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Hartono S, Meijerink MFA, Abee T, Smid EJ, van Mastrigt O. The stressostat: A novel approach in adaptive laboratory evolution to improve end-product resistance. N Biotechnol 2023; 78:123-130. [PMID: 37879567 DOI: 10.1016/j.nbt.2023.10.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 09/18/2023] [Accepted: 10/22/2023] [Indexed: 10/27/2023]
Abstract
End-product inhibition in pH-controlled batch cultures, is the major limiting factor for bacterial biomass formation in the starter culture industry as well as in many other biotechnological processes. Adaptive laboratory evolution (ALE) has emerged over the past decades as a powerful tool for phenotype optimization, but none of the existing ALE methods could select for improved end-product resistance. Therefore, we developed the stressostat (STress Resistance Evolution in Substrate Surplus) as a novel continuous ALE method. Stressostat cultivation applies end-product concentrations as constant evolutionary pressure on microorganisms in the presence of substrate surplus. In this study, we improved the lactate resistance of Lactococcus lactis FM03P in 35 days of stressostat cultivations. The lactate concentrations increased over time from 530 to 675 mM, indicating the successful selection for variants with improved lactate resistance. Thirty-four variants were isolated and grouped into four clusters based on their growth rates at high lactate concentrations. In the high-throughput screening without pH control, most isolated variants could grow at high lactate concentrations (870-928 mM), while the wild type was completely inhibited. The variants grew slower than wild type at low lactate media indicating possible evolutionary trade-off. However, in pH-controlled batch cultivations, most variants produced more biomass than the wild type. In conclusion, stressostat cultivation is a valuable method to obtain L. lactis variants with improved end-product resistance and further characterization is needed to elucidate underlying resistance mechanisms and potential industrial applications.
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Affiliation(s)
- Sylviani Hartono
- Food Microbiology, Wageningen University & Research, P.O. Box 17, 6700AA Wageningen, the Netherlands
| | - Marlisa F A Meijerink
- Food Microbiology, Wageningen University & Research, P.O. Box 17, 6700AA Wageningen, the Netherlands
| | - Tjakko Abee
- Food Microbiology, Wageningen University & Research, P.O. Box 17, 6700AA Wageningen, the Netherlands
| | - Eddy J Smid
- Food Microbiology, Wageningen University & Research, P.O. Box 17, 6700AA Wageningen, the Netherlands
| | - Oscar van Mastrigt
- Food Microbiology, Wageningen University & Research, P.O. Box 17, 6700AA Wageningen, the Netherlands.
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2
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Li M, Chu Y, Dong X, Ji H. General mechanisms of weak acid-tolerance and current strategies for the development of tolerant yeasts. World J Microbiol Biotechnol 2023; 40:49. [PMID: 38133718 DOI: 10.1007/s11274-023-03875-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Accepted: 12/16/2023] [Indexed: 12/23/2023]
Abstract
Yeast cells are often subjected to various types of weak acid stress in the process of industrial production, food processing, and preservation, resulting in growth inhibition and reduced fermentation performance. Under acidic conditions, weak acids enter the near-neutral yeast cytoplasm and dissociate into protons and anions, leading to cytoplasmic acidification and cell damage. Although some yeast strains have developed the ability to survive weak acids, the complexity and diversity of stresses during industrial production still require the application of appropriate strategies for phenotypes improvement. In this review, we summarized current knowledge concerning weak acid stress response and resistance, which may suggest important targets for further construction of more robust strains. We also highlight current feasible strategies for improving the weak acid resistance of yeasts, such as adaptive laboratory evolution, transcription factors engineering, and cell membrane/wall engineering. Moreover, the challenges and perspectives associated with improving the competitiveness of industrial strains are also discussed. This review provides effective strategies for improving the industrial phenotypes of yeast from multiple dimensions in future studies.
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Affiliation(s)
- Mengmeng Li
- Institute of Life Sciences, College of Life and Environmental Science, Wenzhou University, Wenzhou, Zhejiang, 325035, PR China
- Biomedical Collaborative Innovation Center of Zhejiang Province & Engineering Laboratory of Zhejiang Province for Pharmaceutical Development of Growth Factors, Wenzhou University, Wenzhou, Zhejiang, 325035, PR China
| | - Yunfei Chu
- Institute of Life Sciences, College of Life and Environmental Science, Wenzhou University, Wenzhou, Zhejiang, 325035, PR China
- Biomedical Collaborative Innovation Center of Zhejiang Province & Engineering Laboratory of Zhejiang Province for Pharmaceutical Development of Growth Factors, Wenzhou University, Wenzhou, Zhejiang, 325035, PR China
| | - Xiameng Dong
- Department of Agriculture and Biotechnology, Wenzhou Vocational College of Science and Technology, Wenzhou, Zhejiang, 325006, PR China.
| | - Hao Ji
- Institute of Life Sciences, College of Life and Environmental Science, Wenzhou University, Wenzhou, Zhejiang, 325035, PR China.
- Biomedical Collaborative Innovation Center of Zhejiang Province & Engineering Laboratory of Zhejiang Province for Pharmaceutical Development of Growth Factors, Wenzhou University, Wenzhou, Zhejiang, 325035, PR China.
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3
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Zhang FL, Zhang L, Zeng DW, Liao S, Fan Y, Champreda V, Runguphan W, Zhao XQ. Engineering yeast cell factories to produce biodegradable plastics and their monomers: Current status and prospects. Biotechnol Adv 2023; 68:108222. [PMID: 37516259 DOI: 10.1016/j.biotechadv.2023.108222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2023] [Revised: 07/24/2023] [Accepted: 07/24/2023] [Indexed: 07/31/2023]
Abstract
Traditional plastic products have caused serious environmental pollution due to difficulty to be degraded in the natural environment. In the recent years, biodegradable plastics are receiving increasing attention due to advantages in natural degradability and environmental friendliness. Biodegradable plastics have potential to be used in food, agriculture, industry, medicine and other fields. However, the high production cost of such plastics is the bottleneck that limits their commercialization and application. Yeasts, including budding yeast and non-conventional yeasts, are widely studied to produce biodegradable plastics and their organic acid monomers. Compared to bacteria, yeast strains are more tolerable to multiple stress conditions including low pH and high temperature, and also have other advantages such as generally regarded as safe, and no phage infection. In addition, synthetic biology and metabolic engineering of yeast have enabled its rapid and efficient engineering for bioproduction using various renewable feedstocks, especially lignocellulosic biomass. This review focuses on the recent progress in biosynthesis technology and strategies of monomeric organic acids for biodegradable polymers, including polylactic acid (PLA), polyhydroxyalkanoate (PHA), polybutylene succinate (PBS), and polybutylene adipate terephthalate (PBAT) using yeast cell factories. Improving the performance of yeast as a cell factory and strategies to improve yeast acid stress tolerance are also discussed. In addition, the critical challenges and future prospects for the production of biodegradable plastic monomer using yeast are also discussed.
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Affiliation(s)
- Feng-Li Zhang
- Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Lin Zhang
- SINOPEC Dalian Research Institute of Petroleum and Petrochemicals Co., Ltd., Dalian 116045, China
| | - Du-Wen Zeng
- Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Sha Liao
- SINOPEC Dalian Research Institute of Petroleum and Petrochemicals Co., Ltd., Dalian 116045, China
| | - Yachao Fan
- SINOPEC Dalian Research Institute of Petroleum and Petrochemicals Co., Ltd., Dalian 116045, China
| | - Verawat Champreda
- National Center for Genetic Engineering and Biotechnology (BIOTEC), 113 Thailand Science Park, Phaholyothin Road, Khlong Luang, Pathumthani 12120, Thailand
| | - Weerawat Runguphan
- National Center for Genetic Engineering and Biotechnology (BIOTEC), 113 Thailand Science Park, Phaholyothin Road, Khlong Luang, Pathumthani 12120, Thailand
| | - Xin-Qing Zhao
- Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China.
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4
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Tafere Abrha G, Li Q, Kuang X, Xiao D, Ayepa E, Wu J, Chen H, Zhang Z, Liu Y, Yu X, Xiang Q, Ma M. Phenotypic and comparative transcriptomics analysis of RDS1 overexpression reveal tolerance of Saccharomyces cerevisiae to furfural. J Biosci Bioeng 2023; 136:270-277. [PMID: 37544800 DOI: 10.1016/j.jbiosc.2023.06.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 06/18/2023] [Accepted: 06/28/2023] [Indexed: 08/08/2023]
Abstract
The yeast Saccharomyces cerevisiae able to tolerate lignocellulose-derived inhibitors like furfural. Yeast strain performance tolerance has been measured by the length of the lag phase for cell growth in response to the furfural inhibitor challenge. The aims of this work were to obtain RDS1 yeast tolerant strain against furfural through overexpression using a method of in vivo homologous recombination. Here, we report that the overexpressing RDS1 recovered more rapidly and displayed a lag phase at about 12 h than its parental strain. Overexpressing RDS1 strain encodes a novel aldehyde reductase with catalytic function for reduction of furfural with NAD(P)H as the co-factor. It displayed the highest specific activity (24.8 U/mg) for furfural reduction using NADH as a cofactor. Fluorescence microscopy revealed improved accumulation of reactive oxygen species resistance to the damaging effects of inhibitor in contrast to the parental. Comparative transcriptomics revealed key genes potentially associated with stress responses to the furfural inhibitor, including specific and multiple functions involving defensive reduction-oxidation reaction process and cell wall response. A significant change in expression level of log2 (fold change >1) was displayed for RDS1 gene in the recombinant strain, which demonstrated that the introduction of RDS1 overexpression promoted the expression level. Such signature expressions differentiated tolerance phenotypes of RDS1 from the innate stress response of its parental strain. Overexpression of the RDS1 gene involving diversified functional categories is accountable for stress tolerance in yeast S. cerevisiae to survive and adapt the furfural during the lag phase.
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Affiliation(s)
- Getachew Tafere Abrha
- Department of Applied Microbiology, College of Resources, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan 611130, PR China
| | - Qian Li
- Department of Applied Microbiology, College of Resources, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan 611130, PR China
| | - Xiaolin Kuang
- Department of Applied Microbiology, College of Resources, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan 611130, PR China
| | - Difan Xiao
- Department of Applied Microbiology, College of Resources, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan 611130, PR China
| | - Ellen Ayepa
- Department of Applied Microbiology, College of Resources, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan 611130, PR China
| | - Jinjian Wu
- Department of Applied Microbiology, College of Resources, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan 611130, PR China
| | - Huan Chen
- Department of Applied Microbiology, College of Resources, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan 611130, PR China
| | - Zhengyue Zhang
- Department of Applied Microbiology, College of Resources, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan 611130, PR China
| | - Yina Liu
- Department of Applied Microbiology, College of Resources, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan 611130, PR China
| | - Xiumei Yu
- Department of Applied Microbiology, College of Resources, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan 611130, PR China
| | - Quanju Xiang
- Department of Applied Microbiology, College of Resources, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan 611130, PR China
| | - Menggen Ma
- Department of Applied Microbiology, College of Resources, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan 611130, PR China; Institute of Resources and Geographic Information Technology, College of Resources, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan 611130, PR China.
