Improve Ethanol Yield Through Minimizing Glycerol Yield in Ethanol Fermentation of Saccharomyces cerevisiae

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.

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

RSC Advances ◽

10.1039/c9ra08673k ◽

2020 ◽

Vol 10 (4) ◽

pp. 2267-2276 ◽

Cited By ~ 7

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.

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Saccharomyces cerevisiae Fermentation of 28 Barley and 12 Oat Cultivars

Fermentation ◽

10.3390/fermentation7020059 ◽

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

Fermentation ◽

10.3390/fermentation5010016 ◽

2019 ◽

Vol 5 (1) ◽

pp. 16 ◽

Cited By ~ 5

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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Optimization and techno-economic assessment of high-solid fed-batch saccharification and ethanol fermentation by Scheffersomyces stipitis and Saccharomyces cerevisiae consortium

Renewable Energy ◽

10.1016/j.renene.2016.08.019 ◽

2016 ◽

Vol 99 ◽

pp. 1062-1072 ◽

Cited By ~ 14

Author(s):

Pornkamol Unrean ◽

Sutamat Khajeeram

Keyword(s):

Saccharomyces Cerevisiae ◽

Ethanol Fermentation ◽

Economic Assessment ◽

Fed Batch ◽

Scheffersomyces Stipitis ◽

High Solid

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Recombinant Diploid Saccharomyces cerevisiae Strain Development for Rapid Glucose and Xylose Co-Fermentation

Fermentation ◽

10.3390/fermentation4030059 ◽

2018 ◽

Vol 4 (3) ◽

pp. 59 ◽

Cited By ~ 8

Author(s):

Tingting Liu ◽

Shuangcheng Huang ◽

Anli Geng

Keyword(s):

Saccharomyces Cerevisiae ◽

Alcoholic Fermentation ◽

Ethanol Yield ◽

Xylose Isomerase ◽

Cost Effective ◽

Xylose Utilization ◽

Yeast Strains ◽

Multiple Copies ◽

Biomass Sugars ◽

Sugar Conversion

Cost-effective production of cellulosic ethanol requires robust microorganisms for rapid co-fermentation of glucose and xylose. This study aims to develop a recombinant diploid xylose-fermenting Saccharomyces cerevisiae strain for efficient conversion of lignocellulosic biomass sugars to ethanol. Episomal plasmids harboring codon-optimized Piromyces sp. E2 xylose isomerase (PirXylA) and Orpinomyces sp. ukk1 xylose (OrpXylA) genes were constructed and transformed into S. cerevisiae. The strain harboring plasmids with tandem PirXylA was favorable for xylose utilization when xylose was used as the sole carbon source, while the strain harboring plasmids with tandem OrpXylA was beneficial for glucose and xylose cofermentation. PirXylA and OrpXylA genes were also individually integrated into the genome of yeast strains in multiple copies. Such integration was beneficial for xylose alcoholic fermentation. The respiration-deficient strain carrying episomal or integrated OrpXylA genes exhibited the best performance for glucose and xylose co-fermentation. This was partly attributed to the high expression levels and activities of xylose isomerase. Mating a respiration-efficient strain carrying the integrated PirXylA gene with a respiration-deficient strain harboring integrated OrpXylA generated a diploid recombinant xylose-fermenting yeast strain STXQ with enhanced cell growth and xylose fermentation. Co-fermentation of 162 g L−1 glucose and 95 g L−1 xylose generated 120.6 g L−1 ethanol in 23 h, with sugar conversion higher than 99%, ethanol yield of 0.47 g g−1, and ethanol productivity of 5.26 g L−1·h−1.

