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Bitew D, Tesfaye A, Andualem B. Isolation, screening and identification of ethanol producing yeasts from Ethiopian fermented beverages. Biotechnol Rep (Amst) 2023; 40:e00815. [PMID: 37876548 PMCID: PMC10590766 DOI: 10.1016/j.btre.2023.e00815] [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] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Revised: 08/25/2023] [Accepted: 10/02/2023] [Indexed: 10/26/2023]
Abstract
The growing demand for renewable energy sources such as bioethanol is facing a lack of efficient ethanologenic microbes. This study aimed to isolate and screen ethanologenic yeasts from Ethiopian fermented beverages. A progressive screening and selection approach was employed. Selected isolates were evaluated for bioethanol production using banana peel waste as substrate. A total of 102 isolates were obtained. Sixteen isolates were selected based on their tolerance to stress conditions and carbohydrate fermentation and assimilation capacity. Most found moderately tolerant to 10 %, but slightly tolerant at 15 and 20 % (v/v) ethanol concentration. They yield 15.3 to 20.1 g/L and 9.1 ± 0.6 to 12.9 ± 1.3 g/L ethanol from 2 % (w/v) glucose and 80 g/L banana peel, respectively. Molecular characterization identified them as Saccharomyces cerevisiae strains. Results demonstrate insight about their potential role in the ethanol industry. Optimization of the fermentation conditions is recommended.
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Affiliation(s)
- Dagnew Bitew
- Department of Biology, Mizan-Tepi University, P. BOX: 260, Ethiopia
- Institute of Biotechnology, University of Gondar, P.BOX: 196, Ethiopia
| | - Anteneh Tesfaye
- Institute of Biotechnology, Addis Ababa University, P.BOX: 1176, Ethiopia
- BioTEI, Winnipeg, Manitoba, Canada
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2
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Cagnin L, Gronchi N, Basaglia M, Favaro L, Casella S. Selection of Superior Yeast Strains for the Fermentation of Lignocellulosic Steam-Exploded Residues. Front Microbiol 2021; 12:756032. [PMID: 34803979 PMCID: PMC8601721 DOI: 10.3389/fmicb.2021.756032] [Citation(s) in RCA: 3] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 10/06/2021] [Indexed: 11/13/2022] Open
Abstract
The production of lignocellulosic ethanol calls for a robust fermentative yeast able to tolerate a wide range of toxic molecules that occur in the pre-treated lignocellulose. The concentration of inhibitors varies according to the composition of the lignocellulosic material and the harshness of the pre-treatment used. It follows that the versatility of the yeast should be considered when selecting a robust strain. This work aimed at the validation of seven natural Saccharomyces cerevisiae strains, previously selected for their industrial fitness, for their application in the production of lignocellulosic bioethanol. Their inhibitor resistance and fermentative performances were compared to those of the benchmark industrial yeast S. cerevisiae Ethanol Red, currently utilized in the second-generation ethanol plants. The yeast strains were characterized for their tolerance using a synthetic inhibitor mixture formulated with increasing concentrations of weak acids and furans, as well as steam-exploded lignocellulosic pre-hydrolysates, generally containing the same inhibitors. The eight non-diluted liquors have been adopted to assess yeast ability to withstand bioethanol industrial conditions. The most tolerant S. cerevisiae Fm17 strain, together with the reference Ethanol Red, was evaluated for fermentative performances in two pre-hydrolysates obtained from cardoon and common reed, chosen for their large inhibitor concentrations. S. cerevisiae Fm17 outperformed the industrial strain Ethanol Red, producing up to 18 and 39 g/L ethanol from cardoon and common reed, respectively, with ethanol yields always higher than those of the benchmark strain. This natural strain exhibits great potential to be used as superior yeast in the lignocellulosic ethanol plants.
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Affiliation(s)
- Lorenzo Cagnin
- Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padova, Legnaro, Italy
| | - Nicoletta Gronchi
- Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padova, Legnaro, Italy
| | - Marina Basaglia
- Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padova, Legnaro, Italy
| | - Lorenzo Favaro
- Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padova, Legnaro, Italy
| | - Sergio Casella
- Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padova, Legnaro, Italy
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Hovhannisyan H, Saus E, Ksiezopolska E, Hinks Roberts AJ, Louis EJ, Gabaldón T. Integrative Omics Analysis Reveals a Limited Transcriptional Shock After Yeast Interspecies Hybridization. Front Genet 2020; 11:404. [PMID: 32457798 PMCID: PMC7221068 DOI: 10.3389/fgene.2020.00404] [Citation(s) in RCA: 16] [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: 02/05/2020] [Accepted: 03/30/2020] [Indexed: 12/30/2022] Open
Abstract
The formation of interspecific hybrids results in the coexistence of two diverged genomes within the same nucleus. It has been hypothesized that negative epistatic interactions and regulatory interferences between the two sub-genomes may elicit a so-called genomic shock involving, among other alterations, broad transcriptional changes. To assess the magnitude of this shock in hybrid yeasts, we investigated the transcriptomic differences between a newly formed Saccharomyces cerevisiae × Saccharomyces uvarum diploid hybrid and its diploid parentals, which diverged ∼20 mya. RNA sequencing (RNA-Seq) based allele-specific expression (ASE) analysis indicated that gene expression changes in the hybrid genome are limited, with only ∼1–2% of genes significantly altering their expression with respect to a non-hybrid context. In comparison, a thermal shock altered six times more genes. Furthermore, differences in the expression between orthologous genes in the two parental species tended to be diminished for the corresponding homeologous genes in the hybrid. Finally, and consistent with the RNA-Seq results, we show a limited impact of hybridization on chromatin accessibility patterns, as assessed with assay for transposase-accessible chromatin using sequencing (ATAC-Seq). Overall, our results suggest a limited genomic shock in a newly formed yeast hybrid, which may explain the high frequency of successful hybridization in these organisms.
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Affiliation(s)
- Hrant Hovhannisyan
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain.,Department of Health and Life Sciences. Universitat Pompeu Fabra, Barcelona, Spain
| | - Ester Saus
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain.,Department of Health and Life Sciences. Universitat Pompeu Fabra, Barcelona, Spain
| | - Ewa Ksiezopolska
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain.,Department of Health and Life Sciences. Universitat Pompeu Fabra, Barcelona, Spain
| | - Alex J Hinks Roberts
- Centre for Genetic Architecture of Complex Traits, University of Leicester, Leicester, United Kingdom
| | - Edward J Louis
- Centre for Genetic Architecture of Complex Traits, University of Leicester, Leicester, United Kingdom
| | - Toni Gabaldón
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain.,Department of Health and Life Sciences. Universitat Pompeu Fabra, Barcelona, Spain.,Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain
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4
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Srivastava N, Rathour R, Jha S, Pandey K, Srivastava M, Thakur VK, Sengar RS, Gupta VK, Mazumder PB, Khan AF, Mishra PK. Microbial Beta Glucosidase Enzymes: Recent Advances in Biomass Conversation for Biofuels Application. Biomolecules 2019; 9:E220. [PMID: 31174354 PMCID: PMC6627771 DOI: 10.3390/biom9060220] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [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: 03/29/2019] [Revised: 05/28/2019] [Accepted: 05/28/2019] [Indexed: 01/10/2023] Open
Abstract
The biomass to biofuels production process is green, sustainable, and an advanced technique to resolve the current environmental issues generated from fossil fuels. The production of biofuels from biomass is an enzyme mediated process, wherein β-glucosidase (BGL) enzymes play a key role in biomass hydrolysis by producing monomeric sugars from cellulose-based oligosaccharides. However, the production and availability of these enzymes realize their major role to increase the overall production cost of biomass to biofuels production technology. Therefore, the present review is focused on evaluating the production and efficiency of β-glucosidase enzymes in the bioconversion of cellulosic biomass for biofuel production at an industrial scale, providing its mechanism and classification. The application of BGL enzymes in the biomass conversion process has been discussed along with the recent developments and existing issues. Moreover, the production and development of microbial BGL enzymes have been explained in detail, along with the recent advancements made in the field. Finally, current hurdles and future suggestions have been provided for the future developments. This review is likely to set a benchmark in the area of cost effective BGL enzyme production, specifically in the biorefinery area.
