showed improved attenuation and higher ethanol concentrations. These improvements were also observed in pilot fermentations at 1,000-L scale with high-gravity wort. Although the evolved strain exhibited multiple chromosomal copy number changes, analysis of beer made from pilot fermentations showed no negative effects on flavor compound profiles. These results demonstrate the potential of evolutionary engineering for strain improvement of hybrid, alloploid brewing strains.
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Affiliation(s)
- Anja Brickwedde
- Department of Biotechnology, Delft University of TechnologyDelft, Netherlands
| | | | | | | | - Niels G A Kuijpers
- HEINEKEN Supply Chain, Global Innovation and ResearchZoeterwoude, Netherlands
| | - Brian Gibson
- VTT Technical Research Centre of Finland Ltd.Espoo, Finland
| | - Jack T Pronk
- Department of Biotechnology, Delft University of TechnologyDelft, Netherlands
| | - Jean-Marc G Daran
- Department of Biotechnology, Delft University of TechnologyDelft, Netherlands
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22
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Nijland JG, Shin HY, Boender LGM, de Waal PP, Klaassen P, Driessen AJM. Improved Xylose Metabolism by a CYC8 Mutant of Saccharomyces cerevisiae. Appl Environ Microbiol 2017; 83:e00095-17. [PMID: 28363963 DOI: 10.1128/AEM.00095-17] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 03/24/2017] [Indexed: 11/20/2022] Open
Abstract
Engineering Saccharomyces cerevisiae for the utilization of pentose sugars is an important goal for the production of second-generation bioethanol and biochemicals. However, S. cerevisiae lacks specific pentose transporters, and in the presence of glucose, pentoses enter the cell inefficiently via endogenous hexose transporters (HXTs). By means of in vivo engineering, we have developed a quadruple hexokinase deletion mutant of S. cerevisiae that evolved into a strain that efficiently utilizes d-xylose in the presence of high d-glucose concentrations. A genome sequence analysis revealed a mutation (Y353C) in the general corepressor CYC8, or SSN6, which was found to be responsible for the phenotype when introduced individually in the nonevolved strain. A transcriptome analysis revealed altered expression of 95 genes in total, including genes involved in (i) hexose transport, (ii) maltose metabolism, (iii) cell wall function (mannoprotein family), and (iv) unknown functions (seripauperin multigene family). Of the 18 known HXTs, genes for 9 were upregulated, especially the low or nonexpressed HXT10, HXT13, HXT15, and HXT16 Mutant cells showed increased uptake rates of d-xylose in the presence of d-glucose, as well as elevated maximum rates of metabolism (Vmax) for both d-glucose and d-xylose transport. The data suggest that the increased expression of multiple hexose transporters renders d-xylose metabolism less sensitive to d-glucose inhibition due to an elevated transport rate of d-xylose into the cell.IMPORTANCE The yeast Saccharomyces cerevisiae is used for second-generation bioethanol formation. However, growth on xylose is limited by pentose transport through the endogenous hexose transporters (HXTs), as uptake is outcompeted by the preferred substrate, glucose. Mutant strains were obtained with improved growth characteristics on xylose in the presence of glucose, and the mutations mapped to the regulator Cyc8. The inactivation of Cyc8 caused increased expression of HXTs, thereby providing more capacity for the transport of xylose, presenting a further step toward a more robust process of industrial fermentation of lignocellulosic biomass using yeast.
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De Vero L, Bonciani T, Verspohl A, Mezzetti F, Giudici P. High-glutathione producing yeasts obtained by genetic improvement strategies: a focus on adaptive evolution approaches for novel wine strains. AIMS Microbiol 2017; 3:155-170. [PMID: 31294155 PMCID: PMC6605010 DOI: 10.3934/microbiol.2017.2.155] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 03/21/2017] [Indexed: 01/27/2023] Open
Abstract
Glutathione (GSH) is the most abundant non-protein thiol in living organisms. Due to its important antioxidant role, it is widely used in medicine, as a food additive, and in the cosmetic industry. Recently, GSH has received growing attention in winemaking because of its ability to control oxidative spoilage damage and to protect various aromatic compounds. Indeed, GSH concentration in wine is highly variable and several factors are involved in its regulation, ranging from grape must to yeast fermentation activity. This short review aims at highlighting the common genetic strategies, useful for obtaining wine yeasts with enhanced GSH production, paying particular attention to the adaptive evolution approaches. Moreover, other strategies, such as random mutagenesis, metabolic engineering and hybridization have been briefly reviewed with a stress on both their strengths and weaknesses in terms of actual feasibility and acceptance by wine consumers.
