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Saengphing T, Sattayawat P, Kalawil T, Suwannarach N, Kumla J, Yamada M, Panbangred W, Rodrussamee N. Improving furfural tolerance in a xylose-fermenting yeast Spathaspora passalidarum CMUWF1-2 via adaptive laboratory evolution. Microb Cell Fact 2024; 23:80. [PMID: 38481222 PMCID: PMC10936021 DOI: 10.1186/s12934-024-02352-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Accepted: 03/01/2024] [Indexed: 03/17/2024] Open
Abstract
BACKGROUND Spathaspora passalidarum is a yeast with the highly effective capability of fermenting several monosaccharides in lignocellulosic hydrolysates, especially xylose. However, this yeast was shown to be sensitive to furfural released during pretreatment and hydrolysis processes of lignocellulose biomass. We aimed to improve furfural tolerance in a previously isolated S. passalidarum CMUWF1-2, which presented thermotolerance and no detectable glucose repression, via adaptive laboratory evolution (ALE). RESULTS An adapted strain, AF2.5, was obtained from 17 sequential transfers of CMUWF1-2 in YPD broth with gradually increasing furfural concentration. Strain AF2.5 could tolerate higher concentrations of furfural, ethanol and 5-hydroxymethyl furfuraldehyde (HMF) compared with CMUWF1-2 while maintaining the ability to utilize glucose and other sugars simultaneously. Notably, the lag phase of AF2.5 was 2 times shorter than that of CMUWF1-2 in the presence of 2.0 g/l furfural, which allowed the highest ethanol titers to be reached in a shorter period. To investigate more in-depth effects of furfural, intracellular reactive oxygen species (ROS) accumulation was observed and, in the presence of 2.0 g/l furfural, AF2.5 exhibited 3.41 times less ROS accumulation than CMUWF1-2 consistent with the result from nuclear chromatins diffusion, which the cells number of AF2.5 with diffuse chromatins was also 1.41 and 1.24 times less than CMUWF1-2 at 24 and 36 h, respectively. CONCLUSIONS An enhanced furfural tolerant strain of S. passalidarum was achieved via ALE techniques, which shows faster and higher ethanol productivity than that of the wild type. Not only furfural tolerance but also ethanol and HMF tolerances were improved.
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Affiliation(s)
- Thanyalak Saengphing
- Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai, 50200, Thailand
| | - Pachara Sattayawat
- Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai, 50200, Thailand
- Center of Excellence in Microbial Diversity and Sustainable Utilization, Chiang Mai University, Chiang Mai, 50200, Thailand
| | - Thitisuda Kalawil
- Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai, 50200, Thailand
| | - Nakarin Suwannarach
- Center of Excellence in Microbial Diversity and Sustainable Utilization, Chiang Mai University, Chiang Mai, 50200, Thailand
| | - Jaturong Kumla
- Center of Excellence in Microbial Diversity and Sustainable Utilization, Chiang Mai University, Chiang Mai, 50200, Thailand
| | - Mamoru Yamada
- Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, Yamaguchi, 753-8515, Japan
- Life Science, Graduate School of Science and Technology for Innovation, Yamaguchi University, Ube, 755-8611, Japan
- Research Center for Thermotolerant Microbial Resources, Yamaguchi University, Yamaguchi, 753-8515, Japan
| | | | - Nadchanok Rodrussamee
- Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai, 50200, Thailand.
- Center of Excellence in Microbial Diversity and Sustainable Utilization, Chiang Mai University, Chiang Mai, 50200, Thailand.
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Zhu YX, He M, Li KJ, Wang YK, Qian N, Wang ZF, Sheng H, Sui Y, Zhang DD, Zhang K, Qi L, Zheng DQ. Novel insights into the effects of 5-hydroxymethfurural on genomic instability and phenotypic evolution using a yeast model. Appl Environ Microbiol 2024; 90:e0164923. [PMID: 38108644 PMCID: PMC10807415 DOI: 10.1128/aem.01649-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 11/06/2023] [Indexed: 12/19/2023] Open
Abstract
5-Hydroxymethfurural (5-HMF) is naturally found in a variety of foods and beverages and represents a main inhibitor in the lignocellulosic hydrolysates used for fermentation. This study investigated the impact of 5-HMF on the genomic stability and phenotypic plasticity of the yeast Saccharomyces cerevisiae. Using next-generation sequencing technology, we examined the genomic alterations of diploid S. cerevisiae isolates that were subcultured on a medium containing 1.2 g/L 5-HMF. We found that in 5-HMF-treated cells, the rates of chromosome aneuploidy, large deletions/duplications, and loss of heterozygosity were elevated compared with that in untreated cells. 5-HMF exposure had a mild impact on the rate of point mutations but altered the mutation spectrum. Contrary to what was observed in untreated cells, more monosomy than trisomy occurred in 5-HMF-treated cells. The aneuploidy mutant with monosomic chromosome IX was more resistant to 5-HMF than the diploid parent strain because of the enhanced activity of alcohol dehydrogenase. Finally, we found that overexpression of ADH6 and ZWF1 effectively stabilized the yeast genome under 5-HMF stress. Our findings not only elucidated the global effect of 5-HMF on the genomic integrity of yeast but also provided novel insights into how chromosomal instability drives the environmental adaptability of eukaryotic cells.IMPORTANCESingle-cell microorganisms are exposed to a range of stressors in both natural and industrial settings. This study investigated the effects of 5-hydroxymethfurural (5-HMF), a major inhibitor found in baked foods and lignocellulosic hydrolysates, on the chromosomal instability of yeast. We examined the mechanisms leading to the distinct patterns of 5-HMF-induced genomic alterations and discovered that chromosomal loss, typically viewed as detrimental to cell growth under most conditions, can contribute to yeast tolerance to 5-HMF. Our results increased the understanding of how specific stressors stimulate genomic plasticity and environmental adaptation in yeast.
