scholarly journals Production of Ethanol from Starch by Respiration-Deficient Recombinant Saccharomyces cerevisiae

2005 ◽  
Vol 71 (10) ◽  
pp. 6443-6445 ◽  
Author(s):  
Ebru Toksoy Öner ◽  
Stephen G. Oliver ◽  
Betül Kırdar
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ethanol Fermentation ◽  
Ethanol Yield ◽  
Ethanol Productivity ◽  
Recombinant Saccharomyces Cerevisiae ◽  
Direct Fermentation

ABSTRACT A 100%-respiration-deficient nuclear petite amylolytic Saccharomyces cerevisiae NPB-G strain was generated, and its employment for direct fermentation of starch into ethanol was investigated. In a comparison of ethanol fermentation performances with the parental respiration-sufficient WTPB-G strain, the NPB-G strain showed an increase of ca. 48% in both ethanol yield and ethanol productivity.

scholarly journals An Innovative Biocatalyst for Continuous 2G Ethanol Production from Xylo-Oligomers by Saccharomyces cerevisiae through Simultaneous Hydrolysis, Isomerization, and Fermentation (SHIF)

Catalysts ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 225 ◽  
Author(s):  
Thais Milessi-Esteves ◽  
Felipe Corradini ◽  
Willian Kopp ◽  
Teresa Zangirolami ◽  
Paulo Tardioli ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ethanol Production ◽  
Ethanol Yield ◽  
Xylose Isomerase ◽  
Ethanol Productivity ◽  
Spherical Particles ◽  
Birchwood Xylan ◽  
Alginate Gel ◽  
Industrial Implementation ◽  
Ca Alginate

Many approaches have been considered aimed at ethanol production from the hemicellulosic fraction of biomass. However, the industrial implementation of this process has been hindered by some bottlenecks, one of the most important being the ease of contamination of the bioreactor by bacteria that metabolize xylose. This work focuses on overcoming this problem through the fermentation of xylulose (the xylose isomer) by native Saccharomyces cerevisiae using xylo-oligomers as substrate. A new concept of biocatalyst is proposed, containing xylanases and xylose isomerase (XI) covalently immobilized on chitosan, and co-encapsulated with industrial baker’s yeast in Ca-alginate gel spherical particles. Xylo-oligomers are hydrolyzed, xylose is isomerized, and finally xylulose is fermented to ethanol, all taking place simultaneously, in a process called simultaneous hydrolysis, isomerization, and fermentation (SHIF). Among several tested xylanases, Multifect CX XL A03139 was selected to compose the biocatalyst bead. Influences of pH, Ca2+, and Mg2+ concentrations on the isomerization step were assessed. Experiments of SHIF using birchwood xylan resulted in an ethanol yield of 0.39 g/g, (76% of the theoretical), selectivity of 3.12 gethanol/gxylitol, and ethanol productivity of 0.26 g/L/h.

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.

Comparison of Spathaspora passalidarum and recombinant Saccharomyces cerevisiae for integration of first- and second-generation ethanol production

2021 ◽  
Vol 21 (6) ◽  
Author(s):  
Isabela de Oliveira Pereira ◽  
Ângela Alves dos Santos ◽  
Davi L Gonçalves ◽  
Marcela Purificação ◽  
Nick Candiotto Guimarães ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Second Generation ◽  
Ethanol Yield ◽  
Fractionation Process ◽  
Sucrose Hydrolysis ◽  
Recombinant Saccharomyces Cerevisiae ◽  
Hemicellulosic Hydrolysate ◽  
Spathaspora Passalidarum ◽  
Microaerobic Conditions ◽  
Second Generation Ethanol

