scholarly journals Transcriptional factor Cat8 is involved in regulation of xylose fermentation in engineered Saccharomyces cerevisiae

2018 ◽  
Vol 22 ◽  
pp. 329-334
Author(s):  
L. S. Dzanaieva ◽  
K. V. Dmytruk ◽  
A. A. Sybirny
Keyword(s):  
Ethanol Production ◽  
Alcoholic Fermentation ◽  
Xylose Fermentation ◽  
Ethanol Yield ◽  
Knock Out ◽  
Coding Regions ◽  
Gene Coding ◽  
Engineered Saccharomyces Cerevisiae ◽  
Deletion Cassette ◽  
Ethanol Synthesis

Aim. The aim of this work is the construction of cat8Δ strain on the base of xylose-fermenting S. cerevisiae strain and evaluation of the xylose fermentation rate. Methods. The CAT8 deletion cassette harboring natNT2 gene flanking with 5’ and 3’ non-coding regions of CAT8 gene has been constructed. After transformation by the cassette the cat8Δ strain was selected on the nourseothricin containing medium. Xylose fermentation experiments of constructed strain was performed in mineral medium supplemented with xylose under oxygen-limited conditions. Results. Xylose-fermenting cat8Δ S. cerevisiae strain has been constructed by homologous recombination of the CAT8 deletion cassette with target sequences in the genome of GS010 strain. The cat8Δ strain possessed increase in ethanol accumulation, ethanol yield, rate of ethanol production and productivity of ethanol synthesis relative to the parental GS010 strain for 9.5, 6, 20 and 12 %, respectively. Conclusions. The mutant of the xylose-fermenting S. cerevisiae strain with knock out of the CAT8 gene coding for transcriptional activator, has been constructed. The cat8Δ mutant showed 9.5 % increase in ethanol production from xylose relative to parental strain. Keywords: alcoholic fermentation, xylose, S. cerevisiae, Cat8.

scholarly journals Enzymatic Process for Cystoseira barbata Valorization: Ethanol Production and Additional By-Products

Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 741
Author(s):  
Doinita-Roxana Cioroiu Tirpan ◽  
Ancaelena Eliza Sterpu ◽  
Claudia Irina Koncsag ◽  
Alina Georgiana Ciufu ◽  
Tănase Dobre
Keyword(s):  
Ethanol Production ◽  
Alcoholic Fermentation ◽  
Ethanol Yield ◽  
Product Yield ◽  
Liquid Ratio ◽  
Experimental Conditions ◽  
Factors Affecting ◽  
Cystoseira Barbata ◽  
Main Factors ◽  
Process Factors

The aim of this study is to evaluate the potential of dried Cystoseira barbata alga for ethanol production through alcoholic fermentation. The influence of the main factors affecting the fermentation are studied in the frame of a 23 factorial experimental plan. The main factors influencing the process are the fermentation temperature (t from 25 °C to 35 °C), the solid to liquid ratio (S/L from 0.040 g/g to 0.080 g/g), and the cellulase ratio (R from 8 U/g d.m to 16 U/g d.m.). The maximum volatile compounds yield of 0.2808 g/g d.m and ethanol yield of 0.0158 g/g d.m were favored by the following experimental conditions: process temperature of 35 °C, solid to liquid ratio of 0.0415, and enzyme ratio of 16 U/g d.m. A statistical model was used to correlate the product yield with the process factors. Additionally, 19 interesting bioactive compounds were found in the enzymatic hydrolysis and alcoholic fermentation broths which seem likely to maintain natural defence mechanisms against diseases and physical disorders.

scholarly journals Enhanced xylose fermentation and ethanol production by engineered Saccharomyces cerevisiae strain

AMB Express ◽  
2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Leonardo de Figueiredo Vilela ◽  
Verônica Parente Gomes de Araujo ◽  
Raquel de Sousa Paredes ◽  
Elba Pinto da Silva Bon ◽  
Fernando Araripe Gonçalves Torres ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ethanol Production ◽  
Xylose Fermentation ◽  
Engineered Saccharomyces Cerevisiae

scholarly journals Fermentation of sucrose supplemented with monomeric sugars

1969 ◽  
Vol 74 (1) ◽  
pp. 45-50
Author(s):  
Angel Moret Figueroa ◽  
Carlos Basilio Reyes
Keyword(s):  
Ethanol Production ◽  
Zymomonas Mobilis ◽  
Alcoholic Fermentation ◽  
Ethanol Yield ◽  
Basic Medium ◽  
Alcohol Production ◽  
Caribbean Area ◽  
Final Yield ◽  
The Caribbean ◽  
Fermentation Period