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da Silva RR, Zaiter MA, Boscolo M, da Silva R, Gomes E. Xylose consumption and ethanol production by Pichia guilliermondii and Candida oleophila in the presence of furans, phenolic compounds, and organic acids commonly produced during the pre-treatment of plant biomass. Braz J Microbiol 2023; 54:753-759. [PMID: 36826705 PMCID: PMC10234969 DOI: 10.1007/s42770-023-00937-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 02/15/2023] [Indexed: 02/25/2023] Open
Abstract
For 2G ethanol production, pentose fermentation and yeast tolerance to lignocellulosic hydrolyzate components are essential to improve biorefinery yields. Generally, physicochemical pre-treatment methodologies are used to facilitate access to cellulose and hemicellulose in plant material, which consequently can generate microbial growth inhibitory compounds, such as furans, weak acids, and phenolic compounds. Because of the unsatisfactory yield of wild-type Saccharomyces cerevisiae during pentose fermentation, the search for xylose-fermenting yeasts tolerant to microbial growth inhibitors has gained attention. In this study, we investigated the ability of the yeasts Pichia guilliermondii G1.2 and Candida oleophila G10.1 to produce ethanol from xylose and tolerate the inhibitors furfural, 5-hydroxymethylfurfural (HMF), acetic acid, formic acid, ferulic acid, and vanillin. We demonstrated that both yeasts were able to grow and consume xylose in the presence of all single inhibitors, with greater growth limitation in media containing furfural, acetic acid, and vanillin. In saline medium containing a mixture of these inhibitors (2.5-3.5 mM furfural and HMF, 1 mM ferulic acid, 1-1.5 mM vanillin, 10-13 mM acetic acid, and 5-7 mM formic acid), both yeasts were able to produce ethanol from xylose, similar to that detected in the control medium (without inhibitors). In future studies, the proteins involved in the transport of pentose and tolerance to these inhibitors need to be investigated.
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Affiliation(s)
- Ronivaldo Rodrigues da Silva
- Instituto de Biociencias, Letras e Ciencias Exatas, Universidade Estadual Paulista "Julio de Mesquita Filho", Cristovao Colombo, 2265, Jd Nazareth, Ibilce‑Unesp, Sao Jose do Rio Preto, São Paulo, Brazil.
| | - Mohammed Anas Zaiter
- Instituto de Biociencias, Letras e Ciencias Exatas, Universidade Estadual Paulista "Julio de Mesquita Filho", Cristovao Colombo, 2265, Jd Nazareth, Ibilce‑Unesp, Sao Jose do Rio Preto, São Paulo, Brazil
| | - Maurício Boscolo
- Instituto de Biociencias, Letras e Ciencias Exatas, Universidade Estadual Paulista "Julio de Mesquita Filho", Cristovao Colombo, 2265, Jd Nazareth, Ibilce‑Unesp, Sao Jose do Rio Preto, São Paulo, Brazil
| | - Roberto da Silva
- Instituto de Biociencias, Letras e Ciencias Exatas, Universidade Estadual Paulista "Julio de Mesquita Filho", Cristovao Colombo, 2265, Jd Nazareth, Ibilce‑Unesp, Sao Jose do Rio Preto, São Paulo, Brazil
| | - Eleni Gomes
- Instituto de Biociencias, Letras e Ciencias Exatas, Universidade Estadual Paulista "Julio de Mesquita Filho", Cristovao Colombo, 2265, Jd Nazareth, Ibilce‑Unesp, Sao Jose do Rio Preto, São Paulo, Brazil
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6
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Bianchini IDA, Jofre FM, Queiroz SDS, Lacerda TM, Felipe MDGDA. Relation of xylitol formation and lignocellulose degradation in yeast. Appl Microbiol Biotechnol 2023; 107:3143-3151. [PMID: 37039848 DOI: 10.1007/s00253-023-12495-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 03/18/2023] [Accepted: 03/21/2023] [Indexed: 04/12/2023]
Abstract
One of the critical steps of the biotechnological production of xylitol from lignocellulosic biomass is the deconstruction of the plant cell wall. This step is crucial to the bioprocess once the solubilization of xylose from hemicellulose is allowed, which can be easily converted to xylitol by pentose-assimilating yeasts in a microaerobic environment. However, lignocellulosic toxic compounds formed/released during plant cell wall pretreatment, such as aliphatic acids, furans, and phenolic compounds, inhibit xylitol production during fermentation, reducing the fermentative performance of yeasts and impairing the bioprocess productivity. Although the toxicity of lignocellulosic inhibitors is one of the biggest bottlenecks of the biotechnological production of xylitol, most of the studies focus on how much xylitol production is inhibited but not how and where cells are affected. Understanding this mechanism is important in order to develop strategies to overcome lignocellulosic inhibitor toxicity. In this mini-review, we addressed how these inhibitors affect both yeast physiology and metabolism and consequently xylose-to-xylitol bioconversion. In addition, this work also addresses about cellular adaptation, one of the most relevant strategies to overcome lignocellulosic inhibitors toxicity, once it allows the development of robust and tolerant strains, contributing to the improvement of the microbial performance against hemicellulosic hydrolysates toxicity. KEY POINTS: • Impact of lignocellulosic inhibitors on the xylitol production by yeasts • Physiological and metabolic alterations provoked by lignocellulosic inhibitors • Cell adaptation as an efficient strategy to improve yeast's robustness.
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Affiliation(s)
- Italo de Andrade Bianchini
- Department of Biotechnology, Engineering School of Lorena, University of São Paulo, Estrada Municipal do Campinho, 100, Campinho, Lorena, SP, 12602-810, Brazil
| | - Fanny Machado Jofre
- Department of Biotechnology, Engineering School of Lorena, University of São Paulo, Estrada Municipal do Campinho, 100, Campinho, Lorena, SP, 12602-810, Brazil
| | - Sarah de Souza Queiroz
- Department of Biotechnology, Engineering School of Lorena, University of São Paulo, Estrada Municipal do Campinho, 100, Campinho, Lorena, SP, 12602-810, Brazil
| | - Talita Martins Lacerda
- Department of Biotechnology, Engineering School of Lorena, University of São Paulo, Estrada Municipal do Campinho, 100, Campinho, Lorena, SP, 12602-810, Brazil
| | - Maria das Graças de Almeida Felipe
- Department of Biotechnology, Engineering School of Lorena, University of São Paulo, Estrada Municipal do Campinho, 100, Campinho, Lorena, SP, 12602-810, Brazil.
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7
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Alves LDF, Bortolucci J, Reginato V, Guazzaroni ME, Mussatto SI. Improving Saccharomyces cerevisiae acid and oxidative stress resistance using a prokaryotic gene identified by functional metagenomics. Heliyon 2023; 9:e14838. [PMID: 37077683 PMCID: PMC10106912 DOI: 10.1016/j.heliyon.2023.e14838] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Revised: 03/17/2023] [Accepted: 03/20/2023] [Indexed: 04/21/2023] Open
Abstract
Innovations in obtaining products from lignocellulosic biomass have been largely based on the improvement of microorganisms and enzymes capable of degrading these materials. To complete the whole process, microorganisms must be able to ferment the resulting sugars and tolerate high concentrations of product, osmotic pressure, ion toxicity, temperature, toxic compounds from lignocellulose pretreatment, low pH, and oxidative stress. In this work, we engineered laboratory and industrial Saccharomyces cerevisiae strains by combining a gene (hu) recovered from a metagenomic approach with different native and synthetic promoters to obtain improved acid and oxidative stress resistance. Laboratorial strains harboring hu gene under the control of the synthetic stress responsive PCCW14v5 showed increased survival rates after 2 h exposure to pH 1.5. The hu gene was also able to significantly enhance the tolerance of the industrial strain to high concentrations of H2O2 when combined with PTEF1, PYGP1 or PYGP1v7 after 3 h exposure.
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Affiliation(s)
- Luana de Fátima Alves
- Department of Biology, Faculdade de Filosofia, University of São Paulo, Ciências e Letras de Ribeirão Preto, Ribeirão Preto, 14040-901, São Paulo, Brazil
- Department of Biochemistry, Faculdade de Medicina de Ribeirão Preto, University of São Paulo, Ribeirão Preto, 14040-900, São Paulo, Brazil
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet, Building 220, 2800, Kongens Lyngby, Denmark
| | - Jonatã Bortolucci
- Department of Biology, Faculdade de Filosofia, University of São Paulo, Ciências e Letras de Ribeirão Preto, Ribeirão Preto, 14040-901, São Paulo, Brazil
| | - Valeria Reginato
- Department of Biology, Faculdade de Filosofia, University of São Paulo, Ciências e Letras de Ribeirão Preto, Ribeirão Preto, 14040-901, São Paulo, Brazil
| | - María-Eugenia Guazzaroni
- Department of Biology, Faculdade de Filosofia, University of São Paulo, Ciências e Letras de Ribeirão Preto, Ribeirão Preto, 14040-901, São Paulo, Brazil
| | - Solange I. Mussatto
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, Building 223, 2800, Kongens Lyngby, Denmark
- Corresponding author.
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8
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Saini JK. Enhanced cellulosic ethanol production via fed-batch simultaneous saccharification and fermentation of sequential dilute acid-alkali pretreated sugarcane bagasse. BIORESOURCE TECHNOLOGY 2023; 372:128671. [PMID: 36702326 DOI: 10.1016/j.biortech.2023.128671] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 01/18/2023] [Accepted: 01/20/2023] [Indexed: 06/18/2023]
Abstract
This study reports high gravity fed-batch simultaneous saccharification and fermentation (FB-SSF) of sequentially pretreated sugarcane bagasse (SCB) for enhanced bioethanol by employing multiple inhibitor tolerant Kluyveromyces marxianusJKH5 C60. FB-SSF with intermittent feeding of SCB (total 20 % solid loading) and enzyme (total dose of 20 FPU/g) at 6 and 12 h resulted in superior bioethanol production at42 °C. Under optimizedlab-scaleFB-SSF, the maximum ethanoltiter, efficiency and productivities were73.4 ± 1.2 g/L,78 % and 3.0 g/L/h, respectively, after 72 h in presence of inhibitors (acetic acid, furfural, and vanillin at 3, 1, and 1 g/L, respectively). Furthermore, pentose rich dilute acid hydrolysate of SCB was subjected to fermentation by Pichia stipitis NCIM 3499, resulting in ethanol titer of 6.8 g/L. Overall ethanol yield during the developed process was 260.1 g/kg native SCB, which proves industrial potential of the developed bioethanol conversion process.
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Affiliation(s)
- Jitendra Kumar Saini
- Department of Microbiology, Central University of Haryana, Mahenderagrah, Haryana 123031, India.