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Affiliation(s)
- Neha Srivastava
- Department of Chemical Engineering and Technology, IIT (BHU), Varanasi 221005, India.
| | - Rishabh Rathour
- Department of Bioengineering, Integral University, Lucknow 226026, India.
| | - Sonam Jha
- Department of Botany, Banaras Hindu University, Varanasi 221005, India.
| | - Karan Pandey
- Department of Chemical Engineering and Technology, IIT (BHU), Varanasi 221005, India.
| | - Manish Srivastava
- Department of Physics and Astrophysics, University of Delhi, Delhi 110007, India.
| | - Vijay Kumar Thakur
- Enhanced Composites and Structures Center, School of Aerospace, Transport and Manufacturing, Cranfield University, Bedfordshire MK43 0AL, UK.
| | - Rakesh Singh Sengar
- Department of Agriculture Biotechnology, College of Agriculture, Sardar Vallabhbhai Patel, University of Agriculture and Technology, Meerut 250110, U.P., India.
| | - Vijai K Gupta
- Department of Chemistry and Biotechnology, ERA Chair of Green Chemistry, Tallinn University of Technology, 12618 Tallinn, Estonia.
| | | | - Ahamad Faiz Khan
- Department of Bioengineering, Integral University, Lucknow 226026, India.
| | - Pradeep Kumar Mishra
- Department of Chemical Engineering and Technology, IIT (BHU), Varanasi 221005, India.
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Ming M, Wang X, Lian L, Zhang H, Gao W, Zhu B, Lou D. Metabolic responses ofSaccharomyces cerevisiaeto ethanol stress using gas chromatography-mass spectrometry. Mol Omics 2019; 15:216-221. [DOI: 10.1039/c9mo00055k] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Metabolic responses ofSaccharomyces cerevisiaeunder ethanol stress by a metabolomics method based on GC-MS.
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Affiliation(s)
- Ming Ming
- Department of Analytical Chemistry
- Jilin Institute of Chemical Technology
- Jilin
- P. R. China
| | - Xiyue Wang
- Department of Analytical Chemistry
- Jilin Institute of Chemical Technology
- Jilin
- P. R. China
| | - Lili Lian
- Department of Analytical Chemistry
- Jilin Institute of Chemical Technology
- Jilin
- P. R. China
| | - Hao Zhang
- Department of Analytical Chemistry
- Jilin Institute of Chemical Technology
- Jilin
- P. R. China
| | - Wenxiu Gao
- Department of Analytical Chemistry
- Jilin Institute of Chemical Technology
- Jilin
- P. R. China
| | - Bo Zhu
- Department of Analytical Chemistry
- Jilin Institute of Chemical Technology
- Jilin
- P. R. China
| | - Dawei Lou
- Department of Analytical Chemistry
- Jilin Institute of Chemical Technology
- Jilin
- P. R. China
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Štafa A, Žunar B, Pranklin A, Zandona A, Svetec-Miklenić M, Šantek B, Svetec IK. Novel Approach in the Construction of
Bioethanol-Producing Saccharomyces cerevisiae Hybrids §. Food Technol Biotechnol 2019; 57:5-16. [PMID: 31316272 PMCID: PMC6600304 DOI: 10.17113/ftb.57.01.19.5685] [Citation(s) in RCA: 5] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Bioethanol production from lignocellulosic hydrolysates requires a producer strain that tolerates both the presence of growth and fermentation inhibitors and high ethanol concentrations. Therefore, we constructed heterozygous intraspecies hybrid diploids of Saccharomyces cerevisiae by crossing two natural S. cerevisiae isolates, YIIc17_E5 and UWOPS87-2421, a good ethanol producer found in wine and a strain from the flower of the cactus Opuntia megacantha resistant to inhibitors found in lignocellulosic hydrolysates, respectively. Hybrids grew faster than parental strains in the absence and in the presence of acetic and levulinic acids and 2-furaldehyde, inhibitors frequently found in lignocellulosic hydrolysates, and the overexpression of YAP1 gene increased their survival. Furthermore, although originating from the same parental strains, hybrids displayed different fermentative potential in a CO2 production test, suggesting genetic variability that could be used for further selection of desirable traits. Therefore, our results suggest that the construction of intraspecies hybrids coupled with the use of genetic engineering techniques is a promising approach for improvement or development of new biotechnologically relevant strains of S. cerevisiae. Moreover, it was found that the success of gene targeting (gene targeting fidelity) in natural S. cerevisiae isolates (YIIc17_E5α and UWOPS87-2421α) was strikingly lower than in laboratory strains and the most frequent off-targeting event was targeted chromosome duplication.
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Affiliation(s)
- Anamarija Štafa
- University of Zagreb, Faculty of Food Technology and Biotechnology, Department of Biochemical Engineering, Laboratory for Biology and Microbial Genetics, Kršnjavoga 25, 10000 Zagreb, Croatia
| | - Bojan Žunar
- University of Zagreb, Faculty of Food Technology and Biotechnology, Department of Biochemical Engineering, Laboratory for Biology and Microbial Genetics, Kršnjavoga 25, 10000 Zagreb, Croatia
| | - Andrea Pranklin
- University of Zagreb, Faculty of Food Technology and Biotechnology, Department of Biochemical Engineering, Laboratory for Biology and Microbial Genetics, Kršnjavoga 25, 10000 Zagreb, Croatia
| | - Antonio Zandona
- University of Zagreb, Faculty of Food Technology and Biotechnology, Department of Biochemical Engineering, Laboratory for Biology and Microbial Genetics, Kršnjavoga 25, 10000 Zagreb, Croatia
| | - Marina Svetec-Miklenić
- University of Zagreb, Faculty of Food Technology and Biotechnology, Department of Biochemical Engineering, Laboratory for Biology and Microbial Genetics, Kršnjavoga 25, 10000 Zagreb, Croatia
| | - Božidar Šantek
- University of Zagreb, Faculty of Food Technology and Biotechnology, Department of Biochemical Engineering, Laboratory for Biochemical Engineering, Industrial Microbiology and Malting and Brewing Technology, Kačićeva 28, 10000 Zagreb, Croatia
| | - Ivan Krešimir Svetec
- University of Zagreb, Faculty of Food Technology and Biotechnology, Department of Biochemical Engineering, Laboratory for Biology and Microbial Genetics, Kršnjavoga 25, 10000 Zagreb, Croatia
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7
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Cunha JT, Romaní A, Costa CE, Sá-Correia I, Domingues L. Molecular and physiological basis of Saccharomyces cerevisiae tolerance to adverse lignocellulose-based process conditions. Appl Microbiol Biotechnol 2018; 103:159-175. [PMID: 30397768 DOI: 10.1007/s00253-018-9478-3] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 10/19/2018] [Accepted: 10/22/2018] [Indexed: 11/27/2022]
Abstract
Lignocellulose-based biorefineries have been gaining increasing attention to substitute current petroleum-based refineries. Biomass processing requires a pretreatment step to break lignocellulosic biomass recalcitrant structure, which results in the release of a broad range of microbial inhibitors, mainly weak acids, furans, and phenolic compounds. Saccharomyces cerevisiae is the most commonly used organism for ethanol production; however, it can be severely distressed by these lignocellulose-derived inhibitors, in addition to other challenging conditions, such as pentose sugar utilization and the high temperatures required for an efficient simultaneous saccharification and fermentation step. Therefore, a better understanding of the yeast response and adaptation towards the presence of these multiple stresses is of crucial importance to design strategies to improve yeast robustness and bioconversion capacity from lignocellulosic biomass. This review includes an overview of the main inhibitors derived from diverse raw material resultants from different biomass pretreatments, and describes the main mechanisms of yeast response to their presence, as well as to the presence of stresses imposed by xylose utilization and high-temperature conditions, with a special emphasis on the synergistic effect of multiple inhibitors/stressors. Furthermore, successful cases of tolerance improvement of S. cerevisiae are highlighted, in particular those associated with other process-related physiologically relevant conditions. Decoding the overall yeast response mechanisms will pave the way for the integrated development of sustainable yeast cell-based biorefineries.
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Affiliation(s)
- Joana T Cunha
- Centre of Biological Engineering (CEB), University of Minho, 4710-057, Braga, Portugal
| | - Aloia Romaní
- Centre of Biological Engineering (CEB), University of Minho, 4710-057, Braga, Portugal
| | - Carlos E Costa
- Centre of Biological Engineering (CEB), University of Minho, 4710-057, Braga, Portugal
| | - Isabel Sá-Correia
- Institute for Bioengineering and Biosciences, Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001, Lisbon, Portugal
| | - Lucília Domingues
- Centre of Biological Engineering (CEB), University of Minho, 4710-057, Braga, Portugal.