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Affiliation(s)
- Ying-Xuan Zhu
- Hainan Institute of Zhejiang University, Zhejiang University, Sanya, China
- Ocean College, Zhejiang University, Zhoushan, China
| | - Min He
- Hainan Institute of Zhejiang University, Zhejiang University, Sanya, China
| | - Ke-Jing Li
- Ocean College, Zhejiang University, Zhoushan, China
| | - Ye-Ke Wang
- College of Life Science, Zhejiang University, Hangzhou, China
| | - Ning Qian
- Ocean College, Zhejiang University, Zhoushan, China
| | - Ze-Fei Wang
- Hainan Institute of Zhejiang University, Zhejiang University, Sanya, China
| | - Huan Sheng
- Ocean College, Zhejiang University, Zhoushan, China
| | - Yang Sui
- Ocean College, Zhejiang University, Zhoushan, China
| | | | - Ke Zhang
- College of Life Science, Zhejiang University, Hangzhou, China
| | - Lei Qi
- Ocean College, Zhejiang University, Zhoushan, China
| | - Dao-Qiong Zheng
- Hainan Institute of Zhejiang University, Zhejiang University, Sanya, China
- Ocean College, Zhejiang University, Zhoushan, China
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Igreja WS, da Silva Martins LH, de Almeida RR, de Oliveira JAR, Lopes AS, Chisté RC. Açai Seeds ( Euterpe oleracea Mart) Are Agroindustrial Waste with High Potential to Produce Low-Cost Substrates after Acid Hydrolysis. Molecules 2023; 28:6661. [PMID: 37764435 PMCID: PMC10536898 DOI: 10.3390/molecules28186661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 09/09/2023] [Accepted: 09/12/2023] [Indexed: 09/29/2023] Open
Abstract
Açai seeds have been discarded improperly around the Amazonia region, but they can be seen as promising low-cost substrates for fermentation processes. The structural carbohydrates and physicochemical characterization of açai seeds from the Amazonia were assessed followed by the determination of the optimal hydrolysis conditions using H3PO4 (phosphoric acid) and H2SO4 (sulfuric acid) to obtain a liquor with high contents of simple carbohydrates and low levels of potential microbial inhibitors usually generated during acid hydrolysis of carbohydrates. A central composite rotational design was carried out varying the concentrations of diluted acid (0-5%, w/v), solids (0.1-25%, w/v), and hydrolysis time (9.5-110 min). Acid hydrolysis with H2SO4 was more effective in producing reducing sugars (15.9-103.1 g/L) than H3PO4 (2.9-33.9 g/L) during optimization. The optimal hydrolysis conditions with H2SO4 were 3.5% of acid (w/v), 25% of solids during 70 min at 121 °C, which provided a liquor with 55 g/L of reducing sugars and low levels of microbial inhibitors: acetic acid (1.8 g/L), hydroxymethyl furfural (338 mg/L), and furfural (10 mg/L). Thus, açai seeds were characterized as promising agroindustrial waste with high potential to be used as a low-cost substrate in biotechnological processes, comprising relevant environmental and bioeconomic aspects for the development of the Amazonia.
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Affiliation(s)
- Willen Silva Igreja
- Postgraduate Program of Food Science and Technology (PPGCTA), Institute of Technology (ITEC), Federal University of Pará (UFPA), Belém 66075-110, PA, Brazil
| | - Luiza Helena da Silva Martins
- Postgraduate Program of Food Science and Technology (PPGCTA), Institute of Technology (ITEC), Federal University of Pará (UFPA), Belém 66075-110, PA, Brazil
- Instituto de Saúde e Produção Animal (ISPA), Universidade Federal Rural da Amazônia (UFRA), Belém 66075-900, PA, Brazil
| | - Rafaela Rodrigues de Almeida
- School of Food Engineering (FEA), Institute of Technology (ITEC), Federal University of Pará (UFPA), Belém 66075-110, PA, Brazil
| | - Johnatt Allan Rocha de Oliveira
- Postgraduate Program of Food Science and Technology (PPGCTA), Institute of Technology (ITEC), Federal University of Pará (UFPA), Belém 66075-110, PA, Brazil
- Nutrition College, Federal University of Pará (UFPA), Belém 66075-110, PA, Brazil
| | - Alessandra Santos Lopes
- Postgraduate Program of Food Science and Technology (PPGCTA), Institute of Technology (ITEC), Federal University of Pará (UFPA), Belém 66075-110, PA, Brazil
- School of Food Engineering (FEA), Institute of Technology (ITEC), Federal University of Pará (UFPA), Belém 66075-110, PA, Brazil
| | - Renan Campos Chisté
- Postgraduate Program of Food Science and Technology (PPGCTA), Institute of Technology (ITEC), Federal University of Pará (UFPA), Belém 66075-110, PA, Brazil
- School of Food Engineering (FEA), Institute of Technology (ITEC), Federal University of Pará (UFPA), Belém 66075-110, PA, Brazil
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Vanmarcke G, Deparis Q, Vanthienen W, Peetermans A, Foulquié-Moreno MR, Thevelein JM. A novel AST2 mutation generated upon whole-genome transformation of Saccharomyces cerevisiae confers high tolerance to 5-Hydroxymethylfurfural (HMF) and other inhibitors. PLoS Genet 2021; 17:e1009826. [PMID: 34624020 PMCID: PMC8500407 DOI: 10.1371/journal.pgen.1009826] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 09/14/2021] [Indexed: 11/19/2022] Open
Abstract
Development of cell factories for conversion of lignocellulosic biomass hydrolysates into biofuels or bio-based chemicals faces major challenges, including the presence of inhibitory chemicals derived from biomass hydrolysis or pretreatment. Extensive screening of 2526 Saccharomyces cerevisiae strains and 17 non-conventional yeast species identified a Candida glabrata strain as the most 5-hydroxymethylfurfural (HMF) tolerant. Whole-genome (WG) transformation of the second-generation industrial S. cerevisiae strain MD4 with genomic DNA from C. glabrata, but not from non-tolerant strains, allowed selection of stable transformants in the presence of HMF. Transformant GVM0 showed the highest HMF tolerance for growth on plates and in small-scale fermentations. Comparison of the WG sequence of MD4 and GVM1, a diploid segregant of GVM0 with similarly high HMF tolerance, surprisingly revealed only nine non-synonymous SNPs, of which none were present in the C. glabrata genome. Reciprocal hemizygosity analysis in diploid strain GVM1 revealed AST2N406I as the only causative mutation. This novel SNP improved tolerance to HMF, furfural and other inhibitors, when introduced in different yeast genetic backgrounds and both in synthetic media and lignocellulose hydrolysates. It stimulated disappearance of HMF and furfural from the medium and enhanced in vitro furfural NADH-dependent reducing activity. The corresponding mutation present in AST1 (i.e. AST1D405I) the paralog gene of AST2, also improved inhibitor tolerance but only in combination with AST2N406I and in presence of high inhibitor concentrations. Our work provides a powerful genetic tool to improve yeast inhibitor tolerance in lignocellulosic biomass hydrolysates and other inhibitor-rich industrial media, and it has revealed for the first time a clear function for Ast2 and Ast1 in inhibitor tolerance.
