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Ceccato-Antonini SR, Covre EA. From baker's yeast to genetically modified budding yeasts: the scientific evolution of bioethanol industry from sugarcane. FEMS Yeast Res 2020; 20:6021367. [PMID: 33406233 DOI: 10.1093/femsyr/foaa065] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Accepted: 12/02/2020] [Indexed: 12/22/2022] Open
Abstract
The peculiarities of Brazilian fuel ethanol fermentation allow the entry of native yeasts that may dominate over the starter strains of Saccharomyces cerevisiae and persist throughout the sugarcane harvest. The switch from the use of baker's yeast as starter to selected budding yeasts obtained by a selective pressure strategy was followed by a wealth of genomic information that enabled the understanding of the superiority of selected yeast strains. This review describes how the process of yeast selection evolved in the sugarcane-based bioethanol industry, the selection criteria and recent advances in genomics that could advance the fermentation process. The prospective use of genetically modified yeast strains, specially designed for increased robustness and product yield, with special emphasis on those obtained by the CRISPR (clustered regularly interspaced palindromic repeats)-Cas9 (CRISPR-associated protein 9) genome-editing approach, is discussed as a possible solution to confer higher performance and stability to the fermentation process for fuel ethanol production.
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Affiliation(s)
- Sandra Regina Ceccato-Antonini
- Laboratory of Agricultural and Molecular Microbiology, Dept Tecnologia Agroindustrial e Socioeconomia Rural, Centro de Ciências Agrárias, Universidade Federal de São Carlos, Via Anhanguera, km 174, 13600-970 Araras, São Paulo State, Brazil
| | - Elizabete Aparecida Covre
- Laboratory of Agricultural and Molecular Microbiology, Dept Tecnologia Agroindustrial e Socioeconomia Rural, Centro de Ciências Agrárias, Universidade Federal de São Carlos, Via Anhanguera, km 174, 13600-970 Araras, São Paulo State, Brazil
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2
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Bioprospection of Enzymes and Microorganisms in Insects to Improve Second-Generation Ethanol Production. Ind Biotechnol (New Rochelle N Y) 2019. [DOI: 10.1089/ind.2019.0019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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3
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Walker GM, Basso TO. Mitigating stress in industrial yeasts. Fungal Biol 2019; 124:387-397. [PMID: 32389301 DOI: 10.1016/j.funbio.2019.10.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 10/23/2019] [Accepted: 10/25/2019] [Indexed: 01/19/2023]
Abstract
The yeast, Saccharomyces cerevisiae, is the premier fungal cell factory exploited in industrial biotechnology. In particular, ethanol production by yeast fermentation represents the world's foremost biotechnological process, with beverage and fuel ethanol contributing significantly to many countries economic and energy sustainability. During industrial fermentation processes, yeast cells are subjected to several physical, chemical and biological stress factors that can detrimentally affect ethanol yields and overall production efficiency. These stresses include ethanol toxicity, osmostress, nutrient starvation, pH and temperature shock, as well as biotic stress due to contaminating microorganisms. Several cell physiological and genetic approaches to mitigate yeast stress during industrial fermentations can be undertaken, and such approaches will be discussed with reference to stress mitigation in yeasts employed in Brazilian bioethanol processes. This article will highlight the importance of furthering our understanding of key aspects of yeast stress physiology and the beneficial impact this can have more generally on enhancing industrial fungal bioprocesses.
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Affiliation(s)
| | - Thiago O Basso
- Department of Chemical Engineering, Universidade de São Paulo, Brazil.
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4
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Fang T, Yan H, Li G, Chen W, Liu J, Jiang L. Chromatin remodeling complexes are involvesd in the regulation of ethanol production during static fermentation in budding yeast. Genomics 2019; 112:1674-1679. [PMID: 31618673 DOI: 10.1016/j.ygeno.2019.10.005] [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: 11/28/2018] [Revised: 10/02/2019] [Accepted: 10/07/2019] [Indexed: 12/17/2022]
Abstract
The budding yeast Saccharomyces cerevisiae remains a central position among biofuel-producing organisms. However, the gene expression regulatory networks behind the ethanol fermentation is still not fully understood. Using a static fermentation model, we have examined the ethanol yields on biomass of deletion mutants for all yeast nonessential genes encoding transcription factors and their related proteins in the yeast genome. A total of 20 (about 10%) transcription factors are identified to be regulators of ethanol production during fermentation. These transcription factors are mainly involved in cell cycling, chromatin remodeling, transcription, stress response, protein synthesis and lipid synthesis. Our data provides a basis for further understanding mechanisms regulating ethanol production in budding yeast.
