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Trivellin C, Rugbjerg P, Olsson L. Performance and robustness analysis reveals phenotypic trade-offs in yeast. Life Sci Alliance 2024; 7:e202302215. [PMID: 37903627 PMCID: PMC10618107 DOI: 10.26508/lsa.202302215] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 10/20/2023] [Accepted: 10/20/2023] [Indexed: 11/01/2023] Open
Abstract
To design strains that can function efficiently in complex industrial settings, it is crucial to consider their robustness, that is, the stability of their performance when faced with perturbations. In the present study, we cultivated 24 Saccharomyces cerevisiae strains under conditions that simulated perturbations encountered during lignocellulosic bioethanol production, and assessed the performance and robustness of multiple phenotypes simultaneously. The observed negative correlations confirmed a trade-off between performance and robustness of ethanol yield, biomass yield, and cell dry weight. Conversely, the specific growth rate performance positively correlated with the robustness, presumably because of evolutionary selection for robust, fast-growing cells. The Ethanol Red strain exhibited both high performance and robustness, making it a good candidate for bioproduction in the tested perturbation space. Our results experimentally map the robustness-performance trade-offs, previously demonstrated mainly by single-phenotype and computational studies.
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Affiliation(s)
- Cecilia Trivellin
- https://ror.org/040wg7k59 Department of Life Sciences, Division of Industrial Biotechnology, Chalmers University of Technology, Gothenburg, Sweden
| | - Peter Rugbjerg
- https://ror.org/040wg7k59 Department of Life Sciences, Division of Industrial Biotechnology, Chalmers University of Technology, Gothenburg, Sweden
- Enduro Genetics ApS, Copenhagen, Denmark
| | - Lisbeth Olsson
- https://ror.org/040wg7k59 Department of Life Sciences, Division of Industrial Biotechnology, Chalmers University of Technology, Gothenburg, Sweden
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2
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Baptista SL, Romaní A, Cunha JT, Domingues L. Multi-feedstock biorefinery concept: Valorization of winery wastes by engineered yeast. J Environ Manage 2023; 326:116623. [PMID: 36368200 DOI: 10.1016/j.jenvman.2022.116623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 10/21/2022] [Accepted: 10/23/2022] [Indexed: 06/16/2023]
Abstract
The wine industry produces significant amounts of by-products and residues that are not properly managed, posing an environmental problem. Grape must surplus, vine shoots, and wine lees have the potential to be used as renewable resources for the production of energy and chemicals. Metabolic engineering efforts have established Saccharomyces cerevisiae as an efficient microbial cell factory for biorefineries. Current biorefineries designed for producing multiple products often rely on just one feedstock, but the bioeconomy would clearly benefit if these biorefineries could efficiently convert multiple feedstocks. Moreover, to reduce the environmental impact of fossil fuel consumption and maximize production economics, a biorefinery should be capable to supplement the manufacture of biofuel with the production of high-value products. This study proposes an integrated approach for the valorization of diverse wastes resulting from winemaking processes through the biosynthesis of xylitol and ethanol. Using genetically modified S. cerevisiae strains, the xylose-rich hemicellulosic fraction of hydrothermally pretreated vine shoots was converted into xylitol, and the cellulosic fraction was used to produce bioethanol. In addition, grape must, enriched in sugars, was efficiently used as a low-cost source for yeast propagation. The production of xylitol was optimized, in a Simultaneous Saccharification and Fermentation process configuration, by adjusting the inoculum size and enzyme loading. Furthermore, a yeast strain displaying cellulases in the cell surface was applied for the production of bioethanol from the glucan-rich cellulosic. With the addition of grape must and/or wine lees, high ethanol concentrations were reached, which are crucial for the economic feasibility of distillation. This integrated multi-feedstock valorization provides a synergistic alternative for converting a range of winery wastes and by-products into biofuel and an added-value chemical while decreasing waste released to the environment.
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Affiliation(s)
- Sara L Baptista
- CEB - Centre of Biological Engineering, University of Minho, Braga, Portugal; LABBELS - Associate Laboratory, Braga, Guimarães, Portugal
| | - Aloia Romaní
- Department of Chemical Engineering, Faculty of Science, University of Vigo (Campus Ourense), As Lagoas, 32004, Ourense, Spain
| | - Joana T Cunha
- CEB - Centre of Biological Engineering, University of Minho, Braga, Portugal; LABBELS - Associate Laboratory, Braga, Guimarães, Portugal
| | - Lucília Domingues
- CEB - Centre of Biological Engineering, University of Minho, Braga, Portugal; LABBELS - Associate Laboratory, Braga, Guimarães, Portugal.
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González-Gloria K, Rodríguez-Jasso RM, Saxena R, Sindhu R, Ali SS, Singhania RR, Patel AK, Binod P, Ruiz HA. Bubble column bioreactor design and evaluation for bioethanol production using simultaneous saccharification and fermentation strategy from hydrothermally pretreated lignocellulosic biomass. Biochem Eng J 2022. [DOI: 10.1016/j.bej.2022.108645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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4
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Baptista M, Domingues L. Kluyveromyces marxianus as a microbial cell factory for lignocellulosic biomass valorisation. Biotechnol Adv 2022; 60:108027. [PMID: 35952960 DOI: 10.1016/j.biotechadv.2022.108027] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 08/04/2022] [Accepted: 08/04/2022] [Indexed: 11/02/2022]
Abstract
The non-conventional yeast Kluyveromyces marxianus is widely used for several biotechnological applications, mainly due to its thermotolerance, high growth rate, and ability to metabolise a wide range of sugars. These cell traits are strategic for lignocellulosic biomass valorisation and strain diversity prompts the development of robust chassis, either with improved tolerance to lignocellulosic inhibitors or ethanol. This review summarises bioethanol and value-added chemicals production by K. marxianus from different lignocellulosic biomasses. Moreover, metabolic engineering and process optimization strategies developed to expand K. marxianus potential are also compiled, as well as studies reporting cell mechanisms to cope with lignocellulosic-derived inhibitors. The main lignocellulosic-based products are bioethanol, representing 71% of the reports, and xylitol, representing 17% of the reports. K. marxianus also proved to be a good chassis for lactic acid and volatile compounds production from lignocellulosic biomass, although the literature on this matter is still scarce. The increasing advances in genome editing tools and process optimization strategies will widen the K. marxianus-based portfolio products.
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Affiliation(s)
- Marlene Baptista
- CEB-Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal; LABBELS -Associate Laboratory, Braga/Guimarães, Portugal
| | - Lucília Domingues
- CEB-Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal; LABBELS -Associate Laboratory, Braga/Guimarães, Portugal.
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Pant S, Prakash A, Kuila A. Integrated production of ethanol and xylitol from Brassica juncea using Candida sojae JCM 1644. Bioresour Technol 2022; 351:126903. [PMID: 35227916 DOI: 10.1016/j.biortech.2022.126903] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [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: 01/28/2022] [Revised: 02/19/2022] [Accepted: 02/21/2022] [Indexed: 06/14/2023]
Abstract
The present study demonstrates a novel strategy involving two-step fermentation of lignocellulosic hydrolysate for the integrated production of ethanol and xylitol using a newly isolated yeast strain, Candida sojae JCM 1644. The isolated strain was characterised by its carbohydrate assimilation efficiency and tolerance towards inhibitors generated during pretreatment and fermentation of lignocellulosic biomass. In brief, the study comprised alkali treatment of Brassica juncea followed by its saccharification with cellulase consortia. An isolated strain was used for the co-production of xylitol and ethanol from sugar hydrolysate, and several parameters were systematically optimised for maximum co-production of ethanol and xylitol. Out of total glucose (149.72 g/L) and xylose (84.21 g/L) present in biomass hydrolysate, a product yield of 0.45 g/g (ethanol) and 0.62 g/g (xylitol) was achieved for a two-step fermentation process, which was 15.57% and 11.78% higher than the yield achieved for ethanol and xylitol, respectively, in a one-step fermentation process.
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Affiliation(s)
- Shailja Pant
- Department of Bioscience & Biotechnology, Banasthali Vidyapith, Rajasthan 304022, India
| | - Anand Prakash
- Department of Bioscience & Biotechnology, Banasthali Vidyapith, Rajasthan 304022, India
| | - Arindam Kuila
- Department of Bioscience & Biotechnology, Banasthali Vidyapith, Rajasthan 304022, India.
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Stovicek V, Dato L, Almqvist H, Schöpping M, Chekina K, Pedersen LE, Koza A, Figueira D, Tjosås F, Ferreira BS, Forster J, Lidén G, Borodina I. Rational and evolutionary engineering of Saccharomyces cerevisiae for production of dicarboxylic acids from lignocellulosic biomass and exploring genetic mechanisms of the yeast tolerance to the biomass hydrolysate. Biotechnol Biofuels Bioprod 2022; 15:22. [PMID: 35219341 PMCID: PMC8882276 DOI: 10.1186/s13068-022-02121-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 02/12/2022] [Indexed: 12/13/2022]
Abstract
BACKGROUND Lignosulfonates are significant wood chemicals with a $700 million market, produced by sulfite pulping of wood. During the pulping process, spent sulfite liquor (SSL) is generated, which in addition to lignosulfonates contains hemicellulose-derived sugars-in case of hardwoods primarily the pentose sugar xylose. The pentoses are currently underutilized. If they could be converted into value-added chemicals, overall economic profitability of the process would increase. SSLs are typically very inhibitory to microorganisms, which presents a challenge for a biotechnological process. The aim of the present work was to develop a robust yeast strain able to convert xylose in SSL to carboxylic acids. RESULTS The industrial strain Ethanol Red of the yeast Saccharomyces cerevisiae was engineered for efficient utilization of xylose in a Eucalyptus globulus lignosulfonate stream at low pH using CRISPR/Cas genome editing and adaptive laboratory evolution. The engineered strain grew in synthetic medium with xylose as sole carbon source with maximum specific growth rate (µmax) of 0.28 1/h. Selected evolved strains utilized all carbon sources in the SSL at pH 3.5 and grew with µmax between 0.05 and 0.1 1/h depending on a nitrogen source supplement. Putative genetic determinants of the increased tolerance to the SSL were revealed by whole genome sequencing of the evolved strains. In particular, four top-candidate genes (SNG1, FIT3, FZF1 and CBP3) were identified along with other gene candidates with predicted important roles, based on the type and distribution of the mutations across different strains and especially the best performing ones. The developed strains were further engineered for production of dicarboxylic acids (succinic and malic acid) via overexpression of the reductive branch of the tricarboxylic acid cycle (TCA). The production strain produced 0.2 mol and 0.12 mol of malic acid and succinic acid, respectively, per mol of xylose present in the SSL. CONCLUSIONS The combined metabolic engineering and adaptive evolution approach provided a robust SSL-tolerant industrial strain that converts fermentable carbon content of the SSL feedstock into malic and succinic acids at low pH.in production yields reaching 0.1 mol and 0.065 mol per mol of total consumed carbon sources.. Moreover, our work suggests potential genetic background of the tolerance to the SSL stream pointing out potential gene targets for improving the tolerance to inhibitory industrial feedstocks.