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Affiliation(s)
- Gert Vanmarcke
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Leuven-Heverlee, Belgium
- Center for Microbiology, VIB, Leuven-Heverlee, Belgium
| | - Quinten Deparis
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Leuven-Heverlee, Belgium
- Center for Microbiology, VIB, Leuven-Heverlee, Belgium
| | - Ward Vanthienen
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Leuven-Heverlee, Belgium
- Center for Microbiology, VIB, Leuven-Heverlee, Belgium
| | - Arne Peetermans
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Leuven-Heverlee, Belgium
- Center for Microbiology, VIB, Leuven-Heverlee, Belgium
| | - Maria R. Foulquié-Moreno
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Leuven-Heverlee, Belgium
- Center for Microbiology, VIB, Leuven-Heverlee, Belgium
| | - Johan M. Thevelein
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Leuven-Heverlee, Belgium
- Center for Microbiology, VIB, Leuven-Heverlee, Belgium
- NovelYeast bv, Open Bio-Incubator, Erasmus High School, Brussels (Jette), Belgium
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Cortivo PRD, Aydos LF, Hickert LR, Rosa CA, Hector RE, Mertens JA, Ayub MAZ. Performance of xylose-fermenting yeasts in oat and soybean hulls hydrolysate and improvement of ethanol production using immobilized cell systems. Biotechnol Lett 2021; 43:2011-2026. [PMID: 34480641 DOI: 10.1007/s10529-021-03182-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 08/30/2021] [Indexed: 11/25/2022]
Abstract
We investigated the fermentation of a mixture of oat and soybean hulls (1:1) subjected to acid (AH) or enzymatic (EH) hydrolyses, with both showing high osmotic pressures (> 1200 Osm kg-1) for the production of ethanol. Yeasts of genera Spathaspora, Scheffersomyces, Sugiymaella, and Candida, most of them biodiverse Brazilian isolates and previously untested in bioprocesses, were cultivated in these hydrolysates. Spathaspora passalidarum UFMG-CM-469 showed the best ethanol production kinetics in suspended cells cultures in acid hydrolysate, under microaerobic and anaerobic conditions. This strain was immobilized in LentiKats® (polyvinyl alcohol) and cultured in AH and EH. Supplementation of hydrolysates with crude yeast extract and peptone was also performed. The highest ethanol production was obtained using hydrolysates supplemented with crude yeast extract (AH-CYE and EH-CYE) showing yields of 0.40 and 0.44 g g-1, and productivities of 0.39 and 0.29 g (L h)-1, respectively. The reuse of the immobilized cells was tested in sequential fermentations of AH-CYE, EH-CYE, and a mixture of acid and enzymatic hydrolysates (AEH-CYE) operated under batch fluidized bed, with ethanol yields ranging from 0.31 to 0.40 g g-1 and productivities from 0.14 to 0.23 g (L h)-1. These results warrant further research using Spathaspora yeasts for second-generation ethanol production.
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Affiliation(s)
- Paulo Roberto Dall Cortivo
- Biotechnology & Biochemical Engineering Laboratory (BiotecLab), Federal University of Rio Grande do Sul, Av. Bento Gonçalves, 9500, PO Box 15090, Porto Alegre, RS, 91501-970, Brazil
| | - Luiza Fichtner Aydos
- Biotechnology & Biochemical Engineering Laboratory (BiotecLab), Federal University of Rio Grande do Sul, Av. Bento Gonçalves, 9500, PO Box 15090, Porto Alegre, RS, 91501-970, Brazil
| | - Lilian Raquel Hickert
- State University of Rio Grande do Sul, Av. Bento Gonçalves, 8855, Porto Alegre, RS, 91540-000, Brazil
| | - Carlos Augusto Rosa
- Department of Microbiology, ICB, C.P. 486, State University of Minas Gerais, Belo Horizonte, MG, 31270-901, Brazil
| | - Ronald E Hector
- Bioenergy Research Unit, USDA, Agricultural Research Service, National Center for Agricultural Utilization Research, 1815 North University Street, Peoria, IL, 61604, USA
| | - Jeffrey A Mertens
- Bioenergy Research Unit, USDA, Agricultural Research Service, National Center for Agricultural Utilization Research, 1815 North University Street, Peoria, IL, 61604, USA
| | - Marco Antônio Záchia Ayub
- Biotechnology & Biochemical Engineering Laboratory (BiotecLab), Federal University of Rio Grande do Sul, Av. Bento Gonçalves, 9500, PO Box 15090, Porto Alegre, RS, 91501-970, Brazil.
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6
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Brandt BA, García-Aparicio MDP, Görgens JF, van Zyl WH. Rational engineering of Saccharomyces cerevisiae towards improved tolerance to multiple inhibitors in lignocellulose fermentations. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:173. [PMID: 34454598 PMCID: PMC8403374 DOI: 10.1186/s13068-021-02021-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 08/20/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND The fermentation of lignocellulose hydrolysates to ethanol requires robust xylose-capable Saccharomyces cerevisiae strains able to operate in the presence of microbial inhibitory stresses. This study aimed at developing industrial S. cerevisiae strains with enhanced tolerance towards pretreatment-derived microbial inhibitors, by identifying novel gene combinations that confer resistance to multiple inhibitors (thus cumulative inhibitor resistance phenotype) with minimum impact on the xylose fermentation ability. The strategy consisted of multiple sequential delta-integrations of double-gene cassettes containing one gene conferring broad inhibitor tolerance (ARI1, PAD1 or TAL1) coupled with an inhibitor-specific gene (ADH6, FDH1 or ICT1). The performances of the transformants were compared with the parental strain in terms of biomass growth, ethanol yields and productivity, as well as detoxification capacities in a synthetic inhibitor cocktail, sugarcane bagasse hydrolysate as well as hardwood spent sulphite liquor. RESULTS The first and second round of delta-integrated transformants exhibited a trade-off between biomass and ethanol yield. Transformants showed increased inhibitor resistance phenotypes relative to parental controls specifically in fermentations with concentrated spent sulphite liquors at 40% and 80% v/v concentrations in 2% SC media. Unexpectedly, the xylose fermentation capacity of the transformants was reduced compared to the parental control, but certain combinations of genes had a minor impact (e.g. TAL1 + FDH1). The TAL1 + ICT1 combination negatively impacted on both biomass growth and ethanol yield, which could be linked to the ICT1 protein increasing transformant susceptibility to weak acids and temperature due to cell membrane changes. CONCLUSIONS The integration of the selected genes was proven to increase tolerance to pretreatment inhibitors in synthetic or industrial hydrolysates, but they were limited to the fermentation of glucose. However, some gene combination sequences had a reduced impact on xylose conversion.