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Affiliation(s)
- Luciana De Vero
- Unimore Microbial Culture Collection (UMCC), Department of Life Sciences, University of Modena and Reggio Emilia, Italy
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24
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Abstract
To feed a world population projected to reach 9 billion people by 2050, the productivity of major crops must be increased by at least 50%. One potential route to boost the productivity of cereals is to equip them genetically with the 'supercharged' C4 type of photosynthesis; however, the necessary genetic modifications are not sufficiently understood for the corresponding genetic engineering programme. In this opinion paper, we discuss a strategy to solve this problem by developing a new paradigm for plant breeding. We propose combining the bioengineering of well-understood traits with subsequent evolutionary engineering, i.e. mutagenesis and artificial selection. An existing mathematical model of C3-C4 evolution is used to choose the most promising path towards this goal. Based on biomathematical simulations, we engineer Arabidopsis thaliana plants that express the central carbon-fixing enzyme Rubisco only in bundle sheath cells (Ru-BSC plants), the localization characteristic for C4 plants. This modification will initially be deleterious, forcing the Ru-BSC plants into a fitness valley from where previously inaccessible adaptive steps towards C4 photosynthesis become accessible through fitness-enhancing mutations. Mutagenized Ru-BSC plants are then screened for improved photosynthesis, and are expected to respond to imposed artificial selection pressures by evolving towards C4 anatomy and biochemistry.
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Affiliation(s)
- Yuanyuan Li
- Institute of Developmental and Molecular Biology of Plants, Plant Molecular Physiology and Biotechnology Group, Heinrich Heine University, Universitätsstr. 1, 40225 Düsseldorf, Germany
- Institute for Computer Science, Heinrich Heine University, Universitätsstr. 1, 40225 Düsseldorf, Germany
- Cluster of Excellence on Plant Sciences (CEPLAS), 40225 Düsseldorf, Germany
| | - David Heckmann
- Institute for Computer Science, Heinrich Heine University, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Martin J Lercher
- Institute for Computer Science, Heinrich Heine University, Universitätsstr. 1, 40225 Düsseldorf, Germany
- Cluster of Excellence on Plant Sciences (CEPLAS), 40225 Düsseldorf, Germany
| | - Veronica G Maurino
- Institute of Developmental and Molecular Biology of Plants, Plant Molecular Physiology and Biotechnology Group, Heinrich Heine University, Universitätsstr. 1, 40225 Düsseldorf, Germany
- Cluster of Excellence on Plant Sciences (CEPLAS), 40225 Düsseldorf, Germany
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25
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Kozak BU, van Rossum HM, Niemeijer MS, van Dijk M, Benjamin K, Wu L, Daran JMG, Pronk JT, van Maris AJA. Replacement of the initial steps of ethanol metabolism in Saccharomyces cerevisiae by ATP-independent acetylating acetaldehyde dehydrogenase. FEMS Yeast Res 2016; 16:fow006. [PMID: 26818854 PMCID: PMC5815134 DOI: 10.1093/femsyr/fow006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 01/25/2016] [Indexed: 11/17/2022] Open
Abstract
In Saccharomyces cerevisiae ethanol dissimilation is initiated by its oxidation and activation to cytosolic acetyl-CoA. The associated consumption of ATP strongly limits yields of biomass and acetyl-CoA-derived products. Here, we explore the implementation of an ATP-independent pathway for acetyl-CoA synthesis from ethanol that, in theory, enables biomass yield on ethanol that is up to 40% higher. To this end, all native yeast acetaldehyde dehydrogenases (ALDs) were replaced by heterologous acetylating acetaldehyde dehydrogenase (A-ALD). Engineered Ald− strains expressing different A-ALDs did not immediately grow on ethanol, but serial transfer in ethanol-grown batch cultures yielded growth rates of up to 70% of the wild-type value. Mutations in ACS1 were identified in all independently evolved strains and deletion of ACS1 enabled slow growth of non-evolved Ald− A-ALD strains on ethanol. Acquired mutations in A-ALD genes improved affinity—Vmax/Km for acetaldehyde. One of five evolved strains showed a significant 5% increase of its biomass yield in ethanol-limited chemostat cultures. Increased production of acetaldehyde and other by-products was identified as possible cause for lower than theoretically predicted biomass yields. This study proves that the native yeast pathway for conversion of ethanol to acetyl-CoA can be replaced by an engineered pathway with the potential to improve biomass and product yields. This manuscript investigates a metabolic engineering strategy to improve the use of ethanol as a feedstock for production of bio-based fuels and chemicals with yeast.