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9
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Hu M, Dinh HV, Shen Y, Suthers PF, Foster CJ, Call CM, Ye X, Pratas J, Fatma Z, Zhao H, Rabinowitz JD, Maranas CD. Comparative study of two Saccharomyces cerevisiae strains with kinetic models at genome-scale. Metab Eng 2023; 76:1-17. [PMID: 36603705 DOI: 10.1016/j.ymben.2023.01.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 12/22/2022] [Accepted: 01/01/2023] [Indexed: 01/04/2023]
Abstract
The parameterization of kinetic models requires measurement of fluxes and/or metabolite levels for a base strain and a few genetic perturbations thereof. Unlike stoichiometric models that are mostly invariant to the specific strain, it remains unclear whether kinetic models constructed for different strains of the same species have similar or significantly different kinetic parameters. This important question underpins the applicability range and prediction limits of kinetic reconstructions. To this end, herein we parameterize two separate large-scale kinetic models using K-FIT with genome-wide coverage corresponding to two distinct strains of Saccharomyces cerevisiae: CEN.PK 113-7D strain (model k-sacce306-CENPK), and growth-deficient BY4741 (isogenic to S288c; model k-sacce306-BY4741). The metabolic network for each model contains 306 reactions, 230 metabolites, and 119 substrate-level regulatory interactions. The two models (for CEN.PK and BY4741) recapitulate, within one standard deviation, 77% and 75% of the fitted dataset fluxes, respectively, determined by 13C metabolic flux analysis for wild-type and eight single-gene knockout mutants of each strain. Strain-specific kinetic parameterization results indicate that key enzymes in the TCA cycle, glycolysis, and arginine and proline metabolism drive the metabolic differences between these two strains of S. cerevisiae. Our results suggest that although kinetic models cannot be readily used across strains as stoichiometric models, they can capture species-specific information through the kinetic parameterization process.
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Affiliation(s)
- Mengqi Hu
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA; DOE Center for Advanced Bioenergy and Bioproducts Innovation, USA
| | - Hoang V Dinh
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA; DOE Center for Advanced Bioenergy and Bioproducts Innovation, USA
| | - Yihui Shen
- Department of Chemistry, Princeton University, Princeton, NJ, 08544, USA; Lewis Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, 08544, USA; DOE Center for Advanced Bioenergy and Bioproducts Innovation, USA
| | - Patrick F Suthers
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA; DOE Center for Advanced Bioenergy and Bioproducts Innovation, USA
| | - Charles J Foster
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Catherine M Call
- Department of Chemistry, Princeton University, Princeton, NJ, 08544, USA; Lewis Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, 08544, USA; DOE Center for Advanced Bioenergy and Bioproducts Innovation, USA
| | - Xuanjia Ye
- Department of Molecular Biology, Princeton University, Princeton, NJ, 08544, USA
| | - Jimmy Pratas
- Department of Chemistry, Princeton University, Princeton, NJ, 08544, USA; Lewis Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, 08544, USA; DOE Center for Advanced Bioenergy and Bioproducts Innovation, USA
| | - Zia Fatma
- Carl R. Woese Institute for Genomic Biology, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA; DOE Center for Advanced Bioenergy and Bioproducts Innovation, USA
| | - Huimin Zhao
- Carl R. Woese Institute for Genomic Biology, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA; Department of Chemical and Biomolecular Engineering, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA; DOE Center for Advanced Bioenergy and Bioproducts Innovation, USA
| | - Joshua D Rabinowitz
- Department of Chemistry, Princeton University, Princeton, NJ, 08544, USA; Lewis Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, 08544, USA; DOE Center for Advanced Bioenergy and Bioproducts Innovation, USA
| | - Costas D Maranas
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA; DOE Center for Advanced Bioenergy and Bioproducts Innovation, USA.
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10
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Physiological and transcriptome analyses of Kluyveromyces marxianus reveal adaptive traits in stress response. Appl Microbiol Biotechnol 2023; 107:1421-1438. [PMID: 36651929 DOI: 10.1007/s00253-022-12354-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 12/21/2022] [Accepted: 12/24/2022] [Indexed: 01/19/2023]
Abstract
Kluyveromyces marxianus is a non-conventional yeast with outstanding physiological characteristics and a high potential for lignocellulosic ethanol production. However, achieving high ethanol productivity requires overcoming several biotechnological challenges due to the cellular inhibition caused by the inhibitors present in the medium. In this work, K. marxianus SLP1 was adapted to increase its tolerance to a mix of inhibitory compounds using the adaptive laboratory evolution strategy to study the adaptation and stress response mechanisms used by this non-Saccharomyces yeast. The fermentative and physiological parameters demonstrated that the adapted K. marxianus P8 had a better response against the synergistic effects of multiple inhibitors because it reduced the lag phase from 12 to 4 h, increasing the biomass by 40% and improving the volumetric ethanol productivity 16-fold than the parental K. marxianus SLP1. To reveal the effect of adaptation process in P8, transcriptome analysis was carried out; the result showed that the basal gene expression in P8 changed, suggesting the biological capability of K. marxianus to activate the adaptative prediction mechanism. Similarly, we carried out physiologic and transcriptome analyses to reveal the mechanisms involved in the stress response triggered by furfural, the most potent inhibitor in K. marxianus. Stress response studies demonstrated that P8 had a better physiologic response than SLP1, since key genes related to furfural transformation (ALD4 and ALD6) and stress response (STL1) were upregulated. Our study demonstrates the rapid adaptability of K. marxianus to stressful environments, making this yeast a promising candidate to produce lignocellulosic ethanol. KEY POINTS: • K. marxianus was adapted to increase its tolerance to a mix of inhibitory compounds • The basal gene expression of K. marxianus changed after the adaptation process • Adapted K. marxianus showed a better physiological response to stress by inhibitors • Transcriptome analyses revealed key genes involved in the stress response.
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Almeida ELM, Ventorim RZ, Ferreira MAM, Costa MD, Mantovani HC, Silveira WB. New Papiliotrema laurentii UFV-1 strains with improved acetic acid tolerance selected by adaptive laboratory evolution. Fungal Genet Biol 2023; 164:103765. [PMID: 36528339 DOI: 10.1016/j.fgb.2022.103765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 09/26/2022] [Accepted: 11/30/2022] [Indexed: 12/15/2022]
Abstract
The production of yeast oil from lignocellulosic biomasses is impaired by inhibitors formed during the pretreatment step, mainly acetic acid. Herein, we applied Adaptive Laboratory Evolution (ALE) to select three Acetic acid Tolerant Strains (ATS) of P. laurentii UFV-1. Different phenotypes emerged alongside evolution. The ATS II presented trade-offs in the absence of acetic acid, suggesting that it displays a specialized phenotype of tolerance to growth on organic acids. On the other hand, ATS I and ATS III presented phenotypes associated with the behavior of generalists. ATS I was considered the most promising evolved strain as it displayed the oleaginous phenotype in all conditions tested. Thus, we applied whole-genome sequencing to detect the mutations that emerged in this strain during the ALE. We found alterations in genes encoding proteins involved in different cellular functions, including multidrug resistance (MDR) transporters, energy metabolism, detoxification, coenzyme recycling, and cell envelope remodeling. To evaluate acetic acid stress responses, both parental and ATS I strains were cultivated in chemostat mode in the absence and presence of acetic acid. In contrast to ATS I, the parental strain presented alterations in the cell envelope and cell size under acetic acid stress conditions. Furthermore, the parental strain and the ATS I presented differences regarding acetic acid assimilation. Contrary to the parental strain, the ATS I displayed an increase in unsaturated fatty acid content irrespective of acetic acid stress, which might be related to improved tolerance to acetic acid. Altogether, these results provided insights into the mechanisms involved with the acetic acid tolerance displayed by ATS I and the responses of P. laurentii to this stressful condition.
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Affiliation(s)
- E L M Almeida
- Departamento de Microbiologia, Universidade Federal de Viçosa, Viçosa, Minas Gerais 36570-900, Brazil
| | - R Z Ventorim
- Departamento de Microbiologia, Universidade Federal de Viçosa, Viçosa, Minas Gerais 36570-900, Brazil
| | - M A M Ferreira
- Departamento de Microbiologia, Universidade Federal de Viçosa, Viçosa, Minas Gerais 36570-900, Brazil
| | - M D Costa
- Departamento de Microbiologia, Universidade Federal de Viçosa, Viçosa, Minas Gerais 36570-900, Brazil; Bolsista Pesquisador do Conselho Nacional de Desenvolvimento Científico e Tecnológico, CNPq, Brasília, DF, Brazil
| | - H C Mantovani
- Departamento de Microbiologia, Universidade Federal de Viçosa, Viçosa, Minas Gerais 36570-900, Brazil; Bolsista Pesquisador do Conselho Nacional de Desenvolvimento Científico e Tecnológico, CNPq, Brasília, DF, Brazil
| | - W B Silveira
- Departamento de Microbiologia, Universidade Federal de Viçosa, Viçosa, Minas Gerais 36570-900, Brazil; Bolsista Pesquisador do Conselho Nacional de Desenvolvimento Científico e Tecnológico, CNPq, Brasília, DF, Brazil.
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Ribeiro RA, Bourbon-Melo N, Sá-Correia I. The cell wall and the response and tolerance to stresses of biotechnological relevance in yeasts. Front Microbiol 2022; 13:953479. [PMID: 35966694 PMCID: PMC9366716 DOI: 10.3389/fmicb.2022.953479] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 07/11/2022] [Indexed: 01/18/2023] Open
Abstract
In industrial settings and processes, yeasts may face multiple adverse environmental conditions. These include exposure to non-optimal temperatures or pH, osmotic stress, and deleterious concentrations of diverse inhibitory compounds. These toxic chemicals may result from the desired accumulation of added-value bio-products, yeast metabolism, or be present or derive from the pre-treatment of feedstocks, as in lignocellulosic biomass hydrolysates. Adaptation and tolerance to industrially relevant stress factors involve highly complex and coordinated molecular mechanisms occurring in the yeast cell with repercussions on the performance and economy of bioprocesses, or on the microbiological stability and conservation of foods, beverages, and other goods. To sense, survive, and adapt to different stresses, yeasts rely on a network of signaling pathways to modulate the global transcriptional response and elicit coordinated changes in the cell. These pathways cooperate and tightly regulate the composition, organization and biophysical properties of the cell wall. The intricacy of the underlying regulatory networks reflects the major role of the cell wall as the first line of defense against a wide range of environmental stresses. However, the involvement of cell wall in the adaptation and tolerance of yeasts to multiple stresses of biotechnological relevance has not received the deserved attention. This article provides an overview of the molecular mechanisms involved in fine-tuning cell wall physicochemical properties during the stress response of Saccharomyces cerevisiae and their implication in stress tolerance. The available information for non-conventional yeast species is also included. These non-Saccharomyces species have recently been on the focus of very active research to better explore or control their biotechnological potential envisaging the transition to a sustainable circular bioeconomy.
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Affiliation(s)
- Ricardo A. Ribeiro
- Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
- Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
- Associate Laboratory i4HB—Institute for Health and Bioeconomy at Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
| | - Nuno Bourbon-Melo
- Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
| | - Isabel Sá-Correia
- Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
- Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
- Associate Laboratory i4HB—Institute for Health and Bioeconomy at Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
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Tripathi S, Yadav S, Sharma P, Purchase D, Syed A, Chandra R. Plant growth promoting strain Bacillus cereus (RCS-4 MZ520573.1) enhances phytoremediation potential of Cynodon dactylon L. in distillery sludge. ENVIRONMENTAL RESEARCH 2022; 208:112709. [PMID: 35032541 DOI: 10.1016/j.envres.2022.112709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Revised: 12/27/2021] [Accepted: 01/06/2022] [Indexed: 06/14/2023]
Abstract
Elevated levels of physico-chemical pollution including organic pollutants, metals and metalloids were detected in distillery sludges despite of the anaerobic digestion treatment prior to disposal. The concentrations of the metals were (in mg kg-1): Fe (400.98 ± 3.11), Zn (17.21 ± 0.54), Mn (8.32 ± 0.42), Ni (8.00 ± 0.98), Pb (5.09 ± 0.43), Cr (4.00 ± 0.98), and Cu (3.00 ± 0.10). An invasive grass species, Cynodon dactylon L., demonstrated its ability to remediate the distillery waste sludge (DWS) in the field study. All the physico-chemical parameters of the sludge significantly improved (up to 70-75%) in the presence of Cynodon dactylon L. (p < 0.001) than the control with no plant growth. The highest phytoremediation capacity was associated with the uptake of Fe in the root and shoot. Sludge samples collected near the rhizosphere also showed lower amount of organic compounds compared to control sludge samples. Metal resistant Bacillus cereus (RCS-4 MZ520573.1) was isolated from the rhizosphere of Cynodon dactylon L. and showed potential to enhance the process of phytoremediation via plant growth promoting activities such as production of high level of ligninolytic enzymes: manganese peroxidase (35.98 U), lignin peroxidase (23.98 U) and laccase (12.78 U), indole acetic acid (45.87(mgL-1), phosphatase activity (25.76 mg L-1) and siderophore production (23.09 mg L-1). This study presents information on the performance of Cynodon dactylon L., an abundant invasive perennial grass species and its associated plant growth promoting rhizobacteria demonstrated good capacity to remediate and restore contaminated soil contained complex organic and inorganic pollutants, they could be integrated into the disposal system of distillery sludge to improve the treatment efficiency.
