scholarly journals Abatement of Inhibitors in Recycled Process Water from Biomass Fermentations Relieves Inhibition of a Saccharomyces cerevisiae Pentose Phosphate Pathway Mutant

Fermentation ◽  
2020 ◽  
Vol 6 (4) ◽  
pp. 107
Author(s):  
Nancy N. Nichols ◽  
Ronald E. Hector ◽  
Jeffrey A. Mertens ◽  
Sarah E. Frazer
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Fermentation Process ◽  
Pentose Phosphate ◽  
Process Water ◽  
Dilute Acid ◽  
Fermentation Inhibitors ◽  
Acid Hydrolysate ◽  
Fuels And Chemicals ◽  
Biomass Hydrolysates ◽  
Water Inhibition

Understanding the nature of fermentation inhibition in biomass hydrolysates and recycled fermentation process water is important for conversion of biomass to fuels and chemicals. This study used three mutants disrupted in genes important for tolerance to either oxidative stress, salinity, or osmolarity to ferment biomass hydrolysates in a xylose-fermenting Saccharomyces cerevisiae background. The S. cerevisiaeZWF1 mutant with heightened sensitivity to fermentation inhibitors was unable to ferment corn stover dilute-acid hydrolysate without conditioning of hydrolysate using a fungal strain, Coniochaeta ligniaria, to consume inhibitors. Growth of two other strains, a salt-sensitive HAL4 mutant and a GPD1 mutant sensitive to osmotic stress, was not negatively affected in hydrolysate compared to the parent xylose-metabolizing strain. In recycled fermentation process water, inhibition of the ZWF1 mutant could again be remediated by biological abatement, and no effect on growth was observed for any of the mutants compared to the parent strain.

scholarly journals Ethanol Production from Nondetoxified Dilute-Acid Lignocellulosic Hydrolysate by Cocultures of Saccharomyces cerevisiae Y5 and Pichia stipitis CBS6054

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Ping Wan ◽  
Dongmei Zhai ◽  
Zhen Wang ◽  
Xiushan Yang ◽  
Shen Tian
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ethanol Production ◽  
Ethanol Concentration ◽  
Ethanol Yield ◽  
Synthetic Medium ◽  
Pichia Stipitis ◽  
Dilute Acid ◽  
Acid Hydrolysate ◽  
Issatchenkia Orientalis ◽  
Final Ethanol Concentration

Saccharomyces cerevisiae Y5 (CGMCC no. 2660) and Issatchenkia orientalis Y4 (CGMCC no. 2159) were combined individually with Pichia stipitis CBS6054 to establish the cocultures of Y5 + CBS6054 and Y4 + CBS6054. The coculture Y5 + CBS6054 effectively metabolized furfural and HMF and converted xylose and glucose mixture to ethanol with ethanol concentration of 16.6 g/L and ethanol yield of 0.46 g ethanol/g sugar, corresponding to 91.2% of the maximal theoretical value in synthetic medium. Accordingly, the nondetoxified dilute-acid hydrolysate was used to produce ethanol by co-culture Y5 + CBS6054. The co-culture consumed glucose along with furfural and HMF completely in 12 h, and all xylose within 96 h, resulting in a final ethanol concentration of 27.4 g/L and ethanol yield of 0.43 g ethanol/g sugar, corresponding to 85.1% of the maximal theoretical value. The results indicated that the co-culture of Y5 + CBS6054 was a satisfying combination for ethanol production from non-detoxified dilute-acid lignocellulosic hydrolysates. This co-culture showed a promising prospect for industrial application.