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Affiliation(s)
- Tianshu Fang
- Laboratory for Yeast Molecular and Cell Biology, the Research Center of Fermentation Technology, Department of Food Science, School of Agricultural Engineering and Food Sciences, Shandong University of Technology, Zibo 255000, Shandong Province, China
| | - Hongbo Yan
- Laboratory for Yeast Molecular and Cell Biology, the Research Center of Fermentation Technology, Department of Food Science, School of Agricultural Engineering and Food Sciences, Shandong University of Technology, Zibo 255000, Shandong Province, China
| | - Gaozhen Li
- Laboratory for Yeast Molecular and Cell Biology, the Research Center of Fermentation Technology, Department of Food Science, School of Agricultural Engineering and Food Sciences, Shandong University of Technology, Zibo 255000, Shandong Province, China
| | - Weipeng Chen
- Laboratory for Yeast Molecular and Cell Biology, the Research Center of Fermentation Technology, Department of Food Science, School of Agricultural Engineering and Food Sciences, Shandong University of Technology, Zibo 255000, Shandong Province, China
| | - Jian Liu
- Laboratory for Yeast Molecular and Cell Biology, the Research Center of Fermentation Technology, Department of Food Science, School of Agricultural Engineering and Food Sciences, Shandong University of Technology, Zibo 255000, Shandong Province, China
| | - Linghuo Jiang
- Laboratory for Yeast Molecular and Cell Biology, the Research Center of Fermentation Technology, Department of Food Science, School of Agricultural Engineering and Food Sciences, Shandong University of Technology, Zibo 255000, Shandong Province, China.
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Navarro-Tapia E, Querol A, Pérez-Torrado R. Membrane fluidification by ethanol stress activates unfolded protein response in yeasts. Microb Biotechnol 2018; 11:465-475. [PMID: 29469174 PMCID: PMC5902320 DOI: 10.1111/1751-7915.13032] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 09/05/2017] [Accepted: 11/05/2017] [Indexed: 11/28/2022] Open
Abstract
The toxic effect of ethanol is one of the most important handicaps for many biotechnological applications of yeasts, such as bioethanol production. Elucidation of ethanol stress response will help to improve yeast performance in biotechnological processes. In the yeast Saccharomyces cerevisiae, ethanol stress has been recently described as an activator of the unfolded protein response (UPR), a conserved intracellular signalling pathway that regulates the transcription of ER homoeostasis‐related genes. However, the signal and activation mechanism has not yet been unravelled. Here, we studied UPR's activation after ethanol stress and observed the upregulation of the key target genes, like INO1, involved in lipid metabolism. We found that inositol content influenced UPR activation after ethanol stress and we observed significant changes in lipid composition, which correlate with a major membrane fluidity alteration by this amphipathic molecule. Then, we explored the hypothesis that membrane fluidity changes cause UPR activation upon ethanol stress by studying UPR response against fluidification or rigidification agents and by studying a mutant, erg2, with altered membrane fluidity. The results suggest that the membrane fluidification effects of ethanol and other agents are the signal for UPR activation, a mechanism that has been proposed in higher eukaryotes.
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Affiliation(s)
- Elisabet Navarro-Tapia
- Instituto de Agroquímica y Tecnología de los Alimentos, IATA-CSIC, E-46980, Paterna, Valencia, Spain
| | - Amparo Querol
- Instituto de Agroquímica y Tecnología de los Alimentos, IATA-CSIC, E-46980, Paterna, Valencia, Spain
| | - Roberto Pérez-Torrado
- Instituto de Agroquímica y Tecnología de los Alimentos, IATA-CSIC, E-46980, Paterna, Valencia, Spain
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A simple scaled down system to mimic the industrial production of first generation fuel ethanol in Brazil. Antonie van Leeuwenhoek 2017; 110:971-983. [DOI: 10.1007/s10482-017-0868-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 03/30/2017] [Indexed: 01/21/2023]
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Navarro-Tapia E, Pérez-Torrado R, Querol A. Ethanol Effects Involve Non-canonical Unfolded Protein Response Activation in Yeast Cells. Front Microbiol 2017; 8:383. [PMID: 28326077 PMCID: PMC5339281 DOI: 10.3389/fmicb.2017.00383] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 02/23/2017] [Indexed: 12/25/2022] Open
Abstract
The unfolded protein response (UPR) is a conserved intracellular signaling pathway that controls transcription of endoplasmic reticulum (ER) homeostasis related genes. Ethanol stress has been recently described as an activator of the UPR response in yeast Saccharomyces cerevisiae, but very little is known about the causes of this activation. Although some authors ensure that the UPR is triggered by the unfolded proteins generated by ethanol in the cell, there are studies which demonstrate that protein denaturation occurs at higher ethanol concentrations than those used to trigger the UPR. Here, we studied UPR after ethanol stress by three different approaches and we concluded that unfolded proteins do not accumulate in the ER under. We also ruled out inositol depletion as an alternative mechanism to activate the UPR under ethanol stress discarding that ethanol effects on the cell decreased inositol levels by different methods. All these data suggest that ethanol, at relatively low concentrations, does not cause unfolded proteins in the yeasts and UPR activation is likely due to other unknown mechanism related with a restructuring of ER membrane due to the effect of ethanol.