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Affiliation(s)
- Sonam Tripathi
- Department of Environmental Microbiology, School for Environmental Sciences, Babasaheb Bhimrao Ambedkar Central University, Vidya Vihar, Raebareli Road, Lucknow, Uttar Pradesh, 226025, India
| | - Sangeeta Yadav
- Department of Environmental Microbiology, School for Environmental Sciences, Babasaheb Bhimrao Ambedkar Central University, Vidya Vihar, Raebareli Road, Lucknow, Uttar Pradesh, 226025, India
| | - Pooja Sharma
- Department of Environmental Microbiology, School for Environmental Sciences, Babasaheb Bhimrao Ambedkar Central University, Vidya Vihar, Raebareli Road, Lucknow, Uttar Pradesh, 226025, India
| | - Diane Purchase
- Department of Natural Sciences, Faculty of Science and Technology, Middlesex University, The Burroughs, London, NW4 4BT, UK
| | - Asad Syed
- Department of Botany and Microbiology, College of Science, King Saud University, P.O. 2455, Riyadh, 11451, Saudi Arabia
| | - Ram Chandra
- Department of Environmental Microbiology, School for Environmental Sciences, Babasaheb Bhimrao Ambedkar Central University, Vidya Vihar, Raebareli Road, Lucknow, Uttar Pradesh, 226025, India.
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Sharma P, Chaturvedi P, Chandra R, Kumar S. Identification of heavy metals tolerant Brevundimonas sp. from rhizospheric zone of Saccharum munja L. and their efficacy in in-situ phytoremediation. CHEMOSPHERE 2022; 295:133823. [PMID: 35114263 DOI: 10.1016/j.chemosphere.2022.133823] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 01/19/2022] [Accepted: 01/29/2022] [Indexed: 06/14/2023]
Abstract
Heavy metals phytoremediation from pulp and paper industry (PPI) sludge was conducted by employing root-associated Brevundimonas sp (PS-4 MN238722.1) in rhizospheric zone of Saccharum munja L. for its detoxification. The study was aimed to investigate the efficiency of Saccharum munja L. for the removal of heavy metals along with physico-chemical parameters through bacterial interactions. Physico-chemical examination of PPI sludge showed biochemical oxygen demand (8357 ± 94 mg kg-1), electrical conductivity (2264 ± 49 μmhoscm-1), total phenol (521 ± 24 mg kg-1), total dissolve solid (1547 ± 23 mg kg-1), total nitrogen (264 ± 2.13 mg kg-1), pH (8.2 ± 0.11), chemical oxygen demand (34756 ± 214 mg kg-1), color (2434 ± 45 Co-Pt), total suspended solid (76 ± 0.67 mg kg-1), sulphate (2462 ± 13 mg kg-1), chlorolignin (597 ± 13.01 mg kg-1), K+ (21.04 ± 0.26 mg kg-1), total solid (1740 ± 54 mg kg-1), phosphorous, Cl-, and Na+. Heavy metals, such as Fe followed by Zn, Mn, Cd, Cu, Ni, Pb, As, Cr and Hg were above the permissible limit. Root and shoot of Saccharum munja L. revealed highest concentrations of Cd followed by Mn, Ni, Fe, Zn, Cu, As, Cr, Hg, and Pb. Tested metals (Fe, Mn, Pb, Cd, Cr, Cu, Zn, Ni, As, and Hg) bioaccumulation and translocation factors were also revealed to be < 1 and >1, respectively, demonstrating that these plants have considerable absorption and translocation abilities. Plant growth-promoting activity, such as ligninolytic enzymes, hydrolytic enzymes, indole acetic acid, and siderophore production activity of Brevundimonas sp. (PS-4 MN238722.1) were also noted to be higher. These findings support the use of Brevundimonas sp (PS-4 MN238722.1) in combination with Saccharum munja L. plant as interdisciplinary management of industrial sludge at polluted areas for the prevention of soils near the industrial site.
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Affiliation(s)
- Pooja Sharma
- Department of Environmental Microbiology, School for Environmental Sciences, Babasaheb Bhimrao Ambedkar (A Central) University, Vidya Vihar, Raebareli Road, Lucknow, Uttar Pradesh, 226 025, India; CSIR-National Environmental Engineering Research Institute (CSIR-NEERI), Nehru Marg, Nagpur, 440 020, Maharashtra, India.
| | - Preeti Chaturvedi
- Aquatic Toxicology Laboratory, Environmental Toxicology Group, Council of Scientific and Industrial Research-Indian Institute of Toxicology Research (CSIR-IITR), Vishvigyan Bhawan, 31, M.G. Marg, Lucknow, 226 001, Uttar Pradesh, India
| | - Ram Chandra
- Department of Environmental Microbiology, School for Environmental Sciences, Babasaheb Bhimrao Ambedkar (A Central) University, Vidya Vihar, Raebareli Road, Lucknow, Uttar Pradesh, 226 025, India.
| | - Sunil Kumar
- CSIR-National Environmental Engineering Research Institute (CSIR-NEERI), Nehru Marg, Nagpur, 440 020, Maharashtra, India.
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How adaptive laboratory evolution can boost yeast tolerance to lignocellulosic hydrolyses. Curr Genet 2022; 68:319-342. [PMID: 35362784 DOI: 10.1007/s00294-022-01237-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 03/01/2022] [Accepted: 03/06/2022] [Indexed: 12/25/2022]
Abstract
The yeast Saccharomyces cerevisiae is an excellent candidate for establishing cell factories to convert lignocellulosic biomass into chemicals and fuels. To enable this technology, yeast robustness must be improved to withstand the fermentation inhibitors (e.g., weak organic acids, phenols, and furan aldehydes) resulting from biomass pretreatment and hydrolysis. Here, we discuss how evolution experiments performed in the lab, a method commonly known as adaptive laboratory evolution (ALE), may contribute to lifting yeast tolerance against the inhibitors of lignocellulosic hydrolysates (LCHs). The key is that, through the combination of whole-genome sequencing and reverse engineering, ALE provides a robust platform for discovering and testing adaptive alleles, allowing to explore the genetic underpinnings of yeast responses to LCHs. We review the insights gained from past evolution experiments with S. cerevisiae in LCH inhibitors and propose experimental designs to optimise the discovery of genetic variants adaptive to biomass toxicity. The knowledge gathered through ALE projects is envisaged as a roadmap to engineer superior yeast strains for biomass-based bioprocesses.
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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. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2022; 15:22. [PMID: 35219341 PMCID: PMC8882276 DOI: 10.1186/s13068-022-02121-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [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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Patel AK, Saini JK, Singhania RR. Development of multiple inhibitor tolerant yeast via adaptive laboratory evolution for sustainable bioethanol production. BIORESOURCE TECHNOLOGY 2022; 344:126247. [PMID: 34740795 DOI: 10.1016/j.biortech.2021.126247] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 10/24/2021] [Accepted: 10/26/2021] [Indexed: 06/13/2023]
Abstract
The present research work aimed at developing robust yeast cell factory via adaptive laboratory evolution (ALE) for improved cellulosic bioethanol production. Kluyveromyces marxianus JKH5, a newly isolated thermotolerant ethanologenic yeast, was engineered by serial passaging for 60 generations in medium supplemented with gradually higher concentration of inhibitors (acetic acid, furfural, and vanillin) that are generated during dilute acid pretreatment. The improved strain K. marxianus JKH5 C60, showed 3.3-fold higher specific growth rate, 56% reduced lag phase and 80% enhanced fermentation efficiency at 42 °C in comparison to parent strain in inhibitor cocktail comprising medium. Bioethanol production by simultaneous saccharification and fermentation of sequential dilute acid-alkali pretreated sugarcane bagasse in presence of inhibitors, resulted in ethanol titre and yield, respectively, 54.8 ± 0.9 g/L and 0.40 g/g. The adapted yeast can be used to ferment unwashed pretreated biomass, thereby, reducing overall cost, time, and wastewater generation, hence making bioethanol production sustainable.
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Affiliation(s)
- Anil Kumar Patel
- Department of Marine Environmental Engineering, National Kaohsiung University of Science and Technology, Kaohsiung City 81157, Taiwan
| | - Jitendra Kumar Saini
- Department of Microbiology, Central University of Haryana, Mahendergarh, Haryana 123031, India.
| | - Reeta Rani Singhania
- Department of Marine Environmental Engineering, National Kaohsiung University of Science and Technology, Kaohsiung City 81157, Taiwan
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Adaptation of Saccharomyces cerevisiae in a concentrated spent sulphite liquor waste stream for increased inhibitor resistance. Appl Microbiol Biotechnol 2021; 106:455-468. [PMID: 34870737 DOI: 10.1007/s00253-021-11710-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 11/21/2021] [Accepted: 11/24/2021] [Indexed: 10/19/2022]
Abstract
The fermentation of spent sulphite liquor (SSL) from the pulping of hardwoods is limited by the combination of xylose, the primary fermentable sugar and high concentrations of microbial inhibitors that decrease the yeast fermentation ability. The inhibitor resistance phenotypes of xylose-capable Saccharomyces cerevisiae strains were therefore enhanced by combining rational engineering for multi-inhibitor tolerance, with adaptation in concentrated hardwood SSL as selective pressure. The adapted strains were assessed in fermentations with 60-80% v/v concentrated SSL under industrially relevant fermentation conditions. During adaptation, strains produced ethanol concentrations between 11.0 and 15.4 g/L in the range of that reported in literature. The adapted TFA40 and TP50 strains displayed enhanced inhibitor resistance phenotypes and were able to ferment xylose-rich SSL at pH below 5, exhibiting improved ethanol yields relative to the reference strain. Using yeast extract and peptone as nitrogen source in concentrated SSL fermentations further improved ethanol yields. However, strains exhibited a trade-off between resistance and ethanol productivity, indicating a carbon/energy cost for the expression of this inhibitor tolerance phenotype. KEY POINTS : • Achieved fermentation of xylose-rich hardwood spent sulphite liquor at pH below 5.0 • Adaptation of xylose-capable S. cerevisiae in concentrated spent sulphite liquor • Adapted strains exhibited enhanced inhibitor resistance phenotypes.