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Affiliation(s)
- Vratislav Stovicek
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet, Building 220, 2800, Kgs. Lyngby, Denmark
| | - Laura Dato
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet, Building 220, 2800, Kgs. Lyngby, Denmark.,River Stone Biotech ApS, Fruebjergvej 3, 2100, Copenhagen, Denmark
| | - Henrik Almqvist
- Department of Chemical Engineering, Lund University, P.O. Box 124, 221 00, Lund, Sweden
| | - Marie Schöpping
- Department of Chemical Engineering, Lund University, P.O. Box 124, 221 00, Lund, Sweden.,Chr. Hansen A/S, Boge Alle 10-12, 2970, Hørsholm, Denmark.,Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, 412 96, Gothenburg, Sweden
| | - Ksenia Chekina
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet, Building 220, 2800, Kgs. Lyngby, Denmark
| | - Lasse Ebdrup Pedersen
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet, Building 220, 2800, Kgs. Lyngby, Denmark
| | - Anna Koza
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet, Building 220, 2800, Kgs. Lyngby, Denmark.,Chr. Hansen A/S, Boge Alle 10-12, 2970, Hørsholm, Denmark
| | - Diogo Figueira
- Biotrend S.A., Biocant Park Núcleo 04, Lote 2, 3060-197, Cantanhede, Portugal
| | - Freddy Tjosås
- Borregaard ApS, Hjalmar Wessels vei 6, 1721, Sarpsborg, Norway
| | | | - Jochen Forster
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet, Building 220, 2800, Kgs. Lyngby, Denmark
| | - Gunnar Lidén
- Department of Chemical Engineering, Lund University, P.O. Box 124, 221 00, Lund, Sweden
| | - Irina Borodina
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet, Building 220, 2800, Kgs. Lyngby, Denmark.
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Del Río PG, Gullón B, Wu J, Saddler J, Garrote G, Romaní A. Current breakthroughs in the hardwood biorefineries: Hydrothermal processing for the co-production of xylooligosaccharides and bioethanol. Bioresour Technol 2022; 343:126100. [PMID: 34626760 DOI: 10.1016/j.biortech.2021.126100] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 10/04/2021] [Accepted: 10/05/2021] [Indexed: 06/13/2023]
Abstract
The development of lignocellulosic biorefineries requires a first stage of pretreatment which enables the efficient valorization of all fractions present in this renewable material. In this sense, this review aims to show the main advantages of hydrothermal treatment as a first step of a biorefinery infrastructure using hardwood as raw material, as well as, main drawback to overcome. Hydrothermal treatment of hardwood highlights for its high selectivity for hemicelluloses solubilization as xylooligosaccharides (XOS). Nevertheless, the suitable conditions for XOS production are inadequate to achieve an elevate cellulose to glucose conversion. Hence, several strategies namely the combination of hydrothermal treatment with delignification process, in situ modification of lignin and the mixture with another renewable resources (concretely, seaweeds, and by-products generated in the food industry with high sugar content) were pinpointed as promising alternative to increase the final ethanol concentration coupled with XOS recovery in the hydrolysate.
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Affiliation(s)
- Pablo G Del Río
- Universidade de Vigo, Departamento de Enxeñería Química, Facultade de Ciencias, 32004 Ourense, Spain
| | - Beatriz Gullón
- Universidade de Vigo, Departamento de Enxeñería Química, Facultade de Ciencias, 32004 Ourense, Spain
| | - Jie Wu
- Forest Product Biotechnology/Bioenergy Group, Department of Wood Science, Faculty of Forestry, University of British Columbia, 2424 Main Mall, Vancouver, BC V6T 1Z4, Canada
| | - Jack Saddler
- Forest Product Biotechnology/Bioenergy Group, Department of Wood Science, Faculty of Forestry, University of British Columbia, 2424 Main Mall, Vancouver, BC V6T 1Z4, Canada
| | - Gil Garrote
- Universidade de Vigo, Departamento de Enxeñería Química, Facultade de Ciencias, 32004 Ourense, Spain
| | - Aloia Romaní
- Universidade de Vigo, Departamento de Enxeñería Química, Facultade de Ciencias, 32004 Ourense, Spain.
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Baptista M, Cunha JT, Domingues L. Establishment of Kluyveromyces marxianus as a Microbial Cell Factory for Lignocellulosic Processes: Production of High Value Furan Derivatives. J Fungi (Basel) 2021; 7:1047. [PMID: 34947029 PMCID: PMC8708846 DOI: 10.3390/jof7121047] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 11/30/2021] [Accepted: 12/02/2021] [Indexed: 12/19/2022] Open
Abstract
The establishment of lignocellulosic biorefineries is dependent on microorganisms being able to cope with the stressful conditions resulting from the release of inhibitory compounds during biomass processing. The yeast Kluyveromyces marxianus has been explored as an alternative microbial factory due to its thermotolerance and ability to natively metabolize xylose. The lignocellulose-derived inhibitors furfural and 5-hydroxymethylfurfural (HMF) are considered promising building-block platforms that can be converted into a wide variety of high-value derivatives. Here, several K. marxianus strains, isolated from cocoa fermentation, were evaluated for xylose consumption and tolerance towards acetic acid, furfural, and HMF. The potential of this yeast to reduce furfural and HMF at high inhibitory loads was disclosed and characterized. Our results associated HMF reduction with NADPH while furfural-reducing activity was higher with NADH. In addition, furans' inhibitory effect was higher when combined with xylose consumption. The furan derivatives produced by K. marxianus in different conditions were identified. Furthermore, one selected isolate was efficiently used as a whole-cell biocatalyst to convert furfural and HMF into their derivatives, furfuryl alcohol and 2,5-bis(hydroxymethyl)furan (BHMF), with high yields and productivities. These results validate K. marxianus as a promising microbial platform in lignocellulosic biorefineries.
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Affiliation(s)
| | | | - Lucília Domingues
- CEB—Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal; (M.B.); (J.T.C.)
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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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Qiao Y, Li C, Lu X, Zong H, Zhuge B. Transporter engineering promotes the co-utilization of glucose and xylose by Candida glycerinogenes for d-xylonate production. Biochem Eng J 2021; 175:108150. [DOI: 10.1016/j.bej.2021.108150] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Costa CE, Møller-Hansen I, Romaní A, Teixeira JA, Borodina I, Domingues L. Resveratrol Production from Hydrothermally Pretreated Eucalyptus Wood Using Recombinant Industrial Saccharomyces cerevisiae Strains. ACS Synth Biol 2021; 10:1895-1903. [PMID: 34304554 DOI: 10.1021/acssynbio.1c00120] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Resveratrol is a phenolic compound with strong antioxidant activity, being promising for several applications in health, food, and cosmetics. It is generally extracted from plants or chemically synthesized, in both complex and not sustainable processes, but microbial biosynthesis of resveratrol can counter these drawbacks. In this work, resveratrol production by microbial biosynthesis from lignocellulosic materials was assessed. Three robust industrial Saccharomyces cerevisiae strains known for their thermotolerance and/or resistance to inhibitory compounds were identified as suitable hosts for de novo resveratrol production from glucose and ethanol. Through the CRISPR/Cas9 system, all industrial strains, and a laboratory one, were successfully engineered with the resveratrol biosynthetic pathway via the phenylalanine intermediate. All strains were further screened at 30 °C and 39 °C to evaluate thermotolerance, which is a key feature for Simultaneous Saccharification and Fermentation processes. Ethanol Red RBP showed the best performance at 39 °C, with more than 2.6-fold of resveratrol production in comparison with the other strains. This strain was then used to assess resveratrol production from glucose and ethanol. A maximum resveratrol titer of 187.07 ± 19.88 mg/L was attained from a medium with 2% glucose and 5% ethanol (w/v). Lastly, Ethanol Red RBP produced 151.65 ± 3.84 mg/L resveratrol from 2.95% of cellulose from hydrothermally pretreated Eucalyptus globulus wood, at 39 °C, in a Simultaneous Saccharification and Fermentation process. To the best of our knowledge, this is the first report of lignocellulosic resveratrol production, establishing grounds for the implementation of an integrated lignocellulose-to-resveratrol process in an industrial context.
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Affiliation(s)
- Carlos E. Costa
- Centre of Biological Engineering, University of Minho, Campus Gualtar, 4710-057 Braga, Portugal
| | - Iben Møller-Hansen
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Aloia Romaní
- Centre of Biological Engineering, University of Minho, Campus Gualtar, 4710-057 Braga, Portugal
| | - José A. Teixeira
- Centre of Biological Engineering, University of Minho, Campus Gualtar, 4710-057 Braga, Portugal
| | - Irina Borodina
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Lucília Domingues
- Centre of Biological Engineering, University of Minho, Campus Gualtar, 4710-057 Braga, Portugal
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Aparicio E, Rodríguez-Jasso RM, Pinales-Márquez CD, Loredo-Treviño A, Robledo-Olivo A, Aguilar CN, Kostas ET, Ruiz HA. High-pressure technology for Sargassum spp biomass pretreatment and fractionation in the third generation of bioethanol production. Bioresour Technol 2021; 329:124935. [PMID: 33713900 DOI: 10.1016/j.biortech.2021.124935] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [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: 01/16/2021] [Revised: 02/27/2021] [Accepted: 03/01/2021] [Indexed: 06/12/2023]
Abstract
Sargassum spp is an invasive macroalgae and an alternative feedstock for bioethanol production. Sargassum spp biomass was subjected to high-pressure technology for biomass fractionation under different operating conditions of temperature and residence time to obtain glucan enriched pretreated solids (32.22 g/100 g of raw material). Enzyme hydrolysis process at high pretreated solid loading (13%, w/v) and enzyme loading of 10 FPU/g of glucan was performed, obtaining 43.01 g/L of glucose corresponding to a conversion yield of 92.12%. Finally, a pre-simultaneous saccharification and fermentation strategy (PSSF) was performed to produce bioethanol. This operational strategy produced 45.66 g/L of glucose in the pre-saccharification stage, and 18.14 g/L of bioethanol was produced with a glucose to bioethanol conversion yield of 76.23%. The development of this process highlights the feasibility of bioethanol production from macroalgal biomass in the biorefinery concept.
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Affiliation(s)
- E Aparicio
- Biorefinery Group, Food Research Department, Faculty of Chemistry Sciences, Autonomous University of Coahuila, 25280 Saltillo, Coahuila, Mexico
| | - Rosa M Rodríguez-Jasso
- Biorefinery Group, Food Research Department, Faculty of Chemistry Sciences, Autonomous University of Coahuila, 25280 Saltillo, Coahuila, Mexico.
| | - César D Pinales-Márquez
- Biorefinery Group, Food Research Department, Faculty of Chemistry Sciences, Autonomous University of Coahuila, 25280 Saltillo, Coahuila, Mexico
| | - Araceli Loredo-Treviño
- Biorefinery Group, Food Research Department, Faculty of Chemistry Sciences, Autonomous University of Coahuila, 25280 Saltillo, Coahuila, Mexico
| | - Armando Robledo-Olivo
- Food Science & Technology Department, Universidad Autónoma Agraria Antonio Narro, Unidad Saltillo, Blvd Antonio Narro 1923, Buenavista, 25315 Saltillo, Coahuila, Mexico
| | - Cristóbal N Aguilar
- Biorefinery Group, Food Research Department, Faculty of Chemistry Sciences, Autonomous University of Coahuila, 25280 Saltillo, Coahuila, Mexico
| | - Emily T Kostas
- Department of Biochemical Engineering, The Advanced Centre of Biochemical Engineering, Bernard Katz Building, Gower Street, London WC1H 6BT, University College London, London, United Kingdom
| | - Héctor A Ruiz
- Biorefinery Group, Food Research Department, Faculty of Chemistry Sciences, Autonomous University of Coahuila, 25280 Saltillo, Coahuila, Mexico.