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Affiliation(s)
- Bianca A Brandt
- Department of Microbiology, Stellenbosch University, Private Bag X1, Stellenbosch, 7602, South Africa
| | - Maria D P García-Aparicio
- Department of Process Engineering, Stellenbosch University, Private Bag X1, Stellenbosch, 7602, South Africa
| | - Johann F Görgens
- Department of Process Engineering, Stellenbosch University, Private Bag X1, Stellenbosch, 7602, South Africa
| | - Willem H van Zyl
- Department of Microbiology, Stellenbosch University, Private Bag X1, Stellenbosch, 7602, South Africa.
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Stress modulation as a means to improve yeasts for lignocellulose bioconversion. Appl Microbiol Biotechnol 2021; 105:4899-4918. [PMID: 34097119 DOI: 10.1007/s00253-021-11383-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Revised: 05/20/2021] [Accepted: 05/28/2021] [Indexed: 12/15/2022]
Abstract
The second-generation (2G) fermentation environment for lignocellulose conversion presents unique challenges to the fermentative organism that do not necessarily exist in other industrial fermentations. While extreme osmotic, heat, and nutrient starvation stresses are observed in sugar- and starch-based fermentation environments, additional pre-treatment-derived inhibitor stress, potentially exacerbated by stresses such as pH and product tolerance, exist in the 2G environment. Furthermore, in a consolidated bioprocessing (CBP) context, the organism is also challenged to secrete enzymes that may themselves lead to unfolded protein response and other stresses. This review will discuss responses of the yeast Saccharomyces cerevisiae to 2G-specific stresses and stress modulation strategies that can be followed to improve yeasts for this application. We also explore published -omics data and discuss relevant rational engineering, reverse engineering, and adaptation strategies, with the view of identifying genes or alleles that will make positive contributions to the overall robustness of 2G industrial strains. KEYPOINTS: • Stress tolerance is a key driver to successful application of yeast strains in biorefineries. • A wealth of data regarding stress responses has been gained through omics studies. • Integration of this knowledge could inform engineering of fit for purpose strains.
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Liu ZL. Reasons for 2-furaldehyde and 5-hydroxymethyl-2-furaldehyde resistance in Saccharomyces cerevisiae: current state of knowledge and perspectives for further improvements. Appl Microbiol Biotechnol 2021; 105:2991-3007. [PMID: 33830300 DOI: 10.1007/s00253-021-11256-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 03/16/2021] [Accepted: 03/23/2021] [Indexed: 11/25/2022]
Abstract
Common toxic compounds 2-furaldehyde (furfural) and 5-hydroxymethyl-2-furaldehyde (HMF) are formed from dehydration of pentose and hexose, respectively, during decomposition of lignocellulosic biomass polymers. Furfural and HMF represent a major class of aldehyde toxic chemicals that inhibit microbial growth and interfere with subsequent fermentation for production of renewable fuels and chemicals. Understanding mechanisms of yeast tolerance aids development of tolerant strains as the most economic means to overcome the toxicity. This review updates current knowledge on yeast resistance to these toxic chemicals obtained from rapid advances in the past few years. Findings are largely exemplified by an adapted strain NRRL Y-50049 compared with its progenitor, the industrial yeast Saccharomyces cerevisiae type strain NRRL Y-12632. Newly characterized molecular phenotypes distinguished acquired resistant components of Y-50049 from innate stress response of its progenitor Y-12632. These findings also raised important questions on how to address more deeply ingrained changes in addition to local renovations for yeast adaptation. An early review on understandings of yeast tolerance to these inhibitory compounds is available and its contents omitted here to avoid redundancy. Controversial and confusing issues on identification of yeast resistance to furfural and HMF are further clarified aiming improved future research. Propositions and perspectives on research understanding molecular mechanisms of yeast resistance and future improvements are also presented. KEY POINTS: • Distinguished adapted resistance from innate stress response in yeast. • Defined pathway-based molecular phenotypes of yeast resistance. • Proposed genomic insight and perspectives on yeast resistance and adaptation.
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Affiliation(s)
- Z Lewis Liu
- National Center for Agricultural Utilization Research, Bioenergy Research Unit, USDA Agricultural Research Service, 1815 N. University Street, Peoria, IL, 61604, USA.
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9
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Sehnem NT, Machado ÂS, Matte CR, Morais MADE, Ayub MAZ. Second-generation ethanol production by Wickerhamomyces anomalus strain adapted to furfural, 5-hydroxymethylfurfural (HMF), and high osmotic pressure. AN ACAD BRAS CIENC 2020; 92:e20181030. [PMID: 33084752 DOI: 10.1590/0001-3765202020181030] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 04/08/2019] [Indexed: 11/22/2022] Open
Abstract
The aims of this work were to improve cell tolerance towards high concentrations of furfural and 5-hydroxymethylfurfural (HMF) of an osmotolerant strain of Wickerhamomyces anomalus by means of evolutionary engineering, and to determine its ethanol production under stress conditions. Cells were grown in the presence of furfural, HMF, either isolated or in combination, and under high osmotic pressure conditions. The most toxic condition for the parental strain was the combination of both furans, under which it was unable to grow and to produce ethanol. However, the tolerant adapted strain achieved a yield of ethanol of 0.43 g g-1glucose in the presence of furfural and HMF, showing an alcohol dehydrogenase activity of 0.68 mU mg protein-1. For this strain, osmotic pressure, did not affect its growth rate. These results suggest that W. anomalus WA-HF5.5strain shows potential to be used in second-generation ethanol production systems.
