1
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Amaro-Reyes A, Marcial-Ramírez D, Vázquez-Landaverde PA, Utrilla J, Escamilla-García M, Regalado C, Macias-Bobadilla G, Campos-Guillén J, Ramos-López MA, Favela-Camacho SE. Electrostatic Fermentation: Molecular Response Insights for Tailored Beer Production. Foods 2024; 13:600. [PMID: 38397576 PMCID: PMC10887865 DOI: 10.3390/foods13040600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 02/11/2024] [Accepted: 02/14/2024] [Indexed: 02/25/2024] Open
Abstract
Electrostatic fermentation avoids the cellular redox imbalance of traditional fermentation, but knowledge gaps exist. This study explores the impact of electrostatic fermentation on the growth, volatile profile, and genetic response of Saccharomyces pastorianus Saflager S-23. The applied voltage (15 and 30 V) in the electrostatic fermentation system increased the growth and substrate utilization of S. pastorianus while decreasing ethanol production. The aromas typically associated with traditional fermentation, such as alcoholic, grape, apple, and sweet notes, were diminished, while aromas like roses, fruits, flowers, and bananas were augmented in electrostatic fermentation. RNA-seq analysis revealed upregulation of genes involved in cell wall structure, oxidoreductase activity, and iron ion binding, while genes associated with protein synthesis, growth control, homeostasis, and membrane function were downregulated under the influence of applied voltage. The electrostatic fermentation system modulates genetic responses and metabolic pathways in yeast, rendering it a promising method for tailored beer production. Demonstrating feasibility under industrial-scale and realistic conditions is crucial for advancing towards commercialization.
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Affiliation(s)
- Aldo Amaro-Reyes
- Faculty of Chemistry, Autonomous University of Queretaro, C.U., Cerro de las Campanas S/N, Las Campanas, Querétaro 76010, QRO, Mexico; (M.E.-G.); (J.C.-G.); (M.A.R.-L.)
- Department of Food Research and Postgraduate Studies, Faculty of Chemistry, Autonomous University of Queretaro, C.U., Cerro de las Campanas S/N, Las Campanas, Querétaro 76010, QRO, Mexico; (D.M.-R.); (C.R.)
| | - Diana Marcial-Ramírez
- Department of Food Research and Postgraduate Studies, Faculty of Chemistry, Autonomous University of Queretaro, C.U., Cerro de las Campanas S/N, Las Campanas, Querétaro 76010, QRO, Mexico; (D.M.-R.); (C.R.)
| | - Pedro Alberto Vázquez-Landaverde
- Center for Research in Applied Science and Advanced Technology, Querétaro Unit, National Polytechnic Institute, Cerro Blanco 141, Colinas del Cimatario, Querétaro 76090, QRO, Mexico;
| | - José Utrilla
- Synthetic Biology Program, Center for Genomic Sciences, National Autonomous University of Mexico, Avenida Universidad 2001, Chamilpa, Cuernavaca 62210, MOR, Mexico;
| | - Monserrat Escamilla-García
- Faculty of Chemistry, Autonomous University of Queretaro, C.U., Cerro de las Campanas S/N, Las Campanas, Querétaro 76010, QRO, Mexico; (M.E.-G.); (J.C.-G.); (M.A.R.-L.)
| | - Carlos Regalado
- Department of Food Research and Postgraduate Studies, Faculty of Chemistry, Autonomous University of Queretaro, C.U., Cerro de las Campanas S/N, Las Campanas, Querétaro 76010, QRO, Mexico; (D.M.-R.); (C.R.)
| | - Gonzalo Macias-Bobadilla
- Division of Postgraduate Studies, Faculty of Engineering, Autonomous University of Querétaro, Cerro de las Campanas S/N, Las Campanas, Querétaro 76010, QRO, Mexico;
| | - Juan Campos-Guillén
- Faculty of Chemistry, Autonomous University of Queretaro, C.U., Cerro de las Campanas S/N, Las Campanas, Querétaro 76010, QRO, Mexico; (M.E.-G.); (J.C.-G.); (M.A.R.-L.)
| | - Miguel Angel Ramos-López
- Faculty of Chemistry, Autonomous University of Queretaro, C.U., Cerro de las Campanas S/N, Las Campanas, Querétaro 76010, QRO, Mexico; (M.E.-G.); (J.C.-G.); (M.A.R.-L.)
| | - Sarai E. Favela-Camacho
- Institute of Engineering and Technology, Autonomous University of Ciudad Juárez, Avenida del Charro s/n y, Calle Henry Dunant, Omega, Cd Juárez 32584, CHIH, Mexico;
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2
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Bysani VR, Alam AS, Bar-Even A, Machens F. Engineering and evolution of the complete Reductive Glycine Pathway in Saccharomyces cerevisiae for formate and CO 2 assimilation. Metab Eng 2024; 81:167-181. [PMID: 38040111 DOI: 10.1016/j.ymben.2023.11.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 11/08/2023] [Accepted: 11/25/2023] [Indexed: 12/03/2023]
Abstract
Using captured CO2 and C1-feedstocks like formate and methanol derived from electrochemical activation of CO2 are key solutions for transforming industrial processes towards a circular carbon economy. Engineering formate and CO2-based growth in the biotechnologically relevant yeast Saccharomyces cerevisiae could boost the emergence of a formate-mediated circular bio-economy. This study adopts a growth-coupled selection scheme for modular implementation of the Reductive Glycine Pathway (RGP) and subsequent Adaptive Laboratory Evolution (ALE) to enable formate and CO2 assimilation for biomass formation in yeast. We first constructed a serine biosensor strain and then implemented the serine synthesis module of the RGP into yeast, establishing glycine and serine synthesis from formate and CO2. ALE improved the RGP-dependent growth by 8-fold. 13C-labeling experiments reveal glycine, serine, and pyruvate synthesis via the RGP, demonstrating the complete pathway activity. Further, we re-established formate and CO2-dependent growth in non-evolved biosensor strains via reverse-engineering a mutation in GDH1 identified from ALE. This mutation led to significantly more 13C-formate assimilation than in WT without any selection or overexpression of the RGP. Overall, we demonstrated the activity of the complete RGP, showing evidence for carbon transfer from formate to pyruvate coupled with CO2 assimilation.
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Affiliation(s)
- Viswanada R Bysani
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany.
| | - Ayesha S Alam
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Arren Bar-Even
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Fabian Machens
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
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3
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Kurt E, Qin J, Williams A, Zhao Y, Xie D. Perspectives for Using CO 2 as a Feedstock for Biomanufacturing of Fuels and Chemicals. Bioengineering (Basel) 2023; 10:1357. [PMID: 38135948 PMCID: PMC10740661 DOI: 10.3390/bioengineering10121357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 11/20/2023] [Accepted: 11/24/2023] [Indexed: 12/24/2023] Open
Abstract
Microbial cell factories offer an eco-friendly alternative for transforming raw materials into commercially valuable products because of their reduced carbon impact compared to conventional industrial procedures. These systems often depend on lignocellulosic feedstocks, mainly pentose and hexose sugars. One major hurdle when utilizing these sugars, especially glucose, is balancing carbon allocation to satisfy energy, cofactor, and other essential component needs for cellular proliferation while maintaining a robust yield. Nearly half or more of this carbon is inevitably lost as CO2 during the biosynthesis of regular metabolic necessities. This loss lowers the production yield and compromises the benefit of reducing greenhouse gas emissions-a fundamental advantage of biomanufacturing. This review paper posits the perspectives of using CO2 from the atmosphere, industrial wastes, or the exhausted gases generated in microbial fermentation as a feedstock for biomanufacturing. Achieving the carbon-neutral or -negative goals is addressed under two main strategies. The one-step strategy uses novel metabolic pathway design and engineering approaches to directly fix the CO2 toward the synthesis of the desired products. Due to the limitation of the yield and efficiency in one-step fixation, the two-step strategy aims to integrate firstly the electrochemical conversion of the exhausted CO2 into C1/C2 products such as formate, methanol, acetate, and ethanol, and a second fermentation process to utilize the CO2-derived C1/C2 chemicals or co-utilize C5/C6 sugars and C1/C2 chemicals for product formation. The potential and challenges of using CO2 as a feedstock for future biomanufacturing of fuels and chemicals are also discussed.