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Qiao Y, Zhou J, Lu X, Zong H, Zhuge B. Improving the productivity of Candida glycerinogenes in the fermentation of ethanol from non-detoxified sugarcane bagasse hydrolysate by a hexose transporter mutant. J Appl Microbiol 2021; 131:1787-1799. [PMID: 33694233 DOI: 10.1111/jam.15059] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Revised: 02/09/2021] [Accepted: 03/02/2021] [Indexed: 11/27/2022]
Abstract
AIMS In this study, we attempted to increase the productivity of Candida glycerinogenes yeast for ethanol production from non-detoxified sugarcane bagasse hydrolysates (NDSBH) by identifying the hexose transporter in this yeast that makes a high contribution to glucose consumption, and by adding additional copies of this transporter and enhancing its membrane localisation stability (MLS). METHODS AND RESULTS Based on the knockout and overexpression of key hexose transporter genes and the characterisation of their promoter properties, we found that Cghxt4 and Cghxt6 play major roles in the early and late stages of fermentation, respectively, with Cghxt4 contributing most to glucose consumption. Next, subcellular localisation analysis revealed that a common mutation of two ubiquitination sites (K9 and K538) in Cghxt4 improved its MLS. Finally, we overexpressed this Cghxt4 mutant (Cghxt4.2A) using a strong promoter, PCgGAP , which resulted in a significant increase in the ethanol productivity of C. glycerinogenes in the NDSBH medium. Specifically, the recombinant strain showed 18 and 25% higher ethanol productivity than the control in two kinds of YP-NDSBH medium (YP-NDSBH1G160 and YP-NDSBH2G160 ), respectively. CONCLUSIONS The hexose transporter mutant Cghxt4.2A (Cghxt4K9A,K538A ) with multiple copies and high MLS was able to significantly increase the ethanol productivity of C. glycerinogenes in NDSBH. SIGNIFICANCE AND IMPACT OF THE STUDY Our results provide a promising strategy for constructing efficient strains for ethanol production.
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Affiliation(s)
- Y Qiao
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China.,The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China.,Research Centre of Industrial Microbiology, School of Biotechnology, Jiangnan University, Wuxi, China
| | - J Zhou
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China.,The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - X Lu
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China.,The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China.,Research Centre of Industrial Microbiology, School of Biotechnology, Jiangnan University, Wuxi, China
| | - H Zong
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China.,The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China.,Research Centre of Industrial Microbiology, School of Biotechnology, Jiangnan University, Wuxi, China
| | - B Zhuge
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China.,The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China.,Research Centre of Industrial Microbiology, School of Biotechnology, Jiangnan University, Wuxi, China
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14
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Gutmann F, Jann C, Pereira F, Johansson A, Steinmetz LM, Patil KR. CRISPRi screens reveal genes modulating yeast growth in lignocellulose hydrolysate. Biotechnol Biofuels 2021; 14:41. [PMID: 33568224 PMCID: PMC7874482 DOI: 10.1186/s13068-021-01880-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 01/07/2021] [Indexed: 05/13/2023]
Abstract
BACKGROUND Baker's yeast is a widely used eukaryotic cell factory, producing a diverse range of compounds including biofuels and fine chemicals. The use of lignocellulose as feedstock offers the opportunity to run these processes in an environmentally sustainable way. However, the required hydrolysis pretreatment of lignocellulosic material releases toxic compounds that hamper yeast growth and consequently productivity. RESULTS Here, we employ CRISPR interference in S. cerevisiae to identify genes modulating fermentative growth in plant hydrolysate and in presence of lignocellulosic toxins. We find that at least one-third of hydrolysate-associated gene functions are explained by effects of known toxic compounds, such as the decreased growth of YAP1 or HAA1, or increased growth of DOT6 knock-down strains in hydrolysate. CONCLUSION Our study confirms previously known genetic elements and uncovers new targets towards designing more robust yeast strains for the utilization of lignocellulose hydrolysate as sustainable feedstock, and, more broadly, paves the way for applying CRISPRi screens to improve industrial fermentation processes.
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Affiliation(s)
- Friederike Gutmann
- European Molecular Biology Laboratory (EMBL), Structural and Cell Biology Unit, 69117, Heidelberg, Germany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125, Berlin, Germany
| | - Cosimo Jann
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, 69117, Heidelberg, Germany.
- Department of Biology, Institute of Biochemistry, ETH Zurich, Zurich, Switzerland.
| | - Filipa Pereira
- European Molecular Biology Laboratory (EMBL), Structural and Cell Biology Unit, 69117, Heidelberg, Germany.
| | - Andreas Johansson
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, 69117, Heidelberg, Germany
| | - Lars M Steinmetz
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, 69117, Heidelberg, Germany
- Department of Genetics, Stanford University School of Medicine, Stanford, CA, 94305, USA
- Stanford Genome Technology Center, Palo Alto, CA, 94304, USA
| | - Kiran R Patil
- European Molecular Biology Laboratory (EMBL), Structural and Cell Biology Unit, 69117, Heidelberg, Germany.
- MRC Toxicology Unit, University of Cambridge, Cambridge, UK.
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15
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Baptista SL, Costa CE, Cunha JT, Soares PO, Domingues L. Metabolic engineering of Saccharomyces cerevisiae for the production of top value chemicals from biorefinery carbohydrates. Biotechnol Adv 2021; 47:107697. [PMID: 33508428 DOI: 10.1016/j.biotechadv.2021.107697] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Revised: 01/11/2021] [Accepted: 01/13/2021] [Indexed: 12/16/2022]
Abstract
The implementation of biorefineries for a cost-effective and sustainable production of energy and chemicals from renewable carbon sources plays a fundamental role in the transition to a circular economy. The US Department of Energy identified a group of key target compounds that can be produced from biorefinery carbohydrates. In 2010, this list was revised and included organic acids (lactic, succinic, levulinic and 3-hydroxypropionic acids), sugar alcohols (xylitol and sorbitol), furans and derivatives (hydroxymethylfurfural, furfural and furandicarboxylic acid), biohydrocarbons (isoprene), and glycerol and its derivatives. The use of substrates like lignocellulosic biomass that impose harsh culture conditions drives the quest for the selection of suitable robust microorganisms. The yeast Saccharomyces cerevisiae, widely utilized in industrial processes, has been extensively engineered to produce high-value chemicals. For its robustness, ease of handling, genetic toolbox and fitness in an industrial context, S. cerevisiae is an ideal platform for the founding of sustainable bioprocesses. Taking these into account, this review focuses on metabolic engineering strategies that have been applied to S. cerevisiae for converting renewable resources into the previously identified chemical targets. The heterogeneity of each chemical and its manufacturing process leads to inevitable differences between the development stages of each process. Currently, 8 of 11 of these top value chemicals have been already reported to be produced by recombinant S. cerevisiae. While some of them are still in an early proof-of-concept stage, others, like xylitol or lactic acid, are already being produced from lignocellulosic biomass. Furthermore, the constant advances in genome-editing tools, e.g. CRISPR/Cas9, coupled with the application of innovative process concepts such as consolidated bioprocessing, will contribute for the establishment of S. cerevisiae-based biorefineries.
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Affiliation(s)
- Sara L Baptista
- CEB - Centre of Biological Engineering, University of Minho, Campus Gualtar, Braga, Portugal
| | - Carlos E Costa
- CEB - Centre of Biological Engineering, University of Minho, Campus Gualtar, Braga, Portugal
| | - Joana T Cunha
- CEB - Centre of Biological Engineering, University of Minho, Campus Gualtar, Braga, Portugal
| | - Pedro O Soares
- CEB - Centre of Biological Engineering, University of Minho, Campus Gualtar, Braga, Portugal
| | - Lucília Domingues
- CEB - Centre of Biological Engineering, University of Minho, Campus Gualtar, Braga, Portugal.
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16
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Domínguez E, Río PGD, Romaní A, Garrote G, Domingues L. Hemicellulosic Bioethanol Production from Fast-Growing Paulownia Biomass. Processes (Basel) 2021; 9:173. [DOI: 10.3390/pr9010173] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
In order to exploit a fast-growing Paulownia hardwood as an energy crop, a xylose-enriched hydrolysate was obtained in this work to increase the ethanol concentration using the hemicellulosic fraction, besides the already widely studied cellulosic fraction. For that, Paulownia elongata x fortunei was submitted to autohydrolysis treatment (210 °C or S0 of 4.08) for the xylan solubilization, mainly as xylooligosaccharides. Afterwards, sequential stages of acid hydrolysis, concentration, and detoxification were evaluated to obtain fermentable sugars. Thus, detoxified and non-detoxified hydrolysates (diluted or not) were fermented for ethanol production using a natural xylose-consuming yeast, Scheffersomyces stipitis CECT 1922, and an industrial Saccharomyces cerevisiae MEC1133 strain, metabolic engineered strain with the xylose reductase/xylitol dehydrogenase pathway. Results from fermentation assays showed that the engineered S. cerevisiae strain produced up to 14.2 g/L of ethanol (corresponding to 0.33 g/g of ethanol yield) using the non-detoxified hydrolysate. Nevertheless, the yeast S. stipitis reached similar values of ethanol, but only in the detoxified hydrolysate. Hence, the fermentation data prove the suitability and robustness of the engineered strain to ferment non-detoxified liquor, and the appropriateness of detoxification of liquor for the use of less robust yeast. In addition, the success of hemicellulose-to-ethanol production obtained in this work shows the Paulownia biomass as a suitable renewable source for ethanol production following a suitable fractionation process within a biorefinery approach.
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17
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G. del Río P, Gullón P, Rebelo F, Romaní A, Garrote G, Gullón B. A Whole-Slurry Fermentation Approach to High-Solid Loading for Bioethanol Production from Corn Stover. Agronomy 2020; 10:1790. [DOI: 10.3390/agronomy10111790] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Corn stover is the most produced byproduct from maize worldwide. Since it is generated as a residue from maize harvesting, it is an inexpensive and interesting crop residue to be used as a feedstock. An ecologically friendly pretreatment such as autohydrolysis was selected for the manufacture of second-generation bioethanol from corn stover via whole-slurry fermentation at high-solid loadings. Temperatures from 200 to 240 °C were set for the autohydrolysis process, and the solid and liquid phases were analyzed. Additionally, the enzymatic susceptibility of the solid phases was assessed to test the suitability of the pretreatment. Afterward, the production of bioethanol from autohydrolyzed corn stover was carried out, mixing the solid with different percentages of the autohydrolysis liquor (25%, 50%, 75%, and 100%) and water (0% of liquor), from a total whole slurry fermentation (saving energy and water in the liquid–solid separation and subsequent washing of the solid phase) to employing water as only liquid medium. In spite of the challenging scenario of using the liquor fraction as liquid phase in the fermentation, values between 32.2 and 41.9 g ethanol/L and ethanol conversions up to 80% were achieved. This work exhibits the feasibility of corn stover for the production of bioethanol via a whole-slurry fermentation process.
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18
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Mertens JA, Skory CD, Nichols NN, Hector RE. Impact of stress-response related transcription factor overexpression on lignocellulosic inhibitor tolerance of Saccharomyces cerevisiae environmental isolates. Biotechnol Prog 2020; 37:e3094. [PMID: 33085224 DOI: 10.1002/btpr.3094] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 10/02/2020] [Accepted: 10/16/2020] [Indexed: 11/07/2022]
Abstract
Numerous transcription factor genes associated with stress response are upregulated in Saccharomyces cerevisiae grown in the presence of inhibitors that result from pretreatment processes to unlock simple sugars from biomass. To determine if overexpression of transcription factors could improve inhibitor tolerance in robust S. cerevisiae environmental isolates as has been demonstrated in S. cerevisiae haploid laboratory strains, transcription factors were overexpressed at three different expression levels in three S. cerevisiae environmental isolates. Overexpression of the YAP1 transcription factor in these isolates did not lead to increased growth rate or reduced lag in growth, and in some cases was detrimental, when grown in the presence of either lignocellulosic hydrolysates or furfural and 5-hydroxymethyl furfural individually. The expressed Yap1p localized correctly and the expression construct improved inhibitor tolerance of a laboratory strain as previously reported, indicating that lack of improvement in the environmental isolates was due to factors other than nonfunctional expression constructs or mis-folded protein. Additional stress-related transcription factors, MSN2, MSN4, HSF1, PDR1, and RPN4, were also overexpressed at three different expression levels and all failed to improve inhibitor tolerance. Transcription factor overexpression alone is unlikely to be a viable route toward increased inhibitor tolerance of robust environmental S. cerevisiae strains.