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Berninger T, Dietz N, González López Ó. Water-soluble polymers in agriculture: xanthan gum as eco-friendly alternative to synthetics. Microb Biotechnol 2021; 14:1881-1896. [PMID: 34196103 PMCID: PMC8449660 DOI: 10.1111/1751-7915.13867] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 05/31/2021] [Accepted: 05/31/2021] [Indexed: 11/28/2022] Open
Abstract
Water-soluble polymers (WSPs) are a versatile group of chemicals used across industries for different purposes such as thickening, stabilizing, adhesion and gelation. Synthetic polymers have tailored characteristics and are chemically homogeneous, whereas plant-derived biopolymers vary more widely in their specifications and are chemically heterogeneous. Between both sources, microbial polysaccharides are an advantageous compromise. They combine naturalness with defined material properties, precisely controlled by optimizing strain selection, fermentation operational parameters and downstream processes. The relevance of such bio-based and biodegradable materials is rising due to increasing environmental awareness of consumers and a tightening regulatory framework, causing both solid and water-soluble synthetic polymers, also termed 'microplastics', to have come under scrutiny. Xanthan gum is the most important microbial polysaccharide in terms of production volume and diversity of applications, and available as different grades with specific properties. In this review, we will focus on the applicability of xanthan gum in agriculture (drift control, encapsulation and soil improvement), considering its potential to replace traditionally used synthetic WSPs. As a spray adjuvant, xanthan gum prevents the formation of driftable fine droplets and shows particular resistance to mechanical shear. Xanthan gum as a component in encapsulated formulations modifies release properties or provides additional protection to encapsulated agents. In geotechnical engineering, soil amended with xanthan gum has proven to increase water retention, reduce water evaporation, percolation and soil erosion - topics of high relevance in the agriculture of the 21st century. Finally, hands-on formulation tips are provided to facilitate exploiting the full potential of xanthan gum in diverse agricultural applications and thus providing sustainable solutions.
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Affiliation(s)
- Teresa Berninger
- Jungbunzlauer Ladenburg GmbHDr.‐Albert‐Reimann‐Str. 18Ladenburg68526Germany
| | - Natalie Dietz
- Jungbunzlauer Ladenburg GmbHDr.‐Albert‐Reimann‐Str. 18Ladenburg68526Germany
| | - Óscar González López
- Department of Agriculture and FoodUniversidad de la RiojaC/Madre de Dios 53Logroño26006Spain
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Brandt BA, García-Aparicio MDP, Görgens JF, van Zyl WH. Rational engineering of Saccharomyces cerevisiae towards improved tolerance to multiple inhibitors in lignocellulose fermentations. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:173. [PMID: 34454598 PMCID: PMC8403374 DOI: 10.1186/s13068-021-02021-w] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 08/20/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND The fermentation of lignocellulose hydrolysates to ethanol requires robust xylose-capable Saccharomyces cerevisiae strains able to operate in the presence of microbial inhibitory stresses. This study aimed at developing industrial S. cerevisiae strains with enhanced tolerance towards pretreatment-derived microbial inhibitors, by identifying novel gene combinations that confer resistance to multiple inhibitors (thus cumulative inhibitor resistance phenotype) with minimum impact on the xylose fermentation ability. The strategy consisted of multiple sequential delta-integrations of double-gene cassettes containing one gene conferring broad inhibitor tolerance (ARI1, PAD1 or TAL1) coupled with an inhibitor-specific gene (ADH6, FDH1 or ICT1). The performances of the transformants were compared with the parental strain in terms of biomass growth, ethanol yields and productivity, as well as detoxification capacities in a synthetic inhibitor cocktail, sugarcane bagasse hydrolysate as well as hardwood spent sulphite liquor. RESULTS The first and second round of delta-integrated transformants exhibited a trade-off between biomass and ethanol yield. Transformants showed increased inhibitor resistance phenotypes relative to parental controls specifically in fermentations with concentrated spent sulphite liquors at 40% and 80% v/v concentrations in 2% SC media. Unexpectedly, the xylose fermentation capacity of the transformants was reduced compared to the parental control, but certain combinations of genes had a minor impact (e.g. TAL1 + FDH1). The TAL1 + ICT1 combination negatively impacted on both biomass growth and ethanol yield, which could be linked to the ICT1 protein increasing transformant susceptibility to weak acids and temperature due to cell membrane changes. CONCLUSIONS The integration of the selected genes was proven to increase tolerance to pretreatment inhibitors in synthetic or industrial hydrolysates, but they were limited to the fermentation of glucose. However, some gene combination sequences had a reduced impact on xylose conversion.
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Affiliation(s)
- Bianca A Brandt
- Department of Microbiology, Stellenbosch University, Private Bag X1, Stellenbosch, 7602, South Africa
| | - Maria D P García-Aparicio
- Department of Process Engineering, Stellenbosch University, Private Bag X1, Stellenbosch, 7602, South Africa
| | - Johann F Görgens
- Department of Process Engineering, Stellenbosch University, Private Bag X1, Stellenbosch, 7602, South Africa
| | - Willem H van Zyl
- Department of Microbiology, Stellenbosch University, Private Bag X1, Stellenbosch, 7602, South Africa.
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21
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Zheng Y, Hong K, Wang B, Liu D, Chen T, Wang Z. Genetic Diversity for Accelerating Microbial Adaptive Laboratory Evolution. ACS Synth Biol 2021; 10:1574-1586. [PMID: 34129323 DOI: 10.1021/acssynbio.0c00589] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Adaptive laboratory evolution (ALE) is a widely used and highly effective tool for improving microbial phenotypes and investigating the evolutionary roots of biological phenomena. Serving as the raw materials of evolution, mutations have been extensively utilized to increase the chances of engineering molecules or microbes with tailor-made functions. The generation of genetic diversity is therefore a core technology for accelerating ALE, and a high-quality mutant library is crucial to its success. Because of its importance, technologies for generating genetic diversity have undergone rapid development in recent years. Here, we review the existing techniques for the construction of mutant libraries, briefly introduce their mechanisms and applications, discuss ongoing and emerging efforts to apply engineering technologies in the construction of mutant libraries, and suggest future perspectives for library construction.
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Affiliation(s)
- Yangyang Zheng
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, Tianjin 300072, China
| | - Kunqiang Hong
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, Tianjin 300072, China
| | - Baowei Wang
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, Tianjin 300072, China
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
| | - Dingyu Liu
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
| | - Tao Chen
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, Tianjin 300072, China
| | - Zhiwen Wang
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, Tianjin 300072, China
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22
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Mavrommati M, Daskalaki A, Papanikolaou S, Aggelis G. Adaptive laboratory evolution principles and applications in industrial biotechnology. Biotechnol Adv 2021; 54:107795. [PMID: 34246744 DOI: 10.1016/j.biotechadv.2021.107795] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 06/11/2021] [Accepted: 07/05/2021] [Indexed: 12/20/2022]
Abstract
Adaptive laboratory evolution (ALE) is an innovative approach for the generation of evolved microbial strains with desired characteristics, by implementing the rules of natural selection as presented in the Darwinian Theory, on the laboratory bench. New as it might be, it has already been used by several researchers for the amelioration of a variety of characteristics of widely used microorganisms in biotechnology. ALE is used as a tool for the deeper understanding of the genetic and/or metabolic pathways of evolution. Another important field targeted by ALE is the manufacturing of products of (high) added value, such as ethanol, butanol and lipids. In the current review, we discuss the basic principles and techniques of ALE, and then we focus on studies where it has been applied to bacteria, fungi and microalgae, aiming to improve their performance to biotechnological procedures and/or inspect the genetic background of evolution. We conclude that ALE is a promising and efficacious method that has already led to the acquisition of useful new microbiological strains in biotechnology and could possibly offer even more interesting results in the future.
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Affiliation(s)
- Maria Mavrommati
- Unit of Microbiology, Department of Biology, Division of Genetics, Cell Biology and Development, University of Patras, 26504 Patras, Greece; Laboratory of Food Microbiology and Biotechnology, Department of Food Science and Human Nutrition, Agricultural University of Athens, 75 Iera Odos, 11855 Athens, Greece
| | - Alexandra Daskalaki
- Unit of Microbiology, Department of Biology, Division of Genetics, Cell Biology and Development, University of Patras, 26504 Patras, Greece
| | - Seraphim Papanikolaou
- Laboratory of Food Microbiology and Biotechnology, Department of Food Science and Human Nutrition, Agricultural University of Athens, 75 Iera Odos, 11855 Athens, Greece
| | - George Aggelis
- Unit of Microbiology, Department of Biology, Division of Genetics, Cell Biology and Development, University of Patras, 26504 Patras, Greece.
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23
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Gao X, Xu K, Ahmad N, Qin L, Li C. Recent advances in engineering of microbial cell factories for intelligent pH regulation and tolerance. Biotechnol J 2021; 16:e2100151. [PMID: 34164941 DOI: 10.1002/biot.202100151] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 06/09/2021] [Accepted: 06/11/2021] [Indexed: 11/12/2022]
Abstract
pH regulation is a serious concern in the industrial fermentation process as pH adjustment heavily utilizes acid/base and pollutes the environment. Under pH-stress conditions, microbial growth and production of valuable target products may be severely affected. Furthermore, some strains generating acidic or alkaline products require self pH regulation and increased tolerance against pH-stress. For pH control, synthetic biology has provided advanced engineering approaches to construct robust and more intelligent microbial strains, exhibiting tolerance to pH-stress to cope with limitations of pH regulation. This study reviewed the current progress of advanced strain evolution strategies to engineer pH-stress tolerant strains via synthetic biology. In addition, a large number of pH-responsive elements, including promoters, riboswitches, and some proteins have been investigated and applied for construction of pH-responsive genetic circuits and intelligent pH-responsive microbial strains.
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Affiliation(s)
- Xiaopeng Gao
- Key Laboratory of Medical Molecule Science and Pharmaceutics Engineering, Ministry of Industry and Information Technology, Institute of Biochemical Engineering, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, PR China.,School of Life Science, Yan'an University, Shanxi, PR China
| | - Ke Xu
- Key Lab for Industrial Biocatalysis, Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing, PR China.,Tangshan Key Laboratory of Agricultural Pathogenic Fungi and Toxins, Department of Life Science, Tangshan Normal University, Tangshan, PR China
| | - Nadeem Ahmad
- Key Laboratory of Medical Molecule Science and Pharmaceutics Engineering, Ministry of Industry and Information Technology, Institute of Biochemical Engineering, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, PR China
| | - Lei Qin
- Key Lab for Industrial Biocatalysis, Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing, PR China
| | - Chun Li
- Key Laboratory of Medical Molecule Science and Pharmaceutics Engineering, Ministry of Industry and Information Technology, Institute of Biochemical Engineering, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, PR China.,School of Life Science, Yan'an University, Shanxi, PR China.,Key Lab for Industrial Biocatalysis, Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing, PR China
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24
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Chacón SJ, Matias G, Ezeji TC, Maciel Filho R, Mariano AP. Three-stage repeated-batch immobilized cell fermentation to produce butanol from non-detoxified sugarcane bagasse hemicellulose hydrolysates. BIORESOURCE TECHNOLOGY 2021; 321:124504. [PMID: 33307480 DOI: 10.1016/j.biortech.2020.124504] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 11/30/2020] [Accepted: 12/01/2020] [Indexed: 06/12/2023]
Abstract
To enable the production of butanol with undiluted, non-detoxified sugarcane bagasse hemicellulose hydrolysates, this study developed a three-staged repeated-batch immobilized cell fermentation in which the efficiency of a 3D-printed nylon carrier to passively immobilize Clostridium saccharoperbutylacetonicum DSM 14923 was compared with sugarcane bagasse. The first stage consisted of sugarcane molasses fermentation, and in the second stage, non-detoxified sugarcane bagasse hemicellulose hydrolysates (SBHH) was pulse-fed to sugarcane molasses fermentation. In the next four batches, immobilized cells were fed with undiluted SBHH supplemented with molasses, and SBHH-derived xylose accounted for approximately 50% of the sugars. Bagasse was a superior carrier, and the average xylose utilization (33%) was significantly higher than the treatment with the 3D-printed carrier (16%). Notably, bagasse allowed for 43% of the butanol to be SBHH-derived. Overall, cell immobilization on lignocellulosic materials can be an efficient strategy to produce butanol from repeated-batch fermentation of non-detoxified hemicellulose hydrolysates.