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Affiliation(s)
- Elif Kurt
- Department of Chemical Engineering, University of Massachusetts, Lowell, MA 01854, USA; (E.K.); (J.Q.); (A.W.)
| | - Jiansong Qin
- Department of Chemical Engineering, University of Massachusetts, Lowell, MA 01854, USA; (E.K.); (J.Q.); (A.W.)
| | - Alexandria Williams
- Department of Chemical Engineering, University of Massachusetts, Lowell, MA 01854, USA; (E.K.); (J.Q.); (A.W.)
| | - Youbo Zhao
- Physical Sciences Inc., 20 New England Business Ctr., Andover, MA 01810, USA;
| | - Dongming Xie
- Department of Chemical Engineering, University of Massachusetts, Lowell, MA 01854, USA; (E.K.); (J.Q.); (A.W.)
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4
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Liu L, Ma X, Bilal M, Wei L, Tang S, Luo H, Zhao Y, Wang Z, Duan X. Toxicity and inhibition mechanism of gallic acid on physiology and fermentation performance of Escherichia coli. BIORESOUR BIOPROCESS 2022; 9:76. [PMID: 38647760 PMCID: PMC10992115 DOI: 10.1186/s40643-022-00564-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Accepted: 07/10/2022] [Indexed: 11/10/2022] Open
Abstract
Gallic acid is a natural phenolic acid that has a stress inhibition effect on Escherichia coli. This study by integrates fermentation characteristics and transcriptional analyses to elucidate the physiological mechanism of E. coli 3110 response to gallic acid. Compared with the control (without stress), the cell growth was severely retarded, and irregular cell morphology appeared in the case of high levels of gallic acid stress. The glucose consumption of E. coli was reduced successively with the increase of gallic acid content in the fermentation medium. After 20 h of gallic acid stress, cofactor levels (ATP, NAD+ and NADH) of E. coli 3110 were similarly decreased, indicating a more potent inhibitory effect of gallic acid on E. coli. The transcriptional analysis revealed that gallic acid altered the gene expression profiles related to five notable differentially regulated pathways. The genes related to the two-component system were up-regulated, while the genes associated with ABC-transporter, energy metabolism, carbon metabolism, and fatty acid biosynthesis were down-regulated. This is the first report to comprehensively assess the toxicity of gallic acid on E. coli. This study has implications for the efficient production of phenolic compounds by E. coli and provides new ideas for the study of microbial tolerance to environmental stress and the identification of associated tolerance targets.
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Affiliation(s)
- Lina Liu
- School of Life Science and Food Engineering, Huaiyin Institute of Technology, Huaian, 223003, China.
| | - Xiaolong Ma
- School of Life Science and Food Engineering, Huaiyin Institute of Technology, Huaian, 223003, China
| | - Muhammad Bilal
- School of Life Science and Food Engineering, Huaiyin Institute of Technology, Huaian, 223003, China
| | - Linlin Wei
- School of Life Science and Food Engineering, Huaiyin Institute of Technology, Huaian, 223003, China
| | - Shijie Tang
- School of Life Science and Food Engineering, Huaiyin Institute of Technology, Huaian, 223003, China
| | - Hongzhen Luo
- School of Life Science and Food Engineering, Huaiyin Institute of Technology, Huaian, 223003, China
| | - Yuping Zhao
- School of Life Science and Food Engineering, Huaiyin Institute of Technology, Huaian, 223003, China
| | - Zhaoyu Wang
- School of Life Science and Food Engineering, Huaiyin Institute of Technology, Huaian, 223003, China
| | - Xuguo Duan
- College of Light Industry and Food Engineering, Nanjing Forestry University, Nanjing, 210037, Jiangsu, China
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5
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Aliyu H, Gorte O, Neumann A, Ochsenreither K. Global Transcriptome Profile of the Oleaginous Yeast Saitozyma podzolica DSM 27192 Cultivated in Glucose and Xylose. J Fungi (Basel) 2021; 7:758. [PMID: 34575796 PMCID: PMC8466774 DOI: 10.3390/jof7090758] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 09/08/2021] [Accepted: 09/13/2021] [Indexed: 11/29/2022] Open
Abstract
Unlike conventional yeasts, several oleaginous yeasts, including Saitozyma podzolica DSM 27192, possess the innate ability to grow and produce biochemicals from plant-derived lignocellulosic components such as hexose and pentose sugars. To elucidate the genetic basis of S. podzolica growth and lipid production on glucose and xylose, we performed comparative temporal transcriptome analysis using RNA-seq method. Approximately 3.4 and 22.2% of the 10,670 expressed genes were differentially (FDR < 0.05, and log2FC > 1.5) expressed under batch and fed batch modes, respectively. Our analysis revealed that a higher number of sugar transporter genes were significantly overrepresented in xylose relative to glucose-grown cultures. Given the low homology between proteins encoded by most of these genes and those of the well-characterised transporters, it is plausible to conclude that S. podzolica possesses a cache of putatively novel sugar transporters. The analysis also suggests that S. podzolica potentially channels carbon flux from xylose via both the non-oxidative pentose phosphate and potentially via the first steps of the Weimberg pathways to yield xylonic acid. However, only the ATP citrate lyase (ACL) gene showed significant upregulation among the essential oleaginous pathway genes under nitrogen limitation in xylose compared to glucose cultivation. Combined, these findings pave the way toward the design of strategies or the engineering of efficient biomass hydrolysate utilization in S. podzolica for the production of various biochemicals.
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Affiliation(s)
- Habibu Aliyu
- Institute of Process Engineering in Life Science 2: Technical Biology, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany; (O.G.); (A.N.)
| | | | | | - Katrin Ochsenreither
- Institute of Process Engineering in Life Science 2: Technical Biology, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany; (O.G.); (A.N.)