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Affiliation(s)
- Jeffrey A Mertens
- Bioenergy Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, U.S. Department of Agriculture, Peoria, Illinois, USA
| | - Christopher D Skory
- Renewable Product Technology Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, U.S. Department of Agriculture, Peoria, Illinois, USA
| | - Nancy N Nichols
- Bioenergy Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, U.S. Department of Agriculture, Peoria, Illinois, USA
| | - Ronald E Hector
- Bioenergy Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, U.S. Department of Agriculture, Peoria, Illinois, USA
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19
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Romaní A, Morais ES, Soares PO, Freire MG, Freire CSR, Silvestre AJD, Domingues L. Aqueous solutions of deep eutectic systems as reaction media for the saccharification and fermentation of hardwood xylan into xylitol. Bioresour Technol 2020; 311:123524. [PMID: 32447229 DOI: 10.1016/j.biortech.2020.123524] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [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: 03/20/2020] [Revised: 05/07/2020] [Accepted: 05/09/2020] [Indexed: 06/11/2023]
Abstract
The aim of this study was to evaluate the effect of aqueous solutions of deep eutectic solvent, Cholinium Chloride:Urea ([Ch]Cl:U) at 50 wt% and 20 wt%, using different molar ratios (1:1, 2:1 and 1:2) on the enzymatic hydrolysis of xylan for xylose production and its subsequent bioconversion into xylitol using a recombinant yeast strain. The lowest xylan conversion into xylose (45%) was obtained using 1:2 [Ch]Cl:U molar ratio. On the other hand, the 1:1 [Ch]Cl:U molar ratio, at 20 wt% in water, improved this conversion, achieving the highest xylose yield (81.4%). The xylitol production was then optimized with [Ch]Cl:U (1:1) at 20 wt% by simultaneous saccharification and fermentation process, attaining 23.67 g/L, corresponding to 66.04% of xylitol yield. This study reveals the possibility of using xylan solubilized in DES aqueous solutions directly for xylitol production, thus assembling a one-step process.
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Affiliation(s)
- Aloia Romaní
- CEB - Centre of Biological Engineering, University of Minho, Campus Gualtar, 4710-057 Braga, Portugal.
| | - Eduarda S Morais
- CICECO-Aveiro Institute of Materials and Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Pedro O Soares
- CEB - Centre of Biological Engineering, University of Minho, Campus Gualtar, 4710-057 Braga, Portugal
| | - Mara G Freire
- CICECO-Aveiro Institute of Materials and Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Carmen S R Freire
- CICECO-Aveiro Institute of Materials and Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Armando J D Silvestre
- CICECO-Aveiro Institute of Materials and Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Lucília Domingues
- CEB - Centre of Biological Engineering, University of Minho, Campus Gualtar, 4710-057 Braga, Portugal
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20
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Cunha JT, Soares PO, Baptista SL, Costa CE, Domingues L. Engineered Saccharomyces cerevisiae for lignocellulosic valorization: a review and perspectives on bioethanol production. Bioengineered 2020; 11:883-903. [PMID: 32799606 PMCID: PMC8291843 DOI: 10.1080/21655979.2020.1801178] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The biorefinery concept, consisting in using renewable biomass with economical and energy goals, appeared in response to the ongoing exhaustion of fossil reserves. Bioethanol is the most prominent biofuel and has been considered one of the top chemicals to be obtained from biomass. Saccharomyces cerevisiae, the preferred microorganism for ethanol production, has been the target of extensive genetic modifications to improve the production of this alcohol from renewable biomasses. Additionally, S. cerevisiae strains from harsh industrial environments have been exploited due to their robust traits and improved fermentative capacity. Nevertheless, there is still not an optimized strain capable of turning second generation bioprocesses economically viable. Considering this, and aiming to facilitate and guide the future development of effective S. cerevisiae strains, this work reviews genetic engineering strategies envisioning improvements in 2nd generation bioethanol production, with special focus in process-related traits, xylose consumption, and consolidated bioprocessing. Altogether, the genetic toolbox described proves S. cerevisiae to be a key microorganism for the establishment of a bioeconomy, not only for the production of lignocellulosic bioethanol, but also having potential as a cell factory platform for overall valorization of renewable biomasses.
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Affiliation(s)
- Joana T Cunha
- CEB - Centre of Biological Engineering, University of Minho, Campus Gualtar , Braga, Portugal
| | - Pedro O Soares
- CEB - Centre of Biological Engineering, University of Minho, Campus Gualtar , Braga, Portugal
| | - Sara L Baptista
- CEB - Centre of Biological Engineering, University of Minho, Campus Gualtar , Braga, Portugal
| | - Carlos E Costa
- CEB - Centre of Biological Engineering, University of Minho, Campus Gualtar , Braga, Portugal
| | - Lucília Domingues
- CEB - Centre of Biological Engineering, University of Minho, Campus Gualtar , Braga, Portugal
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21
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Cunha JT, Romaní A, Inokuma K, Johansson B, Hasunuma T, Kondo A, Domingues L. Consolidated bioprocessing of corn cob-derived hemicellulose: engineered industrial Saccharomyces cerevisiae as efficient whole cell biocatalysts. Biotechnol Biofuels 2020; 13:138. [PMID: 32782474 PMCID: PMC7414751 DOI: 10.1186/s13068-020-01780-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 07/29/2020] [Indexed: 05/24/2023]
Abstract
BACKGROUND Consolidated bioprocessing, which combines saccharolytic and fermentative abilities in a single microorganism, is receiving increased attention to decrease environmental and economic costs in lignocellulosic biorefineries. Nevertheless, the economic viability of lignocellulosic ethanol is also dependent of an efficient utilization of the hemicellulosic fraction, which contains xylose as a major component in concentrations that can reach up to 40% of the total biomass in hardwoods and agricultural residues. This major bottleneck is mainly due to the necessity of chemical/enzymatic treatments to hydrolyze hemicellulose into fermentable sugars and to the fact that xylose is not readily consumed by Saccharomyces cerevisiae-the most used organism for large-scale ethanol production. In this work, industrial S. cerevisiae strains, presenting robust traits such as thermotolerance and improved resistance to inhibitors, were evaluated as hosts for the cell-surface display of hemicellulolytic enzymes and optimized xylose assimilation, aiming at the development of whole-cell biocatalysts for consolidated bioprocessing of corn cob-derived hemicellulose. RESULTS These modifications allowed the direct production of ethanol from non-detoxified hemicellulosic liquor obtained by hydrothermal pretreatment of corn cob, reaching an ethanol titer of 11.1 g/L corresponding to a yield of 0.328 g/g of potential xylose and glucose, without the need for external hydrolytic catalysts. Also, consolidated bioprocessing of pretreated corn cob was found to be more efficient for hemicellulosic ethanol production than simultaneous saccharification and fermentation with addition of commercial hemicellulases. CONCLUSIONS These results show the potential of industrial S. cerevisiae strains for the design of whole-cell biocatalysts and paves the way for the development of more efficient consolidated bioprocesses for lignocellulosic biomass valorization, further decreasing environmental and economic costs.
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Affiliation(s)
- Joana T. Cunha
- CEB–Centre of Biological Engineering, University of Minho, Campus Gualtar, Braga, Portugal
| | - Aloia Romaní
- CEB–Centre of Biological Engineering, University of Minho, Campus Gualtar, Braga, Portugal
| | - Kentaro Inokuma
- Graduate School of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo 657-8501 Japan
| | - Björn Johansson
- Center of Molecular and Environmental Biology (CBMA), University of Minho, Braga, Portugal
| | - Tomohisa Hasunuma
- Graduate School of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo 657-8501 Japan
- Engineering Biology Research Center, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo 657-8501 Japan
| | - Akihiko Kondo
- Graduate School of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo 657-8501 Japan
- Engineering Biology Research Center, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo 657-8501 Japan
| | - Lucília Domingues
- CEB–Centre of Biological Engineering, University of Minho, Campus Gualtar, Braga, Portugal
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Kuang X, Ouyang Y, Guo Y, Li Q, Wang H, Abrha GT, Ayepa E, Gu Y, Li X, Chen Q, Ma M. New insights into two yeast BDHs from the PDH subfamily as aldehyde reductases in context of detoxification of lignocellulosic aldehyde inhibitors. Appl Microbiol Biotechnol 2020; 104:6679-6692. [PMID: 32556414 DOI: 10.1007/s00253-020-10722-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 05/25/2020] [Accepted: 06/04/2020] [Indexed: 12/30/2022]
Abstract
At least 24 aldehyde reductases from Saccharomyces cerevisiae have been characterized and most function in in situ detoxification of lignocellulosic aldehyde inhibitors, but none is classified into the polyol dehydrogenase (PDH) subfamily of the medium-chain dehydrogenase/reductase (MDR) superfamily. This study confirmed that two (2R,3R)-2,3-butanediol dehydrogenases (BDHs) from industrial (denoted Y)/laboratory (denoted B) strains of S. cerevisiae, Bdh1p(Y)/Bdh1p(B) and Bdh2p(Y)/Bdh2p(B), were members of the PDH subfamily with an NAD(P)H binding domain and a catalytic zinc binding domain, and exhibited reductive activities towards lignocellulosic aldehyde inhibitors, such as acetaldehyde, glycolaldehyde, and furfural. Especially, the highest enzyme activity towards acetaldehyde by Bdh2p(Y) was 117.95 U/mg with cofactor nicotinamide adenine dinucleotide reduced (NADH). Based on the comparative kinetic property analysis, Bdh2p(Y)/Bdh2p(B) possessed higher specific activity, substrate affinity, and catalytic efficiency towards glycolaldehyde than Bdh1p(Y)/Bdh1p(B). This was speculated to be related to their 49% sequence differences and five nonsynonymous substitutions (Ser41Thr, Glu173Gln, Ile270Leu, Ile316Met, and Gly317Cys) occurred in their conserved NAD(P)H binding domains. Compared with BDHs from a laboratory strain, Bdh1p(Y) and Bdh2p(Y) from an industrial strain displayed five nonsynonymous mutations (Thr12, Asn61, Glu168, Val222, and Ala235) and three nonsynonymous mutations (Ala34, Ile96, and Ala369), respectively. From a first analysis with selected aldehydes, their reductase activities were different from BDHs of laboratory strain, and their catalytic efficiency was higher towards glycolaldehyde and lower towards acetaldehyde. Comparative investigation of kinetic properties of BDHs from S. cerevisiae as aldehyde reductases provides a guideline for their practical applications in in situ detoxification of aldehyde inhibitors during lignocellulose bioconversion.Key Points• Two yeast BDHs have enzyme activities for reduction of aldehydes.• Overexpression of BDHs slightly improves yeast tolerance to acetaldehyde and glycolaldehyde.• Bdh1p and Bdh2p differ in enzyme kinetic properties.• BDHs from strains with different genetic backgrounds differ in enzyme kinetic properties.
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Affiliation(s)
- Xiaolin Kuang
- Institute of Resources and Geographic Information Technology, College of Resources, Sichuan Agricultural University, No. 211 Huimin Road, Wenjiang, Chengdu, 611130, Sichuan, People's Republic of China
| | - Yidan Ouyang
- Institute of Resources and Geographic Information Technology, College of Resources, Sichuan Agricultural University, No. 211 Huimin Road, Wenjiang, Chengdu, 611130, Sichuan, People's Republic of China
| | - Yaping Guo
- Institute of Resources and Geographic Information Technology, College of Resources, Sichuan Agricultural University, No. 211 Huimin Road, Wenjiang, Chengdu, 611130, Sichuan, People's Republic of China.,Patent Examination Cooperation Sichuan Center of the Patent Office, SIPO, Chengdu, 610213, Sichuan, People's Republic of China
| | - Qian Li
- Institute of Resources and Geographic Information Technology, College of Resources, Sichuan Agricultural University, No. 211 Huimin Road, Wenjiang, Chengdu, 611130, Sichuan, People's Republic of China
| | - Hanyu Wang
- Institute of Resources and Geographic Information Technology, College of Resources, Sichuan Agricultural University, No. 211 Huimin Road, Wenjiang, Chengdu, 611130, Sichuan, People's Republic of China
| | - Getachew Tafere Abrha
- Institute of Resources and Geographic Information Technology, College of Resources, Sichuan Agricultural University, No. 211 Huimin Road, Wenjiang, Chengdu, 611130, Sichuan, People's Republic of China
| | - Ellen Ayepa
- Institute of Resources and Geographic Information Technology, College of Resources, Sichuan Agricultural University, No. 211 Huimin Road, Wenjiang, Chengdu, 611130, Sichuan, People's Republic of China
| | - Yunfu Gu
- Department of Applied Microbiology, College of Resources, Sichuan Agricultural University, Wenjiang, Chengdu, 611130, Sichuan, People's Republic of China
| | - Xi Li
- College of Landscape Architecture, Sichuan Agricultural University, Wenjiang, Chengdu, 611130, Sichuan, People's Republic of China
| | - Qiang Chen
- Department of Applied Microbiology, College of Resources, Sichuan Agricultural University, Wenjiang, Chengdu, 611130, Sichuan, People's Republic of China
| | - Menggen Ma
- Institute of Resources and Geographic Information Technology, College of Resources, Sichuan Agricultural University, No. 211 Huimin Road, Wenjiang, Chengdu, 611130, Sichuan, People's Republic of China. .,Department of Applied Microbiology, College of Resources, Sichuan Agricultural University, Wenjiang, Chengdu, 611130, Sichuan, People's Republic of China.