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Affiliation(s)
- Barbara U Kozak
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, the Netherlands
| | - Harmen M van Rossum
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, the Netherlands
| | - Matthijs S Niemeijer
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, the Netherlands
| | - Marlous van Dijk
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, the Netherlands
| | - Kirsten Benjamin
- Amyris Inc, 5885 Hollis Street, Ste. 100, Emeryville, CA94608, USA
| | - Liang Wu
- DSM Biotechnology Center, Alexander Fleminglaan 1, 2613 AX Delft, the Netherlands
| | - Jean-Marc G Daran
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, the Netherlands
| | - Jack T Pronk
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, the Netherlands
| | - Antonius J A van Maris
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, the Netherlands
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26
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Qi X, Zha J, Liu GG, Zhang W, Li BZ, Yuan YJ. Heterologous xylose isomerase pathway and evolutionary engineering improve xylose utilization in Saccharomyces cerevisiae. Front Microbiol 2015; 6:1165. [PMID: 26539187 PMCID: PMC4612707 DOI: 10.3389/fmicb.2015.01165] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2015] [Accepted: 10/08/2015] [Indexed: 12/24/2022] Open
Abstract
Xylose utilization is one key issue for the bioconversion of lignocelluloses. It is a promising approach to engineering heterologous pathway for xylose utilization in Saccharomyces cerevisiae. Here, we constructed a xylose-fermenting yeast SyBE001 through combinatorial fine-tuning the expression of XylA and endogenous XKS1. Additional overexpression of genes RKI1, RPE1, TKL1, and TAL1 in the non-oxidative pentose phosphate pathway (PPP) in SyBE001 increased the xylose consumption rate by 1.19-fold. By repetitive adaptation, the xylose utilization rate was further increased by ∼10-fold in the resultant strain SyBE003. Gene expression analysis identified a variety of genes with significantly changed expression in the PPP, glycolysis and the tricarboxylic acid cycle in SyBE003.