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6
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Alonso-Lavin AJ, Bajić D, Poyatos JF. Tolerance to NADH/NAD + imbalance anticipates aging and anti-aging interventions. iScience 2021; 24:102697. [PMID: 34195572 PMCID: PMC8239738 DOI: 10.1016/j.isci.2021.102697] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 03/26/2021] [Accepted: 06/04/2021] [Indexed: 12/31/2022] Open
Abstract
Redox couples coordinate cellular function, but the consequences of their imbalances are unclear. This is somewhat associated with the limitations of their experimental quantification. Here we circumvent these difficulties by presenting an approach that characterizes fitness-based tolerance profiles to redox couple imbalances using an in silico representation of metabolism. Focusing on the NADH/NAD+ redox couple in yeast, we demonstrate that reductive disequilibria generate metabolic syndromes comparable to those observed in cancer cells. The tolerance of yeast mutants to redox disequilibrium can also explain 30% of the variability in their experimentally measured chronological lifespan. Moreover, by predicting the significance of some metabolites to help stand imbalances, we correctly identify nutrients underlying mechanisms of pathology, lifespan-protecting molecules, or caloric restriction mimetics. Tolerance to redox imbalances becomes, in this way, a sound framework to recognize properties of the aging phenotype while providing a consistent biological rationale to assess anti-aging interventions. We simulate how imbalances in NADH/NAD+ ratio modify cellular metabolic behavior This reveals a mechanism to understand metabolic alterations at low growth rates Tolerance to imbalance explains experimentally measured lifespan in yeast We predict lifespan-protecting metabolites in yeast, animal, and human models
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Affiliation(s)
- Alvar J. Alonso-Lavin
- Logic of Genomic Systems Laboratory (CNB-CSIC), Darwin 3, Campus de Cantoblanco, 28049 Madrid, Spain
| | - Djordje Bajić
- Logic of Genomic Systems Laboratory (CNB-CSIC), Darwin 3, Campus de Cantoblanco, 28049 Madrid, Spain
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, USA
- Microbial Sciences Institute, Yale University, New Haven, CT, USA
| | - Juan F. Poyatos
- Logic of Genomic Systems Laboratory (CNB-CSIC), Darwin 3, Campus de Cantoblanco, 28049 Madrid, Spain
- Center for Genomics and Systems Biology, Department of Biology, New York University, New York, USA
- Corresponding author
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7
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Verhagen KJA, van Gulik WM, Wahl SA. Dynamics in redox metabolism, from stoichiometry towards kinetics. Curr Opin Biotechnol 2020; 64:116-123. [DOI: 10.1016/j.copbio.2020.01.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 01/05/2020] [Accepted: 01/06/2020] [Indexed: 12/12/2022]
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8
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Liu CG, Li K, Li KY, Sakdaronnarong C, Mehmood MA, Zhao XQ, Bai FW. Intracellular Redox Perturbation in Saccharomyces cerevisiae Improved Furfural Tolerance and Enhanced Cellulosic Bioethanol Production. Front Bioeng Biotechnol 2020; 8:615. [PMID: 32656198 PMCID: PMC7324476 DOI: 10.3389/fbioe.2020.00615] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 05/20/2020] [Indexed: 12/11/2022] Open
Abstract
Furfural is a major toxic byproduct found in the hydrolysate of lignocellulosic biomass, which adversely interferes with the growth and ethanol fermentation of Saccharomyces cerevisiae. The current study was focused on the impact of cofactor availability derived intracellular redox perturbation on furfural tolerance. Here, three strategies were employed in cofactor conversion in S. cerevisiae: (1) heterologous expression of NADH dehydrogenase (NDH) from E. coli which catalyzed the NADH to NAD+ and increased the cellular sensitivity to furfural, (2) overexpression of GLR1, OYE2, ZWF1, and IDP1 genes responsible for the interconversion of NADPH and NADP+, which enhanced the furfural tolerance, (3) expression of NAD(P)+ transhydrogenase (PNTB) and NAD+ kinase (POS5) which showed a little impact on furfural tolerance. Besides, a substantial redistribution of metabolic fluxes was also observed with the expression of cofactor-related genes. These results indicated that NADPH-based intracellular redox perturbation plays a key role in furfural tolerance, which suggested single-gene manipulation as an effective strategy for enhancing tolerance and subsequently achieving higher ethanol titer using lignocellulosic hydrolysate.
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Affiliation(s)
- Chen-Guang Liu
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Kai Li
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Ke-Yi Li
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Chularat Sakdaronnarong
- Department of Chemical Engineering, Faculty of Engineering, Mahidol University, Nakhon Pathom, Thailand
| | - Muhammad Aamer Mehmood
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China.,Department of Bioinformatics and Biotechnology, Government College University Faisalabad, Faisalabad, Pakistan
| | - Xin-Qing Zhao
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Feng-Wu Bai
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
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9
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Li B, Xie CY, Yang BX, Gou M, Xia ZY, Sun ZY, Tang YQ. The response mechanisms of industrial Saccharomyces cerevisiae to acetic acid and formic acid during mixed glucose and xylose fermentation. Process Biochem 2020. [DOI: 10.1016/j.procbio.2020.01.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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10
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Xu X, Song Y, Guo L, Cheng W, Niu C, Wang J, Liu C, Zheng F, Zhou Y, Li X, Mu Y, Li Q. Higher NADH Availability of Lager Yeast Increases the Flavor Stability of Beer. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:584-590. [PMID: 31623437 DOI: 10.1021/acs.jafc.9b05812] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Flavor stability is a significant concern to brewers as the staling compounds impart unpleasant flavor to beer. Thus, yeasts with antistaling ability have been engineered to produce beer with improved flavor stability. Here, we proposed that increasing the NADH availability of yeast could improve the flavor stability of beer. By engineering endogenous pathways, we obtained an array of yeast strains with a higher reducing activity. Then, we carried out beer fermentation with these strains and found that the antistaling capacities of the beer samples were improved. For a better understanding of the underlying mechanism, we compared the flavor profiles of these strains. The production of staling components was significantly decreased, whereas the content of antistaling components, such as SO2, was increased, in line with the increased antistaling ability. The other aroma components were marginally changed, indicating that this concept was useful for improving the antistaling stability without changing the flavor of beer.
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Affiliation(s)
| | - Yumei Song
- Beijing Yanjing Brewery Group Co., Ltd. , Beijing 101300 , China
| | - Liyun Guo
- Beijing Yanjing Brewery Group Co., Ltd. , Beijing 101300 , China
| | | | | | | | | | | | | | | | - Yingjian Mu
- Beijing Yanjing Brewery Group Co., Ltd. , Beijing 101300 , China
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11
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Evaluating the Pathway for Co-fermentation of Glucose and Xylose for Enhanced Bioethanol Production Using Flux Balance Analysis. BIOTECHNOL BIOPROC E 2019. [DOI: 10.1007/s12257-019-0026-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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12
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Zhuang Z, Zhang L, Yang C, Zhu D, Mao Q, Wang Q, Gao S. Enhanced lincomycin A production by calcium gluconate feeding in fermentation of Streptomyces lincolnensis. BIORESOUR BIOPROCESS 2019. [DOI: 10.1186/s40643-019-0266-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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13
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Anand G, Waiger D, Vital N, Maman J, Ma LJ, Covo S. How Does Fusarium oxysporum Sense and Respond to Nicotinaldehyde, an Inhibitor of the NAD + Salvage Biosynthesis Pathway? Front Microbiol 2019; 10:329. [PMID: 30873138 PMCID: PMC6400851 DOI: 10.3389/fmicb.2019.00329] [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] [Received: 11/27/2018] [Accepted: 02/08/2019] [Indexed: 11/13/2022] Open
Abstract
Plant pathogenic fungi are a major threat to food security and impose a severe economic burden, thus there is a continuous need to develop new strategies to manage them. NAD+ is a co-factor in numerous enzymatic activities and determines the metabolic fate of the cell. Therefore, maintenance of NAD+ concentration is important for cellular viability. Consequently, the NAD+ biosynthetic pathway and redox homeostasis was suggested as a target for antifungal development. We aimed to study how Fusarium oxysporum senses and responds to nicotinaldehyde (NA), an inhibitor of Pnc1, a key enzyme in the salvage pathway of NAD+ biosynthesis. We were able to show that NA was inhibitory in high concentrations to several fungal plant pathogens, with much milder effects on tomato growth. Under low nutrient conditions NA reduced the total amounts of NAD+ in the fungal cell, a trend that was also observed in rich media, although without statistical significance. In low and high nutrient availability NA dramatically reduced the NAD+/NADH ratio. After exposure to NA, NADH levels were increased and NAD+ levels and the biomass were greatly reduced. Cells responded to NA by up-regulation of oxidoreductases, with hardly any up-regulation of the classic response to oxidative stress. Direct measurement of oxidative stress response showed that unlike formaldehyde and hydrogen peroxide, NA caused reductive rather than oxidative stress. Surprisingly, alcohol dehydrogenases were significantly up-regulated more than any other dehydrogenases, including aldehyde dehydrogenases. We propose that conidia of F. oxysporum efficiently detoxified the aldehyde group of NA by reducing NAD+ to NADH; the high concentrations of the latter provoked the expression of alcohol dehydrogenases that in yeast can act to reduce NADH and increase NAD+ amounts, respectively. Overall, the results suggest that targeting NAD+ biosynthesis pathway and redox homeostasis can be a potential approach to manage fungal plant pathogens. Many of the natural antifungal compounds produced by bio-control agents or even the natural biome are aldehydes, and thus the results presented here predict the possible response of Fusarium to wide sources of toxicity in the environment.