Zymomonas mobilis is a bacterium which presents several advantages over yeast with respect to ethanol production. It ferments monosaccarides with higher yields and tolerates higher concentrations of ethanol and sugars. However, the alcoholic fermentation of sucrose, which is the most widely used sugar for alcohol production in the Caribbean area, is poor. Therefore, it is important to find how to increase ethanol yield by using Zymomonas mobilis with sucrose as starting material. Our experimental results demonstrated that the addition of monosaccharides to a basic medium containing 6% sucrose increased ethanol yield by at least 10%. The addition of 2% fructose at the beginning of the fermentation period increased ethanol yield from 87.4% to 100%, whereas the addition of 2% glucose produced a yield of 97.5%. When 1% of both monosaccharides was added the final yield was 99.8%.

scholarly journals Enhanced ethanol production from sugarcane molasses by industrially engineered Saccharomyces cerevisiae via replacement of the PHO4 gene

RSC Advances ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 2267-2276 ◽  
Author(s):  
Renzhi Wu ◽  
Dong Chen ◽  
Shuwei Cao ◽  
Zhilong Lu ◽  
Jun Huang ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ethanol Production ◽  
Ethanol Fermentation ◽  
Ethanol Yield ◽  
Regulatory Gene ◽  
Sugarcane Molasses ◽  
Fermentation Time ◽  
Fast Growing ◽  
Novel Strategy ◽  
Engineered Saccharomyces Cerevisiae

Replacement of a novel candidate ethanol fermentation-associated regulatory gene, PHO4, from a fast-growing strain through a novel strategy (SHPERM-bCGHR), is hypothesised to shorten fermentation time and enhance ethanol yield from sugarcane molasses.

scholarly journals Shuffling of Promoters for Multiple Genes To Optimize Xylose Fermentation in an Engineered Saccharomyces cerevisiae Strain

2007 ◽  
Vol 73 (19) ◽  
pp. 6072-6077 ◽  
Author(s):  
Chenfeng Lu ◽  
Thomas Jeffries
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ethanol Production ◽  
Xylose Fermentation ◽  
Xylose Reductase ◽  
Gene Promoter ◽  
Expression Levels ◽  
Multiple Genes ◽  
Expression Of Genes ◽  
Xylulose Kinase ◽  
Engineered Saccharomyces Cerevisiae

ABSTRACT We describe here a useful metabolic engineering tool, multiple-gene-promoter shuffling (MGPS), to optimize expression levels for multiple genes. This method approaches an optimized gene overexpression level by fusing promoters of various strengths to genes of interest for a particular pathway. Selection of these promoters is based on the expression levels of the native genes under the same physiological conditions intended for the application. MGPS was implemented in a yeast xylose fermentation mixture by shuffling the promoters for GND2 and HXK2 with the genes for transaldolase (TAL1), transketolase (TKL1), and pyruvate kinase (PYK1) in the Saccharomyces cerevisiae strain FPL-YSX3. This host strain has integrated xylose-metabolizing genes, including xylose reductase, xylitol dehydrogenase, and xylulose kinase. The optimal expression levels for TAL1, TKL1, and PYK1 were identified by analysis of volumetric ethanol production by transformed cells. We found the optimal combination for ethanol production to be GND2-TAL1-HXK2-TKL1-HXK2-PYK1. The MGPS method could easily be adapted for other eukaryotic and prokaryotic organisms to optimize expression of genes for industrial fermentation.

scholarly journals Engineering of Saccharomyces cerevisiae for Efficient Anaerobic Alcoholic Fermentation of l-Arabinose