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Strain Selection and Medium Optimization for Aspergillus niger and Saccharomyces cerevisiae for Ethanol Fermentation

10.13031/aim.20141899729 ◽

2014 ◽

Keyword(s):

Saccharomyces Cerevisiae ◽

Aspergillus Niger ◽

Ethanol Fermentation ◽

Medium Optimization ◽

Strain Selection

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Food Grade Ethanol Production Process of Sorghum Stem Juice Using Immobilized Cells Technique

Modern Applied Science ◽

10.5539/mas.v9n7p8 ◽

2015 ◽

Vol 9 (7) ◽

pp. 8 ◽

Cited By ~ 1

Author(s):

Tri Widjaja ◽

Ali Altway ◽

Arief Widjaja ◽

Umi Rofiqah ◽

Rr Whiny Hardiyati Erlian

Keyword(s):

Saccharomyces Cerevisiae ◽

Molecular Sieve ◽

Zymomonas Mobilis ◽

Immobilized Cells ◽

Ethanol Yield ◽

Continuous Fermentation ◽

Continuous Process ◽

Pichia Stipitis ◽

Batch Process ◽

Food Grade

One form of economic development efforts for waste utilization in rural communities is to utilize stem sorghum to produce food grade ethanol. Sorghum stem juice with 150 g/L of sugar concentration was fermented using conventional batch process and cell immobilization continuous process with K-carrageenan as a supporting matrix. The microorganism used was Mutated Zymomonas Mobilis to be compared with a mixture of Saccharomyces Cerevisiae and Pichia Stipitis, and a mixture of Mutated Zymomonas Mobilis and Pichia Stipitis. Ethanol in the broth, result of fermentation process, was separated in packed distillation column. Distilate of the column, still contain water and other impurities, was flown into molecular sieve for dehydration and activated carbon adsorption column to remove the other impurities to meet food grade ethanol specification. The packing used in distillation process was steel wool. For batch fermentation, the fermentation using a combination of Saccharomyces Cerevisiae and Pichia Stipitis produced the best ethanol with 12.07% of concentration, where the yield and the productivity were 63.49%, and 1.06 g/L.h, respectively. And for continuous fermentation, the best ethanol with 9.02% of concentration, where the yield and the productivity were 47.42% and 174.27 g/L.h, respectively, is obtained from fermentation using a combination of Saccharomyces Cerevisiae and Pichia Stipitis also. Fermentation using combination microorganism of Saccharomyces Cerevisiae and Pichia Stipitis produced higher concentration of ethanol, yield, and productivity than other microorganisms. Distillation, molecular sieve dehydration and adsorption process is quite successful in generating sufficient levels of ethanol with relatively low amount of impurities.

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High Productivity Ethanol Fermentation of Glucose & Xylose Using Membrane Assisted Continuous Cell Recycle

Sustainable Chemical Engineering ◽

10.37256/sce.212021634 ◽

2021 ◽

pp. 8-19

Author(s):

Gautam Degweker ◽

Arvind Lali

Keyword(s):

Ethanol Fermentation ◽

Ethanol Yield ◽

Continuous Fermentation ◽

Cost Effective ◽

High Yield ◽

High Cell ◽

Cell Recycle ◽

High Productivity ◽

Ethanol Yields ◽

Cell Densities

Rapid and high yield conversion of xylose to ethanol remains a signi cant bottleneck in the cost-effective production of ethanol using mixed sugars derived from lignocellulosic biomass (LBM). The present study attempts to circumvent this by separate continuous fermentation of glucose and xylose using high cell densities of a Saccharomyces cerevisiae mutant (ICT-1) and a Scheffersomyces stipitis mutant (M1CD), respectively with the help of external micro ltration membrane assisted cell recycle. Different cell densities and aeration rates for xylose fermentation were studied for optimizing continuous fermentation. Consistent high ethanol yields and productivities of 0.46 g/g and 5.19 g/L/h with glucose; and 0.38 g/g and 1.62 g/L/h with xylose; were achieved in simple media. This provided an average ethanol yield of 0.44 g/g on combined sugars, and average productivity of 3.4 g/L/h which is higher than typical molasses-based batch ethanol fermentation. The study thus highlights the potential of high cell density recycle strategy as an effective approach for separate ethanol fermentation of LBM derived sugars.

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