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Affiliation(s)
- Gautam Anand
- Department of Plant Pathology and Microbiology, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Daniel Waiger
- Department of Plant Pathology and Microbiology, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Nuria Vital
- Department of Plant Pathology and Microbiology, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Jacob Maman
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, MA, United States
| | - Li Jun Ma
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, MA, United States
| | - Shay Covo
- Department of Plant Pathology and Microbiology, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
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14
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Xu X, Niu C, Liu C, Li Q. Unraveling the Mechanisms for Low-Level Acetaldehyde Production during Alcoholic Fermentation in Saccharomyces pastorianus Lager Yeast. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2019; 67:2020-2027. [PMID: 30666873 DOI: 10.1021/acs.jafc.8b06868] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Acetaldehyde is produced by yeast during alcoholic fermentation, and its modification greatly affects beer flavor and quality. In the current study, we analyzed two yeast strains with a low level of acetaldehyde to reveal the potential mechanism underpinning the desirable low acetaldehyde production by these strains. We demonstrated that high alcohol dehydrogenase (ADH) activity and high NADH availability were the dominant factors for the low level of acetaldehyde in the fermentation liquor at the end of fermentation. High ADH activity resulted in reduced accumulation of acetaldehyde during the cell growth phase by increasing the flux to ethanol, whereas high NADH availability (in the cytosol or mitochondria) enhanced acetaldehyde reduction at the later phase of main fermentation. Furthermore, NADH availability is a more useful target trait than ADH activity for constructing yeast strains with a low level of acetaldehyde for industrial applications in terms of flavor contribution and unaltered fermentation period.
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Affiliation(s)
- Xin Xu
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology , Jiangnan University , Wuxi , Jiangsu 214122 , People's Republic of China
- State Key Laboratory of Food Science and Technology , Jiangnan University , Wuxi , Jiangsu 214000 , People's Republic of China
- School of Biotechnology , Jiangnan University , 1800 Lihu Avenue , Wuxi , Jiangsu 214122 , People's Republic of China
| | - Chengtuo Niu
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology , Jiangnan University , Wuxi , Jiangsu 214122 , People's Republic of China
- State Key Laboratory of Food Science and Technology , Jiangnan University , Wuxi , Jiangsu 214000 , People's Republic of China
- School of Biotechnology , Jiangnan University , 1800 Lihu Avenue , Wuxi , Jiangsu 214122 , People's Republic of China
| | - Chunfeng Liu
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology , Jiangnan University , Wuxi , Jiangsu 214122 , People's Republic of China
- State Key Laboratory of Food Science and Technology , Jiangnan University , Wuxi , Jiangsu 214000 , People's Republic of China
- School of Biotechnology , Jiangnan University , 1800 Lihu Avenue , Wuxi , Jiangsu 214122 , People's Republic of China
| | - Qi Li
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology , Jiangnan University , Wuxi , Jiangsu 214122 , People's Republic of China
- State Key Laboratory of Food Science and Technology , Jiangnan University , Wuxi , Jiangsu 214000 , People's Republic of China
- School of Biotechnology , Jiangnan University , 1800 Lihu Avenue , Wuxi , Jiangsu 214122 , People's Republic of China
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15
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Zerfaß C, Asally M, Soyer OS. Interrogating metabolism as an electron flow system. CURRENT OPINION IN SYSTEMS BIOLOGY 2019; 13:59-67. [PMID: 31008413 PMCID: PMC6472609 DOI: 10.1016/j.coisb.2018.10.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Metabolism is generally considered as a neatly organised system of modular pathways, shaped by evolution under selection for optimal cellular growth. This view falls short of explaining and predicting a number of key observations about the structure and dynamics of metabolism. We highlight these limitations of a pathway-centric view on metabolism and summarise studies suggesting how these could be overcome by viewing metabolism as a thermodynamically and kinetically constrained, dynamical flow system. Such a systems-level, first-principles based view of metabolism can open up new avenues of metabolic engineering and cures for metabolic diseases and allow better insights to a myriad of physiological processes that are ultimately linked to metabolism. Towards further developing this view, we call for a closer interaction among physical and biological disciplines and an increased use of electrochemical and biophysical approaches to interrogate cellular metabolism together with the microenvironment in which it exists.
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Affiliation(s)
- Christian Zerfaß
- Bio-Electrical Engineering (BEE) Innovation Hub, University of Warwick, Coventry, CV4 7AL, UK
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | - Munehiro Asally
- Bio-Electrical Engineering (BEE) Innovation Hub, University of Warwick, Coventry, CV4 7AL, UK
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
- Warwick Integrative Synthetic Biology Centre (WISB), University of Warwick, Coventry, CV4 7AL, UK
| | - Orkun S. Soyer
- Bio-Electrical Engineering (BEE) Innovation Hub, University of Warwick, Coventry, CV4 7AL, UK
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
- Warwick Integrative Synthetic Biology Centre (WISB), University of Warwick, Coventry, CV4 7AL, UK
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16
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Xu X, Bao M, Niu C, Wang J, Liu C, Zheng F, Li Y, Li Q. Engineering the cytosolic NADH availability in lager yeast to improve the aroma profile of beer. Biotechnol Lett 2019; 41:363-369. [PMID: 30707389 DOI: 10.1007/s10529-019-02653-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 01/25/2019] [Indexed: 12/27/2022]
Abstract
OBJECTIVE To improve the aroma profile of beer by using metabolic engineering to increase the availability of cytosolic NADH in lager yeast. RESULTS To alter NADH levels in lager yeast, the native FDH1 (YOR388C) encoding NAD+-dependent formate dehydrogenase was overexpressed in the yeast strain M14, yielding strain M-FDH1. This led to a simultaneous increase of NADH availability and NADH/NAD+ ratio in the M-FDH1 strain during fermentation. At the end of the main fermentation period, ethanol production by strain M-FDH1 was decreased by 13.2%, while glycerol production was enhanced by 129.4%, compared to the parental strain respectively. The production of esters and fusel alcohols by strains M14 and M-FDH1 was similar. By contrast, strain M-FDH1 generally produced less organic acids and off-flavor components than strain M14, improving the beer aroma. CONCLUSIONS Increased NADH availability led to rerouting of the carbon flux toward NADH-consuming pathways and accelerated the NADH-dependent reducing reactions in yeast, greatly impacting the formation of aroma compounds and improving the beer aroma.
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Affiliation(s)
- Xin Xu
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214000, China
- School of Biotechnology, Jiangnan University, No. 1800, Lihu Avenue, Wuxi, 214122, Jiangsu, China
| | - Min Bao
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214000, China
- School of Biotechnology, Jiangnan University, No. 1800, Lihu Avenue, Wuxi, 214122, Jiangsu, China
| | - Chengtuo Niu
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214000, China
- School of Biotechnology, Jiangnan University, No. 1800, Lihu Avenue, Wuxi, 214122, Jiangsu, China
| | - Jinjing Wang
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214000, China
- School of Biotechnology, Jiangnan University, No. 1800, Lihu Avenue, Wuxi, 214122, Jiangsu, China
| | - Chunfeng Liu
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214000, China
- School of Biotechnology, Jiangnan University, No. 1800, Lihu Avenue, Wuxi, 214122, Jiangsu, China
| | - Feiyun Zheng
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214000, China
- School of Biotechnology, Jiangnan University, No. 1800, Lihu Avenue, Wuxi, 214122, Jiangsu, China
| | - Yongxian Li
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214000, China
- School of Biotechnology, Jiangnan University, No. 1800, Lihu Avenue, Wuxi, 214122, Jiangsu, China
| | - Qi Li
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China.