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Peris D, Pérez-Torrado R, Hittinger CT, Barrio E, Querol A. On the origins and industrial applications ofSaccharomyces cerevisiae×Saccharomyces kudriavzeviihybrids. Yeast 2017; 35:51-69. [DOI: 10.1002/yea.3283] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 09/15/2017] [Accepted: 09/27/2017] [Indexed: 12/22/2022] Open
Affiliation(s)
- David Peris
- Laboratory of Genetics, Wisconsin Energy Institute, J. F. Crow Institute for the Study of Evolution, Genome Center of Wisconsin, DOE Great Lakes Bioenergy Research Center; University of Wisconsin-Madison; Madison WI USA
- Department of Food Biotechnology; Institute of Agrochemistry and Food Technology (IATA), CSIC; Valencia Spain
| | - Roberto Pérez-Torrado
- Department of Food Biotechnology; Institute of Agrochemistry and Food Technology (IATA), CSIC; Valencia Spain
| | - Chris Todd Hittinger
- Laboratory of Genetics, Wisconsin Energy Institute, J. F. Crow Institute for the Study of Evolution, Genome Center of Wisconsin, DOE Great Lakes Bioenergy Research Center; University of Wisconsin-Madison; Madison WI USA
| | - Eladio Barrio
- Department of Food Biotechnology; Institute of Agrochemistry and Food Technology (IATA), CSIC; Valencia Spain
- Department of Genetics; University of Valencia; Valencia Spain
| | - Amparo Querol
- Department of Food Biotechnology; Institute of Agrochemistry and Food Technology (IATA), CSIC; Valencia Spain
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Ryden P, Efthymiou MN, Tindyebwa TAM, Elliston A, Wilson DR, Waldron KW, Malakar PK. Bioethanol production from spent mushroom compost derived from chaff of millet and sorghum. Biotechnol Biofuels 2017; 10:195. [PMID: 28785311 PMCID: PMC5545022 DOI: 10.1186/s13068-017-0880-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 07/26/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND In Uganda, the chaff remaining from threshed panicles of millet and sorghum is a low value, lignocellulose-rich agricultural by-product. Currently, it is used as a substrate for the cultivation of edible Oyster mushrooms (Pleurotus ostreatus). The aim of this study was to assess the potential to exploit the residual post-harvest compost for saccharification and fermentation to produce ethanol. RESULTS Sorghum and millet chaff-derived spent oyster mushroom composts minus large mycelium particles were assessed at small-scale and low substrate concentrations (5% w/v) for optimal severity hydrothermal pre-treatment, enzyme loading and fermentation with robust yeasts to produce ethanol. These conditions were then used as a basis for larger scale assessments with high substrate concentrations (30% w/v). Millet-based compost had a low cellulose content and, at a high substrate concentration, did not liquefy effectively. The ethanol yield was 63.9 g/kg dry matter (DM) of original material with a low concentration (19.6 g/L). Compost derived from sorghum chaff had a higher cellulose content and could be liquefied at high substrate concentration (30% w/v). This enabled selected furfural-resistant yeasts to produce ethanol at up to 186.9 g/kg DM of original material and a concentration of 45.8 g/L. CONCLUSIONS Spent mushroom compost derived from sorghum chaff has the potential to be an industrially useful substrate for producing second-generation bioethanol. This might be improved further through fractionation and exploitation of hemicellulosic moieties, and possibly the exploitation of the mycelium-containing final residue for animal feed. However, spent compost derived from millet does not provide a suitably high concentration of ethanol to make it industrially attractive. Further research on the difficulty in quantitatively saccharifying cellulose from composted millet chaff and other similar substrates such as rice husk is required.
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Affiliation(s)
- Peter Ryden
- The Biorefinery Centre, Quadram Institute Bioscience, Colney, Norwich Research Park, Norwich, NR4 7UA UK
| | - Maria-Nefeli Efthymiou
- The Biorefinery Centre, Quadram Institute Bioscience, Colney, Norwich Research Park, Norwich, NR4 7UA UK
| | - Teddy A. M. Tindyebwa
- School of Biological Sciences, College of Natural Sciences, Makerere University, P.O. Box 7062, Kampala, Uganda
| | - Adam Elliston
- The Biorefinery Centre, Quadram Institute Bioscience, Colney, Norwich Research Park, Norwich, NR4 7UA UK
| | - David R. Wilson
- The Biorefinery Centre, Quadram Institute Bioscience, Colney, Norwich Research Park, Norwich, NR4 7UA UK
| | - Keith W. Waldron
- The Biorefinery Centre, Quadram Institute Bioscience, Colney, Norwich Research Park, Norwich, NR4 7UA UK
| | - Pradeep K. Malakar
- The Biorefinery Centre, Quadram Institute Bioscience, Colney, Norwich Research Park, Norwich, NR4 7UA UK
- College of Food Science and Technology, Shanghai Ocean University, 999 Hu Cheng Huan Road, Shanghai, 201306 People’s Republic of China
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10
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Jansen MLA, Bracher JM, Papapetridis I, Verhoeven MD, de Bruijn H, de Waal PP, van Maris AJA, Klaassen P, Pronk JT. Saccharomyces cerevisiae strains for second-generation ethanol production: from academic exploration to industrial implementation. FEMS Yeast Res 2017; 17:3868933. [PMID: 28899031 PMCID: PMC5812533 DOI: 10.1093/femsyr/fox044] [Citation(s) in RCA: 98] [Impact Index Per Article: 14.0] [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: 04/13/2017] [Accepted: 06/15/2017] [Indexed: 11/18/2022] Open
Abstract
The recent start-up of several full-scale 'second generation' ethanol plants marks a major milestone in the development of Saccharomyces cerevisiae strains for fermentation of lignocellulosic hydrolysates of agricultural residues and energy crops. After a discussion of the challenges that these novel industrial contexts impose on yeast strains, this minireview describes key metabolic engineering strategies that have been developed to address these challenges. Additionally, it outlines how proof-of-concept studies, often developed in academic settings, can be used for the development of robust strain platforms that meet the requirements for industrial application. Fermentation performance of current engineered industrial S. cerevisiae strains is no longer a bottleneck in efforts to achieve the projected outputs of the first large-scale second-generation ethanol plants. Academic and industrial yeast research will continue to strengthen the economic value position of second-generation ethanol production by further improving fermentation kinetics, product yield and cellular robustness under process conditions.