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Affiliation(s)
- Nicole T Sehnem
- Universidade Federal do Rio Grande do Sul, Departamento de Tecnologia de Alimentos, Av. Bento Gonçalves, 9500, Campus do Vale, 91501-970 Porto Alegre, RS, Brazil
| | - Ângela S Machado
- Universidade Federal do Rio Grande do Sul, Departamento de Tecnologia de Alimentos, Av. Bento Gonçalves, 9500, Campus do Vale, 91501-970 Porto Alegre, RS, Brazil
| | - Carla R Matte
- Universidade Federal do Rio Grande do Sul, Departamento de Tecnologia de Alimentos, Av. Bento Gonçalves, 9500, Campus do Vale, 91501-970 Porto Alegre, RS, Brazil
| | - Marcos Antonio DE Morais
- Universidade Federal de Pernambuco, Departamento de Genética, Av. Moraes Rego, 1235, Cidade Universitária, 50670901 Recife, PE, Brazil
| | - Marco AntÔnio Z Ayub
- Universidade Federal do Rio Grande do Sul, Departamento de Tecnologia de Alimentos, Av. Bento Gonçalves, 9500, Campus do Vale, 91501-970 Porto Alegre, RS, Brazil
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10
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Dielectric property measurements as a method to determine the physiological state of Kluyveromyces marxianus and Saccharomyces cerevisiae stressed with furan aldehydes. Appl Microbiol Biotechnol 2019; 103:9633-9642. [DOI: 10.1007/s00253-019-10152-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 09/06/2019] [Accepted: 09/22/2019] [Indexed: 02/07/2023]
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11
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Sandberg TE, Salazar MJ, Weng LL, Palsson BO, Feist AM. The emergence of adaptive laboratory evolution as an efficient tool for biological discovery and industrial biotechnology. Metab Eng 2019; 56:1-16. [PMID: 31401242 DOI: 10.1016/j.ymben.2019.08.004] [Citation(s) in RCA: 244] [Impact Index Per Article: 48.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 08/01/2019] [Accepted: 08/05/2019] [Indexed: 12/21/2022]
Abstract
Harnessing the process of natural selection to obtain and understand new microbial phenotypes has become increasingly possible due to advances in culturing techniques, DNA sequencing, bioinformatics, and genetic engineering. Accordingly, Adaptive Laboratory Evolution (ALE) experiments represent a powerful approach both to investigate the evolutionary forces influencing strain phenotypes, performance, and stability, and to acquire production strains that contain beneficial mutations. In this review, we summarize and categorize the applications of ALE to various aspects of microbial physiology pertinent to industrial bioproduction by collecting case studies that highlight the multitude of ways in which evolution can facilitate the strain construction process. Further, we discuss principles that inform experimental design, complementary approaches such as computational modeling that help maximize utility, and the future of ALE as an efficient strain design and build tool driven by growing adoption and improvements in automation.
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Affiliation(s)
- Troy E Sandberg
- Department of Bioengineering, University of California, San Diego, CA, 92093, USA
| | - Michael J Salazar
- Department of Bioengineering, University of California, San Diego, CA, 92093, USA
| | - Liam L Weng
- Department of Bioengineering, University of California, San Diego, CA, 92093, USA
| | - Bernhard O Palsson
- Department of Bioengineering, University of California, San Diego, CA, 92093, USA; Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800, Lyngby, Denmark
| | - Adam M Feist
- Department of Bioengineering, University of California, San Diego, CA, 92093, USA; Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800, Lyngby, Denmark.
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12
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The biotechnological potential of the yeast Dekkera bruxellensis. World J Microbiol Biotechnol 2019; 35:103. [PMID: 31236799 DOI: 10.1007/s11274-019-2678-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2019] [Accepted: 06/15/2019] [Indexed: 10/26/2022]
Abstract
Dekkera bruxellensis is an industrial yeast mainly regarded as a contaminant species in fermentation processes. In winemaking, it is associated with off-flavours that cause wine spoilage, while in bioethanol production this yeast is linked to a reduction of industrial productivity by competing with Saccharomyces cerevisiae for the substrate. In spite of that, this point of view is gradually changing, mostly because D. bruxellensis is also able to produce important metabolites, such as ethanol, acetate, fusel alcohols, esters and others. This dual role is likely due to the fact that this yeast presents a set of metabolic traits that might be either industrially attractive or detrimental, depending on how they are faced and explored. Therefore, a proper industrial application for D. bruxellensis depends on the correct assembly of its central metabolic puzzle. In this sense, researchers have addressed issues regarding the physiological and genetic aspects of D. bruxellensis, which have brought to light much of our current knowledge on this yeast. In this review, we shall outline what is presently understood about the main metabolic features of D. bruxellensis and how they might be managed to improve its current or future industrial applications (except for winemaking, in which it is solely regarded as a contaminant). Moreover, we will discuss the advantages and challenges that must be overcome in order to take advantage of the full biotechnological potential of this yeast.
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13
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Protein expression analysis revealed a fine-tuned mechanism of in situ detoxification pathway for the tolerant industrial yeast Saccharomyces cerevisiae. Appl Microbiol Biotechnol 2019; 103:5781-5796. [PMID: 31139900 DOI: 10.1007/s00253-019-09906-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 05/07/2019] [Accepted: 05/07/2019] [Indexed: 12/18/2022]
Abstract
Inhibitory compounds liberated from lignocellulose pretreatment are representative toxic chemicals that repress microbial growth and metabolism. A tolerant strain of the industrial yeast Saccharomyces cerevisiae is able to detoxify a major class of toxic compounds while producing ethanol. Knowledge on the yeast tolerance was mostly obtained by gene expression analysis and limited protein expression evidence is yet available underlying the yeast adaptation. Here we report a comparative protein expression profiling study on Y-50049, a tolerant strain compared with its parental industrial type strain Y-12632. We found a distinctive protein expression of glucose-6-phosphate dehydrogenase (Zwf1) in Y-50049 but not in Y-12632, in the relatively conserved glycolysis and pentose phosphate pathway (PPP) in response to a combinational challenge of 2-furaldehyde (furfural) and 5-hydroxymethyl-2-furaldehyde (HMF). A group of proteins with aldehyde reduction activity was uniquely induced expressed in Y-50049 but not in Y-12632. Such evidence allowed fine-tuning a mechanism of the renovated in situ detoxification by Y-50049. As the key protein, Zwf1 drove the glucose metabolism in favor of the oxidative branch of the PPP facilitating in situ detoxification of the toxic chemicals by Y-50049. The activated expression of Zwf1 generated the essential cofactor nicotinamide adenine dinucleotide phosphate (NADPH) enabling reduction of furfural and HMF through a group of aldehyde reduction enzymes. In return, the activate aldehyde reductions released desirable feedbacks of NADP+ stimulating continued oxidative activity of Zwf1. Thus, a well-maintained cofactor regeneration cycle was established to restore the cofactor imbalance caused by furfural-HMF. Challenges and perspectives on adaptation of significantly differential expressions of ribosomal proteins and other unique proteins are also discussed.