Recycle of fermentation process water through mitigation of inhibitors in dilute-acid corn stover hydrolysate

2020 ◽  
Vol 9 ◽  
pp. 100349 ◽  
Author(s):  
Nancy N. Nichols ◽  
Jeffrey A. Mertens ◽  
Bruce S. Dien ◽  
Ronald E. Hector ◽  
Sarah E. Frazer
Keyword(s):  
Corn Stover ◽  
Fermentation Process ◽  
Process Water ◽  
Dilute Acid ◽  
Corn Stover Hydrolysate

Fungal metabolism of fermentation inhibitors present in corn stover dilute acid hydrolysate

2008 ◽  
Vol 42 (7) ◽  
pp. 624-630 ◽  
Author(s):  
Nancy N. Nichols ◽  
Lekh N. Sharma ◽  
Richard A. Mowery ◽  
C. Kevin Chambliss ◽  
G. Peter van Walsum ◽  
...  
Keyword(s):  
Corn Stover ◽  
Dilute Acid ◽  
Fermentation Inhibitors ◽  
Fungal Metabolism ◽  
Acid Hydrolysate ◽  
Dilute Acid Hydrolysate

scholarly journals Deletion ofPHO13, Encoding Haloacid Dehalogenase Type IIA Phosphatase, Results in Upregulation of the Pentose Phosphate Pathway in Saccharomyces cerevisiae

2014 ◽  
Vol 81 (5) ◽  
pp. 1601-1609 ◽  
Author(s):  
Soo Rin Kim ◽  
Haiqing Xu ◽  
Anastashia Lesmana ◽  
Uros Kuzmanovic ◽  
Matthew Au ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Molecular Mechanisms ◽  
Pentose Phosphate ◽  
Sequencing Analysis ◽  
Xylose Metabolism ◽  
Fermentation Inhibitors ◽  
Haloacid Dehalogenase ◽  
Content Type ◽  
Had Superfamily ◽  
Transcriptomic Level

ABSTRACTThe haloacid dehalogenase (HAD) superfamily is one of the largest enzyme families, consisting mainly of phosphatases. Although intracellular phosphate plays important roles in many cellular activities, the biological functions of HAD enzymes are largely unknown. Pho13 is 1 of 16 putative HAD enzymes inSaccharomyces cerevisiae. Pho13 has not been studied extensively, but previous studies have identifiedPHO13to be a deletion target for the generation of industrially attractive phenotypes, namely, efficient xylose fermentation and high tolerance to fermentation inhibitors. In order to understand the molecular mechanisms underlying the improved xylose-fermenting phenotype produced by deletion ofPHO13(pho13Δ), we investigated the response ofS. cerevisiaetopho13Δ at the transcriptomic level when cells were grown on glucose or xylose. Transcriptome sequencing analysis revealed thatpho13Δ resulted in upregulation of the pentose phosphate (PP) pathway and NADPH-producing enzymes when cells were grown on glucose or xylose. We also found that the transcriptional changes induced bypho13Δ required the transcription factor Stb5, which is activated specifically under NADPH-limiting conditions. Thus,pho13Δ resulted in the upregulation of the PP pathway and NADPH-producing enzymes as a part of an oxidative stress response mediated by activation of Stb5. Because the PP pathway is the primary pathway for xylose, its upregulation bypho13Δ might explain the improved xylose metabolism. These findings will be useful for understanding the biological function ofS. cerevisiaePho13 and the HAD superfamily enzymes and for developingS. cerevisiaestrains with industrially attractive phenotypes.

Bioconversion of Lignocellulose to Ethanol: A Review of Production Process

2011 ◽  
Vol 280 ◽  
pp. 246-249 ◽  
Author(s):  
Kun Chen ◽  
Long Jun Xu ◽  
Jun Yi
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Fermentation Process ◽  
Raw Materials ◽  
Hot Spot ◽  
Fermentation Inhibitors ◽  
Double Function ◽  
Key Technologies ◽  
Pretreatment Technology ◽  
Biomass To Ethanol ◽  
Lignocellulose Biomass

Lignocellulose biomass is a kind of rich reserve in china, and it is a renewable bio-resource. Researches on the bioconversion of lignocellulose (lignocellulosic biomass) to ethanol have been hot spot in recent years. The key technologies of producing fuel alcohol by aspects of lignocellulosic raw materials, pretreatment technology, fermentation process, enzymatic hydrolysis and fermentation of strains as well as the removal of fermentation inhibitors have been reviewed. It is pointed out that the improvement of fermentation strains, exploitation of double function saccharomyces cerevisiae (glucose and xylose fermenting) to ethanol, will be the direction and focus in future researches.