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Affiliation(s)
- Xin Qi
- Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University Tianjin, China ; SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University Tianjin, China
| | - Jian Zha
- Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University Tianjin, China ; SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University Tianjin, China
| | - Gao-Gang Liu
- Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University Tianjin, China ; SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University Tianjin, China
| | - Weiwen Zhang
- Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University Tianjin, China ; SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University Tianjin, China
| | - Bing-Zhi Li
- Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University Tianjin, China ; SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University Tianjin, China
| | - Ying-Jin Yuan
- Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University Tianjin, China ; SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University Tianjin, China
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27
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Smith J, van Rensburg E, Görgens JF. Simultaneously improving xylose fermentation and tolerance to lignocellulosic inhibitors through evolutionary engineering of recombinant Saccharomyces cerevisiae harbouring xylose isomerase. BMC Biotechnol 2014; 14:41. [PMID: 24884721 PMCID: PMC4026109 DOI: 10.1186/1472-6750-14-41] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Accepted: 05/06/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Yeasts tolerant to toxic inhibitors from steam-pretreated lignocellulose with xylose co-fermentation capability represent an appealing approach for 2nd generation ethanol production. Whereas rational engineering, mutagenesis and evolutionary engineering are established techniques for either improved xylose utilisation or enhancing yeast tolerance, this report focuses on the simultaneous enhancement of these attributes through mutagenesis and evolutionary engineering of Saccharomyces cerevisiae harbouring xylose isomerase in anoxic chemostat culture using non-detoxified pretreatment liquor from triticale straw. RESULTS Following ethyl methanesulfonate (EMS) mutagenesis, Saccharomyces cerevisiae strain D5A⁺ (ATCC 200062 strain platform), harbouring the xylose isomerase (XI) gene for pentose co-fermentation was grown in anoxic chemostat culture for 100 generations at a dilution rate of 0.10 h⁻¹ in a medium consisting of 60% (v/v) non-detoxified hydrolysate liquor from steam-pretreated triticale straw, supplemented with 20 g/L xylose as carbon source. In semi-aerobic batch cultures in the same medium, the isolated strain D5A(+H) exhibited a slightly lower maximum specific growth rate (μ(max) = 0.12 ± 0.01 h⁻¹) than strain TMB3400, with no ethanol production observed by the latter strain. Strain D5A(+H) also exhibited a shorter lag phase (4 h vs. 30 h) and complete removal of HMF, furfural and acetic acid from the fermentation broth within 24 h, reaching an ethanol concentration of 1.54 g/L at a yield (Y(p/s)) of 0.06 g/g xylose and a specific productivity of 2.08 g/gh. Evolutionary engineering profoundly affected the yeast metabolism, given that parental strain D5A+ exhibited an oxidative metabolism on xylose prior to strain development. CONCLUSIONS Physiological adaptations confirm improvements in the resistance to and conversion of inhibitors from pretreatment liquor with simultaneous enhancement of xylose to ethanol fermentation. These data support the sequential application of random mutagenesis followed by continuous culture under simultaneous selective pressure from inhibitors and xylose as primary carbon source.
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Affiliation(s)
- Justin Smith
- Department of Process Engineering, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa
| | - Eugéne van Rensburg
- Department of Process Engineering, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa
| | - Johann F Görgens
- Department of Process Engineering, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa
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28
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Steensels J, Snoek T, Meersman E, Picca Nicolino M, Voordeckers K, Verstrepen KJ. Improving industrial yeast strains: exploiting natural and artificial diversity. FEMS Microbiol Rev 2014; 38:947-95. [PMID: 24724938 PMCID: PMC4293462 DOI: 10.1111/1574-6976.12073] [Citation(s) in RCA: 257] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2013] [Revised: 01/31/2014] [Accepted: 04/02/2014] [Indexed: 12/23/2022] Open
Abstract
Yeasts have been used for thousands of years to make fermented foods and beverages, such as beer, wine, sake, and bread. However, the choice for a particular yeast strain or species for a specific industrial application is often based on historical, rather than scientific grounds. Moreover, new biotechnological yeast applications, such as the production of second-generation biofuels, confront yeast with environments and challenges that differ from those encountered in traditional food fermentations. Together, this implies that there are interesting opportunities to isolate or generate yeast variants that perform better than the currently used strains. Here, we discuss the different strategies of strain selection and improvement available for both conventional and nonconventional yeasts. Exploiting the existing natural diversity and using techniques such as mutagenesis, protoplast fusion, breeding, genome shuffling and directed evolution to generate artificial diversity, or the use of genetic modification strategies to alter traits in a more targeted way, have led to the selection of superior industrial yeasts. Furthermore, recent technological advances allowed the development of high-throughput techniques, such as ‘global transcription machinery engineering’ (gTME), to induce genetic variation, providing a new source of yeast genetic diversity.