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Affiliation(s)
- Suranny Jiménez Chacón
- Laboratory of Optimization, Design, and Advanced Control - Fermentation Division (LOPCA-Ferm), School of Chemical Engineering, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Gabriela Matias
- Laboratory of Optimization, Design, and Advanced Control - Fermentation Division (LOPCA-Ferm), School of Chemical Engineering, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Thaddeus Chukwuemeka Ezeji
- The Ohio State University, Department of Animal Sciences, Ohio State Agricultural Research and Development Center, Wooster, OH, USA
| | - Rubens Maciel Filho
- Laboratory of Optimization, Design, and Advanced Control - Fermentation Division (LOPCA-Ferm), School of Chemical Engineering, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Adriano Pinto Mariano
- Laboratory of Optimization, Design, and Advanced Control - Fermentation Division (LOPCA-Ferm), School of Chemical Engineering, University of Campinas (UNICAMP), Campinas, SP, Brazil.
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25
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Ouyang S, Zou L, Qiao H, Shi J, Zheng Z, Ouyang J. One-pot process for lactic acid production from wheat straw by an adapted Bacillus coagulans and identification of genes related to hydrolysate-tolerance. BIORESOURCE TECHNOLOGY 2020; 315:123855. [PMID: 32707506 DOI: 10.1016/j.biortech.2020.123855] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Revised: 07/12/2020] [Accepted: 07/13/2020] [Indexed: 05/26/2023]
Abstract
In this study, Bacillus coagulans CC17A with highly tolerant to hydrolysate was obtained through adaptive evolution. After 63 generations, the strain CC17A was stably in 45% (v/v) hydrolysate media and could digest multiple inhibitors in the hydrolysate. Based on its promising features, a one-pot process was developed to produce lactic acid (LA) from wheat straw. After dilute acid pretreatment of wheat straw, simultaneous saccharification and co-fermentation was conducted using CC17A without any solid-liquid separation and pre-detoxification. Total 35.50 g LA was produced from 80 g raw substrate and the production yield was as high as 70.9% of theoretical. To elucidate the tolerance mechanism, transcriptomic profiling of CC17A was studied. The highly up-regulated oxidoreductases and phenolic acid decarboxylase are considered to be involved with the inhibitors-tolerance of B. coagulans CC17A.
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Affiliation(s)
- Shuiping Ouyang
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, People's Republic of China
| | - Lihua Zou
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, People's Republic of China
| | - Hui Qiao
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, People's Republic of China
| | - Jinjie Shi
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, People's Republic of China
| | - Zhaojuan Zheng
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, People's Republic of China
| | - Jia Ouyang
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, People's Republic of China.
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26
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Origin, Impact and Control of Lignocellulosic Inhibitors in Bioethanol Production—A Review. ENERGIES 2020. [DOI: 10.3390/en13184751] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Bioethanol production from lignocellulosic biomass is still struggling with many obstacles. One of them is lignocellulosic inhibitors. The aim of this review is to discuss the most known inhibitors. Additionally, the review addresses different detoxification methods to degrade or to remove inhibitors from lignocellulosic hydrolysates. Inhibitors are formed during the pretreatment of biomass. They derive from the structural polymers-cellulose, hemicellulose and lignin. The formation of inhibitors depends on the pretreatment conditions. Inhibitors can have a negative influence on both the enzymatic hydrolysis and fermentation of lignocellulosic hydrolysates. The inhibition mechanisms can be, for example, deactivation of enzymes or impairment of vital cell structures. The toxicity of each inhibitor depends on its chemical and physical properties. To decrease the negative effects of inhibitors, different detoxification methods have been researched. Those methods focus on the chemical modification of inhibitors into less toxic forms or on the separation of inhibitors from lignocellulosic hydrolysates. Each detoxification method has its limitations on the removal of certain inhibitors. To choose a suitable detoxification method, a deep molecular understanding of the inhibition mechanism and the inhibitor formation is necessary.
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27
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van Dijk M, Erdei B, Galbe M, Nygård Y, Olsson L. Strain-dependent variance in short-term adaptation effects of two xylose-fermenting strains of Saccharomyces cerevisiae. BIORESOURCE TECHNOLOGY 2019; 292:121922. [PMID: 31398543 DOI: 10.1016/j.biortech.2019.121922] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 07/26/2019] [Accepted: 07/27/2019] [Indexed: 06/10/2023]
Abstract
The limited tolerance of Saccharomyces cerevisiae to the inhibitors present in lignocellulosic hydrolysates is a major challenge in second-generation bioethanol production. Short-term adaptation of the yeast to lignocellulosic hydrolysates during cell propagation has been shown to improve its tolerance, and thus its performance in lignocellulose fermentation. The aim of this study was to investigate the short-term adaptation effects in yeast strains with different genetic backgrounds. Fed-batch propagation cultures were supplemented with 40% wheat straw hydrolysate during the feed phase to adapt two different pentose-fermenting strains, CR01 and KE6-12. The harvested cells were used to inoculate fermentation media containing 80% or 90% wheat straw hydrolysate. The specific ethanol productivity during fermentation was up to 3.6 times higher for CR01 and 1.6 times higher for KE6-12 following adaptation. The influence of physiological parameters such as viability, storage carbohydrate content, and metabolite yields following short-term adaptation demonstrated that short-term adaptation was strain dependent.
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Affiliation(s)
- Marlous van Dijk
- Chalmers University of Technology, Dept. Biology and Bioengineering, Division of Industrial Biotechnology, Kemivägen 10, SE-412 96 Göteborg, Sweden
| | - Borbála Erdei
- Lund University, Dept. Chemical Engineering, P.O. Box 124, SE-221 00 Lund, Sweden
| | - Mats Galbe
- Lund University, Dept. Chemical Engineering, P.O. Box 124, SE-221 00 Lund, Sweden
| | - Yvonne Nygård
- Chalmers University of Technology, Dept. Biology and Bioengineering, Division of Industrial Biotechnology, Kemivägen 10, SE-412 96 Göteborg, Sweden
| | - Lisbeth Olsson
- Chalmers University of Technology, Dept. Biology and Bioengineering, Division of Industrial Biotechnology, Kemivägen 10, SE-412 96 Göteborg, Sweden.
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28
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Kim MS, Cho KH, Park KH, Jang J, Hahn JS. Activation of Haa1 and War1 transcription factors by differential binding of weak acid anions in Saccharomyces cerevisiae. Nucleic Acids Res 2019; 47:1211-1224. [PMID: 30476185 PMCID: PMC6379682 DOI: 10.1093/nar/gky1188] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 10/31/2018] [Accepted: 11/07/2018] [Indexed: 01/03/2023] Open
Abstract
In Saccharomyces cerevisiae, Haa1 and War1 transcription factors are involved in cellular adaptation against hydrophilic weak acids and lipophilic weak acids, respectively. However, it is unclear how these transcription factors are differentially activated depending on the identity of the weak acid. Using a field-effect transistor (FET)-type biosensor based on carbon nanofibers, in the present study we demonstrate that Haa1 and War1 directly bind to various weak acid anions with different affinities. Haa1 is most sensitive to acetate, followed by lactate, whereas War1 is most sensitive to benzoate, followed by sorbate, reflecting their differential activation during weak acid stresses. We show that DNA binding by Haa1 is induced in the presence of acetic acid and that the N-terminal Zn-binding domain is essential for this activity. Acetate binds to the N-terminal 150-residue region, and the transcriptional activation domain is located between amino acid residues 230 and 483. Our data suggest that acetate binding converts an inactive Haa1 to the active form, which is capable of DNA binding and transcriptional activation.
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Affiliation(s)
- Myung Sup Kim
- School of Chemical and Biological Engineering, Seoul National University, Institute of Chemical Processes, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
| | - Kyung Hee Cho
- School of Chemical and Biological Engineering, Seoul National University, Institute of Chemical Processes, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
| | - Kwang Hyun Park
- School of Chemical and Biological Engineering, Seoul National University, Institute of Chemical Processes, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
| | - Jyongsik Jang
- School of Chemical and Biological Engineering, Seoul National University, Institute of Chemical Processes, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
| | - Ji-Sook Hahn
- School of Chemical and Biological Engineering, Seoul National University, Institute of Chemical Processes, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
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29
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Duan G, Wu B, Qin H, Wang W, Tan Q, Dai Y, Qin Y, Tan F, Hu G, He M. Replacing water and nutrients for ethanol production by ARTP derived biogas slurry tolerant Zymomonas mobilis strain. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:124. [PMID: 31139254 PMCID: PMC6528197 DOI: 10.1186/s13068-019-1463-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Accepted: 05/04/2019] [Indexed: 06/09/2023]
Abstract
BACKGROUND Reducing fresh water consumption and nutrient addition will be an effective way to reduce the whole cost of bioethanol production. On the other hand, treatment of biogas slurry derived from anaerobic digestion (AD), in which a great amount of nutrients is still left, costs too much to remove these pollutants. It would be beneficial for both digestate valorization and ethanol production if biogas slurry is used for producing bioethanol. However, both hyperosmosis and potential biotoxic components of the biogas slurry can severely inhibit fermentation. RESULTS In this study, two rounds of atmospheric and room temperature plasma (ARTP) mutagenesis combined with adaptive laboratory evolution (ALE) were applied to improve the adaptability and genetic stability of Zymomonas mobilis in biogas slurry. Mutants D95 and S912 were identified. Growth of the mutants was remarkably improved in biogas slurry. The highest ethanol productivity reached 0.63 g/L/h which was 61.7% higher than ZM4 (0.39 g/L/h). Genomic re-sequencing results also revealed that single nucleic variations (SNVs) and Indels occurred in the mutants, which are likely related to inhibitor in biogas slurry and low pH tolerance. CONCLUSIONS Our study demonstrated that these mutant strains have great potential to produce ethanol using biogas slurry to replace fresh water and nutrients.