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Bermejo PM, Raghavendran V, Gombert AK. Neither 1G nor 2G fuel ethanol: setting the ground for a sugarcane-based biorefinery using an iSUCCELL yeast platform. FEMS Yeast Res 2020; 20:5836716. [PMID: 32401320 DOI: 10.1093/femsyr/foaa027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 05/11/2020] [Indexed: 11/12/2022] Open
Abstract
First-generation (1G) fuel ethanol production in sugarcane-based biorefineries is an established economic enterprise in Brazil. Second-generation (2G) fuel ethanol from lignocellulosic materials, though extensively investigated, is currently facing severe difficulties to become economically viable. Some of the challenges inherent to these processes could be resolved by efficiently separating and partially hydrolysing the cellulosic fraction of the lignocellulosic materials into the disaccharide cellobiose. Here, we propose an alternative biorefinery, where the sucrose-rich stream from the 1G process is mixed with a cellobiose-rich stream in the fermentation step. The advantages of mixing are 3-fold: (i) decreased concentrations of metabolic inhibitors that are typically produced during pretreatment and hydrolysis of lignocellulosic materials; (ii) decreased cooling times after enzymatic hydrolysis prior to fermentation; and (iii) decreased availability of free glucose for contaminating microorganisms and undesired glucose repression effects. The iSUCCELL platform will be built upon the robust Saccharomyces cerevisiae strains currently present in 1G biorefineries, which offer competitive advantage in non-aseptic environments, and into which intracellular hydrolyses of sucrose and cellobiose will be engineered. It is expected that high yields of ethanol can be achieved in a process with cell recycling, lower contamination levels and decreased antibiotic use, when compared to current 2G technologies.
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Affiliation(s)
| | - Vijayendran Raghavendran
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK
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Davison SA, den Haan R, van Zyl WH. Exploiting strain diversity and rational engineering strategies to enhance recombinant cellulase secretion by Saccharomyces cerevisiae. Appl Microbiol Biotechnol 2020; 104:5163-84. [PMID: 32337628 DOI: 10.1007/s00253-020-10602-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 03/26/2020] [Accepted: 03/31/2020] [Indexed: 12/14/2022]
Abstract
Consolidated bioprocessing (CBP) of lignocellulosic material into bioethanol has progressed in the past decades; however, several challenges still exist which impede the industrial application of this technology. Identifying the challenges that exist in all unit operations is crucial and needs to be optimised, but only the barriers related to the secretion of recombinant cellulolytic enzymes in Saccharomyces cerevisiae will be addressed in this review. Fundamental principles surrounding CBP as a biomass conversion platform have been established through the successful expression of core cellulolytic enzymes, namely β-glucosidases, endoglucanases, and exoglucanases (cellobiohydrolases) in S. cerevisiae. This review will briefly address the challenges involved in the construction of an efficient cellulolytic yeast, with particular focus on the secretion efficiency of cellulases from this host. Additionally, strategies for studying enhanced cellulolytic enzyme secretion, which include both rational and reverse engineering approaches, will be discussed. One such technique includes bio-engineering within genetically diverse strains, combining the strengths of both natural strain diversity and rational strain development. Furthermore, with the advancement in next-generation sequencing, studies that utilise this method of exploiting intra-strain diversity for industrially relevant traits will be reviewed. Finally, future prospects are discussed for the creation of ideal CBP strains with high enzyme production levels.Key Points• Several challenges are involved in the construction of efficient cellulolytic yeast, in particular, the secretion efficiency of cellulases from the hosts.• Strategies for enhancing cellulolytic enzyme secretion, a core requirement for CBP host microorganism development, include both rational and reverse engineering approaches.• One such technique includes bio-engineering within genetically diverse strains, combining the strengths of both natural strain diversity and rational strain development.
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Pinheiro T, Coelho E, Romaní A, Domingues L. Intensifying ethanol production from brewer’s spent grain waste: Use of whole slurry at high solid loadings. N Biotechnol 2019; 53:1-8. [DOI: 10.1016/j.nbt.2019.06.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 05/28/2019] [Accepted: 06/08/2019] [Indexed: 12/29/2022]
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Azambuja SPH, Teixeira GS, Andrietta MGS, Torres-Mayanga PC, Forster-Carneiro T, Rosa CA, Goldbeck R. Analysis of metabolite profiles of Saccharomyces cerevisiae strains suitable for butanol production. FEMS Microbiol Lett 2019; 366:5539971. [PMID: 31350996 DOI: 10.1093/femsle/fnz164] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Accepted: 07/25/2019] [Indexed: 01/21/2023] Open
Abstract
Butanol has advantages over ethanol as a biofuel. Although butanol is naturally produced by some Clostridium species, clostridial fermentation has inherent characteristics that prevent its industrial application. Butanol-producing Saccharomyces cerevisiae strains may be a solution to this problem. The aim of this study was to evaluate the ability of wild-type and industrial Brazilian strains of S. cerevisiae to produce n-butanol using glycine as co-substrate and evaluate the relationship between the production of this alcohol and other metabolites in fermented broth. Of the 48 strains analyzed, 25 were able to produce n-butanol in a glycine-containing medium. Strains exhibited different profiles of n-butanol, isobutanol, ethanol, glycerol and acetic acid production. Some wild-type strains showed substantial n-butanol production capability, for instance UFMG-CM-Y267, which produced about 12.7 mg/L of butanol. Although this concentration is low, it demonstrates that wild-type S. cerevisiae can synthesize butanol, suggesting that selection and genetic modification of this microorganism could yield promising results. The findings presented here may prove useful for future studies aimed at optimizing S. cerevisiae strains for butanol production.
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Affiliation(s)
- Suéllen P H Azambuja
- Laboratory of Bioprocesses and Metabolic Engineering, Department of Food Engineering, School of Food Engineering, University of Campinas, Campinas, SP, Brazil 13083-862
| | - Gleidson S Teixeira
- Laboratory of Bioprocesses and Metabolic Engineering, Department of Food Engineering, School of Food Engineering, University of Campinas, Campinas, SP, Brazil 13083-862
| | - Maria G S Andrietta
- Chemical, Biological, and Agricultural Pluridisciplinary Research Center (CPQBA), University of Campinas, Campinas, SP, Brazil 13148-218
| | - Paulo C Torres-Mayanga
- Laboratory of Bioengineering and Water and Waste Treatment, Department of Food Engineering, School of Food Engineering, University of Campinas, Campinas, SP, Brazil 13083-862
| | - Tânia Forster-Carneiro
- Laboratory of Bioengineering and Water and Waste Treatment, Department of Food Engineering, School of Food Engineering, University of Campinas, Campinas, SP, Brazil 13083-862
| | - Carlos A Rosa
- Department of Microbiology, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil 31270-901
| | - Rosana Goldbeck
- Laboratory of Bioprocesses and Metabolic Engineering, Department of Food Engineering, School of Food Engineering, University of Campinas, Campinas, SP, Brazil 13083-862
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Pomraning KR, Collett JR, Kim J, Panisko EA, Culley DE, Dai Z, Deng S, Hofstad BA, Butcher MG, Magnuson JK. Transcriptomic analysis of the oleaginous yeast Lipomyces starkeyi during lipid accumulation on enzymatically treated corn stover hydrolysate. Biotechnol Biofuels 2019; 12:162. [PMID: 31289462 PMCID: PMC6593508 DOI: 10.1186/s13068-019-1510-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2019] [Accepted: 06/19/2019] [Indexed: 05/24/2023]
Abstract
BACKGROUND Efficient and economically viable production of biofuels from lignocellulosic biomass is dependent on mechanical and chemical pretreatment and enzymatic hydrolysis of plant material. These processing steps yield simple sugars as well as plant-derived and process-added organic acids, sugar-derived dehydration products, aldehydes, phenolics and other compounds that inhibit the growth of many microorganisms. Lipomyces starkeyi is an oleaginous yeast capable of robust growth on a variety of sugars and lipid accumulation on pretreated lignocellulosic substrates making it attractive as an industrial producer of biofuels. Here, we examined gene expression during batch growth and lipid accumulation in a 20-L bioreactor with either a blend of pure glucose and xylose or pretreated corn stover (PCS) that had been enzymatically hydrolyzed as the carbon sources. RESULTS We monitored sugar and ammonium utilization as well as biomass accumulation and found that growth of L. starkeyi is inhibited with PCS hydrolysate as the carbon source. Both acetic acid and furfural are present at concentrations toxic to L. starkeyi in PCS hydrolysate. We quantified gene expression at seven time-points for each carbon source during batch growth and found that gene expression is similar at physiologically equivalent points. Analysis of promoter regions revealed that gene expression during the transition to lipid accumulation is regulated by carbon and nitrogen catabolite repression, regardless of carbon source and is associated with decreased expression of the translation machinery and suppression of the cell cycle. We identified 73 differentially expressed genes during growth phase in the bioreactor that may be involved in detoxification of corn stover hydrolysate. CONCLUSIONS Growth of L. starkeyi is inhibited by compounds present in PCS hydrolysate. Here, we monitored key metabolites to establish physiologically equivalent comparisons during a batch bioreactor run comparing PCS hydrolysate and purified sugars. L. starkeyi's response to PCS hydrolysate is primarily at the beginning of the run during growth phase when inhibitory compounds are presumably at their highest concentration and inducing the general detoxification response by L. starkeyi. Differentially expressed genes identified herein during growth phase will aid in the improvement of industrial strains capable of robust growth on substrates containing various growth inhibitory compounds.