2007 ◽  
Vol 73 (15) ◽  
pp. 4881-4891 ◽  
Author(s):  
H. Wouter Wisselink ◽  
Maurice J. Toirkens ◽  
M. del Rosario Franco Berriel ◽  
Aaron A. Winkler ◽  
Johannes P. van Dijken ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ethanol Production ◽  
Alcoholic Fermentation ◽  
Plant Biomass ◽  
Ethanol Yield ◽  
Dry Weight ◽  
Pentose Phosphate ◽  
Anaerobic Growth ◽  
Evolutionary Engineering ◽  
First Case

ABSTRACT For cost-effective and efficient ethanol production from lignocellulosic fractions of plant biomass, the conversion of not only major constituents, such as glucose and xylose, but also less predominant sugars, such as l-arabinose, is required. Wild-type strains of Saccharomyces cerevisiae, the organism used in industrial ethanol production, cannot ferment xylose and arabinose. Although metabolic and evolutionary engineering has enabled the efficient alcoholic fermentation of xylose under anaerobic conditions, the conversion of l-arabinose into ethanol by engineered S. cerevisiae strains has previously been demonstrated only under oxygen-limited conditions. This study reports the first case of fast and efficient anaerobic alcoholic fermentation of l-arabinose by an engineered S. cerevisiae strain. This fermentation was achieved by combining the expression of the structural genes for the l-arabinose utilization pathway of Lactobacillus plantarum, the overexpression of the S. cerevisiae genes encoding the enzymes of the nonoxidative pentose phosphate pathway, and extensive evolutionary engineering. The resulting S. cerevisiae strain exhibited high rates of arabinose consumption (0.70 g h−1 g [dry weight]−1) and ethanol production (0.29 g h−1 g [dry weight]−1) and a high ethanol yield (0.43 g g−1) during anaerobic growth on l-arabinose as the sole carbon source. In addition, efficient ethanol production from sugar mixtures containing glucose and arabinose, which is crucial for application in industrial ethanol production, was achieved.

Thermodynamics Simulation of Ethanol Synthesis via Biomass Gasification

2012 ◽  
Vol 608-609 ◽  
pp. 210-213
Author(s):  
Chun Yu Yan ◽  
Feng Pan ◽  
Cai Xin Li ◽  
Ya Li Li ◽  
Yan Fei Wu ◽  
...  
Keyword(s):  
High Pressure ◽  
Low Temperature ◽  
Ethanol Production ◽  
Synthesis Gas ◽  
Ethanol Yield ◽  
Biomass Gasification ◽  
Co2 Conversion ◽  
Gas Composition ◽  
Reactor Pressure ◽  
Ethanol Synthesis

Based on Aspen Plus software platform, a simulation of ethanol synthesis from biomass-derived synthesis gas processed on the assumption of both physical and thermodynamic equilibrium. The influences of these conditions such as temperature, reactor pressure and the H2 to (CO+CO2) mole ratio in the feed gas on CO and CO2 conversion and ethanol yield were investigated. The results showed that reaction temperature, pressure and synthesis gas composition have the most important effect on ethanol synthesis behavior. In this process, low temperature and high pressure would be advantageous for ethanol production.

scholarly journals Saccharomyces cerevisiae Fermentation of 28 Barley and 12 Oat Cultivars

Fermentation ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 59
Author(s):  
Timothy J. Tse ◽  
Daniel J. Wiens ◽  
Jianheng Shen ◽  
Aaron D. Beattie ◽  
Martin J. T. Reaney
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Acetic Acid ◽  
Lactic Acid ◽  
Succinic Acid ◽  
Alcoholic Fermentation ◽  
Ethanol Yield ◽  
Cereal Crops ◽  
Fermentation Products ◽  
Barley Cultivars ◽  
Oat Cultivars

As barley and oat production have recently increased in Canada, it has become prudent to investigate these cereal crops as potential feedstocks for alcoholic fermentation. Ethanol and other coproduct yields can vary substantially among fermented feedstocks, which currently consist primarily of wheat and corn. In this study, the liquified mash of milled grains from 28 barley (hulled and hull-less) and 12 oat cultivars were fermented with Saccharomyces cerevisiae to determine concentrations of fermentation products (ethanol, isopropanol, acetic acid, lactic acid, succinic acid, α-glycerylphosphorylcholine (α-GPC), and glycerol). On average, the fermentation of barley produced significantly higher amounts of ethanol, isopropanol, acetic acid, succinic acid, α-GPC, and glycerol than that of oats. The best performing barley cultivars were able to produce up to 78.48 g/L (CDC Clear) ethanol and 1.81 g/L α-GPC (CDC Cowboy). Furthermore, the presence of milled hulls did not impact ethanol yield amongst barley cultivars. Due to its superior ethanol yield compared to oats, barley is a suitable feedstock for ethanol production. In addition, the accumulation of α-GPC could add considerable value to the fermentation of these cereal crops.