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Affiliation(s)
- Mickel L. A. Jansen
- DSM Biotechnology Centre, Alexander Fleminglaan 1, 2613 AX Delft, The
Netherlands
| | - Jasmine M. Bracher
- Department of Biotechnology, Delft University of Technology, Van der Maasweg
9, 2629 HZ Delft, The Netherlands
| | - Ioannis Papapetridis
- Department of Biotechnology, Delft University of Technology, Van der Maasweg
9, 2629 HZ Delft, The Netherlands
| | - Maarten D. Verhoeven
- Department of Biotechnology, Delft University of Technology, Van der Maasweg
9, 2629 HZ Delft, The Netherlands
| | - Hans de Bruijn
- DSM Biotechnology Centre, Alexander Fleminglaan 1, 2613 AX Delft, The
Netherlands
| | - Paul P. de Waal
- DSM Biotechnology Centre, Alexander Fleminglaan 1, 2613 AX Delft, The
Netherlands
| | - Antonius J. A. van Maris
- Department of Biotechnology, Delft University of Technology, Van der Maasweg
9, 2629 HZ Delft, The Netherlands
| | - Paul Klaassen
- DSM Biotechnology Centre, Alexander Fleminglaan 1, 2613 AX Delft, The
Netherlands
| | - Jack T. Pronk
- Department of Biotechnology, Delft University of Technology, Van der Maasweg
9, 2629 HZ Delft, The Netherlands
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11
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Peris D, Moriarty RV, Alexander WG, Baker E, Sylvester K, Sardi M, Langdon QK, Libkind D, Wang QM, Bai FY, Leducq JB, Charron G, Landry CR, Sampaio JP, Gonçalves P, Hyma KE, Fay JC, Sato TK, Hittinger CT. Hybridization and adaptive evolution of diverse Saccharomyces species for cellulosic biofuel production. Biotechnol Biofuels 2017; 10:78. [PMID: 28360936 PMCID: PMC5369230 DOI: 10.1186/s13068-017-0763-7] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 03/18/2017] [Indexed: 06/01/2023]
Abstract
BACKGROUND Lignocellulosic biomass is a common resource across the globe, and its fermentation offers a promising option for generating renewable liquid transportation fuels. The deconstruction of lignocellulosic biomass releases sugars that can be fermented by microbes, but these processes also produce fermentation inhibitors, such as aromatic acids and aldehydes. Several research projects have investigated lignocellulosic biomass fermentation by the baker's yeast Saccharomyces cerevisiae. Most projects have taken synthetic biological approaches or have explored naturally occurring diversity in S. cerevisiae to enhance stress tolerance, xylose consumption, or ethanol production. Despite these efforts, improved strains with new properties are needed. In other industrial processes, such as wine and beer fermentation, interspecies hybrids have combined important traits from multiple species, suggesting that interspecies hybridization may also offer potential for biofuel research. RESULTS To investigate the efficacy of this approach for traits relevant to lignocellulosic biofuel production, we generated synthetic hybrids by crossing engineered xylose-fermenting strains of S. cerevisiae with wild strains from various Saccharomyces species. These interspecies hybrids retained important parental traits, such as xylose consumption and stress tolerance, while displaying intermediate kinetic parameters and, in some cases, heterosis (hybrid vigor). Next, we exposed them to adaptive evolution in ammonia fiber expansion-pretreated corn stover hydrolysate and recovered strains with improved fermentative traits. Genome sequencing showed that the genomes of these evolved synthetic hybrids underwent rearrangements, duplications, and deletions. To determine whether the genus Saccharomyces contains additional untapped potential, we screened a genetically diverse collection of more than 500 wild, non-engineered Saccharomyces isolates and uncovered a wide range of capabilities for traits relevant to cellulosic biofuel production. Notably, Saccharomyces mikatae strains have high innate tolerance to hydrolysate toxins, while some Saccharomyces species have a robust native capacity to consume xylose. CONCLUSIONS This research demonstrates that hybridization is a viable method to combine industrially relevant traits from diverse yeast species and that members of the genus Saccharomyces beyond S. cerevisiae may offer advantageous genes and traits of interest to the lignocellulosic biofuel industry.
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Affiliation(s)
- David Peris
- Laboratory of Genetics, Wisconsin Energy Institute, J. F. Crow Institute for the Study of Evolution, Genome Center of Wisconsin, University of Wisconsin-Madison, Madison, WI USA
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI USA
| | - Ryan V. Moriarty
- Laboratory of Genetics, Wisconsin Energy Institute, J. F. Crow Institute for the Study of Evolution, Genome Center of Wisconsin, University of Wisconsin-Madison, Madison, WI USA
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI USA
| | - William G. Alexander
- Laboratory of Genetics, Wisconsin Energy Institute, J. F. Crow Institute for the Study of Evolution, Genome Center of Wisconsin, University of Wisconsin-Madison, Madison, WI USA
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI USA
| | - EmilyClare Baker
- Laboratory of Genetics, Wisconsin Energy Institute, J. F. Crow Institute for the Study of Evolution, Genome Center of Wisconsin, University of Wisconsin-Madison, Madison, WI USA
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, WI USA
| | - Kayla Sylvester
- Laboratory of Genetics, Wisconsin Energy Institute, J. F. Crow Institute for the Study of Evolution, Genome Center of Wisconsin, University of Wisconsin-Madison, Madison, WI USA
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI USA
| | - Maria Sardi
- Laboratory of Genetics, Wisconsin Energy Institute, J. F. Crow Institute for the Study of Evolution, Genome Center of Wisconsin, University of Wisconsin-Madison, Madison, WI USA
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI USA
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, WI USA
| | - Quinn K. Langdon
- Laboratory of Genetics, Wisconsin Energy Institute, J. F. Crow Institute for the Study of Evolution, Genome Center of Wisconsin, University of Wisconsin-Madison, Madison, WI USA
| | - Diego Libkind
- Laboratorio de Microbiología Aplicada, Biotecnología y Bioinformática, Instituto Andino Patagónico de Tecnologías Biológicas y Geoambientales, IPATEC (CONICET-UNComahue), Centro Regional Universitario Bariloche, Bariloche, Río Negro Argentina
| | - Qi-Ming Wang
- Laboratory of Genetics, Wisconsin Energy Institute, J. F. Crow Institute for the Study of Evolution, Genome Center of Wisconsin, University of Wisconsin-Madison, Madison, WI USA
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Feng-Yan Bai
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Jean-Baptiste Leducq
- Departement des Sciences Biologiques, Université de Montréal, Montreal, QC Canada
- Département de Biologie, PROTEO, Pavillon Charles-Eugène-Marchand, Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Quebec City, QC Canada
| | - Guillaume Charron
- Département de Biologie, PROTEO, Pavillon Charles-Eugène-Marchand, Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Quebec City, QC Canada
| | - Christian R. Landry
- Département de Biologie, PROTEO, Pavillon Charles-Eugène-Marchand, Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Quebec City, QC Canada
| | - José Paulo Sampaio
- UCIBIO-REQUIMTE, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
| | - Paula Gonçalves
- UCIBIO-REQUIMTE, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
| | - Katie E. Hyma
- Department of Genetics, Center for Genome Sciences and Systems Biology, Washington University in St. Louis, St. Louis, MO USA
| | - Justin C. Fay
- Department of Genetics, Center for Genome Sciences and Systems Biology, Washington University in St. Louis, St. Louis, MO USA
| | - Trey K. Sato
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI USA
| | - Chris Todd Hittinger
- Laboratory of Genetics, Wisconsin Energy Institute, J. F. Crow Institute for the Study of Evolution, Genome Center of Wisconsin, University of Wisconsin-Madison, Madison, WI USA
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI USA
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, WI USA
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12
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Tian J, Zhang S, Li H. Changes in intracellular metabolism underlying the adaptation of Saccharomyces cerevisiae strains to ethanol stress. ANN MICROBIOL 2017. [DOI: 10.1007/s13213-016-1251-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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13
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Kitichantaropas Y, Boonchird C, Sugiyama M, Kaneko Y, Harashima S, Auesukaree C. Cellular mechanisms contributing to multiple stress tolerance in Saccharomyces cerevisiae strains with potential use in high-temperature ethanol fermentation. AMB Express 2016; 6:107. [PMID: 27826949 PMCID: PMC5101244 DOI: 10.1186/s13568-016-0285-x] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [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: 11/01/2016] [Accepted: 11/02/2016] [Indexed: 11/10/2022] Open
Abstract
High-temperature ethanol fermentation has several benefits including a reduction in cooling cost, minimizing risk of bacterial contamination, and enabling simultaneous saccharification and fermentation. To achieve the efficient ethanol fermentation at high temperature, yeast strain that tolerates to not only high temperature but also the other stresses present during fermentation, e.g., ethanol, osmotic, and oxidative stresses, is indispensable. The C3253, C3751, and C4377 Saccharomyces cerevisiae strains, which have been previously isolated as thermotolerant yeasts, were found to be multiple stress-tolerant. In these strains, continuous expression of heat shock protein genes and intracellular trehalose accumulation were induced in response to stresses causing protein denaturation. Compared to the control strains, these multiple stress-tolerant strains displayed low intracellular reactive oxygen species levels and effective cell wall remodeling upon exposures to almost all stresses tested. In response to simultaneous multi-stress mimicking fermentation stress, cell wall remodeling and redox homeostasis seem to be the primary mechanisms required for protection against cell damage. Moreover, these strains showed better performances of ethanol production than the control strains at both optimal and high temperatures, suggesting their potential use in high-temperature ethanol fermentation.