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14
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Selection of Saccharomyces cerevisiae isolates for ethanol production in the presence of inhibitors. 3 Biotech 2019; 9:6. [PMID: 30622844 DOI: 10.1007/s13205-018-1541-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 12/16/2018] [Indexed: 12/29/2022] Open
Abstract
Eight yeast isolates identified as Saccharomyces cerevisiae were recovered from molasses-using Cuban distilleries and discriminated by nucleotide sequence analysis of ITS locus. The isolates L/25-7-81 and L/25-7-86 showed the highest ethanol yield from sugarcane juice, while L/25-7-12 and L/25-7-79 showed high ethanol yield from sugarcane molasses. The isolate L/25-7-86 also displayed high fermentation capacity when molasses was diluted with vinasse. In addition, stress tolerance was evaluated on the basis of growth in the presence of inhibitors (acetic acid, lactic acid, 5-hydroxymethylfurfural and sulfuric acid) and the results indicated that L/25-7-77 and L/25-7-79 congregated the highest score for cross-tolerance and fermentation capacity. Hence, these isolates, especially L/25-7-77, could serve as potential biological platform for the arduous task of fermenting complex substrates that contain inhibitors. The use of these yeasts was discussed in the context of second-generation ethanol and the environmental and economic implications of the use of vinasse, saving the use of water for substrate dilution.
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15
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Wang H, Li Q, Kuang X, Xiao D, Han X, Hu X, Li X, Ma M. Functions of aldehyde reductases from Saccharomyces cerevisiae in detoxification of aldehyde inhibitors and their biotechnological applications. Appl Microbiol Biotechnol 2018; 102:10439-10456. [PMID: 30306200 DOI: 10.1007/s00253-018-9425-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2018] [Revised: 09/28/2018] [Accepted: 09/28/2018] [Indexed: 11/25/2022]
Abstract
Bioconversion of lignocellulosic biomass to high-value bioproducts by fermentative microorganisms has drawn extensive attentions worldwide. Lignocellulosic biomass cannot be efficiently utilized by microorganisms, such as Saccharomyces cerevisiae, but has to be pretreated prior to fermentation. Aldehyde compounds, as the by-products generated in the pretreatment process of lignocellulosic biomass, are considered as the most important toxic inhibitors to S. cerevisiae cells for their growth and fermentation. Aldehyde group in the aldehyde inhibitors, including furan aldehydes, aliphatic aldehydes, and phenolic aldehydes, is identified as the toxic factor. It has been demonstrated that S. cerevisiae has the ability to in situ detoxify aldehydes to their corresponding less or non-toxic alcohols. This reductive reaction is catalyzed by the NAD(P)H-dependent aldehyde reductases. In recent years, detoxification of aldehyde inhibitors by S. cerevisiae has been extensively studied and a huge progress has been made. This mini-review summarizes the classifications and structural features of the characterized aldehyde reductases from S. cerevisiae, their catalytic abilities to exogenous and endogenous aldehydes and effects of metal ions, chemical protective additives, and salts on enzyme activities, subcellular localization of the aldehyde reductases and their possible roles in protection of the subcellular organelles, and transcriptional regulation of the aldehyde reductase genes by the key stress-response transcription factors. Cofactor preference of the aldehyde reductases and their molecular mechanisms and efficient supply pathways of cofactors, as well as biotechnological applications of the aldehyde reductases in the detoxification of aldehyde inhibitors derived from pretreatment of lignocellulosic biomass, are also included or supplemented in this mini-review.
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Affiliation(s)
- Hanyu Wang
- Institute of Natural Resources and Geographic Information Technology, College of Resources, Sichuan Agricultural University, No. 211 Huimin Road, Wenjiang, Chengdu, 611130, Sichuan, People's Republic of China
| | - Qian Li
- Institute of Natural Resources and Geographic Information Technology, College of Resources, Sichuan Agricultural University, No. 211 Huimin Road, Wenjiang, Chengdu, 611130, Sichuan, People's Republic of China
| | - Xiaolin Kuang
- Institute of Natural Resources and Geographic Information Technology, College of Resources, Sichuan Agricultural University, No. 211 Huimin Road, Wenjiang, Chengdu, 611130, Sichuan, People's Republic of China
| | - Difan Xiao
- Institute of Natural Resources and Geographic Information Technology, College of Resources, Sichuan Agricultural University, No. 211 Huimin Road, Wenjiang, Chengdu, 611130, Sichuan, People's Republic of China
| | - Xuebing Han
- Institute of Natural Resources and Geographic Information Technology, College of Resources, Sichuan Agricultural University, No. 211 Huimin Road, Wenjiang, Chengdu, 611130, Sichuan, People's Republic of China
| | - Xiangdong Hu
- Institute of Natural Resources and Geographic Information Technology, College of Resources, Sichuan Agricultural University, No. 211 Huimin Road, Wenjiang, Chengdu, 611130, Sichuan, People's Republic of China
| | - Xi Li
- College of Landscape Architecture, Sichuan Agricultural University, Wenjiang, Chengdu, 611130, Sichuan, People's Republic of China
| | - Menggen Ma
- Institute of Natural Resources and Geographic Information Technology, College of Resources, Sichuan Agricultural University, No. 211 Huimin Road, Wenjiang, Chengdu, 611130, Sichuan, People's Republic of China.