scholarly journals Flocculation Causes Inhibitor Tolerance in Saccharomyces cerevisiae for Second-Generation Bioethanol Production

2014 ◽  
Vol 80 (22) ◽  
pp. 6908-6918 ◽  
Author(s):  
Johan O. Westman ◽  
Valeria Mapelli ◽  
Mohammad J. Taherzadeh ◽  
Carl Johan Franzén
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Second Generation ◽  
Raw Materials ◽  
Defined Medium ◽  
Bioethanol Production ◽  
Dilute Acid ◽  
Fermentation Inhibitors ◽  
Inhibitor Tolerance ◽  
Content Type ◽  
Second Generation Bioethanol

ABSTRACTYeast has long been considered the microorganism of choice for second-generation bioethanol production due to its fermentative capacity and ethanol tolerance. However, tolerance toward inhibitors derived from lignocellulosic materials is still an issue. Flocculating yeast strains often perform relatively well in inhibitory media, but inhibitor tolerance has never been clearly linked to the actual flocculation abilityper se. In this study, variants of the flocculation geneFLO1were transformed into the genome of the nonflocculating laboratory yeast strainSaccharomyces cerevisiaeCEN.PK 113-7D. Three mutants with distinct differences in flocculation properties were isolated and characterized. The degree of flocculation and hydrophobicity of the cells were correlated to the length of the gene variant. The effect of different strength of flocculation on the fermentation performance of the strains was studied in defined medium with or without fermentation inhibitors, as well as in media based on dilute acid spruce hydrolysate. Strong flocculation aided against the readily convertible inhibitor furfural but not against less convertible inhibitors such as carboxylic acids. During fermentation of dilute acid spruce hydrolysate, the most strongly flocculating mutant with dense cell flocs showed significantly faster sugar consumption. The modified strain with the weakest flocculation showed a hexose consumption profile similar to the untransformed strain. These findings may explain why flocculation has evolved as a stress response and can find application in fermentation-based biorefinery processes on lignocellulosic raw materials.

Achieving Procedure of a Kinetic Model to Predict the Influence of the Process Global Temperature on a Technological Alcoholic Fermentation II. An Arrhenius type Kinetic Model

2008 ◽  
Vol 59 (4) ◽  
Author(s):  
Neculai Catalin Lungu ◽  
Maria Alexandroaei
Keyword(s):  
Experimental Data ◽  
Saccharomyces Cerevisiae ◽  
Kinetic Model ◽  
Economic Efficiency ◽  
Fermentation Process ◽  
Alcoholic Fermentation ◽  
Global Temperature ◽  
Medium Temperature ◽  
Biotechnological Process

The aim of the present work is to offer a practical methodology to realise an Arrhenius type kinetic model for a biotechnological process of alcoholic fermentation based on the Saccharomyces cerevisiae yeast. Using the experimental data we can correlate the medium temperature of fermentation with the time needed for a fermentation process under imposed conditions of economic efficiency.

Renewable Energy from Agricultural Waste

2018 ◽  
Vol 69 (6) ◽  
pp. 1363-1366 ◽  
Author(s):  
Stefania Daniela Bran ◽  
Petre Chipurici ◽  
Mariana Bran ◽  
Alexandru Vlaicu
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Gas Chromatography ◽  
Continuous Flow ◽  
Laboratory Experiments ◽  
Fermentation Process ◽  
Flow Reactor ◽  
Agricultural Waste ◽  
Continuous Flow Reactor ◽  
Natural Support ◽  
Co2 Flow

This paper has aimed at evaluating the concentration of bioethanol obtained using sunflower stem as natural support, molasses as carbon source and Saccharomyces cerevisiae yeast in a continuous flow reactor. The natural support was tested to investigate the immobilization/growth of S. cerevisiae yeast. The concentration of bioethanol produced by fermentation was analyzed by gas chromatography using two methods: aqueous solutions and extraction in organic phase. The CO2 flow obtained during the fermentation process was considered to estimate when the yeast was deactivated. The laboratory experiments have highlighted that the use of plant-based wastes to bioconversion in ethanol could be a non-pollutant and sustainable alternative.