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214000, China.
- School of Biotechnology, Jiangnan University, No. 1800, Lihu Avenue, Wuxi, 214122, Jiangsu, China.
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17
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Xu X, Wang J, Bao M, Niu C, Liu C, Zheng F, Li Y, Li Q. Reverse metabolic engineering in lager yeast: impact of the NADH/NAD + ratio on acetaldehyde production during the brewing process. Appl Microbiol Biotechnol 2018; 103:869-880. [PMID: 30535678 DOI: 10.1007/s00253-018-9517-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 10/15/2018] [Accepted: 11/11/2018] [Indexed: 01/15/2023]
Abstract
Acetaldehyde is synthesized by yeast during the main fermentation period of beer production, which causes an unpleasant off-flavor. Therefore, there has been extensive effort toward reducing acetaldehyde to obtain a beer product with better flavor and anti-staling ability. In this study, we discovered that acetaldehyde production in beer brewing is closely related with the intracellular NADH equivalent regulated by the citric acid cycle. However, there was no significant relationship between acetaldehyde production and amino acid metabolism. A reverse engineering strategy to increase the intracellular NADH/NAD+ ratio reduced the final acetaldehyde production level, and vice versa. This work offers new insight into acetaldehyde metabolism and further provides efficient strategies for reducing acetaldehyde production by the regulating the intracellular NADH/NAD+ ratio through cofactor engineering.
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Affiliation(s)
- Xin Xu
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China.,State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214000, China.,School of Biotechnology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu, 214122, People's Republic of China
| | - Jinjing Wang
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China.,State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214000, China.,School of Biotechnology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu, 214122, People's Republic of China
| | - Min Bao
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China.,State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214000, China.,School of Biotechnology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu, 214122, People's Republic of China
| | - Chengtuo Niu
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China.,State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214000, China.,School of Biotechnology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu, 214122, People's Republic of China
| | - Chunfeng Liu
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China.,State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214000, China.,School of Biotechnology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu, 214122, People's Republic of China
| | - Feiyun Zheng
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China.,State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214000, China.,School of Biotechnology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu, 214122, People's Republic of China
| | - Yongxian Li
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China.,State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214000, China.,School of Biotechnology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu, 214122, People's Republic of China
| | - Qi Li
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China. .,State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214000, China. .,School of Biotechnology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu, 214122, People's Republic of China.
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18
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Inactivation of the transcription factor mig1 (YGL035C) in Saccharomyces cerevisiae improves tolerance towards monocarboxylic weak acids: acetic, formic and levulinic acid. ACTA ACUST UNITED AC 2018; 45:735-751. [DOI: 10.1007/s10295-018-2053-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 05/29/2018] [Indexed: 10/14/2022]
Abstract
Abstract
Toxic concentrations of monocarboxylic weak acids present in lignocellulosic hydrolyzates affect cell integrity and fermentative performance of Saccharomyces cerevisiae. In this work, we report the deletion of the general catabolite repressor Mig1p as a strategy to improve the tolerance of S. cerevisiae towards inhibitory concentrations of acetic, formic or levulinic acid. In contrast with the wt yeast, where the growth and ethanol production were ceased in presence of acetic acid 5 g/L or formic acid 1.75 g/L (initial pH not adjusted), the m9 strain (Δmig1::kan) produced 4.06 ± 0.14 and 3.87 ± 0.06 g/L of ethanol, respectively. Also, m9 strain tolerated a higher concentration of 12.5 g/L acetic acid (initial pH adjusted to 4.5) without affecting its fermentative performance. Moreover, m9 strain produced 33% less acetic acid and 50–70% less glycerol in presence of weak acids, and consumed acetate and formate as carbon sources under aerobic conditions. Our results show that the deletion of Mig1p provides a single gene deletion target for improving the acid tolerance of yeast strains significantly.
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19
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Bertrand E, Pasquier C, Duchez D, Girard S, Pons A, Bonnet P, Creuly C, Dussap CG. High-frequency, high-intensity electromagnetic field effects on Saccharomyces cerevisiae conversion yields and growth rates in a reverberant environment. BIORESOURCE TECHNOLOGY 2018; 260:264-272. [PMID: 29631176 DOI: 10.1016/j.biortech.2018.03.130] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 03/27/2018] [Accepted: 03/29/2018] [Indexed: 06/08/2023]
Abstract
Studies of the effects of electromagnetic waves on Saccharomyces cerevisiae emphasize the need to develop instrumented experimental systems ensuring a characterization of the exposition level to enable unambiguous assessment of their potential effects on living organisms. A bioreactor constituted with two separate compartments has been designed. The main element (75% of total volume) supporting all measurement and control systems (temperature, pH, agitation, and aeration) is placed outside the exposure room whereas the secondary element is exposed to irradiation. Measurements of the medium dielectric properties allow the determination of the electromagnetic field at any point inside the irradiated part of the reactor and are consistent with numerical simulations. In these conditions, the growth rate of Saccharomyces cerevisiae and the ethanol yield in aerobic conditions are not significantly modified when submitted to an electromagnetic field of 900 and 2400 MHz with an average exposition of 6.11 V.m-1 and 3.44 V.m-1 respectively.
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Affiliation(s)
- Emmanuel Bertrand
- Université Clermont Auvergne, CS 60032, 63001 Clermont-Ferrand, France; Institut Pascal, UMR CNRS 6602 Team GePEB, Chemical Engineering, Applied Thermodynamics and Biosystems, BP 10448, F-63000 Clermont-Ferrand, France; Aix-Marseille Université, INRA, Polytech' Marseille, UMR 1163 Biodiversité et Biotechnologie Fongiques, 163 Avenue de Luminy, CP225, 13288 Marseille Cedex 09, France.