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Affiliation(s)
- Guowei Duan
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs) Biogas Institute of Ministry of Agriculture and Rural Affairs, Section 4-13, Renmin Rd. South, Chengdu, 610041 People’s Republic of China
- Graduate School of Chinese Academy of Agricultural Science, Beijing, 100081 People’s Republic of China
| | - Bo Wu
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs) Biogas Institute of Ministry of Agriculture and Rural Affairs, Section 4-13, Renmin Rd. South, Chengdu, 610041 People’s Republic of China
| | - Han Qin
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs) Biogas Institute of Ministry of Agriculture and Rural Affairs, Section 4-13, Renmin Rd. South, Chengdu, 610041 People’s Republic of China
| | - Weiting Wang
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs) Biogas Institute of Ministry of Agriculture and Rural Affairs, Section 4-13, Renmin Rd. South, Chengdu, 610041 People’s Republic of China
- Graduate School of Chinese Academy of Agricultural Science, Beijing, 100081 People’s Republic of China
| | - Qiong Tan
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs) Biogas Institute of Ministry of Agriculture and Rural Affairs, Section 4-13, Renmin Rd. South, Chengdu, 610041 People’s Republic of China
- Graduate School of Chinese Academy of Agricultural Science, Beijing, 100081 People’s Republic of China
| | - Yonghua Dai
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs) Biogas Institute of Ministry of Agriculture and Rural Affairs, Section 4-13, Renmin Rd. South, Chengdu, 610041 People’s Republic of China
- Graduate School of Chinese Academy of Agricultural Science, Beijing, 100081 People’s Republic of China
| | - Yao Qin
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs) Biogas Institute of Ministry of Agriculture and Rural Affairs, Section 4-13, Renmin Rd. South, Chengdu, 610041 People’s Republic of China
- College of Pharmacy and Biological Engineering, Chengdu University, Chengdu, 610041 People’s Republic of China
| | - Furong Tan
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs) Biogas Institute of Ministry of Agriculture and Rural Affairs, Section 4-13, Renmin Rd. South, Chengdu, 610041 People’s Republic of China
- Graduate School of Chinese Academy of Agricultural Science, Beijing, 100081 People’s Republic of China
| | - Guoquan Hu
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs) Biogas Institute of Ministry of Agriculture and Rural Affairs, Section 4-13, Renmin Rd. South, Chengdu, 610041 People’s Republic of China
- Graduate School of Chinese Academy of Agricultural Science, Beijing, 100081 People’s Republic of China
| | - Mingxiong He
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs) Biogas Institute of Ministry of Agriculture and Rural Affairs, Section 4-13, Renmin Rd. South, Chengdu, 610041 People’s Republic of China
- Graduate School of Chinese Academy of Agricultural Science, Beijing, 100081 People’s Republic of China
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30
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Engineering microbial membranes to increase stress tolerance of industrial strains. Metab Eng 2019; 53:24-34. [DOI: 10.1016/j.ymben.2018.12.010] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 12/29/2018] [Accepted: 12/29/2018] [Indexed: 12/29/2022]
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31
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Palakawong Na Ayutthaya P, Charoenrat T, Krusong W, Pornpukdeewattana S. Repeated cultures of Saccharomyces cerevisiae SC90 to tolerate inhibitors generated during cassava processing waste hydrolysis for bioethanol production. 3 Biotech 2019; 9:76. [PMID: 30800587 PMCID: PMC6370576 DOI: 10.1007/s13205-019-1607-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 02/01/2019] [Indexed: 12/29/2022] Open
Abstract
Large amount of cassava pulp is produced as by-product of industrial tapioca production. The value-added process of this low-cost waste is to use it as a substrate for bioethanol production. However, during the pulp pretreatment by acidification combined with steam explosion, many yeast inhibitors including acetic acid, formic acid, levulinic acid, furfural and 5-hydroxymethylfurfural are generated and these compounds have negative effects on the subsequent fermentation step. Therefore, the objective of this study was to investigate whether the repeated cultures of Saccharomyces cerevisiae SC90 could alleviate this problem. To obtain the inhibitor tolerable cells, the repeated culture was performed by growing yeast cells to a specific growth rate (µ) of 0.22 h-1 or higher (80% of the µ in control) and then transferring them to progressively higher concentrations of hydrolysate ranging from 20 to 100% (v/v). The results showed a tendency of longer lag phase as well as time to reach maximum cell number (t maxc) with an increase in hydrolysate concentration. However, the repeated culture at the same hydrolysate concentration could shorten both lag period and t maxc. Interestingly, the growth and fermentation efficiency of adapted cells in 100% hydrolysate were significantly higher (p ≤ 0.05) than those of non-adapted cells by 38% and 27%, respectively.
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Affiliation(s)
- Pakathamon Palakawong Na Ayutthaya
- Division of Fermentation Technology, Faculty of Agro-Industry, King Mongkut’s Institute of Technology Ladkrabang, Bangkok, 10520 Thailand
| | - Theppanya Charoenrat
- Department of Biotechnology, Faculty of Science and Technology, Thammasat University (Rangsit Center), Pathum Thani, 12120 Thailand
| | - Warawut Krusong
- Division of Fermentation Technology, Faculty of Agro-Industry, King Mongkut’s Institute of Technology Ladkrabang, Bangkok, 10520 Thailand
| | - Soisuda Pornpukdeewattana
- Division of Fermentation Technology, Faculty of Agro-Industry, King Mongkut’s Institute of Technology Ladkrabang, Bangkok, 10520 Thailand
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Gu H, Zhu Y, Peng Y, Liang X, Liu X, Shao L, Xu Y, Xu Z, Liu R, Li J. Physiological mechanism of improved tolerance of Saccharomyces cerevisiae to lignin-derived phenolic acids in lignocellulosic ethanol fermentation by short-term adaptation. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:268. [PMID: 31755875 PMCID: PMC6854637 DOI: 10.1186/s13068-019-1610-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 11/04/2019] [Indexed: 05/08/2023]
Abstract
BACKGROUND Phenolic acids are lignin-derived fermentation inhibitors formed during many pretreatment processes of lignocellulosic biomass. In this study, vanillic, p-hydroxybenzoic, and syringic acids were selected as the model compounds of phenolic acids, and the effect of short-term adaptation strategies on the tolerance of S. cerevisiae to phenolic acids was investigated. The mechanism of phenolic acids tolerance in the adapted yeast strains was studied at the morphological and physiological levels. RESULTS The multiple phenolic acids exerted the synergistic inhibitory effect on the yeast cell growth. In particular, a significant interaction between vanillic and hydroxybenzoic acids was found. The optimal short-term adaptation strategies could efficiently improve the growth and fermentation performance of the yeast strain not only in the synthetic media with phenolic acids, but also in the simultaneous saccharification and ethanol fermentation of corncob residue. Morphological analysis showed that phenolic acids caused the parental strain to generate many cytoplasmic membrane invaginations with crack at the top of these sites and some mitochondria gathered around. The adapted strain presented the thicker cell wall and membrane and smaller cell size than those of the parental strain. In particular, the cytoplasmic membrane generated many little protrusions with regular shape. The cytoplasmic membrane integrity was analyzed by testing the relative electrical conductivity, leakage of intracellular substance, and permeation of fluorescent probe. The results indicated that the short-term adaptation improved the membrane integrity of yeast cell. CONCLUSION The inhibition mechanism of phenolic acid might be attributed to the combined effect of the cytoplasmic membrane damage and the intracellular acidification. The short-term adaptation strategy with varied stressors levels and adaptive processes accelerated the stress response of yeast cell structure to tolerate phenolic acids. This strategy will contribute to the development of robust microbials for biofuel production from lignocellulosic biomass.
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Affiliation(s)
- Hanqi Gu
- Department of Biology and Food Science, Hebei Normal University for Nationalities, Chengde, 067000 Hebei China
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237 China
| | - Yuyong Zhu
- Department of Biology and Food Science, Hebei Normal University for Nationalities, Chengde, 067000 Hebei China
| | - Yanfang Peng
- Department of Biology and Food Science, Hebei Normal University for Nationalities, Chengde, 067000 Hebei China
| | - Xiujun Liang
- Basic Medical Institute, Chengde Medical University, Chengde, 067000 Hebei China
| | - Xiaoguang Liu
- Department of Biology and Food Science, Hebei Normal University for Nationalities, Chengde, 067000 Hebei China
| | - Lingzhi Shao
- Department of Biology and Food Science, Hebei Normal University for Nationalities, Chengde, 067000 Hebei China
| | - Yanyan Xu
- Department of Biology and Food Science, Hebei Normal University for Nationalities, Chengde, 067000 Hebei China
| | - Zhaohe Xu
- Department of Biology and Food Science, Hebei Normal University for Nationalities, Chengde, 067000 Hebei China
| | - Ran Liu
- Department of Biology and Food Science, Hebei Normal University for Nationalities, Chengde, 067000 Hebei China
| | - Jie Li
- Department of Biology and Food Science, Hebei Normal University for Nationalities, Chengde, 067000 Hebei China
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Wu B, Qin H, Yang Y, Duan G, Yang S, Xin F, Zhao C, Shao H, Wang Y, Zhu Q, Tan F, Hu G, He M. Engineered Zymomonas mobilis tolerant to acetic acid and low pH via multiplex atmospheric and room temperature plasma mutagenesis. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:10. [PMID: 30627218 PMCID: PMC6321654 DOI: 10.1186/s13068-018-1348-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 12/24/2018] [Indexed: 05/19/2023]
Abstract
BACKGROUND Cellulosic biofuels are sustainable compared to fossil fuels. However, inhibitors, such as acetic acid generated during lignocellulose pretreatment and hydrolysis, would significantly inhibit microbial fermentation efficiency. Microbial mutants able to tolerate high concentration of acetic acid are needed urgently to alleviate this inhibition. RESULTS Zymomonas mobilis mutants AQ8-1 and AC8-9 with enhanced tolerance against acetic acid were generated via a multiplex atmospheric and room temperature plasma (mARTP) mutagenesis. The growth and ethanol productivity of AQ8-1 and AC8-9 were both improved in the presence of 5.0-8.0 g/L acetic acid. Ethanol yield reached 84% of theoretical value in the presence of 8.0 g/L acetic acid (~ pH 4.0). Furthermore, a mutant tolerant to pH 3.5, named PH1-29, was generated via the third round of ARTP mutagenesis. PH1-29 showed enhanced growth and ethanol production under both sterilized/unsterilized conditions at pH 4.0 or 3.5. Intracellular NAD levels revealed that mARTP mutants could modulate NADH/NAD+ ratio to respond to acetic acid and low pH stresses. Moreover, genomic re-sequencing revealed that eleven single nucleic variations (SNVs) were likely related to acetic acid and low pH tolerance. Most SNVs were targeted in regions between genes ZMO0952 and ZMO0956, ZMO0152 and ZMO0153, and ZMO0373 and ZMO0374. CONCLUSIONS The multiplex mutagenesis strategy mARTP was efficient for enhancing the tolerance in Z. mobilis. The ARTP mutants generated in this study could serve as potential cellulosic ethanol producers.