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Romaní A, Tomaz PD, Garrote G, Teixeira JA, Domingues L. Combined alkali and hydrothermal pretreatments for oat straw valorization within a biorefinery concept. Bioresour Technol 2016; 220:323-332. [PMID: 27591518 DOI: 10.1016/j.biortech.2016.08.077] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 08/18/2016] [Accepted: 08/20/2016] [Indexed: 05/16/2023]
Abstract
The aim of this work was the evaluation of lime pretreatment combined or not with previous step of autohydrolysis for oat straw valorization. Under selected conditions of lime pretreatment, 96% of glucan and 77% of xylan were recovered and 42% of delignification was achieved. Xylose fermentation to ethanol by metabolic engineered Saccharomyces cerevisiae (MEC1133) strain improved the ethanol production by 22% achieving 41g/L. Alternatively, first step of autohydrolysis (S0=4.22) allowed a high oligosaccharides recovery (68%) and subsequent lime pretreatment attained a 57% of delignification and 99% of glucan to glucose conversion. Oat straw processed by autohydrolysis and lime pretreatment reached the maximal ethanol concentration (50g/L). Both strategies led to oat straw valorization into bioethanol, oligosaccharides and lignin indicating that these pretreatments are adequate as a first stage within an oat straw biorefinery.
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Affiliation(s)
- Aloia Romaní
- CEB-Centre of Biological Engineering, University of Minho, Campus Gualtar, 4710-057 Braga, Portugal; Department of Chemical Engineering, Faculty of Science, University of Vigo (Campus Ourense), As Lagoas, 32004 Ourense, Spain
| | - Pablo D Tomaz
- Department of Chemical Engineering, Faculty of Science, University of Vigo (Campus Ourense), As Lagoas, 32004 Ourense, Spain
| | - Gil Garrote
- Department of Chemical Engineering, Faculty of Science, University of Vigo (Campus Ourense), As Lagoas, 32004 Ourense, Spain; CITI-Tecnopole, San Ciprián das Viñas, 32901 Ourense, Spain
| | - José A Teixeira
- CEB-Centre of Biological Engineering, University of Minho, Campus Gualtar, 4710-057 Braga, Portugal
| | - Lucília Domingues
- CEB-Centre of Biological Engineering, University of Minho, Campus Gualtar, 4710-057 Braga, Portugal.
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15
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García M, Greetham D, Wimalasena T, Phister T, Cabellos J, Arroyo T. The phenotypic characterization of yeast strains to stresses inherent to wine fermentation in warm climates. J Appl Microbiol 2016; 121:215-33. [DOI: 10.1111/jam.13139] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Revised: 02/05/2016] [Accepted: 03/11/2016] [Indexed: 11/30/2022]
Affiliation(s)
- M. García
- Departamento de Calidad Agroalimentaria; IMIDRA; Alcalá de Henares Spain
| | - D. Greetham
- Bioenergy & Brewing Science; School of Biosciences; University of Nottingham; Loughborough UK
| | - T.T. Wimalasena
- Bioenergy & Brewing Science; School of Biosciences; University of Nottingham; Loughborough UK
| | | | - J.M. Cabellos
- Departamento de Calidad Agroalimentaria; IMIDRA; Alcalá de Henares Spain
| | - T. Arroyo
- Departamento de Calidad Agroalimentaria; IMIDRA; Alcalá de Henares Spain
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16
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Dubey R, Jakeer S, Gaur NA. Screening of natural yeast isolates under the effects of stresses associated with second-generation biofuel production. J Biosci Bioeng 2016; 121:509-16. [DOI: 10.1016/j.jbiosc.2015.09.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Revised: 09/04/2015] [Accepted: 09/08/2015] [Indexed: 11/16/2022]
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17
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Wang D, Li FL, Wang SA. Engineering a natural Saccharomyces cerevisiae strain for ethanol production from inulin by consolidated bioprocessing. Biotechnol Biofuels 2016; 9:96. [PMID: 27134653 PMCID: PMC4851821 DOI: 10.1186/s13068-016-0511-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 04/19/2016] [Indexed: 05/23/2023]
Abstract
BACKGROUND The yeast Saccharomyces cerevisiae is an important eukaryotic workhorse in traditional and modern biotechnology. At present, only a few S. cerevisiae strains have been extensively used as engineering hosts. Recently, an astonishing genotypic and phenotypic diversity of S. cerevisiae was disclosed in natural populations. We suppose that some natural strains can be recruited as superior host candidates in bioengineering. This study engineered a natural S. cerevisiae strain with advantages in inulin utilization to produce ethanol from inulin resources by consolidated bioprocess. Rational engineering strategies were employed, including secretive co-expression of heterologous exo- and endo-inulinases, repression of a protease, and switch between haploid and diploid strains. RESULTS Results from co-expressing endo- and exo-inulinase genes showed that the extracellular inulinase activity increased 20 to 30-fold in engineered S. cerevisiae strains. Repression of the protease PEP4 influenced cell physiology in late stationary phase. Comparison between haploid and diploid engineered strains indicated that diploid strains were superior to haploid strains in ethanol production albeit not in production and secretion of inulinases. Ethanol fermentation from both inulin and Jerusalem artichoke tuber powder was dramatically improved in most engineered strains. Ethanol yield achieved in the ultimate diploid strain JZD-InuMKCP was close to the theoretical maximum. Productivity achieved in the strain JZD-InuMKCP reached to 2.44 and 3.13 g/L/h in fermentation from 200 g/L inulin and 250 g/L raw Jerusalem artichoke tuber powder, respectively. To our knowledge, these are the highest productivities reported up to now in ethanol fermentation from inulin resources. CONCLUSIONS Although model S. cerevisiae strains are preferentially used as hosts in bioengineering, some natural strains do have specific excellent properties. This study successfully engineered a natural S. cerevisiae strain for efficient ethanol production from inulin resources by consolidated bioprocess, which indicated the feasibility of natural strains used as bioengineering hosts. This study also presented different properties in enzyme secretion and ethanol fermentation between haploid and diploid engineering strains. These findings provided guidelines for host selection in bioengineering.
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Affiliation(s)
- Da Wang
- />Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 China
- />University of Chinese Academy of Sciences, Beijing, 100039 China
| | - Fu-Li Li
- />Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 China
| | - Shi-An Wang
- />Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 China
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De la Torre-González FJ, Narváez-Zapata JA, López-y-López VE, Larralde-Corona CP. Ethanol tolerance is decreased by fructose in Saccharomyces and non-Saccharomyces yeasts. Lebensm Wiss Technol 2016. [DOI: 10.1016/j.lwt.2015.11.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Pérez-Torrado R, Oliveira BM, Zemančíková J, Sychrová H, Querol A. Alternative Glycerol Balance Strategies among Saccharomyces Species in Response to Winemaking Stress. Front Microbiol 2016; 7:435. [PMID: 27064588 PMCID: PMC4814467 DOI: 10.3389/fmicb.2016.00435] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [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: 02/10/2016] [Accepted: 03/17/2016] [Indexed: 01/15/2023] Open
Abstract
Production and balance of glycerol is essential for the survival of yeast cells in certain stressful conditions as hyperosmotic or cold shock that occur during industrial processes as winemaking. These stress responses are well-known in S. cerevisiae, however, little is known in other phylogenetically close related Saccharomyces species associated with natural or fermentation environments such as S. uvarum, S. paradoxus or S. kudriavzevii. In this work we have investigated the expression of four genes (GPD1, GPD2, STL1, and FPS1) crucial in the glycerol pool balance in the four species with a biotechnological potential (S. cerevisiae; S. paradoxus; S. uvarum; and S. kudriavzevii), and the ability of strains to grow under osmotic and cold stresses. The results show different pattern and level of expression among the different species, especially for STL1. We also studied the function of Stl1 glycerol symporter in the survival to osmotic changes and cell growth capacity in winemaking environments. These experiments also revealed a different functionality of the glycerol transporters among the different species studied. All these data point to different strategies to handle glycerol accumulation in response to winemaking stresses as hyperosmotic or cold-hyperosmotic stress in the different species, with variable emphasis in the production, influx, or efflux of glycerol.