| | - Christophe Pasquier
- Université Clermont Auvergne, CS 60032, 63001 Clermont-Ferrand, France; Institut Pascal, UMR CNRS 6602 Team PHOTON, Photonics, Waves, Nanomaterials, BP 10448, F-63000 Clermont-Ferrand, France
| | - David Duchez
- Université Clermont Auvergne, CS 60032, 63001 Clermont-Ferrand, France; Institut Pascal, UMR CNRS 6602 Team GePEB, Chemical Engineering, Applied Thermodynamics and Biosystems, BP 10448, F-63000 Clermont-Ferrand, France
| | - Sebastien Girard
- Université Clermont Auvergne, CS 60032, 63001 Clermont-Ferrand, France; Institut Pascal, UMR CNRS 6602 Team PHOTON, Photonics, Waves, Nanomaterials, BP 10448, F-63000 Clermont-Ferrand, France
| | - Agnès Pons
- Université Clermont Auvergne, CS 60032, 63001 Clermont-Ferrand, France; Institut Pascal, UMR CNRS 6602 Team GePEB, Chemical Engineering, Applied Thermodynamics and Biosystems, BP 10448, F-63000 Clermont-Ferrand, France
| | - Pierre Bonnet
- Université Clermont Auvergne, CS 60032, 63001 Clermont-Ferrand, France; Institut Pascal, UMR CNRS 6602 Team PHOTON, Photonics, Waves, Nanomaterials, BP 10448, F-63000 Clermont-Ferrand, France
| | - Catherine Creuly
- Université Clermont Auvergne, CS 60032, 63001 Clermont-Ferrand, France; Institut Pascal, UMR CNRS 6602 Team GePEB, Chemical Engineering, Applied Thermodynamics and Biosystems, BP 10448, F-63000 Clermont-Ferrand, France
| | - Claude-Gilles Dussap
- Université Clermont Auvergne, CS 60032, 63001 Clermont-Ferrand, France; Institut Pascal, UMR CNRS 6602 Team GePEB, Chemical Engineering, Applied Thermodynamics and Biosystems, BP 10448, F-63000 Clermont-Ferrand, France
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20
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Martínez-Cárdenas A, Chávez-Cabrera C, Vasquez-Bahena JM, Flores-Cotera LB. A common mechanism explains the induction of aerobic fermentation and adaptive antioxidant response in Phaffia rhodozyma. Microb Cell Fact 2018; 17:53. [PMID: 29615045 PMCID: PMC5883411 DOI: 10.1186/s12934-018-0898-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 03/26/2018] [Indexed: 01/07/2023] Open
Abstract
Background Growth conditions that bring about stress on Phaffia rhodozyma cells encourage the synthesis of astaxanthin, an antioxidant carotenoid, which protects cells against oxidative damage. Using P. rhodozyma cultures performed with and without copper limitation, we examined the kinetics of astaxanthin synthesis along with the expression of asy, the key astaxanthin synthesis gene, as well as aox, which encodes an alternative oxidase protein. Results Copper deficiency had a detrimental effect on the rates of oxygen consumption and ethanol reassimilation at the diauxic shift. In contrast, copper deficiency prompted alcoholic fermentation under aerobic conditions and had a favorable effect on the astaxanthin content of cells, as well as on aox expression. Both cultures exhibited strong aox expression while consuming ethanol, but particularly when copper was absent. Conclusion We show that the induction of either astaxanthin production, aox expression, or aerobic fermentation exemplifies the crucial role that redox imbalance plays in triggering any of these phenomena. Based on our own results and data from others, we propose a mechanism that rationalizes the central role played by changes of respiratory activity, which lead to redox imbalances, in triggering both the short-term antioxidant response as well as fermentation in yeasts and other cell types.
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Affiliation(s)
- Anahí Martínez-Cárdenas
- Department of Biotechnology and Bioengineering, Cinvestav-IPN, Av. Instituto Politécnico Nacional 2508, Col. San Pedro Zacatenco, 07360, Mexico City, Mexico
| | - Cipriano Chávez-Cabrera
- Department of Biotechnology and Bioengineering, Cinvestav-IPN, Av. Instituto Politécnico Nacional 2508, Col. San Pedro Zacatenco, 07360, Mexico City, Mexico.,College of Science and Technology Studies of the State of Michoacán, Loma de las Liebres 180, Fraccionamiento Lomas del Sur, 58095, Morelia, Michoacán, Mexico
| | - Jazmín M Vasquez-Bahena
- Avi-mex Laboratory S.A de C.V, Trigo 169, Col. Granjas Esmeralda, 09810, Mexico City, Mexico
| | - Luis B Flores-Cotera
- Department of Biotechnology and Bioengineering, Cinvestav-IPN, Av. Instituto Politécnico Nacional 2508, Col. San Pedro Zacatenco, 07360, Mexico City, Mexico.
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21
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Jayachandran C, Palanisamy Athiyaman B, Sankaranarayanan M. Cofactor engineering improved CALB production in Pichia pastoris through heterologous expression of NADH oxidase and adenylate kinase. PLoS One 2017; 12:e0181370. [PMID: 28715469 PMCID: PMC5513558 DOI: 10.1371/journal.pone.0181370] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 06/29/2017] [Indexed: 12/26/2022] Open
Abstract
The cofactor engineering strategy can relieve the metabolic stress induced by expression of recombinant protein in cellular metabolism related to cofactor and energy reactions. To study the effect of cofactor regeneration on recombinant protein expression, NADH oxidase (noxE) was engineered in P. pastoris expressing lipase B (GSCALB). Expression of noxE in P. pastoris (GSCALBNOX) increased NAD+ levels by 85% with a concomitant reduction in NADH/NAD+ ratio of 67% compared to GSCALB. The change in the redox level positively influenced the methanol uptake rate and made 34% augment in CALB activity. The decline in NADH level (44%) by noxE expression had lowered the adenylate energy charge (AEC) and ATP level in GSCALBNOX. In order to regenerate ATP in GSCALBNOX, adenylate kinase (ADK1) gene from S. cerevisiae S288c was co-expressed. Expression of ADK1 showed a remarkable increase in AEC and co-expression of both the genes synergistically improved CALB activity. This study shows the importance of maintenance of cellular redox homeostasis and adenylate energy charge during recombinant CALB expression in P. pastoris.
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22
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Acevedo A, Conejeros R, Aroca G. Ethanol production improvement driven by genome-scale metabolic modeling and sensitivity analysis in Scheffersomyces stipitis. PLoS One 2017; 12:e0180074. [PMID: 28658270 PMCID: PMC5489217 DOI: 10.1371/journal.pone.0180074] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 06/11/2017] [Indexed: 11/18/2022] Open
Abstract
The yeast Scheffersomyces stipitis naturally produces ethanol from xylose, however reaching high ethanol yields is strongly dependent on aeration conditions. It has been reported that changes in the availability of NAD(H/+) cofactors can improve fermentation in some microorganisms. In this work genome-scale metabolic modeling and phenotypic phase plane analysis were used to characterize metabolic response on a range of uptake rates. Sensitivity analysis was used to assess the effect of ARC on ethanol production indicating that modifying ARC by inhibiting the respiratory chain ethanol production can be improved. It was shown experimentally in batch culture using Rotenone as an inhibitor of the mitochondrial NADH dehydrogenase complex I (CINADH), increasing ethanol yield by 18%. Furthermore, trajectories for uptakes rates, specific productivity and specific growth rate were determined by modeling the batch culture, to calculate ARC associated to the addition of CINADH inhibitor. Results showed that the increment in ethanol production via respiratory inhibition is due to excess in ARC, which generates an increase in ethanol production. Thus ethanol production improvement could be predicted by a change in ARC.