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Affiliation(s)
- Bo Wu
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture), Biogas Institute of Ministry of Agriculture, Section 4-13, Renmin Rd. South, Chengdu, 610041 China
| | - Han Qin
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture), Biogas Institute of Ministry of Agriculture, Section 4-13, Renmin Rd. South, Chengdu, 610041 China
| | - Yiwei Yang
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture), Biogas Institute of Ministry of Agriculture, Section 4-13, Renmin Rd. South, Chengdu, 610041 China
| | - Guowei Duan
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture), Biogas Institute of Ministry of Agriculture, Section 4-13, Renmin Rd. South, Chengdu, 610041 China
| | - Shihui Yang
- Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Environmental Microbial Technology Center of Hubei Province, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Fengxue Xin
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30 Puzhu Rd, Pukou District, Nanjing, 211816 China
| | - Chunyan Zhao
- College of Life Science, Sichuan Normal University, Section 2-1819, Chenglong Avenue, Chengdu, 610101 China
| | - Huanhuan Shao
- College of Life Science, Sichuan Normal University, Section 2-1819, Chenglong Avenue, Chengdu, 610101 China
| | - Yanwei Wang
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture), Biogas Institute of Ministry of Agriculture, Section 4-13, Renmin Rd. South, Chengdu, 610041 China
| | - Qili Zhu
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture), Biogas Institute of Ministry of Agriculture, Section 4-13, Renmin Rd. South, Chengdu, 610041 China
| | - Furong Tan
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture), Biogas Institute of Ministry of Agriculture, Section 4-13, Renmin Rd. South, Chengdu, 610041 China
| | - Guoquan Hu
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture), Biogas Institute of Ministry of Agriculture, Section 4-13, Renmin Rd. South, Chengdu, 610041 China
| | - Mingxiong He
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture), Biogas Institute of Ministry of Agriculture, Section 4-13, Renmin Rd. South, Chengdu, 610041 China
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Štafa A, Žunar B, Pranklin A, Zandona A, Svetec-Miklenić M, Šantek B, Svetec IK. Novel Approach in the Construction of
Bioethanol-Producing Saccharomyces cerevisiae Hybrids §. Food Technol Biotechnol 2019; 57:5-16. [PMID: 31316272 PMCID: PMC6600304 DOI: 10.17113/ftb.57.01.19.5685] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [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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Ambye-Jensen M, Balzarotti R, Thomsen ST, Fonseca C, Kádár Z. Combined ensiling and hydrothermal processing as efficient pretreatment of sugarcane bagasse for 2G bioethanol production. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:336. [PMID: 30598698 PMCID: PMC6300893 DOI: 10.1186/s13068-018-1338-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Accepted: 12/11/2018] [Indexed: 05/31/2023]
Abstract
BACKGROUND Ensiling cannot be utilized as a stand-alone pretreatment for sugar-based biorefinery processes but, in combination with hydrothermal processing, it can enhance pretreatment while ensuring a stable long-term storage option for abundant but moist biomass. The effectiveness of combining ensiling with hydrothermal pretreatment depends on biomass nature, pretreatment, and silage conditions. RESULTS In the present study, the efficiency of the combined pretreatment was assessed by enzymatic hydrolysis and ethanol fermentation, and it was demonstrated that ensiling of sugarcane bagasse produces organic acids that can partly degrade biomass structure when in combination with hydrothermal treatment, with the consequent improvement of the enzymatic hydrolysis of cellulose and of the overall 2G bioethanol process efficiency. The optimal pretreatment conditions found in this study were those using ensiling and/or hydrothermal pretreatment at 190 °C for 10 min as this yielded the highest overall glucose recovery yield and ethanol yield from the raw material (0.28-0.30 g/g and 0.14 g/g, respectively). CONCLUSION Ensiling prior to hydrothermal pretreatment offers a controlled solution for wet storage and long-term preservation for sugarcane bagasse, thus avoiding the need for drying. This preservation method combined with long-term storage practice can be an attractive option for integrated 1G/2G bioethanol plants, as it does not require large capital investments or energy inputs and leads to comparable or higher overall sugar recovery and ethanol yields.
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Affiliation(s)
- Morten Ambye-Jensen
- Center for BioProcess Engineering, Department of Chemical and Biochemical Engineering, Technical University of Denmark, DTU, Søltofts Plads 229, 2800 Kgs. Lyngby, Denmark
- Present Address: Department of Engineering, Biological and Chemical Engineering, Aarhus University, Finlandsgade 22, 8200 Aarhus N, Denmark
| | - Riccardo Balzarotti
- Center for BioProcess Engineering, Department of Chemical and Biochemical Engineering, Technical University of Denmark, DTU, Søltofts Plads 229, 2800 Kgs. Lyngby, Denmark
| | - Sune Tjalfe Thomsen
- Center for BioProcess Engineering, Department of Chemical and Biochemical Engineering, Technical University of Denmark, DTU, Søltofts Plads 229, 2800 Kgs. Lyngby, Denmark
- Present Address: Department of Geosciences and Natural Resource Management (IGN), University of Copenhagen, Rolighedsvej 23, 1958 Frederiksberg C, Denmark
| | - César Fonseca
- Bioenergy Unit, Laboratório Nacional de Energia e Geologia, I.P., Estrada do Paço do Lumiar 22, 1649-038 Lisbon, Portugal
- Present Address: Section for Sustainable Biotechnology, Department of Chemistry and Bioscience, Aalborg University, A C Mæyers Vænge 15, 2450 Copenhagen SV, Denmark
| | - Zsófia Kádár
- Center for BioProcess Engineering, Department of Chemical and Biochemical Engineering, Technical University of Denmark, DTU, Søltofts Plads 229, 2800 Kgs. Lyngby, Denmark
- Present Address: Section for Sustainable Biotechnology, Department of Chemistry and Bioscience, Aalborg University, A C Mæyers Vænge 15, 2450 Copenhagen SV, Denmark
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Schelezki OJ, Smith PA, Hranilovic A, Bindon KA, Jeffery DW. Comparison of consecutive harvests versus blending treatments to produce lower alcohol wines from Cabernet Sauvignon grapes: Impact on polysaccharide and tannin content and composition. Food Chem 2017; 244:50-59. [PMID: 29120804 DOI: 10.1016/j.foodchem.2017.10.024] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 10/04/2017] [Accepted: 10/06/2017] [Indexed: 10/18/2022]
Abstract
A changing climate has led to winegrapes being harvested with increased sugar levels and at greater risk of berry shrivel. A suggested easy-to-adopt strategy to manage the associated rising wine alcohol levels is the pre-fermentative substitution of juice with either "green harvest wine" or water. Our study investigates the effects of this approach on Vitis vinifera L. cv. Cabernet Sauvignon wine quality attributes. Wines were also made from fruit collected at consecutive earlier harvest time points to produce wines comparable in alcohol to the substituted wines. Tannin concentrations and colour did not change significantly in the wines with modified alcohol content even at higher juice substitution rates. Differences in polysaccharide and tannin composition indicated variability in extraction dynamics according to substitution rate and type of blending component. In scenarios where berry shrivel is inevitable, the incorporation of water in particular offers much promise as part of a strategy to manage wine alcohol content.
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Affiliation(s)
- Olaf J Schelezki
- The Australian Research Council Training Centre for Innovative Wine Production, and Department of Wine and Food Science, The University of Adelaide, Waite Campus, PMB 1, Glen Osmond, SA 5064, Australia
| | - Paul A Smith
- The Australian Wine Research Institute, PO Box 197, Glen Osmond, SA 5064, Australia
| | - Ana Hranilovic
- The Australian Research Council Training Centre for Innovative Wine Production, and Department of Wine and Food Science, The University of Adelaide, Waite Campus, PMB 1, Glen Osmond, SA 5064, Australia
| | - Keren A Bindon
- The Australian Wine Research Institute, PO Box 197, Glen Osmond, SA 5064, Australia
| | - David W Jeffery
- The Australian Research Council Training Centre for Innovative Wine Production, and Department of Wine and Food Science, The University of Adelaide, Waite Campus, PMB 1, Glen Osmond, SA 5064, Australia.
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Narayanan V, Schelin J, Gorwa-Grauslund M, van Niel EWJ, Carlquist M. Increased lignocellulosic inhibitor tolerance of Saccharomyces cerevisiae cell populations in early stationary phase. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:114. [PMID: 28484514 PMCID: PMC5418707 DOI: 10.1186/s13068-017-0794-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Accepted: 04/18/2017] [Indexed: 05/23/2023]
Abstract
BACKGROUND Production of second-generation bioethanol and other bulk chemicals by yeast fermentation requires cells that tolerate inhibitory lignocellulosic compounds at low pH. Saccharomyces cerevisiae displays high plasticity with regard to inhibitor tolerance, and adaptation of cell populations to process conditions is essential for reaching efficient and robust fermentations. RESULTS In this study, we assessed responses of isogenic yeast cell populations in different physiological states to combinations of acetic acid, vanillin and furfural at low pH. We found that cells in early stationary phase (ESP) exhibited significantly increased tolerance compared to cells in logarithmic phase, and had a similar ability to initiate growth in the presence of inhibitors as pre-adapted cells. The ESP cultures consisted of subpopulations with different buoyant cell densities which were isolated with flotation and analysed separately. These so-called quiescent (Q) and non-quiescent (NQ) cells were found to possess similar abilities to initiate growth in the presence of lignocellulosic inhibitors at pH 3.7, and had similar viabilities under static conditions. Therefore, differentiation into Q-cells was not the cause for increased tolerance of ESP cultures. Flow cytometry analysis of cell viability, intracellular pH and reactive oxygen species levels revealed that tolerant cell populations had a characteristic response upon inhibitor perturbations. Growth in the presence of a combination of inhibitors at low pH correlated with pre-cultures having a high frequency of cells with low pHi and low ROS levels. Furthermore, only a subpopulation of ESP cultures was able to tolerate lignocellulosic inhibitors at low pH, while pre-adapted cell populations displayed an almost uniform high tolerance to the adverse condition. This was in stark contrast to cell populations growing exponentially in non-inhibitory medium that were uniformly sensitive to the inhibitors at low pH. CONCLUSIONS ESP cultures of S. cerevisiae were found to have high tolerance to lignocellulosic inhibitors at low pH, and were able to initiate growth to the same degree as cells that were pre-adapted to inhibitors at a slightly acidic pH. Carbon starvation may thus be a potential strategy to prepare cell populations for adjacent stressful environments which may be beneficial from a process perspective for fermentation of non-detoxified lignocellulosic substrates at low pH. Furthermore, flow cytometry analysis of pHi and ROS level distributions in ESP cultures revealed responses that were characteristic for populations with high tolerance to lignocellulosic inhibitors. Measurement of population distribution responses as described herein may be applied to predict the outcome of environmental perturbations and thus can function as feedback for process control of yeast fitness during lignocellulosic fermentation.
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Affiliation(s)
- Venkatachalam Narayanan
- Division of Applied Microbiology, Department of Chemistry, Lund University, P.O. Box 124, SE 221 00 Lund, Sweden
| | - Jenny Schelin
- Division of Applied Microbiology, Department of Chemistry, Lund University, P.O. Box 124, SE 221 00 Lund, Sweden
| | - Marie Gorwa-Grauslund
- Division of Applied Microbiology, Department of Chemistry, Lund University, P.O. Box 124, SE 221 00 Lund, Sweden
| | - Ed WJ van Niel
- Division of Applied Microbiology, Department of Chemistry, Lund University, P.O. Box 124, SE 221 00 Lund, Sweden
| | - Magnus Carlquist
- Division of Applied Microbiology, Department of Chemistry, Lund University, P.O. Box 124, SE 221 00 Lund, Sweden
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Evolutionary engineering reveals divergent paths when yeast is adapted to different acidic environments. Metab Eng 2017; 39:19-28. [DOI: 10.1016/j.ymben.2016.10.010] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 10/01/2016] [Accepted: 10/21/2016] [Indexed: 12/30/2022]
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