scholarly journals Mead Production Using Immobilized Cells of Saccharomyces cerevisiae: Reuse of Sodium Alginate Beads

Processes ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 724
Author(s):  
Miguel L. Sousa-Dias ◽  
Vanessa Branco Paula ◽  
Luís G. Dias ◽  
Letícia M. Estevinho
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Sodium Alginate ◽  
Fermentation Process ◽  
Immobilized Cells ◽  
Alginate Beads ◽  
Production Medium ◽  
Alcohol Content ◽  
Volatile Acidity ◽  
The Matrix ◽  
Second Category

This work studied the production of mead using second category honey and the immobilized cells of Saccharomyces cerevisiae in sodium alginate, with concentrations of 2% and 4%, and their reuse in five successive fermentations. The immobilized cells with 4% alginate beads were mechanically more stable and able to allow a greater number of reuses, making the process more economical. The fermentation’s consumption of sugars with free cells (control) and immobilized cells showed a similar profile, being completed close to 72 h, while the first use of immobilized cells finished at 96 h. The immobilized cells did not significantly influence some oenological parameters, such as the yield of the consumed sugars/ethanol, the alcohol content, the pH and the total acidity. There was a slight increase in the volatile acidity and a decrease in the production of SO2. The alginate concentrations did not significantly influence either the parameters used to monitor the fermentation process or the characteristics of the mead. Mead fermentations with immobilized cells showed the release of cells into the wort due to the disintegration of the beads, indicating that the matrix used for the yeast’s immobilization should be optimized, considering the mead production medium.

scholarly journals Adaptation of central metabolite pools to variations in growth rate and cultivation conditions in Saccharomyces cerevisiae

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Kanhaiya Kumar ◽  
Vishwesh Venkatraman ◽  
Per Bruheim
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Growth Rate ◽  
Amino Acid ◽  
Growth Rates ◽  
Pentose Phosphate Pathway ◽  
Pentose Phosphate ◽  
Relative Reduction ◽  
Central Metabolism ◽  
Cultivation Conditions ◽  
Biological Studies

Abstract Background Saccharomyces cerevisiae is a well-known popular model system for basic biological studies and serves as a host organism for the heterologous production of commercially interesting small molecules and proteins. The central metabolism is at the core to provide building blocks and energy to support growth and survival in normal situations as well as during exogenous stresses and forced heterologous protein production. Here, we present a comprehensive study of intracellular central metabolite pool profiling when growing S. cerevisiae on different carbon sources in batch cultivations and at different growth rates in nutrient-limited glucose chemostats. The latest versions of absolute quantitative mass spectrometry-based metabolite profiling methodology were applied to cover glycolytic and pentose phosphate pathway metabolites, tricarboxylic acid cycle (TCA), complete amino acid, and deoxy-/nucleoside phosphate pools. Results Glutamate, glutamine, alanine, and citrate were the four most abundant metabolites for most conditions tested. The amino acid is the dominant metabolite class even though a marked relative reduction compared to the other metabolite classes was observed for nitrogen and phosphate limited chemostats. Interestingly, glycolytic and pentose phosphate pathway (PPP) metabolites display the largest variation among the cultivation conditions while the nucleoside phosphate pools are more stable and vary within a closer concentration window. The overall trends for glucose and nitrogen-limited chemostats were increased metabolite pools with the increasing growth rate. Next, comparing the chosen chemostat reference growth rate (0.12 h−1, approximate one-fourth of maximal unlimited growth rate) illuminates an interesting pattern: almost all pools are lower in nitrogen and phosphate limited conditions compared to glucose limitation, except for the TCA metabolites citrate, isocitrate and α-ketoglutarate. Conclusions This study provides new knowledge-how the central metabolism is adapting to various cultivations conditions and growth rates which is essential for expanding our understanding of cellular metabolism and the development of improved phenotypes in metabolic engineering.

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