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Affiliation(s)
| | | | - Joonhoon Kim
- Pacific Northwest National Laboratory, Richland, WA USA
- Joint BioEnergy Institute, Emeryville, CA USA
| | | | | | - Ziyu Dai
- Pacific Northwest National Laboratory, Richland, WA USA
| | - Shuang Deng
- Pacific Northwest National Laboratory, Richland, WA USA
| | | | | | - Jon K. Magnuson
- Pacific Northwest National Laboratory, Richland, WA USA
- Joint BioEnergy Institute, Emeryville, CA USA
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Favaro L, Jansen T, van Zyl WH. Exploring industrial and naturalSaccharomyces cerevisiaestrains for the bio-based economy from biomass: the case of bioethanol. Crit Rev Biotechnol 2019; 39:800-816. [DOI: 10.1080/07388551.2019.1619157] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Lorenzo Favaro
- Department of Agronomy Food Natural resources Animals and Environment (DAFNAE), University of Padova, Legnaro, Italy
| | - Trudy Jansen
- Department of Microbiology, Stellenbosch University, Stellenbosch, South Africa
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Pandey AK, Kumar M, Kumari S, Kumari P, Yusuf F, Jakeer S, Naz S, Chandna P, Bhatnagar I, Gaur NA. Evaluation of divergent yeast genera for fermentation-associated stresses and identification of a robust sugarcane distillery waste isolate Saccharomyces cerevisiae NGY10 for lignocellulosic ethanol production in SHF and SSF. Biotechnol Biofuels 2019; 12:40. [PMID: 30858877 PMCID: PMC6391804 DOI: 10.1186/s13068-019-1379-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [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: 10/01/2018] [Accepted: 02/15/2019] [Indexed: 06/09/2023]
Abstract
BACKGROUND Lignocellulosic hydrolysates contain a mixture of hexose (C6)/pentose (C5) sugars and pretreatment-generated inhibitors (furans, weak acids and phenolics). Therefore, robust yeast isolates with characteristics of C6/C5 fermentation and tolerance to pretreatment-derived inhibitors are pre-requisite for efficient lignocellulosic material based biorefineries. Moreover, use of thermotolerant yeast isolates will further reduce cooling cost, contamination during fermentation, and required for developing simultaneous saccharification and fermentation (SSF), simultaneous saccharification and co-fermentation (SScF), and consolidated bio-processing (CBP) strategies. RESULTS In this study, we evaluated thirty-five yeast isolates (belonging to six genera including Saccharomyces, Kluyveromyces, Candida, Scheffersomyces, Ogatea and Wickerhamomyces) for pretreatment-generated inhibitors {furfural, 5-hydroxymethyl furfural (5-HMF) and acetic acid} and thermotolerant phenotypes along with the fermentation performances at 40 °C. Among them, a sugarcane distillery waste isolate, Saccharomyces cerevisiae NGY10 produced maximum 49.77 ± 0.34 g/l and 46.81 ± 21.98 g/l ethanol with the efficiency of 97.39% and 93.54% at 30 °C and 40 °C, respectively, in 24 h using glucose as a carbon source. Furthermore, isolate NGY10 produced 12.25 ± 0.09 g/l and 7.18 ± 0.14 g/l of ethanol with 92.81% and 91.58% efficiency via SHF, and 30.22 g/l and 25.77 g/l ethanol with 86.43% and 73.29% efficiency via SSF using acid- and alkali-pretreated rice straw as carbon sources, respectively, at 40 °C. In addition, isolate NGY10 also produced 92.31 ± 3.39 g/l (11.7% v/v) and 33.66 ± 1.04 g/l (4.26% v/v) ethanol at 40 °C with the yields of 81.49% and 73.87% in the presence of 30% w/v glucose or 4× concentrated acid-pretreated rice straw hydrolysate, respectively. Moreover, isolate NGY10 displayed furfural- (1.5 g/l), 5-HMF (3.0 g/l), acetic acid- (0.2% v/v) and ethanol-(10.0% v/v) tolerant phenotypes. CONCLUSION A sugarcane distillery waste isolate NGY10 demonstrated high potential for ethanol production, C5 metabolic engineering and developing strategies for SSF, SScF and CBP.
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Affiliation(s)
- Ajay Kumar Pandey
- Yeast Biofuel Group, DBT-ICGEB Center for Advanced Bioenergy Research, International Center for Genetic Engineering and Biotechnology (ICGEB), New Delhi, 110067 India
| | - Mohit Kumar
- Yeast Biofuel Group, DBT-ICGEB Center for Advanced Bioenergy Research, International Center for Genetic Engineering and Biotechnology (ICGEB), New Delhi, 110067 India
| | - Sonam Kumari
- Yeast Biofuel Group, DBT-ICGEB Center for Advanced Bioenergy Research, International Center for Genetic Engineering and Biotechnology (ICGEB), New Delhi, 110067 India
| | - Priya Kumari
- Yeast Biofuel Group, DBT-ICGEB Center for Advanced Bioenergy Research, International Center for Genetic Engineering and Biotechnology (ICGEB), New Delhi, 110067 India
| | - Farnaz Yusuf
- Yeast Biofuel Group, DBT-ICGEB Center for Advanced Bioenergy Research, International Center for Genetic Engineering and Biotechnology (ICGEB), New Delhi, 110067 India
| | - Shaik Jakeer
- Yeast Biofuel Group, DBT-ICGEB Center for Advanced Bioenergy Research, International Center for Genetic Engineering and Biotechnology (ICGEB), New Delhi, 110067 India
| | - Sumera Naz
- Yeast Biofuel Group, DBT-ICGEB Center for Advanced Bioenergy Research, International Center for Genetic Engineering and Biotechnology (ICGEB), New Delhi, 110067 India
| | - Piyush Chandna
- Yeast Biofuel Group, DBT-ICGEB Center for Advanced Bioenergy Research, International Center for Genetic Engineering and Biotechnology (ICGEB), New Delhi, 110067 India
| | - Ishita Bhatnagar
- Yeast Biofuel Group, DBT-ICGEB Center for Advanced Bioenergy Research, International Center for Genetic Engineering and Biotechnology (ICGEB), New Delhi, 110067 India
| | - Naseem A. Gaur
- Yeast Biofuel Group, DBT-ICGEB Center for Advanced Bioenergy Research, International Center for Genetic Engineering and Biotechnology (ICGEB), New Delhi, 110067 India
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Cagnin L, Favaro L, Gronchi N, Rose SH, Basaglia M, van Zyl WH, Casella S. Comparing laboratory and industrial yeast platforms for the direct conversion of cellobiose into ethanol under simulated industrial conditions. FEMS Yeast Res 2019; 19:5333308. [DOI: 10.1093/femsyr/foz018] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2018] [Accepted: 02/15/2019] [Indexed: 11/13/2022] Open
Affiliation(s)
- Lorenzo Cagnin
- Department of Agronomy Food Natural resources Animals and Enviroment (DAFNAE), University of Padova, Agripolis, Viale dell'Università 16, 35020 Legnaro (PD), Italy
| | - Lorenzo Favaro
- Department of Agronomy Food Natural resources Animals and Enviroment (DAFNAE), University of Padova, Agripolis, Viale dell'Università 16, 35020 Legnaro (PD), Italy
| | - Nicoletta Gronchi
- Department of Agronomy Food Natural resources Animals and Enviroment (DAFNAE), University of Padova, Agripolis, Viale dell'Università 16, 35020 Legnaro (PD), Italy
| | - Shaunita Hellouise Rose
- Department of Microbiology, Stellenbosch University, Private Bag X1, Matieland, 7602, Stellenbosch, South Africa
| | - Marina Basaglia
- Department of Agronomy Food Natural resources Animals and Enviroment (DAFNAE), University of Padova, Agripolis, Viale dell'Università 16, 35020 Legnaro (PD), Italy
| | - Willem Heber van Zyl
- Department of Microbiology, Stellenbosch University, Private Bag X1, Matieland, 7602, Stellenbosch, South Africa
| | - Sergio Casella
- Department of Agronomy Food Natural resources Animals and Enviroment (DAFNAE), University of Padova, Agripolis, Viale dell'Università 16, 35020 Legnaro (PD), Italy
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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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Cunha JT, Soares PO, Romaní A, Thevelein JM, Domingues L. Xylose fermentation efficiency of industrial Saccharomyces cerevisiae yeast with separate or combined xylose reductase/xylitol dehydrogenase and xylose isomerase pathways. Biotechnol Biofuels 2019; 12:20. [PMID: 30705706 PMCID: PMC6348659 DOI: 10.1186/s13068-019-1360-8] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 01/18/2019] [Indexed: 05/12/2023]
Abstract
BACKGROUND Xylose isomerase (XI) and xylose reductase/xylitol dehydrogenase (XR/XDH) pathways have been extensively used to confer xylose assimilation capacity to Saccharomyces cerevisiae and tackle one of the major bottlenecks in the attainment of economically viable lignocellulosic ethanol production. Nevertheless, there is a lack of studies comparing the efficiency of those pathways both separately and combined. In this work, the XI and/or XR/XDH pathways were introduced into two robust industrial S. cerevisiae strains, evaluated in synthetic media and corn cob hemicellulosic hydrolysate and the results were correlated with the differential enzyme activities found in the xylose-pathway engineered strains. RESULTS The sole expression of XI was found to increase the fermentative capacity of both strains in synthetic media at 30 °C and 40 °C: decreasing xylitol accumulation and improving xylose consumption and ethanol production. Similar results were observed in fermentations of detoxified hydrolysate. However, in the presence of lignocellulosic-derived inhibitors, a positive synergistic effect resulted from the expression of both XI and XR/XDH, possibly caused by a cofactor equilibrium between the XDH and furan detoxifying enzymes, increasing the ethanol yield by more than 38%. CONCLUSIONS This study clearly shows an advantage of using the XI from Clostridium phytofermentans to attain high ethanol productivities and yields from xylose. Furthermore, and for the first time, the simultaneous utilization of XR/XDH and XI pathways was compared to the single expression of XR/XDH or XI and was found to improve ethanol production from non-detoxified hemicellulosic hydrolysates. These results extend the knowledge regarding S. cerevisiae xylose assimilation metabolism and pave the way for the construction of more efficient strains for use in lignocellulosic industrial processes.
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Affiliation(s)
- Joana T. Cunha
- CEB-Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal
| | - Pedro O. Soares
- CEB-Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal
| | - Aloia Romaní
- CEB-Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal
| | - Johan M. Thevelein
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, Department of Biology, KU Leuven, Kasteelpark Arenberg 31, 3001 Leuven-Heverlee, Flanders Belgium
- Center for Microbiology, VIB, Kasteelpark Arenberg 31, 3001 Leuven-Heverlee, Flanders Belgium
| | - Lucília Domingues
- CEB-Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal
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Silva PC, Domingues L, Collins T, Oliveira R, Johansson B. Quantitative assessment of DNA damage in the industrial ethanol production strain Saccharomyces cerevisiae PE-2. FEMS Yeast Res 2018; 18:5097783. [PMID: 30219865 DOI: 10.1093/femsyr/foy101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 09/12/2018] [Indexed: 11/14/2022] Open
Abstract
Lignocellulosic hydrolysates remain one of the most abundantly used substrates for the sustainable production of second generation fuels and chemicals with Saccharomyces cerevisiae. Nevertheless, fermentation inhibitors such as acetic acid, furfural and hydroxymethylfurfural are formed during the process and can lead to slow or stuck fermentations and/or act as genotoxic agents leading to production strain genetic instability. We have developed a novel dominant deletion (DEL) cassette assay for quantification of DNA damage in both wild-type and industrial yeast strains. Using this assay, the ethanol production strain S. cerevisiae PE-2 was shown to be more resistant to hydrogen peroxide and furfural than the laboratory DEL strain RS112. Indeed, the PE-2 strain also showed a lower tendency for recombination, consistent with a more efficient DNA protection. The dominant DEL assay presented herein should prove to be a useful tool in the selection of robust yeast strains and process conditions for second generation feedstock fermentations.
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Affiliation(s)
| | - Lucília Domingues
- CEB-Centre of Biological Engineering, University of Minho, Campus de Gualtar, Braga 4710-057, Portugal
| | - Tony Collins
- CBMA - Center of Molecular and Environmental Biology
| | - Rui Oliveira
- CEB-Centre of Biological Engineering, University of Minho, Campus de Gualtar, Braga 4710-057, Portugal.,Centre for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), Department of Biology, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
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Romero Cortes T, Cuervo-Parra JA, José Robles-Olvera V, Rangel Cortes E, López Pérez PA. Experimental and Kinetic Production of Ethanol Using Mucilage Juice Residues from Cocoa Processing. International Journal of Chemical Reactor Engineering 2018. [DOI: 10.1515/ijcre-2017-0262] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractEthanol was produced using mucilage juice residues from processed cocoa with Pichia kudriavzevii in batch fermentation. Experimental results showed that maximum ethanol concentration was 13.8 g/L, ethanol yield was 0.50 g-ethanol/g glucose with a productivity of 0.25 g/L h. Likewise, a novel phenomenological model based on the mechanism of multiple parallel coupled reactions was used to describe the kinetics of substrate, enzyme, biomass and product formation. Model parameters were optimized by applying the Levenberg-Marquardt approach. Analysis of results was based on statistical metrics (such as confidence interval), sensitivity and by comparing calculated curves with the experimental data (residual plots). The efficacy of the proposed mathematical model was statistically evaluated using the dimensionless coefficient for efficiency. Results indicated that the proposed model can be applied as a way of augmenting bioethanol production from laboratory scale up to semi-pilot scale.