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Affiliation(s)
- Jan Steensels
- Laboratory for Genetics and Genomics, Centre of Microbial and Plant Genetics (CMPG), KU Leuven, Leuven, Belgium; Laboratory for Systems Biology, VIB, Leuven, Belgium
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29
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Betts A, Vasse M, Kaltz O, Hochberg ME. Back to the future: evolving bacteriophages to increase their effectiveness against the pathogen Pseudomonas aeruginosa PAO1. Evol Appl 2013; 6:1054-63. [PMID: 24187587 PMCID: PMC3804238 DOI: 10.1111/eva.12085] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Accepted: 05/30/2013] [Indexed: 12/26/2022] Open
Abstract
Antibiotic resistance is becoming increasingly problematic for the treatment of infectious disease in both humans and livestock. The bacterium Pseudomonas aeruginosa is often found to be resistant to multiple antibiotics and causes high patient mortality in hospitals. Bacteriophages represent a potential option to combat pathogenic bacteria through their application in phage therapy. Here, we capitalize on previous studies showing how evolution may increase phage infection capacity relative to ancestral genotypes. We passaged four different phage isolates (podoviridae, myoviridae) through six serial transfers on the ancestral strain of Pseudomonas aeruginosa PAO1. We first demonstrate that repeated serial passage on ancestral bacteria increases infection capacity of bacteriophage on ancestral hosts and on those evolved for one transfer. This result is confirmed when examining the ability of evolved phage to reduce ancestral host population sizes. Second, through interaction with a single bacteriophage for 24 h, P. aeruginosa can evolve resistance to the ancestor of that bacteriophage; this also provides these evolved bacteria with cross-resistance to the other three bacteriophages. We discuss how the evolutionary training of phages could be employed as effective means of combatting bacterial infections or disinfecting surfaces in hospital settings, with reduced risk of bacterial resistance compared with conventional methods.
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Affiliation(s)
- Alex Betts
- Institut des Sciences de l'Evolution, UMR 5554, Université Montpellier 2 Montpellier CEDEX 05, France
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30
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Demeke MM, Dietz H, Li Y, Foulquié-Moreno MR, Mutturi S, Deprez S, Den Abt T, Bonini BM, Liden G, Dumortier F, Verplaetse A, Boles E, Thevelein JM. Development of a D-xylose fermenting and inhibitor tolerant industrial Saccharomyces cerevisiae strain with high performance in lignocellulose hydrolysates using metabolic and evolutionary engineering. Biotechnol Biofuels 2013; 6:89. [PMID: 23800147 PMCID: PMC3698012 DOI: 10.1186/1754-6834-6-89] [Citation(s) in RCA: 182] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Accepted: 06/12/2013] [Indexed: 05/04/2023]
Abstract
BACKGROUND The production of bioethanol from lignocellulose hydrolysates requires a robust, D-xylose-fermenting and inhibitor-tolerant microorganism as catalyst. The purpose of the present work was to develop such a strain from a prime industrial yeast strain, Ethanol Red, used for bioethanol production. RESULTS An expression cassette containing 13 genes including Clostridium phytofermentans XylA, encoding D-xylose isomerase (XI), and enzymes of the pentose phosphate pathway was inserted in two copies in the genome of Ethanol Red. Subsequent EMS mutagenesis, genome shuffling and selection in D-xylose-enriched lignocellulose hydrolysate, followed by multiple rounds of evolutionary engineering in complex medium with D-xylose, gradually established efficient D-xylose fermentation. The best-performing strain, GS1.11-26, showed a maximum specific D-xylose consumption rate of 1.1 g/g DW/h in synthetic medium, with complete attenuation of 35 g/L D-xylose in about 17 h. In separate hydrolysis and fermentation of lignocellulose hydrolysates of Arundo donax (giant reed), spruce and a wheat straw/hay mixture, the maximum specific D-xylose consumption rate was 0.36, 0.23 and 1.1 g/g DW inoculum/h, and the final ethanol titer was 4.2, 3.9 and 5.8% (v/v), respectively. In simultaneous saccharification and fermentation of Arundo hydrolysate, GS1.11-26 produced 32% more ethanol than the parent strain Ethanol Red, due to efficient D-xylose utilization. The high D-xylose fermentation capacity was stable after extended growth in glucose. Cell extracts of strain GS1.11-26 displayed 17-fold higher XI activity compared to the parent strain, but overexpression of XI alone was not enough to establish D-xylose fermentation. The high D-xylose consumption rate was due to synergistic interaction between the high XI activity and one or more mutations in the genome. The GS1.11-26 had a partial respiratory defect causing a reduced aerobic growth rate. CONCLUSIONS An industrial yeast strain for bioethanol production with lignocellulose hydrolysates has been developed in the genetic background of a strain widely used for commercial bioethanol production. The strain uses glucose and D-xylose with high consumption rates and partial cofermentation in various lignocellulose hydrolysates with very high ethanol yield. The GS1.11-26 strain shows highly promising potential for further development of an all-round robust yeast strain for efficient fermentation of various lignocellulose hydrolysates.