ABSTRACT First-generation ethanol (E1G) is based on the fermentation of sugars released from saccharine or starch sources, while second-generation ethanol (E2G) is focused on the fermentation of sugars released from lignocellulosic feedstocks. During the fractionation process to release sugars from hemicelluloses (mainly xylose), some inhibitor compounds are released hindering fermentation. Thus, the biggest challenge of using hemicellulosic hydrolysate is selecting strains and processes able to efficiently ferment xylose and tolerate inhibitors. With the aim of diluting inhibitors, sugarcane molasses (80% of sucrose content) can be mixed to hemicellulosic hydrolysate in an integrated E1G–E2G process. Cofermentations of xylose and sucrose were evaluated for the native xylose consumer Spathaspora passalidarum and a recombinant Saccharomyces cerevisiae strain. The industrial S. cerevisiae strain CAT-1 was modified to overexpress the XYL1, XYL2 and XKS1 genes and a mutant ([4–59Δ]HXT1) version of the low-affinity HXT1 permease, generating strain MP-C5H1. Although S. passalidarum showed better results for xylose fermentation, this yeast showed intracellular sucrose hydrolysis and low sucrose consumption in microaerobic conditions. Recombinant S. cerevisiae showed the best performance for cofermentation, and a batch strategy at high cell density in bioreactor achieved unprecedented results of ethanol yield, titer and volumetric productivity in E1G–E2G production process.

scholarly journals Improvement in cell growth and ethanol productivity of Saccharomyces cerevisiae due to poultry litter biochar

2019 ◽  
Vol 6 (4) ◽  
pp. 179-186
Author(s):  
Foster A Agblevor ◽  
Oumou Diallo
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Corn Stover ◽  
Ethanol Fermentation ◽  
Poultry Litter ◽  
Fermentation Medium ◽  
Ethanol Productivity ◽  
Poplar Wood ◽  
Fermentation Time ◽  
Poultry Litter Biochar ◽  
Effective Additive

The effect of poultry litter biochar on Saccharomyces cerevisiae growth and ethanol fermentation was investigated for glucose, steam exploded corn stover and poplar wood. S. cerevisiae grew faster in both anaerobic and aerobic biochar medium than the control media. For the same initial concentration of glucose, the biochar medium glucose was consumed in 12 hours compared to 24 hours for control and the maximum ethanol productivity were higher for the biochar compared to the control medium. When the initial glucose concentration was increased the maximum ethanol productivity for the biochar media was more than two times that for the control. Similarly, addition of poultry litter biochar to steam exploded poplar wood and corn stover improved the ethanol productivity depending on the amount of biochar added to the fermentation medium. Thus, biochar is an effective additive to reduce ethanol fermentation time

scholarly journals 3′ Truncation of theGPD1Promoter in Saccharomyces cerevisiae for Improved Ethanol Yield and Productivity

2013 ◽  
Vol 79 (10) ◽  
pp. 3273-3281 ◽  
Author(s):  
Wen-Tao Ding ◽  
Guo-Chang Zhang ◽  
Jing-Jing Liu
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ethanol Yield ◽  
Research Effort ◽  
Final Concentration ◽  
Ethanol Productivity ◽  
Promoter Strength ◽  
Content Type ◽  
Very High Gravity ◽  
New Strategy ◽  
Glycerol Formation

ABSTRACTGlycerol is a major by-product in bioethanol fermentation by the yeastSaccharomyces cerevisiae, and decreasing glycerol formation for increased ethanol yield has been a major research effort in the bioethanol field. A new strategy has been used in the present study for reduced glycerol formation and improved ethanol fermentation performance by finely modulating the expression ofGPD1in the KAM15 strain (fps1ΔpPGK1-GLT1 gpd2Δ). TheGPD1promoter was serially truncated from the 3′ end by 20 bp to result in a different expression strength ofGPD1. The two engineered promoters carrying 60- and 80-bp truncations exhibited reduced promoter strength but unaffected osmostress response. These two promoters were integrated into the KAM15 strain, generating strains LE34U and LE35U, respectively. The transcription levels of LE34U and LE35U were 37.77 to 45.12% and 21.34 to 24.15% of that of KAM15U, respectively, depending on osmotic stress imposed by various glucose concentrations. In very high gravity (VHG) fermentation, the levels of glycerol for LE34U and LE35U were reduced by 15.81% and 30.66%, respectively, compared to KAM15U. The yield and final concentration of ethanol for LE35U were 3.46% and 0.33% higher, respectively, than those of KAM15U. However, fermentation rate and ethanol productivity for LE35U were reduced. On the other hand, the ethanol yield and final concentration for LE34U were enhanced by 2.28% and 2.32%, respectively, compared to those of KAM15U. In addition, a 2.31% increase in ethanol productivity was observed for LE34U compared to KAM15U. These results verified the feasibility of our strategy for yeast strain development.

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.

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