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Affiliation(s)
- Roberto Pérez-Torrado
- Food Biotechnology Department, Systems Biology in Yeast of Biotechnological Interest, Instituto de Agroquímica y Tecnología de los Alimentos, IATA-CSIC Valencia, Spain
| | - Bruno M Oliveira
- Food Biotechnology Department, Systems Biology in Yeast of Biotechnological Interest, Instituto de Agroquímica y Tecnología de los Alimentos, IATA-CSIC Valencia, Spain
| | - Jana Zemančíková
- Department of Membrane Transport, Institute of Physiology CAS, Prague, Czech Republic
| | - Hana Sychrová
- Department of Membrane Transport, Institute of Physiology CAS, Prague, Czech Republic
| | - Amparo Querol
- Food Biotechnology Department, Systems Biology in Yeast of Biotechnological Interest, Instituto de Agroquímica y Tecnología de los Alimentos, IATA-CSIC Valencia, Spain
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Jönsson LJ, Martín C. Pretreatment of lignocellulose: Formation of inhibitory by-products and strategies for minimizing their effects. Bioresour Technol 2016; 199:103-112. [PMID: 26482946 DOI: 10.1016/j.biortech.2015.10.009] [Citation(s) in RCA: 783] [Impact Index Per Article: 97.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 10/05/2015] [Accepted: 10/06/2015] [Indexed: 05/07/2023]
Abstract
Biochemical conversion of lignocellulosic feedstocks to advanced biofuels and other commodities through a sugar-platform process involves a pretreatment step enhancing the susceptibility of the cellulose to enzymatic hydrolysis. A side effect of pretreatment is formation of lignocellulose-derived by-products that inhibit microbial and enzymatic biocatalysts. This review provides an overview of the formation of inhibitory by-products from lignocellulosic feedstocks as a consequence of using different pretreatment methods and feedstocks as well as an overview of different strategies used to alleviate problems with inhibitors. As technologies for biorefining of lignocellulose become mature and are transferred from laboratory environments to industrial contexts, the importance of management of inhibition problems is envisaged to increase as issues that become increasingly relevant will include the possibility to use recalcitrant feedstocks, obtaining high product yields and high productivity, minimizing the charges of enzymes and microorganisms, and using high solids loadings to obtain high product titers.
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Affiliation(s)
- Leif J Jönsson
- Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden.
| | - Carlos Martín
- Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden
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Kostas ET, White DA, Du C, Cook DJ. Selection of yeast strains for bioethanol production from UK seaweeds. J Appl Phycol 2016; 28:1427-1441. [PMID: 27057090 PMCID: PMC4789230 DOI: 10.1007/s10811-015-0633-2] [Citation(s) in RCA: 19] [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] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Revised: 05/24/2015] [Accepted: 05/24/2015] [Indexed: 05/13/2023]
Abstract
Macroalgae (seaweeds) are a promising feedstock for the production of third generation bioethanol, since they have high carbohydrate contents, contain little or no lignin and are available in abundance. However, seaweeds typically contain a more diverse array of monomeric sugars than are commonly present in feedstocks derived from lignocellulosic material which are currently used for bioethanol production. Hence, identification of a suitable fermentative microorganism that can utilise the principal sugars released from the hydrolysis of macroalgae remains a major objective. The present study used a phenotypic microarray technique to screen 24 different yeast strains for their ability to metabolise individual monosaccharides commonly found in seaweeds, as well as hydrolysates following an acid pre-treatment of five native UK seaweed species (Laminaria digitata, Fucus serratus, Chondrus crispus, Palmaria palmata and Ulva lactuca). Five strains of yeast (three Saccharomyces spp, one Pichia sp and one Candida sp) were selected and subsequently evaluated for bioethanol production during fermentation of the hydrolysates. Four out of the five selected strains converted these monomeric sugars into bioethanol, with the highest ethanol yield (13 g L-1) resulting from a fermentation using C. crispus hydrolysate with Saccharomyces cerevisiae YPS128. This study demonstrated the novel application of a phenotypic microarray technique to screen for yeast capable of metabolising sugars present in seaweed hydrolysates; however, metabolic activity did not always imply fermentative production of ethanol.
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Affiliation(s)
- Emily T. Kostas
- />The University of Nottingham, Sutton Bonington Campus, Bioenergy and Brewing Science Building, Loughborough, Leicestershire LE12 5RD UK
| | - Daniel A. White
- />Plymouth Marine Laboratory, Prospect Pl, Plymouth, Devon PL1 3DH UK
| | - Chenyu Du
- />The University of Nottingham, Sutton Bonington Campus, Bioenergy and Brewing Science Building, Loughborough, Leicestershire LE12 5RD UK
| | - David J. Cook
- />The University of Nottingham, Sutton Bonington Campus, Bioenergy and Brewing Science Building, Loughborough, Leicestershire LE12 5RD UK
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Kumar V, Hart AJ, Keerthiraju ER, Waldron PR, Tucker GA, Greetham D. Expression of Mitochondrial Cytochrome C Oxidase Chaperone Gene (COX20) Improves Tolerance to Weak Acid and Oxidative Stress during Yeast Fermentation. PLoS One 2015; 10:e0139129. [PMID: 26427054 PMCID: PMC4591339 DOI: 10.1371/journal.pone.0139129] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 09/08/2015] [Indexed: 11/19/2022] Open
Abstract
INTRODUCTION Saccharomyces cerevisiae is the micro-organism of choice for the conversion of fermentable sugars released by the pre-treatment of lignocellulosic material into bioethanol. Pre-treatment of lignocellulosic material releases acetic acid and previous work identified a cytochrome oxidase chaperone gene (COX20) which was significantly up-regulated in yeast cells in the presence of acetic acid. RESULTS A Δcox20 strain was sensitive to the presence of acetic acid compared with the background strain. Overexpressing COX20 using a tetracycline-regulatable expression vector system in a Δcox20 strain, resulted in tolerance to the presence of acetic acid and tolerance could be ablated with addition of tetracycline. Assays also revealed that overexpression improved tolerance to the presence of hydrogen peroxide-induced oxidative stress. CONCLUSION This is a study which has utilised tetracycline-regulated protein expression in a fermentation system, which was characterised by improved (or enhanced) tolerance to acetic acid and oxidative stress.
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Affiliation(s)
- Vinod Kumar
- University of Nottingham, School of Biosciences, Sutton Bonington Campus, Loughborough, LE12 5RD, United Kingdom
| | - Andrew J. Hart
- University of Nottingham, School of Biosciences, Sutton Bonington Campus, Loughborough, LE12 5RD, United Kingdom
| | - Ethiraju R. Keerthiraju
- University of Nottingham, School of Biosciences, Sutton Bonington Campus, Loughborough, LE12 5RD, United Kingdom
| | - Paul R. Waldron
- University of Nottingham, School of Biosciences, Sutton Bonington Campus, Loughborough, LE12 5RD, United Kingdom
| | - Gregory A. Tucker
- University of Nottingham, School of Biosciences, Sutton Bonington Campus, Loughborough, LE12 5RD, United Kingdom
| | - Darren Greetham
- University of Nottingham, School of Biosciences, Sutton Bonington Campus, Loughborough, LE12 5RD, United Kingdom
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Oshoma CE, Greetham D, Louis EJ, Smart KA, Phister TG, Powell C, Du C. Screening of Non- Saccharomyces cerevisiae Strains for Tolerance to Formic Acid in Bioethanol Fermentation. PLoS One 2015; 10:e0135626. [PMID: 26284784 PMCID: PMC4540574 DOI: 10.1371/journal.pone.0135626] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Accepted: 07/24/2015] [Indexed: 11/18/2022] Open
Abstract
Formic acid is one of the major inhibitory compounds present in hydrolysates derived from lignocellulosic materials, the presence of which can significantly hamper the efficiency of converting available sugars into bioethanol. This study investigated the potential for screening formic acid tolerance in non-Saccharomyces cerevisiae yeast strains, which could be used for the development of advanced generation bioethanol processes. Spot plate and phenotypic microarray methods were used to screen the formic acid tolerance of 7 non-Saccharomyces cerevisiae yeasts. S. kudriavzeii IFO1802 and S. arboricolus 2.3319 displayed a higher formic acid tolerance when compared to other strains in the study. Strain S. arboricolus 2.3319 was selected for further investigation due to its genetic variability among the Saccharomyces species as related to Saccharomyces cerevisiae and availability of two sibling strains: S. arboricolus 2.3317 and 2.3318 in the lab. The tolerance of S. arboricolus strains (2.3317, 2.3318 and 2.3319) to formic acid was further investigated by lab-scale fermentation analysis, and compared with S. cerevisiae NCYC2592. S. arboricolus 2.3319 demonstrated improved formic acid tolerance and a similar bioethanol synthesis capacity to S. cerevisiae NCYC2592, while S. arboricolus 2.3317 and 2.3318 exhibited an overall inferior performance. Metabolite analysis indicated that S. arboricolus strain 2.3319 accumulated comparatively high concentrations of glycerol and glycogen, which may have contributed to its ability to tolerate high levels of formic acid.