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Affiliation(s)
- Mekonnen M Demeke
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Belgium
- Department of Molecular Microbiology, VIB, Kasteelpark Arenberg 31, B-3001 Leuven, Heverlee, Flanders, Belgium
| | - Heiko Dietz
- Institute of Molecular Biosciences, Goethe-University Frankfurt, Max-von-Laue-Str. 9, D-60438 Frankfurt am Main, Germany
| | - Yingying Li
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Belgium
- Department of Molecular Microbiology, VIB, Kasteelpark Arenberg 31, B-3001 Leuven, Heverlee, Flanders, Belgium
| | - María R Foulquié-Moreno
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Belgium
- Department of Molecular Microbiology, VIB, Kasteelpark Arenberg 31, B-3001 Leuven, Heverlee, Flanders, Belgium
| | - Sarma Mutturi
- Department of Chemical Engineering, Lund University, P.O. Box 124, 22100 Lund, Sweden
| | - Sylvie Deprez
- Laboratory of Enzyme, Fermentation and Brewing Technology, KAHO Sint-Lieven University College, KU Leuven Association, Gebroeders De Smetstraat 1, 9000, Ghent, Flanders, Belgium
| | - Tom Den Abt
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Belgium
- Department of Molecular Microbiology, VIB, Kasteelpark Arenberg 31, B-3001 Leuven, Heverlee, Flanders, Belgium
| | - Beatriz M Bonini
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Belgium
- Department of Molecular Microbiology, VIB, Kasteelpark Arenberg 31, B-3001 Leuven, Heverlee, Flanders, Belgium
| | - Gunnar Liden
- Department of Chemical Engineering, Lund University, P.O. Box 124, 22100 Lund, Sweden
| | - Françoise Dumortier
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Belgium
- Department of Molecular Microbiology, VIB, Kasteelpark Arenberg 31, B-3001 Leuven, Heverlee, Flanders, Belgium
| | - Alex Verplaetse
- Laboratory of Enzyme, Fermentation and Brewing Technology, KAHO Sint-Lieven University College, KU Leuven Association, Gebroeders De Smetstraat 1, 9000, Ghent, Flanders, Belgium
| | - Eckhard Boles
- Institute of Molecular Biosciences, Goethe-University Frankfurt, Max-von-Laue-Str. 9, D-60438 Frankfurt am Main, Germany
| | - Johan M Thevelein
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Belgium
- Department of Molecular Microbiology, VIB, Kasteelpark Arenberg 31, B-3001 Leuven, Heverlee, Flanders, Belgium
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González-Ramos D, van den Broek M, van Maris AJA, Pronk JT, Daran JMG. Genome-scale analyses of butanol tolerance in Saccharomyces cerevisiae reveal an essential role of protein degradation. Biotechnol Biofuels 2013; 6:48. [PMID: 23552365 PMCID: PMC3621596 DOI: 10.1186/1754-6834-6-48] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Accepted: 03/22/2013] [Indexed: 05/04/2023]
Abstract
BACKGROUND n-Butanol and isobutanol produced from biomass-derived sugars are promising renewable transport fuels and solvents. Saccharomyces cerevisiae has been engineered for butanol production, but its high butanol sensitivity poses an upper limit to product titers that can be reached by further pathway engineering. A better understanding of the molecular basis of butanol stress and tolerance of S. cerevisiae is important for achieving improved tolerance. RESULTS By combining a screening of the haploid S. cerevisiae knock-out library, gene overexpression, and genome analysis of evolutionary