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Affiliation(s)
| | | | - Amparo Querol
- Instituto de Agroquímica y Tecnología de los Alimentos-CSIC Valencia, Spain
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Santos RM, Nogueira FC, Brasil AA, Carvalho PC, Leprevost FV, Domont GB, Eleutherio EC. Quantitative proteomic analysis of the Saccharomyces cerevisiae industrial strains CAT-1 and PE-2. J Proteomics 2017; 151:114-121. [DOI: 10.1016/j.jprot.2016.08.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 05/25/2016] [Accepted: 08/25/2016] [Indexed: 10/21/2022]
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Lopes ML, Paulillo SCDL, Godoy A, Cherubin RA, Lorenzi MS, Giometti FHC, Bernardino CD, Amorim Neto HBD, Amorim HVD. Ethanol production in Brazil: a bridge between science and industry. Braz J Microbiol 2016; 47 Suppl 1:64-76. [PMID: 27818090 PMCID: PMC5156502 DOI: 10.1016/j.bjm.2016.10.003] [Citation(s) in RCA: 109] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 10/05/2016] [Indexed: 12/13/2022] Open
Abstract
In the last 40 years, several scientific and technological advances in microbiology of the fermentation have greatly contributed to evolution of the ethanol industry in Brazil. These contributions have increased our view and comprehension about fermentations in the first and, more recently, second-generation ethanol. Nowadays, new technologies are available to produce ethanol from sugarcane, corn and other feedstocks, reducing the off-season period. Better control of fermentation conditions can reduce the stress conditions for yeast cells and contamination by bacteria and wild yeasts. There are great research opportunities in production processes of the first-generation ethanol regarding high-value added products, cost reduction and selection of new industrial yeast strains that are more robust and customized for each distillery. New technologies have also focused on the reduction of vinasse volumes by increasing the ethanol concentrations in wine during fermentation. Moreover, conversion of sugarcane biomass into fermentable sugars for second-generation ethanol production is a promising alternative to meet future demands of biofuel production in the country. However, building a bridge between science and industry requires investments in research, development and transfer of new technologies to the industry as well as specialized personnel to deal with new technological challenges.
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Improving conversion yield of fermentable sugars into fuel ethanol in 1st generation yeast-based production processes. Curr Opin Biotechnol 2015; 33:81-6. [DOI: 10.1016/j.copbio.2014.12.012] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 12/08/2014] [Accepted: 12/14/2014] [Indexed: 11/22/2022]
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Malavazi I, Goldman GH, Brown NA. The importance of connections between the cell wall integrity pathway and the unfolded protein response in filamentous fungi. Brief Funct Genomics 2014; 13:456-70. [PMID: 25060881 DOI: 10.1093/bfgp/elu027] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In the external environment, or within a host organism, filamentous fungi experience sudden changes in nutrient availability, osmolality, pH, temperature and the exposure to toxic compounds. The fungal cell wall represents the first line of defense, while also performing essential roles in morphology, development and virulence. A polarized secretion system is paramount for cell wall biosynthesis, filamentous growth, nutrient acquisition and interactions with the environment. The unique ability of filamentous fungi to secrete has resulted in their industrial adoption as fungal cell factories. Protein maturation and secretion commences in the endoplasmic reticulum (ER). The unfolded protein response (UPR) maintains ER functionality during exposure to secretion and cell wall stress. UPR, therefore, influences secretion and cell wall homeostasis, which in turn impacts upon numerous fungal traits important to pathogenesis and biotechnology. Subsequently, this review describes the relevance of the cell wall and UPR systems to filamentous fungal pathogens or industrial microbes and then highlights interconnections between the two systems. Ultimately, the possible biotechnological applications of an enhanced understanding of such regulatory systems in combating fungal disease, or the removal of natural bottlenecks in protein secretion in an industrial setting, are discussed.
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Zheng DQ, Chen J, Zhang K, Gao KH, Li O, Wang PM, Zhang XY, Du FG, Sun PY, Qu AM, Wu S, Wu XC. Genomic structural variations contribute to trait improvement during whole-genome shuffling of yeast. Appl Microbiol Biotechnol 2013; 98:3059-70. [PMID: 24346281 DOI: 10.1007/s00253-013-5423-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 11/17/2013] [Accepted: 11/18/2013] [Indexed: 11/24/2022]
Abstract
Whole-genome shuffling (WGS) is a powerful technology of improving the complex traits of many microorganisms. However, the molecular mechanisms underlying the altered phenotypes in isolates were less clarified. Isolates with significantly enhanced stress tolerance and ethanol titer under very-high-gravity conditions were obtained after WGS of the bioethanol Saccharomyces cerevisiae strain ZTW1. Karyotype analysis and RT-qPCR showed that chromosomal rearrangement occurred frequently in genome shuffling. Thus, the phenotypic effects of genomic structural variations were determined in this study. RNA-Seq and physiological analyses revealed the diverse transcription pattern and physiological status of the isolate S3-110 and ZTW1. Our observations suggest that the improved stress tolerance of S3-110 can be largely attributed to the copy number variations in large DNA regions, which would adjust the ploidy of yeast cells and expression levels of certain genes involved in stress response. Overall, this work not only constructed shuffled S. cerevisiae strains that have potential industrial applications but also provided novel insights into the molecular mechanisms of WGS and enhanced our knowledge on this useful breeding strategy.
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Affiliation(s)
- Dao-Qiong Zheng
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, 310058, Zhejiang Province, China
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