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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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Baptista SL, Cunha JT, Romaní A, Domingues L. Xylitol production from lignocellulosic whole slurry corn cob by engineered industrial Saccharomyces cerevisiae PE-2. Bioresour Technol 2018; 267:481-491. [PMID: 30041142 DOI: 10.1016/j.biortech.2018.07.068] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [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: 05/25/2018] [Revised: 07/12/2018] [Accepted: 07/13/2018] [Indexed: 06/08/2023]
Abstract
In this work, the industrial Saccharomyces cerevisiae PE-2 strain, presenting innate capacity for xylitol accumulation, was engineered for xylitol production by overexpression of the endogenous GRE3 gene and expression of different xylose reductases from Pichia stipitis. The best-performing GRE3-overexpressing strain was capable to produce 148.5 g/L of xylitol from high xylose-containing media, with a 0.95 g/g yield, and maintained close to maximum theoretical yields (0.89 g/g) when tested in non-detoxified corn cob hydrolysates. Furthermore, a successful integrated strategy was developed for the production of xylitol from whole slurry corn cob in a presaccharification and simultaneous saccharification and fermentation process (15% solid loading and 36 FPU) reaching xylitol yield of 0.93 g/g and a productivity of 0.54 g/L·h. This novel approach results in an intensified valorization of lignocellulosic biomass for xylitol production in a fully integrated process and represents an advance towards a circular economy.
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Affiliation(s)
- Sara L Baptista
- CEB - Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal
| | - Joana T Cunha
- CEB - Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal
| | - Aloia Romaní
- CEB - Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal
| | - Lucília Domingues
- CEB - Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal.
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Mertens JA, Kelly A, Hector RE. Screening for inhibitor tolerant Saccharomyces cerevisiae strains from diverse environments for use as platform strains for production of fuels and chemicals from biomass. ACTA ACUST UNITED AC 2018. [DOI: 10.1016/j.biteb.2018.07.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Aguilar DL, Rodríguez-Jasso RM, Zanuso E, de Rodríguez DJ, Amaya-Delgado L, Sanchez A, Ruiz HA. Scale-up and evaluation of hydrothermal pretreatment in isothermal and non-isothermal regimen for bioethanol production using agave bagasse. Bioresour Technol 2018; 263:112-119. [PMID: 29734065 DOI: 10.1016/j.biortech.2018.04.100] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [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: 03/08/2018] [Revised: 04/24/2018] [Accepted: 04/25/2018] [Indexed: 06/08/2023]
Abstract
The production of tequila in Mexico generates a large amount of agave bagasse per year. However, this biomass can be considered as a potential source for biofuel production. In this study, it is described how the hydrothermal pretreatment was scaled in a bench scale, considering the severity index as a strategy. The best condition was at 180 °C in isothermal regime for 20 min with 65.87% of cellulose content and high concentration of xylooligosaccharides (15.31 g/L). This condition was scaled up (using severity factor: [logR0] = 4.11), in order to obtain a rich pretreated solid in cellulose to perform the enzymatic hydrolysis, obtaining saccharification yields of 98.5 and 99.5% at high-solids loading (10 and 15%, respectively). The pre-saccharification and fermentation strategy was used in the bioethanol production at 10 and 15% of total pretreated solids, obtaining 38.39 and 55.02 g/L of ethanol concentration, corresponding to 90.84% and 87.56% of ethanol yield, respectively.
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Affiliation(s)
- Daniela L Aguilar
- Biorefinery Group, Food Research Department, Faculty of Chemistry Sciences, Autonomous University of Coahuila, Saltillo, Coahuila 25280, Mexico; Cluster of Bioalcohols, Mexican Centre for Innovation in Bioenergy (Cemie-Bio), Mexico
| | - Rosa M Rodríguez-Jasso
- Biorefinery Group, Food Research Department, Faculty of Chemistry Sciences, Autonomous University of Coahuila, Saltillo, Coahuila 25280, Mexico; Cluster of Bioalcohols, Mexican Centre for Innovation in Bioenergy (Cemie-Bio), Mexico
| | - Elisa Zanuso
- Biorefinery Group, Food Research Department, Faculty of Chemistry Sciences, Autonomous University of Coahuila, Saltillo, Coahuila 25280, Mexico; Cluster of Bioalcohols, Mexican Centre for Innovation in Bioenergy (Cemie-Bio), Mexico
| | - Diana Jasso de Rodríguez
- Universidad Autónoma Agraria Antonio Narro, 1923 Antonio Narro St., Buenavista, Saltillo, Coahuila 25315, Mexico
| | - Lorena Amaya-Delgado
- Cluster of Bioalcohols, Mexican Centre for Innovation in Bioenergy (Cemie-Bio), Mexico; Unidad de Biotecnología Industrial, Centro de Investigación y Asistencia en Tecnología y Diseño del Estado de Jalisco A.C., Zapopan, Jalisco, Mexico
| | - Arturo Sanchez
- Cluster of Bioalcohols, Mexican Centre for Innovation in Bioenergy (Cemie-Bio), Mexico; Laboratorio de Futuros en Bioenergía, Unidad Guadalajara de Ingeniería Avanzada, Centro de Investigación y Estudios Avanzados (CINVESTAV), Zapopan, Jalisco, Mexico
| | - Héctor A Ruiz
- Biorefinery Group, Food Research Department, Faculty of Chemistry Sciences, Autonomous University of Coahuila, Saltillo, Coahuila 25280, Mexico; Cluster of Bioalcohols, Mexican Centre for Innovation in Bioenergy (Cemie-Bio), Mexico.
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Liu ZL. Understanding the tolerance of the industrial yeast Saccharomyces cerevisiae against a major class of toxic aldehyde compounds. Appl Microbiol Biotechnol 2018; 102:5369-5390. [PMID: 29725719 DOI: 10.1007/s00253-018-8993-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 04/03/2018] [Accepted: 04/05/2018] [Indexed: 12/27/2022]
Abstract
Development of the next-generation biocatalyst is vital for fermentation-based industrial applications and a sustainable bio-based economy. Overcoming the major class of toxic compounds associated with lignocellulose-to-biofuels conversion is one of the significant challenges for new strain development. A significant number of investigations have been made to understand mechanisms of the tolerance for industrial yeast. It is humbling to learn how complicated the cell's response to the toxic chemicals is and how little we have known about yeast tolerance in the universe of the living cell. This study updates our current knowledge on the tolerance of industrial yeast against aldehyde inhibitory compounds at cellular, molecular and the genomic levels. It is comprehensive yet specific based on reproducible evidence and cross confirmed findings from different investigations using varied experimental approaches. This research approaches a rational foundation toward a more comprehensive understanding on the yeast tolerance. Discussions and perspectives are also proposed for continued exploring the puzzle of the yeast tolerance to aid the next-generation biocatalyst development.
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Affiliation(s)
- ZongLin Lewis Liu
- The US Department of Agriculture, Agricultural Research Service, National Center for Agricultural Utilization Research, Bioenergy Research Unit, 1815 N University Street, Peoria, IL, 61604, USA.
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40
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Cunha JT, Costa CE, Ferraz L, Romaní A, Johansson B, Sá-Correia I, Domingues L. HAA1 and PRS3 overexpression boosts yeast tolerance towards acetic acid improving xylose or glucose consumption: unravelling the underlying mechanisms. Appl Microbiol Biotechnol 2018; 102:4589-4600. [PMID: 29607452 DOI: 10.1007/s00253-018-8955-z] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 03/12/2018] [Accepted: 03/18/2018] [Indexed: 11/28/2022]
Abstract
Acetic acid tolerance and xylose consumption are desirable traits for yeast strains used in industrial biotechnological processes. In this work, overexpression of a weak acid stress transcriptional activator encoded by the gene HAA1 and a phosphoribosyl pyrophosphate synthetase encoded by PRS3 in a recombinant industrial Saccharomyces cerevisiae strain containing a xylose metabolic pathway was evaluated in the presence of acetic acid in xylose- or glucose-containing media. HAA1 or PRS3 overexpression resulted in superior yeast growth and higher sugar consumption capacities in the presence of 4 g/L acetic acid, and a positive synergistic effect resulted from the simultaneous overexpression of both genes. Overexpressing these genes also improved yeast adaptation to a non-detoxified hardwood hydrolysate with a high acetic acid content. Furthermore, the overexpression of HAA1 and/or PRS3 was found to increase the robustness of yeast cell wall when challenged with acetic acid stress, suggesting the involvement of the modulation of the cell wall integrity pathway. This study clearly shows HAA1 and/or, for the first time, PRS3 overexpression to play an important role in the improvement of industrial yeast tolerance towards acetic acid. The results expand the molecular toolbox and add to the current understanding of the mechanisms involved in higher acetic acid tolerance, paving the way for the further development of more efficient industrial processes.
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Affiliation(s)
- Joana T Cunha
- Centre of Biological Engineering (CEB), University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - Carlos E Costa
- Centre of Biological Engineering (CEB), University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - Luís Ferraz
- Centre of Biological Engineering (CEB), University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - Aloia Romaní
- Centre of Biological Engineering (CEB), University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - Björn Johansson
- Center of Molecular and Environmental Biology (CBMA), University of Minho, Campus de Gualtar, 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, Campus de Gualtar, 4710-057, Braga, Portugal.
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Cunha M, Romaní A, Carvalho M, Domingues L. Boosting bioethanol production from Eucalyptus wood by whey incorporation. Bioresour Technol 2018; 250:256-264. [PMID: 29174903 DOI: 10.1016/j.biortech.2017.11.023] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [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: 09/29/2017] [Revised: 11/07/2017] [Accepted: 11/08/2017] [Indexed: 06/07/2023]
Abstract
The mixture of Eucalyptus globulus wood (EGW) and cheese whey powder (CWP) was proposed for intensification of simultaneous saccharification and fermentation (SSF) at high temperature and solid loadings using the industrial Saccharomyces cerevisiae Ethanol Red® strain. High ethanol concentration (93 g/L), corresponding to 94% ethanol yield, was obtained at 35 °C from 37% of solid mixture using cellulase and β-galactosidase enzymes (24.2 FPU/g and 20.0 U/g, respectively). The use of CWP mixed with pretreated EGW increased the ethanol concentration in 1.5-fold, in comparison with SSF experiments without CWP for both Ethanol Red® and CEN.PK113-7D strains. Moreover, 1.4-fold higher ethanol concentration was obtained with Ethanol Red®, in comparison with CEN.PK113-7D strain. Ethanol Red® strain was genetically engineered for β-galactosidase production in order to advance towards a fully integrated process. This work shows the feasibility of attaining high ethanol concentrations in second generation bioprocesses by a multi-waste valorization approach.
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Affiliation(s)
- Manuel Cunha
- CEB - Centre of Biological Engineering, University of Minho, Campus Gualtar, 4710-057 Braga, Portugal
| | - Aloia Romaní
- CEB - Centre of Biological Engineering, University of Minho, Campus Gualtar, 4710-057 Braga, Portugal
| | - Margarida Carvalho
- 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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42
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Rodriguez A, Strucko T, Stahlhut SG, Kristensen M, Svenssen DK, Forster J, Nielsen J, Borodina I. Metabolic engineering of yeast for fermentative production of flavonoids. Bioresour Technol 2017. [PMID: 28634125 DOI: 10.1016/j.biortech.2017.06.043] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Yeast Saccharomyces cerevisiae was engineered for de novo production of six different flavonoids (naringenin, liquiritigenin, kaempferol, resokaempferol, quercetin, and fisetin) directly from glucose, without supplementation of expensive intermediates. This required reconstruction of long biosynthetic pathways, comprising up to eight heterologous genes from plants. The obtained titers of kaempferol 26.57±2.66mgL-1 and quercetin 20.38±2.57mgL-1 exceed the previously reported titers in yeast. This is also the first report of de novo biosynthesis of resokaempferol and fisetin in yeast. The work demonstrates the potential of flavonoid-producing yeast cell factories.