engineered n-butanol-tolerant strains, we established that protein degradation plays an essential role in tolerance. Strains deleted in genes involved in the ubiquitin-proteasome system and in vacuolar degradation of damaged proteins showed hypersensitivity to n-butanol. Overexpression of YLR224W, encoding the subunit responsible for the recognition of damaged proteins of an ubiquitin ligase complex, resulted in a strain with a higher n-butanol tolerance. Two independently evolved n-butanol-tolerant strains carried different mutations in both RPN4 and RTG1, which encode transcription factors involved in the expression of proteasome and peroxisomal genes, respectively. Introduction of these mutated alleles in the reference strain increased butanol tolerance, confirming their relevance in the higher tolerance phenotype. The evolved strains, in addition to n-butanol, were also more tolerant to 2-butanol, isobutanol and 1-propanol, indicating a common molecular basis for sensitivity and tolerance to C3 and C4 alcohols. CONCLUSIONS This study shows that maintenance of protein integrity plays an essential role in butanol tolerance and demonstrates new promising targets to engineer S. cerevisiae for improved tolerance.
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Affiliation(s)
- Daniel González-Ramos
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, Delft 2628 BC, The Netherlands
- Kluyver Centre for Genomics of Industrial Fermentation, P.O. Box 5057, Delft 2600 GA, The Netherlands
| | - Marcel van den Broek
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, Delft 2628 BC, The Netherlands
- Kluyver Centre for Genomics of Industrial Fermentation, P.O. Box 5057, Delft 2600 GA, The Netherlands
| | - Antonius JA van Maris
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, Delft 2628 BC, The Netherlands
- Kluyver Centre for Genomics of Industrial Fermentation, P.O. Box 5057, Delft 2600 GA, The Netherlands
| | - Jack T Pronk
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, Delft 2628 BC, The Netherlands
- Kluyver Centre for Genomics of Industrial Fermentation, P.O. Box 5057, Delft 2600 GA, The Netherlands
- Platform for Green Synthetic Biology, P.O. Box 5057, Delft 2600 GA, The Netherlands
| | - Jean-Marc G Daran
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, Delft 2628 BC, The Netherlands
- Kluyver Centre for Genomics of Industrial Fermentation, P.O. Box 5057, Delft 2600 GA, The Netherlands
- Platform for Green Synthetic Biology, P.O. Box 5057, Delft 2600 GA, The Netherlands
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Abstract
The adaptive landscape for an industrially relevant phenotype is determined by the effects of the genetic determinants on the fitness of the microbial system. Identifying the underlying adaptive landscape for a particular phenotype of interest will greatly enhance our abilities to engineer more robust microbial strains. Visualizing evolution in real-time (VERT) is a recently developed method based on in vitro adaptive evolution that facilitates the identification of fitter mutants throughout the course of evolution. Combined with high-throughput genomic tools, VERT can greatly enhance the mapping of adaptive landscapes of industrially relevant phenotypes in microbial systems, thereby expanding our knowledge on the parameters that can be used for strain engineering.