- Department of Applied Microbiology, College of Resources, Sichuan Agricultural University, Wenjiang, Chengdu, 611130, Sichuan, People's Republic of China.
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Liu ZL. Understanding the tolerance of the industrial yeast Saccharomyces cerevisiae against a major class of toxic aldehyde compounds. Appl Microbiol Biotechnol 2018; 102:5369-5390. [PMID: 29725719 DOI: 10.1007/s00253-018-8993-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 04/03/2018] [Accepted: 04/05/2018] [Indexed: 12/27/2022]
Abstract
Development of the next-generation biocatalyst is vital for fermentation-based industrial applications and a sustainable bio-based economy. Overcoming the major class of toxic compounds associated with lignocellulose-to-biofuels conversion is one of the significant challenges for new strain development. A significant number of investigations have been made to understand mechanisms of the tolerance for industrial yeast. It is humbling to learn how complicated the cell's response to the toxic chemicals is and how little we have known about yeast tolerance in the universe of the living cell. This study updates our current knowledge on the tolerance of industrial yeast against aldehyde inhibitory compounds at cellular, molecular and the genomic levels. It is comprehensive yet specific based on reproducible evidence and cross confirmed findings from different investigations using varied experimental approaches. This research approaches a rational foundation toward a more comprehensive understanding on the yeast tolerance. Discussions and perspectives are also proposed for continued exploring the puzzle of the yeast tolerance to aid the next-generation biocatalyst development.
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Affiliation(s)
- ZongLin Lewis Liu
- The US Department of Agriculture, Agricultural Research Service, National Center for Agricultural Utilization Research, Bioenergy Research Unit, 1815 N University Street, Peoria, IL, 61604, USA.
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17
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Caspeta L, Castillo T, Nielsen J. Modifying Yeast Tolerance to Inhibitory Conditions of Ethanol Production Processes. Front Bioeng Biotechnol 2015; 3:184. [PMID: 26618154 PMCID: PMC4641163 DOI: 10.3389/fbioe.2015.00184] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2015] [Accepted: 10/28/2015] [Indexed: 11/17/2022] Open
Abstract
Saccharomyces cerevisiae strains having a broad range of substrate utilization, rapid substrate consumption, and conversion to ethanol, as well as good tolerance to inhibitory conditions are ideal for cost-competitive ethanol production from lignocellulose. A major drawback to directly design S. cerevisiae tolerance to inhibitory conditions of lignocellulosic ethanol production processes is the lack of knowledge about basic aspects of its cellular signaling network in response to stress. Here, we highlight the inhibitory conditions found in ethanol production processes, the targeted cellular functions, the key contributions of integrated -omics analysis to reveal cellular stress responses according to these inhibitors, and current status on design-based engineering of tolerant and efficient S. cerevisiae strains for ethanol production from lignocellulose.
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Affiliation(s)
- Luis Caspeta
- Centro de Investigación en Biotecnología, Universidad Autónoma del Estado de Morelos , Cuernavaca , Mexico
| | - Tania Castillo
- Centro de Investigación en Biotecnología, Universidad Autónoma del Estado de Morelos , Cuernavaca , Mexico
| | - Jens Nielsen
- Novo Nordisk Foundation Center for Biosustainability, Chalmers University of Technology , Gothenburg , Sweden ; Department of Biology and Biological Engineering, Chalmers University of Technology , Gothenburg , Sweden ; Novo Nordisk Foundation Center for Biosustainability , Hørsholm , Denmark
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18
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Wallace-Salinas V, Brink DP, Ahrén D, Gorwa-Grauslund MF. Cell periphery-related proteins as major genomic targets behind the adaptive evolution of an industrial Saccharomyces cerevisiae strain to combined heat and hydrolysate stress. BMC Genomics 2015; 16:514. [PMID: 26156140 PMCID: PMC4496855 DOI: 10.1186/s12864-015-1737-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 06/29/2015] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Laboratory evolution is an important tool for developing robust yeast strains for bioethanol production since the biological basis behind combined tolerance requires complex alterations whose proper regulation is difficult to achieve by rational metabolic engineering. Previously, we reported on the evolved industrial Saccharomyces cerevisiae strain ISO12 that had acquired improved tolerance to grow and ferment in the presence of lignocellulose-derived inhibitors at high temperature (39 °C). In the current study, we used comparative genomics to uncover the extent of the genomic alterations that occurred during the evolution process and investigated possible associations between the mutations and the phenotypic traits in ISO12. RESULTS Through whole-genome sequencing and variant calling we identified a high number of strain-unique SNPs and INDELs in both ISO12 and the parental strain Ethanol Red. The variants were predicted to have 760 non-synonymous effects in both strains combined and were significantly enriched in Gene Ontology terms related to cell periphery, membranes and cell wall. Eleven genes, including MTL1, FLO9/FLO11, and CYC3 were found to be under positive selection in ISO12. Additionally, the FLO genes exhibited changes in copy number, and the alterations to this gene family were correlated with experimental results of multicellularity and invasive growth in the adapted strain. An independent lipidomic analysis revealed further differences between the strains in the content of nine lipid species. Finally, ISO12 displayed improved viability in undiluted spruce hydrolysate that was unrelated to reduction of inhibitors and changes in cell wall integrity, as shown by HPLC and lyticase assays. CONCLUSIONS Together, the results of the sequence comparison and the physiological characterisations indicate that cell-periphery proteins (e.g. extracellular sensors such as MTL1) and peripheral lipids/membranes are important evolutionary targets in the process of adaptation to the combined stresses. The capacity of ISO12 to develop complex colony formation also revealed multicellularity as a possible evolutionary strategy to improve competitiveness and tolerance to environmental stresses (also reflected by the FLO genes). Although a panel of altered genes with high relevance to the novel phenotype was detected, this study also demonstrates that the observed long-term molecular effects of thermal and inhibitor stress have polygenetic basis.