scholarly journals Hemicellulosic Bioethanol Production from Fast-Growing Paulownia Biomass

Processes ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 173
Author(s):  
Elena Domínguez ◽  
Pablo G. del Río ◽  
Aloia Romaní ◽  
Gil Garrote ◽  
Lucília Domingues
Keyword(s):  
Ethanol Production ◽  
Ethanol Concentration ◽  
Ethanol Yield ◽  
Xylose Reductase ◽  
Energy Crop ◽  
Scheffersomyces Stipitis ◽  
Fractionation Process ◽  
Renewable Source ◽  
Fast Growing ◽  
Engineered Strain

In order to exploit a fast-growing Paulownia hardwood as an energy crop, a xylose-enriched hydrolysate was obtained in this work to increase the ethanol concentration using the hemicellulosic fraction, besides the already widely studied cellulosic fraction. For that, Paulownia elongata x fortunei was submitted to autohydrolysis treatment (210 °C or S0 of 4.08) for the xylan solubilization, mainly as xylooligosaccharides. Afterwards, sequential stages of acid hydrolysis, concentration, and detoxification were evaluated to obtain fermentable sugars. Thus, detoxified and non-detoxified hydrolysates (diluted or not) were fermented for ethanol production using a natural xylose-consuming yeast, Scheffersomyces stipitis CECT 1922, and an industrial Saccharomyces cerevisiae MEC1133 strain, metabolic engineered strain with the xylose reductase/xylitol dehydrogenase pathway. Results from fermentation assays showed that the engineered S. cerevisiae strain produced up to 14.2 g/L of ethanol (corresponding to 0.33 g/g of ethanol yield) using the non-detoxified hydrolysate. Nevertheless, the yeast S. stipitis reached similar values of ethanol, but only in the detoxified hydrolysate. Hence, the fermentation data prove the suitability and robustness of the engineered strain to ferment non-detoxified liquor, and the appropriateness of detoxification of liquor for the use of less robust yeast. In addition, the success of hemicellulose-to-ethanol production obtained in this work shows the Paulownia biomass as a suitable renewable source for ethanol production following a suitable fractionation process within a biorefinery approach.

scholarly journals Effects of Ultrasound on Fermentation of Glucose to Ethanol by Saccharomyces cerevisiae

Fermentation ◽  
2019 ◽  
Vol 5 (1) ◽  
pp. 16 ◽  
Author(s):  
Luis Huezo ◽  
Ajay Shah ◽  
Frederick Michel
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mass Transfer ◽  
Glucose Uptake ◽  
Ethanol Production ◽  
Ethanol Yield ◽  
Biofuel Production ◽  
Inhibitory Effects ◽  
Negative Effects ◽  
Intraparticle Mass Transfer ◽  
Improve Mass Transfer

Previous studies have shown that pretreatment of corn slurries using ultrasound improves starch release and ethanol yield during biofuel production. However, studies on its effects on the mass transfer of substrates and products during fermentation have shown that it can have both beneficial and inhibitory effects. In this study, the effects of ultrasound on mass transfer limitations during fermentation were examined. Calculation of the external and intraparticle observable moduli under a range of conditions indicate that no external or intraparticle mass transfer limitations should exist for the mass transfer of glucose, ethanol, or carbon dioxide. Fermentations of glucose to ethanol using Saccharomyces cerevisiae were conducted at different ultrasound intensities to examine its effects on glucose uptake, ethanol production, and yeast population and viability. Four treatments were compared: direct ultrasound at intensities of 23 and 32 W/L, indirect ultrasound (1.4 W/L), and no-ultrasound. Direct and indirect ultrasound had negative effects on yeast performance and viability, and reduced the rates of glucose uptake and ethanol production. These results indicate that ultrasound during fermentation, at the levels applied, is inhibitory and not expected to improve mass transfer limitations.

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