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Affiliation(s)
- Alejandro Acevedo
- Escuela de Ingeniería Bioquímica, Pontificia Universidad Católica de Valparaíso, Av. Brasil 2085, Valparaíso, Chile
| | - Raúl Conejeros
- Escuela de Ingeniería Bioquímica, Pontificia Universidad Católica de Valparaíso, Av. Brasil 2085, Valparaíso, Chile
- * E-mail:
| | - Germán Aroca
- Escuela de Ingeniería Bioquímica, Pontificia Universidad Católica de Valparaíso, Av. Brasil 2085, Valparaíso, Chile
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23
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Kaneko M, Ishikawa M, Hashimoto K, Nakanishi S. Molecular design of cytocompatible amphiphilic redox-active polymers for efficient extracellular electron transfer. Bioelectrochemistry 2017; 114:8-12. [DOI: 10.1016/j.bioelechem.2016.11.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 10/28/2016] [Accepted: 11/03/2016] [Indexed: 10/20/2022]
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24
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Wang L, Ji D, Liu Y, Wang Q, Wang X, Zhou YJ, Zhang Y, Liu W, Zhao ZK. Synthetic Cofactor-Linked Metabolic Circuits for Selective Energy Transfer. ACS Catal 2017. [DOI: 10.1021/acscatal.6b03579] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Lei Wang
- Division
of Biotechnology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- Dalian
National Laboratory for Clean Energy, Dalian Institute of Chemical
Physics, Chinese Academy of Sciences, Dalian 116023, China
- Institute
of Green Conversion of Biological Bioresource and Metabolic Engineering,
College of Chemical Engineering, Northeast Electric Power University, Jilin 132012, China
| | - Debin Ji
- Division
of Biotechnology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Yuxue Liu
- Division
of Biotechnology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Qian Wang
- Division
of Biotechnology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- Dalian
National Laboratory for Clean Energy, Dalian Institute of Chemical
Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Xueying Wang
- Division
of Biotechnology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Yongjin J. Zhou
- Division
of Biotechnology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Yixin Zhang
- Division
of Biotechnology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Wujun Liu
- Division
of Biotechnology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- Dalian
National Laboratory for Clean Energy, Dalian Institute of Chemical
Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Zongbao K. Zhao
- Division
of Biotechnology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- Dalian
National Laboratory for Clean Energy, Dalian Institute of Chemical
Physics, Chinese Academy of Sciences, Dalian 116023, China
- State Key
Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
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25
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Shi X, Zou Y, Chen Y, Zheng C, Ying H. Overexpression of a Water-Forming NADH Oxidase Improves the Metabolism and Stress Tolerance of Saccharomyces cerevisiae in Aerobic Fermentation. Front Microbiol 2016; 7:1427. [PMID: 27679617 PMCID: PMC5020133 DOI: 10.3389/fmicb.2016.01427] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2016] [Accepted: 08/29/2016] [Indexed: 01/01/2023] Open
Abstract
Redox homeostasis is fundamental to the maintenance of metabolism. Redox imbalance can cause oxidative stress, which affects metabolism and growth. Water-forming NADH oxidase regulates the redox balance by oxidizing cytosolic NADH to NAD+, which relieves cytosolic NADH accumulation through rapid glucose consumption in Saccharomyces cerevisiae, thus decreasing the production of the by product glycerol in industrial ethanol production. Here, we studied the effects of overexpression of a water-forming NADH oxidase from Lactococcus lactis on the stress response of S. cerevisiae in aerobic batch fermentation, and we constructed an interaction network of transcriptional regulation and metabolic networks to study the effects of and mechanisms underlying NADH oxidase regulation. The oxidase-overexpressing strain (NOX) showed increased glucose consumption, growth, and ethanol production, while glycerol production was remarkably lower. Glucose was exhausted by NOX at 26 h, while 18.92 ± 0.94 g/L residual glucose was left in the fermentation broth of the control strain (CON) at this time point. At 29.5 h, the ethanol concentration for NOX peaked at 35.25 ± 1.76 g/L, which was 14.37% higher than that for CON (30.82 ± 1.54 g/L). Gene expression involved in the synthesis of thiamine, which is associated with stress responses in various organisms, was increased in NOX. The transcription factor HAP4 was significantly upregulated in NOX at the late-exponential phase, indicating a diauxic shift in response to starvation. The apoptosis-inducing factor Nuc1 was downregulated while the transcription factor Sok2, which regulates the production of the small signaling molecule ammonia, was upregulated at the late-exponential phase, benefiting young cells on the rim. Reactive oxygen species production was decreased by 10% in NOX, supporting a decrease in apoptosis. The HOG pathway was not activated, although the osmotic stress was truly higher, indicating improved osmotolerance. Thus, the NADH oxidase can regulate the metabolism during aerobic fermentation in S. cerevisiae, thereby protecting cells against several stresses. Our findings indicate its suitability for use in industrial processes.
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Affiliation(s)
- Xinchi Shi
- National Engineering Research Center for Biotechnology, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech UniversityNanjing, China; State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech UniversityNanjing, China
| | - Yanan Zou
- National Engineering Research Center for Biotechnology, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech UniversityNanjing, China; State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech UniversityNanjing, China
| | - Yong Chen
- National Engineering Research Center for Biotechnology, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech UniversityNanjing, China; State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech UniversityNanjing, China; Jiangsu National Synergistic Innovation Center for Advanced MaterialsNanjing, China
| | - Cheng Zheng
- National Engineering Research Center for Biotechnology, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech UniversityNanjing, China; State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech UniversityNanjing, China
| | - Hanjie Ying
- National Engineering Research Center for Biotechnology, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech UniversityNanjing, China; State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech UniversityNanjing, China; Jiangsu National Synergistic Innovation Center for Advanced MaterialsNanjing, China
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Tian X, Zhang N, Yang Y, Wang Y, Chu J, Zhuang Y, Zhang S. The effect of redox environment on l -lactic acid production by Lactobacillus paracasei —A proof by genetically encoded in vivo NADH biosensor. Process Biochem 2015. [DOI: 10.1016/j.procbio.2015.10.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Optimization of lipid production with a genome-scale model of Yarrowia lipolytica. BMC SYSTEMS BIOLOGY 2015; 9:72. [PMID: 26503450 PMCID: PMC4623914 DOI: 10.1186/s12918-015-0217-4] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 10/07/2015] [Indexed: 12/19/2022]
Abstract
Background Yarrowia lipolytica is a non-conventional yeast that is extensively investigated for its ability to excrete citrate or to accumulate large amounts of storage lipids, which is of great significance for single cell oil production. Both traits are thus of interest for basic research as well as for biotechnological applications but they typically occur simultaneously thus lowering the respective yields. Therefore, engineering of strains with high lipid content relies on novel concepts such as computational simulation to better understand the two competing processes and to eliminate citrate excretion. Results Using a genome-scale model (GSM) of baker's yeast as a scaffold, we reconstructed the metabolic network of Y. lipolytica and optimized it for use in flux balance analysis (FBA), with the aim to simulate growth and lipid production phases of this yeast. We validated our model and found the predictions of the growth behavior of Y. lipolytica in excellent agreement with experimental data. Based on these data, we successfully designed a fed-batch strategy to avoid citrate excretion during the lipid production phase. Further analysis of the network suggested that the oxygen demand of Y. lipolytica is reduced upon induction of lipid synthesis. According to this finding we hypothesized that a reduced aeration rate might induce lipid accumulation. This prediction was indeed confirmed experimentally. In a fermentation combining these two strategies lipid content of the biomass was increased by 80 %, and lipid yield was improved more than four-fold, compared to standard conditions. Conclusions Genome scale network reconstructions provide a powerful tool to predict the effects of genetic modifications and the metabolic response to environmental conditions. The high accuracy and the predictive value of a newly reconstructed GSM of Y. lipolytica to optimize growth conditions for lipid accumulation are demonstrated. Based on these findings, further strategies for engineering Y. lipolytica towards higher efficiency in single cell oil production are discussed. Electronic supplementary material The online version of this article (doi:10.1186/s12918-015-0217-4) contains supplementary material, which is available to authorized users.
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Delvigne F, Zune Q, Lara AR, Al-Soud W, Sørensen SJ. Metabolic variability in bioprocessing: implications of microbial phenotypic heterogeneity. Trends Biotechnol 2014; 32:608-16. [DOI: 10.1016/j.tibtech.2014.10.002] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Revised: 09/24/2014] [Accepted: 10/01/2014] [Indexed: 12/19/2022]
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Acevedo A, Aroca G, Conejeros R. Genome-scale NAD(H/(+)) availability patterns as a differentiating feature between Saccharomyces cerevisiae and Scheffersomyces stipitis in relation to fermentative metabolism. PLoS One 2014; 9:e87494. [PMID: 24489927 PMCID: PMC3906188 DOI: 10.1371/journal.pone.0087494] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 12/26/2013] [Indexed: 11/18/2022] Open
Abstract
Scheffersomyces stipitis is a yeast able to ferment pentoses to ethanol, unlike Saccharomyces cerevisiae, it does not present the so-called overflow phenomenon. Metabolic features characterizing the presence or not of this phenomenon have not been fully elucidated. This work proposes that genome-scale metabolic response to variations in NAD(H/+) availability characterizes fermentative behavior in both yeasts. Thus, differentiating features in S. stipitis and S. cerevisiae were determined analyzing growth sensitivity response to changes in available reducing capacity in relation to ethanol production capacity and overall metabolic flux span. Using genome-scale constraint-based metabolic models, phenotypic phase planes and shadow price analyses, an excess of available reducing capacity for growth was found in S. cerevisiae at every metabolic phenotype where growth is limited by oxygen uptake, while in S. stipitis this was observed only for a subset of those phenotypes. Moreover, by using flux variability analysis, an increased metabolic flux span was found in S. cerevisiae at growth limited by oxygen uptake, while in S. stipitis flux span was invariant. Therefore, each yeast can be characterized by a significantly different metabolic response and flux span when growth is limited by oxygen uptake, both features suggesting a higher metabolic flexibility in S. cerevisiae. By applying an optimization-based approach on the genome-scale models, three single reaction deletions were found to generate in S. stipitis the reducing capacity availability pattern found in S. cerevisiae, two of them correspond to reactions involved in the overflow phenomenon. These results show a close relationship between the growth sensitivity response given by the metabolic network and fermentative behavior.