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Affiliation(s)
- Angelica Rodriguez
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet 220, 2800 Kgs Lyngby, Denmark
| | - Tomas Strucko
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet 220, 2800 Kgs Lyngby, Denmark
| | - Steen Gustav Stahlhut
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet 220, 2800 Kgs Lyngby, Denmark
| | - Mette Kristensen
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet 220, 2800 Kgs Lyngby, Denmark
| | - Daniel Killerup Svenssen
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet 220, 2800 Kgs Lyngby, Denmark
| | - Jochen Forster
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet 220, 2800 Kgs Lyngby, Denmark
| | - Jens Nielsen
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet 220, 2800 Kgs Lyngby, Denmark; Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivägen 10, SE412 96 Gothenburg, Sweden
| | - Irina Borodina
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet 220, 2800 Kgs Lyngby, Denmark.
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Lopes DD, Rosa CA, Hector RE, Dien BS, Mertens JA, Ayub MAZ. Influence of genetic background of engineered xylose-fermenting industrial Saccharomyces cerevisiae strains for ethanol production from lignocellulosic hydrolysates. J Ind Microbiol Biotechnol 2017; 44:1575-88. [PMID: 28891041 DOI: 10.1007/s10295-017-1979-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Accepted: 09/05/2017] [Indexed: 10/18/2022]
Abstract
An industrial ethanol-producing Saccharomyces cerevisiae strain with genes of fungal oxido-reductive pathway needed for xylose fermentation integrated into its genome (YRH1415) was used to obtain haploids and diploid isogenic strains. The isogenic strains were more effective in metabolizing xylose than YRH1415 strain and able to co-ferment glucose and xylose in the presence of high concentrations of inhibitors resulting from the hydrolysis of lignocellulosic biomass (switchgrass). The rate of xylose consumption did not appear to be affected by the ploidy of strains or the presence of two copies of the xylose fermentation genes but by heterozygosity of alleles for xylose metabolism in YRH1415. Furthermore, inhibitor tolerance was influenced by the heterozygous genome of the industrial strain, which also showed a marked influenced on tolerance to increasing concentrations of toxic compounds, such as furfural. In this work, selection of haploid derivatives was found to be a useful strategy to develop efficient xylose-fermenting industrial yeast strains.
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Yu H, Guo J, Chen Y, Fu G, Li B, Guo X, Xiao D. Efficient utilization of hemicellulose and cellulose in alkali liquor-pretreated corncob for bioethanol production at high solid loading by Spathaspora passalidarum U1-58. Bioresour Technol 2017; 232:168-175. [PMID: 28231534 DOI: 10.1016/j.biortech.2017.01.077] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [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: 11/05/2016] [Revised: 01/20/2017] [Accepted: 01/21/2017] [Indexed: 06/06/2023]
Abstract
The bioethanol fermentation of pretreated corncob was investigated using Spathaspora passalidarum U1-58, which simultaneously utilizes glucose and xylose for high-efficiency ethanol production. Two approaches, namely, separate hydrolysis and co-fermentation (SHCF) and simultaneous saccharification and co-fermentation (SSCF), were optimized to test the ethanol fermentation potential of U1-58. The highest ethanol titer of 42.46g/L and yield of 72.12% were acquired in SHCF, whereas 53.24g/L ethanol and yield of 75.35% were obtained in SSCF at solid-to-liquid ratio of 1:5 (w/v). Approximately 86.20% of cellulose and 82.99% of hemicellulose were consumed in SSCF after 96h, and at least 10.49g/L ethanol was produced from hemicellulose, which corresponded to 37.59% of the theoretical yield. Compared with the published cellulosic ethanol fermentation cases, the present work presented high ethanol titer and yield, and cellulose and hemicellulose could be efficiently utilized for ethanol production.
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Affiliation(s)
- Hai Yu
- School of Food Science and Engineering, Yangzhou University, Yangzhou 225127, PR China
| | - Jian Guo
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Industrial Microbiology Key Laboratory, College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, PR China
| | - Yefu Chen
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Industrial Microbiology Key Laboratory, College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, PR China.
| | - Gengxin Fu
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Industrial Microbiology Key Laboratory, College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, PR China
| | - Baozhong Li
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Industrial Microbiology Key Laboratory, College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, PR China
| | - Xuewu Guo
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Industrial Microbiology Key Laboratory, College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, PR China
| | - Dongguang Xiao
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Industrial Microbiology Key Laboratory, College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, PR China
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Costa CE, Romaní A, Cunha JT, Johansson B, Domingues L. Integrated approach for selecting efficient Saccharomyces cerevisiae for industrial lignocellulosic fermentations: Importance of yeast chassis linked to process conditions. Bioresour Technol 2017; 227:24-34. [PMID: 28013133 DOI: 10.1016/j.biortech.2016.12.016] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2016] [Revised: 12/02/2016] [Accepted: 12/04/2016] [Indexed: 05/22/2023]
Abstract
In this work, four robust yeast chassis isolated from industrial environments were engineered with the same xylose metabolic pathway. The recombinant strains were physiologically characterized in synthetic xylose and xylose-glucose medium, on non-detoxified hemicellulosic hydrolysates of fast-growing hardwoods (Eucalyptus and Paulownia) and agricultural residues (corn cob and wheat straw) and on Eucalyptus hydrolysate at different temperatures. Results show that the co-consumption of xylose-glucose was dependent on the yeast background. Moreover, heterogeneous results were obtained among different hydrolysates and temperatures for each individual strain pointing to the importance of designing from the very beginning a tailor-made yeast considering the specific raw material and process.
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Affiliation(s)
- Carlos E Costa
- CEB - Centre of Biological Engineering, University of Minho, Campus de Gualtar, Braga 4710-057, Portugal
| | - Aloia Romaní
- CEB - Centre of Biological Engineering, University of Minho, Campus de Gualtar, Braga 4710-057, Portugal
| | - Joana T Cunha
- CEB - Centre of Biological Engineering, University of Minho, Campus de Gualtar, Braga 4710-057, Portugal
| | - Björn Johansson
- CBMA - Center of Molecular and Environmental Biology, University of Minho, Campus de Gualtar, Braga 4710-057, Portugal
| | - Lucília Domingues
- CEB - Centre of Biological Engineering, University of Minho, Campus de Gualtar, Braga 4710-057, Portugal.
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46
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Øverland M, Skrede A. Yeast derived from lignocellulosic biomass as a sustainable feed resource for use in aquaculture. J Sci Food Agric 2017; 97:733-742. [PMID: 27558451 DOI: 10.1002/jsfa.8007] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [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: 06/21/2016] [Revised: 08/19/2016] [Accepted: 08/22/2016] [Indexed: 06/06/2023]
Abstract
The global expansion in aquaculture production implies an emerging need of suitable and sustainable protein sources. Currently, the fish feed industry is dependent on high-quality protein sources of marine and plant origin. Yeast derived from processing of low-value and non-food lignocellulosic biomass is a potential sustainable source of protein in fish diets. Following enzymatic hydrolysis, the hexose and pentose sugars of lignocellulosic substrates and supplementary nutrients can be converted into protein-rich yeast biomass by fermentation. Studies have shown that yeasts such as Saccharomyces cerevisiae, Candida utilis and Kluyveromyces marxianus have favourable amino acid composition and excellent properties as protein sources in diets for fish, including carnivorous species such as Atlantic salmon and rainbow trout. Suitable downstream processing of the biomass to disrupt cell walls is required to secure high nutrient digestibility. A number of studies have shown various immunological and health benefits from feeding fish low levels of yeast and yeast-derived cell wall fractions. This review summarises current literature on the potential of yeast from lignocellulosic biomass as an alternative protein source for the aquaculture industry. It is concluded that further research and development within yeast production can be important to secure the future sustainability and economic viability of intensive aquaculture. © 2016 Society of Chemical Industry.
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Affiliation(s)
- Margareth Øverland
- Department of Animal and Aquacultural Sciences, Norwegian University of Life Sciences, P.O. Box 5003, N-1432, Ås, Norway
| | - Anders Skrede
- Department of Animal and Aquacultural Sciences, Norwegian University of Life Sciences, P.O. Box 5003, N-1432, Ås, Norway
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Abstract
The development prospects of the world markets for petroleum and other liquid fuels are diverse and partly contradictory. However, comprehensive changes for the energy supply of the future are essential. Notwithstanding the fact that there are still very large deposits of energy resources from a geological point of view, the finite nature of conventional oil reserves is indisputable. To reduce our dependence on oil, the EU, the USA, and other major economic zones rely on energy diversification. For this purpose, alternative materials and technologies are being sought, and is most obvious in the transport sector. The objective is to progressively replace fossil fuels with renewable and more sustainable fuels. In this respect, biofuels have a pre-eminent position in terms of their capability of blending with fossil fuels and being usable in existing cars without substantial modification. Ethanol can be considered as the primary renewable liquid fuel. In this chapter enzymes, micro-organisms, and processes for ethanol production based on renewable resources are described.
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Affiliation(s)
- A Duwe
- Institute of Bioprocess Engineering, University of Kaiserslautern, Gottlieb-Daimler-Str. 49, 67663, Kaiserslautern, Germany.
| | - N Tippkötter
- Institute of Bioprocess Engineering, University of Kaiserslautern, Gottlieb-Daimler-Str. 49, 67663, Kaiserslautern, Germany
| | - R Ulber
- Institute of Bioprocess Engineering, University of Kaiserslautern, Gottlieb-Daimler-Str. 49, 67663, Kaiserslautern, Germany
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Mehmood MA, Shahid A, Xiong L, Ahmad N, Liu C, Bai F, Zhao X. Development of Synthetic Microbial Platforms to Convert Lignocellulosic Biomass to Biofuels. Advances in Bioenergy 2017. [DOI: 10.1016/bs.aibe.2016.12.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
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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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Zhao X, Xiong L, Zhang M, Bai F. Towards efficient bioethanol production from agricultural and forestry residues: Exploration of unique natural microorganisms in combination with advanced strain engineering. Bioresour Technol 2016; 215:84-91. [PMID: 27067672 DOI: 10.1016/j.biortech.2016.03.158] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [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: 02/08/2016] [Revised: 03/29/2016] [Accepted: 03/30/2016] [Indexed: 05/14/2023]
Abstract
Production of fuel ethanol from lignocellulosic feedstocks such as agricultural and forestry residues is receiving increasing attention due to the unsustainable supply of fossil fuels. Three key challenges include high cellulase production cost, toxicity of the cellulosic hydrolysate to microbial strains, and poor ability of fermenting microorganisms to utilize certain fermentable sugars in the hydrolysate. In this article, studies on searching of natural microbial strains for production of unique cellulase for biorefinery of agricultural and forestry wastes, as well as development of strains for improved cellulase production were reviewed. In addition, progress in the construction of yeast strains with improved stress tolerance and the capability to fully utilize xylose and glucose in the cellulosic hydrolysate was also summarized. With the superior microbial strains for high titer cellulase production and efficient utilization of all fermentable sugars in the hydrolysate, economic biofuels production from agricultural residues and forestry wastes can be realized.
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Affiliation(s)
- Xinqing Zhao
- State Key Laboratory of Microbial Metabolism, School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China.
| | - Liang Xiong
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian 116024, China
| | - Mingming Zhang
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian 116024, China
| | - Fengwu Bai
- State Key Laboratory of Microbial Metabolism, School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China; School of Life Science and Biotechnology, Dalian University of Technology, Dalian 116024, China
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