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Affiliation(s)
- Valeria Wallace-Salinas
- Applied Microbiology, Department of Chemistry, Lund University, P.O. Box 124, Lund, SE-22100, Sweden.
| | - Daniel P Brink
- Applied Microbiology, Department of Chemistry, Lund University, P.O. Box 124, Lund, SE-22100, Sweden.
| | - Dag Ahrén
- Microbial Ecology Group, Department of Biology, Lund University, Ecology Building, Lund, Sweden.
| | - Marie F Gorwa-Grauslund
- Applied Microbiology, Department of Chemistry, Lund University, P.O. Box 124, Lund, SE-22100, Sweden.
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Zhao X, Tang J, Wang X, Yang R, Zhang X, Gu Y, Li X, Ma M. YNL134C from Saccharomyces cerevisiae encodes a novel protein with aldehyde reductase activity for detoxification of furfural derived from lignocellulosic biomass. Yeast 2015; 32:409-22. [PMID: 25656244 DOI: 10.1002/yea.3068] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 12/28/2014] [Accepted: 01/28/2015] [Indexed: 02/03/2023] Open
Abstract
Furfural and 5-hydroxymethylfurfural (HMF) are the two main aldehyde compounds derived from pentoses and hexoses, respectively, during lignocellulosic biomass pretreatment. These two compounds inhibit microbial growth and interfere with subsequent alcohol fermentation. Saccharomyces cerevisiae has the in situ ability to detoxify furfural and HMF to the less toxic 2-furanmethanol (FM) and furan-2,5-dimethanol (FDM), respectively. Herein, we report that an uncharacterized gene, YNL134C, was highly up-regulated under furfural or HMF stress and Yap1p and Msn2/4p transcription factors likely controlled its up-regulated expression. Enzyme activity assays showed that YNL134C is an NADH-dependent aldehyde reductase, which plays a role in detoxification of furfural to FM. However, no NADH- or NADPH-dependent enzyme activity was observed for detoxification of HMF to FDM. This enzyme did not catalyse the reverse reaction of FM to furfural or FDM to HMF. Further studies showed that YNL134C is a broad-substrate aldehyde reductase, which can reduce multiple aldehydes to their corresponding alcohols. Although YNL134C is grouped into the quinone oxidoreductase family, no quinone reductase activity was observed using 1,2-naphthoquinone or 9,10-phenanthrenequinone as a substrate, and phylogenetic analysis indicates that it is genetically distant to quinone reductases. Proteins similar to YNL134C in sequence from S. cerevisiae and other microorganisms were phylogenetically analysed.
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Affiliation(s)
- Xianxian Zhao
- Institute of Ecological and Environmental Sciences, College of Resources and Environmental Sciences, Sichuan Agricultural University, Wenjiang, Sichuan, People's Republic of China
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Tiukova IA, de Barros Pita W, Sundell D, Haddad Momeni M, Horn SJ, Ståhlberg J, de Morais MA, Passoth V. Adaptation of Dekkera bruxellensis to lignocellulose-based substrate. Biotechnol Appl Biochem 2014; 61:51-7. [PMID: 23941546 DOI: 10.1002/bab.1145] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Accepted: 07/18/2013] [Indexed: 11/10/2022]
Abstract
Adaptation of Dekkera bruxellensis to lignocellulose hydrolysate was investigated. Cells of D. bruxellensis were grown for 72 and 192 H in batch and continuous culture, respectively (adapted cells). Cultivations in semisynthetic medium were run as controls (nonadapted cells). To test the adaptation, cells from these cultures were reinoculated in the lignocellulose medium, and growth and ethanol production characteristics were monitored. Cells adapted to lignocellulose hydrolysate had a shorter lag phase, grew faster, and produced a higher ethanol concentration as compared with nonadapted cells. A stability test showed that after cultivation in rich medium, cells partially lost the adapted phenotype but still showed faster growth and higher ethanol production as compared with nonadapted cells. Because alcohol dehydrogenase genes have been described to be involved in the adaptation to furfural in Saccharomyces cerevisiae, an analogous mechanism of adaptation to lignocelluloses hydrolysate of D. bruxellensis was hypothesized. However, gene expression analysis showed that genes homologous to S. cerevisiae ADH1 were not involved in the adaptation to lignocelluloses hydrolysate in D. bruxellensis.
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Affiliation(s)
- Ievgeniia A Tiukova
- Uppsala Biocenter, Department of Microbiology, Swedish University of Agricultural Sciences, Box 7025750 07, Uppsala, Sweden
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Genomic and transcriptome analyses reveal that MAPK- and phosphatidylinositol-signaling pathways mediate tolerance to 5-hydroxymethyl-2-furaldehyde for industrial yeast Saccharomyces cerevisiae. Sci Rep 2014; 4:6556. [PMID: 25296911 PMCID: PMC4190571 DOI: 10.1038/srep06556] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Accepted: 09/10/2014] [Indexed: 12/15/2022] Open
Abstract
The industrial yeast Saccharomyces cerevisiae is a traditional ethanologenic agent and a promising biocatalyst for advanced biofuels production using lignocellulose materials. Here we present the genomic background of type strain NRRL Y-12632 and its transcriptomic response to 5-hydroxymethyl-2-furaldehyde (HMF), a commonly encountered toxic compound liberated from lignocellulosic-biomass pretreatment, in dissecting the genomic mechanisms of yeast tolerance. Compared with the genome of laboratory model strain S288C, we identified more than 32,000 SNPs in Y-12632 with 23,000 missense and nonsense SNPs. Enriched sequence mutations occurred for genes involved in MAPK- and phosphatidylinositol (PI)- signaling pathways in strain Y-12632, with 41 and 13 genes containing non-synonymous SNPs, respectively. Many of these mutated genes displayed consistent up-regulated signature expressions in response to challenges of 30 mM HMF. Analogous single-gene deletion mutations of these genes showed significantly sensitive growth response on a synthetic medium containing 20 mM HMF. Our results suggest at least three MAPK-signaling pathways, especially for the cell-wall integrity pathway, and PI-signaling pathways to be involved in mediation of yeast tolerance against HMF in industrial yeast Saccharomyces cerevisiae. Higher levels of sequence variations were also observed for genes involved in purine and pyrimidine metabolism pathways.
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Microbial tolerance engineering toward biochemical production: from lignocellulose to products. Curr Opin Biotechnol 2014; 29:99-106. [DOI: 10.1016/j.copbio.2014.03.005] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2013] [Revised: 03/01/2014] [Accepted: 03/18/2014] [Indexed: 11/19/2022]
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