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Affiliation(s)
- Alejandro Acevedo
- Escuela de Ingeniería Bioquímica/Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
- Bioenercel S.A., Barrio Universitario, Concepción, Chile
| | - German Aroca
- Escuela de Ingeniería Bioquímica/Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
- Bioenercel S.A., Barrio Universitario, Concepción, Chile
| | - Raul Conejeros
- Escuela de Ingeniería Bioquímica/Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
- Bioenercel S.A., Barrio Universitario, Concepción, Chile
- * E-mail:
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Lo TM, Teo WS, Ling H, Chen B, Kang A, Chang MW. Microbial engineering strategies to improve cell viability for biochemical production. Biotechnol Adv 2013; 31:903-14. [PMID: 23403071 DOI: 10.1016/j.biotechadv.2013.02.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Revised: 02/05/2013] [Accepted: 02/05/2013] [Indexed: 11/16/2022]
Abstract
Efficient production of biochemicals using engineered microbes as whole-cell biocatalysts requires robust cell viability. Robust viability leads to high productivity and improved bioprocesses by allowing repeated cell recycling. However, cell viability is negatively affected by a plethora of stresses, namely chemical toxicity and metabolic imbalances, primarily resulting from bio-synthesis pathways. Chemical toxicity is caused by substrates, intermediates, products, and/or by-products, and these compounds often interfere with important metabolic processes and damage cellular infrastructures such as cell membrane, leading to poor cell viability. Further, stresses on engineered cells are accentuated by metabolic imbalances, which are generated by heavy metabolic resource consumption due to enzyme overexpression, redistribution of metabolic fluxes, and impaired intracellular redox state by co-factor imbalance. To address these challenges, herein, we discuss a range of key microbial engineering strategies, substantiated by recent advances, to improve cell viability for commercially sustainable production of biochemicals from renewable resources.
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Affiliation(s)
- Tat-Ming Lo
- School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, Singapore 637459, Singapore
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Liu CG, Xue C, Lin YH, Bai FW. Redox potential control and applications in microaerobic and anaerobic fermentations. Biotechnol Adv 2012. [PMID: 23178703 DOI: 10.1016/j.biotechadv.2012.11.005] [Citation(s) in RCA: 142] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Many fermentation products are produced under microaerobic or anaerobic conditions, in which oxygen is undetectable by dissolved oxygen probe, presenting a challenge for process monitoring and control. Extracellular redox potentials that can be detected conveniently affect intracellular redox homeostasis and metabolism, and consequently control profiles of fermentation products, which provide an alternative for monitoring and control of these fermentation processes. This article reviews updated progress in the impact of redox potentials on gene expression, protein biosynthesis and metabolism as well as redox potential control strategies for more efficient production of fermentation products, taking ethanol fermentation by the yeast Saccharomyces under microaerobic conditions and butanol production by the bacterium Clostridium under anaerobic conditions as examples.
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Affiliation(s)
- Chen-Guang Liu
- School of Life Sciences and Biotechnology, Dalian University of Technology, Dalian 116023, China
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Scalcinati G, Partow S, Siewers V, Schalk M, Daviet L, Nielsen J. Combined metabolic engineering of precursor and co-factor supply to increase α-santalene production by Saccharomyces cerevisiae. Microb Cell Fact 2012; 11:117. [PMID: 22938570 PMCID: PMC3527295 DOI: 10.1186/1475-2859-11-117] [Citation(s) in RCA: 103] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Accepted: 08/18/2012] [Indexed: 11/21/2022] Open
Abstract
Background Sesquiterpenes are a class of natural products with a diverse range of attractive industrial proprieties. Due to economic difficulties of sesquiterpene production via extraction from plants or chemical synthesis there is interest in developing alternative and cost efficient bioprocesses. The hydrocarbon α-santalene is a precursor of sesquiterpenes with relevant commercial applications. Here, we construct an efficient Saccharomyces cerevisiae cell factory for α-santalene production. Results A multistep metabolic engineering strategy targeted to increase precursor and cofactor supply was employed to manipulate the yeast metabolic network in order to redirect carbon toward the desired product. To do so, genetic modifications were introduced acting to optimize the farnesyl diphosphate branch point, modulate the mevalonate pathway, modify the ammonium assimilation pathway and enhance the activity of a transcriptional activator. The approach employed resulted in an overall α-santalene yield of a 0.0052 Cmmol (Cmmol glucose)-1 corresponding to a 4-fold improvement over the reference strain. This strategy, combined with a specifically developed continuous fermentation process, led to a final α-santalene productivity of 0.036 Cmmol (g biomass)-1 h-1. Conclusions The results reported in this work illustrate how the combination of a metabolic engineering strategy with fermentation technology optimization can be used to obtain significant amounts of the high-value sesquiterpene α-santalene. This represents a starting point toward the construction of a yeast “sesquiterpene factory” and for the development of an economically viable bio-based process that has the potential to replace the current production methods.
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Affiliation(s)
- Gionata Scalcinati
- Department of Chemical and Biological Engineering, Chalmers University of Technology, SE-412 96, Göteborg, Sweden
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Determining the extremes of the cellular NAD(H) level by using an Escherichia coli NAD(+)-auxotrophic mutant. Appl Environ Microbiol 2011; 77:6133-40. [PMID: 21742902 DOI: 10.1128/aem.00630-11] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
NAD (NAD(+)) and its reduced form (NADH) are omnipresent cofactors in biological systems. However, it is difficult to determine the extremes of the cellular NAD(H) level in live cells because the NAD(+) level is tightly controlled by a biosynthesis regulation mechanism. Here, we developed a strategy to determine the extreme NAD(H) levels in Escherichia coli cells that were genetically engineered to be NAD(+) auxotrophic. First, we expressed the ntt4 gene encoding the NAD(H) transporter in the E. coli mutant YJE001, which had a deletion of the nadC gene responsible for NAD(+) de novo biosynthesis, and we showed NTT4 conferred on the mutant strain better growth in the presence of exogenous NAD(+). We then constructed the NAD(+)-auxotrophic mutant YJE003 by disrupting the essential gene nadE, which is responsible for the last step of NAD(+) biosynthesis in cells harboring the ntt4 gene. The minimal NAD(+) level was determined in M9 medium in proliferating YJE003 cells that were preloaded with NAD(+), while the maximal NAD(H) level was determined by exposing the cells to high concentrations of exogenous NAD(H). Compared with supplementation of NADH, cells grew faster and had a higher intracellular NAD(H) level when NAD(+) was fed. The intracellular NAD(H) level increased with the increase of exogenous NAD(+) concentration, until it reached a plateau. Thus, a minimal NAD(H) level of 0.039 mM and a maximum of 8.49 mM were determined, which were 0.044× and 9.6× those of wild-type cells, respectively. Finally, the potential application of this strategy in biotechnology is briefly discussed.
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Current awareness on yeast. Yeast 2010. [DOI: 10.1002/yea.1718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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