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Affiliation(s)
- Cyprian E. Oshoma
- Bioenergy and Brewing Science Building, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, Leics, United Kingdom
| | - Darren Greetham
- Bioenergy and Brewing Science Building, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, Leics, United Kingdom
| | - Edward J. Louis
- Centre for Genetic Architecture of Complex Traits, University of Leicester, Leicester, United Kingdom
| | | | - Trevor G. Phister
- PepsiCo Int. Beaumont Park, Leycroft Road, Leicester, United Kingdom
| | - Chris Powell
- Bioenergy and Brewing Science Building, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, Leics, United Kingdom
| | - Chenyu Du
- Bioenergy and Brewing Science Building, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, Leics, United Kingdom
- School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield, United Kingdom
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24
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Zheng YL, Wang SA. Stress Tolerance Variations in Saccharomyces cerevisiae Strains from Diverse Ecological Sources and Geographical Locations. PLoS One 2015; 10:e0133889. [PMID: 26244846 PMCID: PMC4526645 DOI: 10.1371/journal.pone.0133889] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 07/03/2015] [Indexed: 11/17/2022] Open
Abstract
The budding yeast Saccharomyces cerevisiae is a platform organism for bioethanol production from various feedstocks and robust strains are desirable for efficient fermentation because yeast cells inevitably encounter stressors during the process. Recently, diverse S. cerevisiae lineages were identified, which provided novel resources for understanding stress tolerance variations and related shaping factors in the yeast. This study characterized the tolerance of diverse S. cerevisiae strains to the stressors of high ethanol concentrations, temperature shocks, and osmotic stress. The results showed that the isolates from human-associated environments overall presented a higher level of stress tolerance compared with those from forests spared anthropogenic influences. Statistical analyses indicated that the variations of stress tolerance were significantly correlated with both ecological sources and geographical locations of the strains. This study provides guidelines for selection of robust S. cerevisiae strains for bioethanol production from nature.
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Affiliation(s)
- Yan-Lin Zheng
- College of Mathematics and Systems Science, Shandong University of Science and Technology, Qingdao, 266590, China
| | - Shi-An Wang
- Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
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25
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dos Santos SC, Sá-correia I. Yeast toxicogenomics: lessons from a eukaryotic cell model and cell factory. Curr Opin Biotechnol 2015; 33:183-91. [DOI: 10.1016/j.copbio.2015.03.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 02/16/2015] [Accepted: 03/05/2015] [Indexed: 12/21/2022]
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Su H, Jiang J, Lu Q, Zhao Z, Xie T, Zhao H, Wang M. Engineering Corynebacterium crenatum to produce higher alcohols for biofuel using hydrolysates of duckweed (Landoltia punctata) as feedstock. Microb Cell Fact 2015; 14:16. [PMID: 25889648 PMCID: PMC4324788 DOI: 10.1186/s12934-015-0199-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2014] [Accepted: 01/26/2015] [Indexed: 11/10/2022] Open
Abstract
Early trials have demonstrated great potential for the use of duckweed (family Lemnaceae) as the next generation of energy plants for the production of biofuels. Achieving this technological advance demands research to develop novel bioengineering microorganisms that can ferment duckweed feedstock to produce higher alcohols. In this study, we used relevant genes to transfer five metabolic pathways of isoleucine, leucine and valine from the yeast Saccharomyces cerevisiae into the bioengineered microorganism Corynebacterium crenatum. Experimental results showed that the bioengineered strain was able to produce 1026.61 mg/L of 2-methyl-1-butanol by fermenting glucose, compared to 981.79 mg/L from the acid hydrolysates of duckweed. The highest isobutanol yields achieved were 1264.63 mg/L from glucose and 1154.83 mg/L from duckweed, and the corresponding highest yields of 3-methyl-1-butanol were 748.35 and 684.79 mg/L. Our findings demonstrate the feasibility of using bioengineered C. crenatum as a platform to construct a bacterial strain that is capable of producing higher alcohols. We have also shown the promise of using duckweed as the basis for developing higher alcohols, illustrating that this group of plants represents an ideal fermentation substrate that can be considered the next generation of alternative energy feedstocks.
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Affiliation(s)
- Haifeng Su
- Key Laboratory of Bio-resources and Eco-environment of the Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610064, Sichuan, PR China.
| | - Juan Jiang
- Key Laboratory of Bio-resources and Eco-environment of the Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610064, Sichuan, PR China.
| | - Qiuli Lu
- Key Laboratory of Bio-resources and Eco-environment of the Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610064, Sichuan, PR China.
| | - Zhao Zhao
- Key Laboratory of Bio-resources and Eco-environment of the Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610064, Sichuan, PR China.
| | - Tian Xie
- Key Laboratory of Bio-resources and Eco-environment of the Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610064, Sichuan, PR China.
| | - Hai Zhao
- Bioenergy Laboratory, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, Sichuan, PR China.
| | - Maolin Wang
- Key Laboratory of Bio-resources and Eco-environment of the Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610064, Sichuan, PR China.
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Yang Z, Bai Z, Sun H, Yu Z, Li X, Guo Y, Zhang H. Biomass pyrolysis liquid to citric acid via 2-step bioconversion. Microb Cell Fact 2014; 13:182. [PMID: 25551193 PMCID: PMC4299680 DOI: 10.1186/s12934-014-0182-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 12/12/2014] [Indexed: 11/17/2022] Open
Abstract
Background The use of fossil carbon sources for fuels and petrochemicals has serious impacts on our environment and is unable to meet the demand in the future. A promising and sustainable alternative is to substitute fossil carbon sources with microbial cell factories converting lignocellulosic biomass into desirable value added products. However, such bioprocesses require tolerance to inhibitory compounds generated during pretreatment of biomass. In this study, the process of sequential two-step bio-conversion of biomass pyrolysis liquid containing levoglucosan (LG) to citric acid without chemical detoxification has been explored, which can greatly improve the utilization efficiency of lignocellulosic biomass. Results The sequential two-step bio-conversion of corn stover pyrolysis liquid to citric acid has been established. The first step conversion by Phanerochaete chrysosporium (P. chrysosporium) is desirable to decrease the content of other compounds except levoglucosan as a pretreatment for the second conversion. The remaining levoglucosan in solution was further converted into citric acid by Aspergillus niger (A. niger) CBX-209. Thus the conversion of cellulose to citric acid is completed by both pyrolysis and bio-conversion technology. Under experimental conditions, levoglucosan yield is 12% based on the feedstock and the citric acid yield can reach 82.1% based on the levoglucosan content in the pyrolysis liquid (namely 82.1 g of citric acid per 100 g of levoglucosan). Conclusion The study shows that P. chrysosporium and A. niger have the potential to be used as production platforms for value-added products from pyrolyzed lignocellulosic biomass. Selected P. chrysosporium is able to decrease the content of other compounds except levoglucosan and levoglucosan can be further converted into citric acid in the residual liquids by A. niger. Thus the conversion of cellulose to citric acid is completed by both pyrolysis and bio-conversion technology.
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Affiliation(s)
- Zhiguang Yang
- Department of Environmental and Municipal Engineering, Henan University of Urban Construction, Pingdingshan, 467036, China. .,Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.
| | - Zhihui Bai
- Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.
| | - Hongyan Sun
- Department of Environmental and Municipal Engineering, Henan University of Urban Construction, Pingdingshan, 467036, China.
| | - Zhisheng Yu
- Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.
| | - Xingxing Li
- Department of Environmental and Municipal Engineering, Henan University of Urban Construction, Pingdingshan, 467036, China.
| | - Yifei Guo
- Department of Environmental and Municipal Engineering, Henan University of Urban Construction, Pingdingshan, 467036, China.
| | - Hongxun Zhang
- Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.
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Ruyters S, Mukherjee V, Verstrepen KJ, Thevelein JM, Willems KA, Lievens B. Assessing the potential of wild yeasts for bioethanol production. J Ind Microbiol Biotechnol 2015; 42:39-48. [PMID: 25413210 DOI: 10.1007/s10295-014-1544-y] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Accepted: 11/07/2014] [Indexed: 10/24/2022]
Abstract
Bioethanol fermentations expose yeasts to a new, complex and challenging fermentation medium with specific inhibitors and sugar mixtures depending on the type of carbon source. It is, therefore, suggested that the natural diversity of yeasts should be further exploited in order to find yeasts with good ethanol yield in stressed fermentation media. In this study, we screened more than 50 yeast isolates of which we selected five isolates with promising features. The species Candida bombi, Wickerhamomyces anomalus and Torulaspora delbrueckii showed better osmo- and hydroxymethylfurfural tolerance than Saccharomyces cerevisiae. However, S. cerevisiae isolates had the highest ethanol yield in fermentation experiments mimicking high gravity fermentations (25 % glucose) and artificial lignocellulose hydrolysates (with a myriad of inhibitors). Interestingly, among two tested S. cerevisiae strains, a wild strain isolated from an oak tree performed better than Ethanol Red, a S. cerevisiae strain which is currently commonly used in industrial bioethanol fermentations. Additionally, a W. anomalus strain isolated from sugar beet thick juice was found to have a comparable ethanol yield, but needed longer fermentation time. Other non-Saccharomyces yeasts yielded lower ethanol amounts.