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Affiliation(s)
| | | | - Katy C. Kao
- Department of Chemical Engineering, Texas A&M University, College Station,TX, USA
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Koppram R, Albers E, Olsson L. Evolutionary engineering strategies to enhance tolerance of xylose utilizing recombinant yeast to inhibitors derived from spruce biomass. Biotechnol Biofuels 2012; 5:32. [PMID: 22578262 PMCID: PMC3408370 DOI: 10.1186/1754-6834-5-32] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2012] [Accepted: 05/11/2012] [Indexed: 05/03/2023]
Abstract
BACKGROUND One of the crucial factors for a sustainable and economical production of lignocellulosic based bioethanol is the availability of a robust fermenting microorganism with high tolerance to inhibitors generated during the pretreatment of lignocellulosic raw materials, since these inhibitors are known to severely hinder growth and fermentation. RESULTS A long-term adaptation in repetitive batch cultures in shake flasks using a cocktail of 12 different inhibitors and a long-term chemostat adaptation using spruce hydrolysate were used as evolutionary engineering strategies to improve the inhibitor tolerance in the metabolically engineered xylose utilizing Saccharomyces cerevisiae strain, TMB3400. The yeast was evolved for a period of 429 and 97 generations in repetitive batch cultures and chemostat cultivation, respectively. During the evolutionary engineering in repetitive batch cultures the maximum specific growth rate increased from 0.18 h-1 to 0.33 h-1 and the time of lag phase was decreased from 48 h to 24 h. In the chemostat adaptation, after 97 generations, the specific conversion rates of HMF and furfural were found to be 3.5 and 4 folds higher respectively, compared to rates after three generations. Two evolved strains (RK60-5, RKU90-3) and one evolved strain (KE1-17) were isolated from evolutionary engineering in repetitive batches and chemostat cultivation, respectively. The strains displayed significantly improved growth performance over TMB3400 when cultivated in spruce hydrolysate under anaerobic conditions, the evolved strains exhibited 25 to 38% increase in specific consumption rate of sugars and 32 to 50% increased specific ethanol productivity compared to TMB3400. The evolved strains RK60-5 and RKU90-3 were unable to consume xylose under anaerobic conditions, whereas, KE1-17 was found to consume xylose at similar rates as TMB3400. CONCLUSION Using evolutionary engineering strategies in batch and chemostat cultivations we have generated three evolved strains that show significantly better tolerance to inhibitors in spruce hydrolysate and displayed a shorter time for overall fermentation of sugars compared to the parental strain.
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Affiliation(s)
- Rakesh Koppram
- Department of Chemical and Biological Engineering, Industrial Biotechnology, Chalmers University of Technology, Göteborg, SE-412 96, Sweden
| | - Eva Albers
- Department of Chemical and Biological Engineering, Industrial Biotechnology, Chalmers University of Technology, Göteborg, SE-412 96, Sweden
- Taurus Energy AB, Ideon, Ole Römers väg 12, Lund, SE-223 70, Sweden
| | - Lisbeth Olsson
- Department of Chemical and Biological Engineering, Industrial Biotechnology, Chalmers University of Technology, Göteborg, SE-412 96, Sweden
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34
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Abstract
We describe a novel method for constructing pools of DNA sequences that encode large proteins with molecular diversity. Sets of primer pairs that form 8 to 10 complementary base pairs in the 3' region and have double mismatch pairs at their 3'-OH ends were designed so that primer dimers recreated short stretches of DNA (microgenes) devoid of termination codons. Cycles of denaturation and elongation reactions with a pair of primers, four dNTPs, and 3'-5' exo+ thermostable DNA polymerase gave head-to-tail polymers of the primer dimer unit (microgene) whose sizes exceeded 12 kb. No template was required in this reaction, but mismatched nucleotides at 3'-OH ends of the primers were critical for efficient polymerization. At end-joining junctions of a microgene, nucleotide insertions and deletions randomly occurred, resulting in combinatorial libraries of three reading frames from a single microgene. Further molecular diversity could be incorporated by using a mixture of primers. The resultant polymers have long ORFs whose products have a repetitious nature that could facilitate the formation of higher structures of translated products. Thus, microgene polymers may be used as a source of libraries for in vitro protein evolution experiments. Ligation of a microgene is apparently related to the nonhomologous recombination of double-strand breaks in DNA that has been shown to be catalyzed by DNA polymerases. We named this polymerization reaction the "microgene polymerization reaction."
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Affiliation(s)
- K Shiba
- PRESTO, Japan Science and Technology Corporation, Tokyo.
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