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Mukherjee V, Steensels J, Lievens B, Van de Voorde I, Verplaetse A, Aerts G, Willems KA, Thevelein JM, Verstrepen KJ, Ruyters S. Phenotypic evaluation of natural and industrial Saccharomyces yeasts for different traits desirable in industrial bioethanol production. Appl Microbiol Biotechnol 2014; 98:9483-98. [PMID: 25267160 DOI: 10.1007/s00253-014-6090-z] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Revised: 09/09/2014] [Accepted: 09/10/2014] [Indexed: 01/17/2023]
Abstract
Saccharomyces cerevisiae is the organism of choice for many food and beverage fermentations because it thrives in high-sugar and high-ethanol conditions. However, the conditions encountered in bioethanol fermentation pose specific challenges, including extremely high sugar and ethanol concentrations, high temperature, and the presence of specific toxic compounds. It is generally considered that exploring the natural biodiversity of Saccharomyces strains may be an interesting route to find superior bioethanol strains and may also improve our understanding of the challenges faced by yeast cells during bioethanol fermentation. In this study, we phenotypically evaluated a large collection of diverse Saccharomyces strains on six selective traits relevant for bioethanol production with increasing stress intensity. Our results demonstrate a remarkably large phenotypic diversity among different Saccharomyces species and among S. cerevisiae strains from different origins. Currently applied bioethanol strains showed a high tolerance to many of these relevant traits, but several other natural and industrial S. cerevisiae strains outcompeted the bioethanol strains for specific traits. These multitolerant strains performed well in fermentation experiments mimicking industrial bioethanol production. Together, our results illustrate the potential of phenotyping the natural biodiversity of yeasts to find superior industrial strains that may be used in bioethanol production or can be used as a basis for further strain improvement through genetic engineering, experimental evolution, or breeding. Additionally, our study provides a basis for new insights into the relationships between tolerance to different stressors.
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Affiliation(s)
- Vaskar Mukherjee
- Laboratory for Process Microbial Ecology and Bioinspirational Management, Cluster for Bioengineering Technology (CBeT), Department of Microbial and Molecular Systems (M2S), Campus De Nayer, KU Leuven, Fortsesteenweg 30A, B-2860, Sint-Katelijne-Waver, Belgium
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Zaki AM, Wimalasena TT, Greetham D. Phenotypic characterisation of Saccharomyces spp. for tolerance to 1-butanol. J Ind Microbiol Biotechnol 2014; 41:1627-36. [PMID: 25242291 DOI: 10.1007/s10295-014-1511-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Accepted: 09/12/2014] [Indexed: 11/29/2022]
Abstract
Biofuels are expected to play a role in replacing crude oil as a liquid transportation fuel, and research into butanol has highlighted the importance of this alcohol as a fuel. Butanol has a higher energy density than ethanol, butanol-gasoline blends do not separate in the presence of water, and butanol is miscible with gasoline (Szulczyk, Int J Energy Environ 1(1):2876-2895, 40). Saccharomyces cerevisiae has been used as a fermentative organism in the biofuel industry producing ethanol from glucose derived from starchy plant material; however, it typically cannot tolerate butanol concentrations greater than 2 % (Luong, Biotechnol Bioeng 29 (2):242-248, 27). 90 Saccharomyces spp. strains were screened for tolerance to 1-butanol via a phenotypic microarray assay and we observed significant variation in response with the most tolerant strains (S. cerevisiae DBVPG1788, S. cerevisiae DBVPG6044 and S. cerevisiae YPS128) exhibiting tolerance to 4 % 1-butanol compared with S. uvarum and S. castelli strains, which were sensitive to 3 % 1-butanol. Response to butanol was confirmed using traditional yeast methodologies such as growth; it was observed that fermentations in the presence of butanol, when using strains with a tolerant background, were significantly faster. Assessing for genetic rationale for tolerance, it was observed that 1-butanol-tolerant strains, when compared with 1-butanol-sensitive strains, had an up-regulation of RPN4, a transcription factor which regulates proteasome genes. Analysing for the importance of RPN4, we observed that a Δrpn4 strain displayed a reduced rate of fermentation in the presence of 1-butanol when compared with the BY4741 background strain. This data will aid the development of breeding programmes to produce better strains for future bio-butanol production.
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Affiliation(s)
- A M Zaki
- University of Nottingham, School of Biosciences, Sutton Bonington Campus, Loughborough, LE12 5RD, UK
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31
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Greetham D, Wimalasena TT, Leung K, Marvin ME, Chandelia Y, Hart AJ, Phister TG, Tucker GA, Louis EJ, Smart KA. The genetic basis of variation in clean lineages of Saccharomyces cerevisiae in response to stresses encountered during bioethanol fermentations. PLoS One 2014; 9:e103233. [PMID: 25116161 PMCID: PMC4130530 DOI: 10.1371/journal.pone.0103233] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 06/30/2014] [Indexed: 11/20/2022] Open
Abstract
Saccharomyces cerevisiae is the micro-organism of choice for the conversion of monomeric sugars into bioethanol. Industrial bioethanol fermentations are intrinsically stressful environments for yeast and the adaptive protective response varies between strain backgrounds. With the aim of identifying quantitative trait loci (QTL's) that regulate phenotypic variation, linkage analysis on six F1 crosses from four highly divergent clean lineages of S. cerevisiae was performed. Segregants from each cross were assessed for tolerance to a range of stresses encountered during industrial bioethanol fermentations. Tolerance levels within populations of F1 segregants to stress conditions differed and displayed transgressive variation. Linkage analysis resulted in the identification of QTL's for tolerance to weak acid and osmotic stress. We tested candidate genes within loci identified by QTL using reciprocal hemizygosity analysis to ascertain their contribution to the observed phenotypic variation; this approach validated a gene (COX20) for weak acid stress and a gene (RCK2) for osmotic stress. Hemizygous transformants with a sensitive phenotype carried a COX20 allele from a weak acid sensitive parent with an alteration in its protein coding compared with other S. cerevisiae strains. RCK2 alleles reveal peptide differences between parental strains and the importance of these changes is currently being ascertained.
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Affiliation(s)
- Darren Greetham
- School of Biosciences, University of Nottingham, Sutton Bonington campus, Loughborough, United Kingdom
| | - Tithira T. Wimalasena
- School of Biosciences, University of Nottingham, Sutton Bonington campus, Loughborough, United Kingdom
| | - Kay Leung
- Centre for Genetic Architecture of Complex Traits, Department of Genetics, University of Leicester, Adrian Building, Leicester, Leicestershire, United Kingdom
| | - Marcus E. Marvin
- Centre for Genetic Architecture of Complex Traits, Department of Genetics, University of Leicester, Adrian Building, Leicester, Leicestershire, United Kingdom
| | - Yogeshwar Chandelia
- School of Biosciences, University of Nottingham, Sutton Bonington campus, Loughborough, United Kingdom
| | - Andrew J. Hart
- School of Biosciences, University of Nottingham, Sutton Bonington campus, Loughborough, United Kingdom
| | - Trevor G. Phister
- School of Biosciences, University of Nottingham, Sutton Bonington campus, Loughborough, United Kingdom
| | - Gregory A. Tucker
- School of Biosciences, University of Nottingham, Sutton Bonington campus, Loughborough, United Kingdom
| | - Edward J. Louis
- Centre for Genetic Architecture of Complex Traits, Department of Genetics, University of Leicester, Adrian Building, Leicester, Leicestershire, United Kingdom
| | - Katherine A. Smart
- School of Biosciences, University of Nottingham, Sutton Bonington campus, Loughborough, United Kingdom
- * E-mail:
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