Physiological characterization of thermotolerant yeast for cellulosic ethanol production

Abstract Background The use of thermotolerant yeast strains can improve the efficiency of ethanol fermentation, allowing fermentation to occur at temperatures higher than 40 °C. This increment in temperature could benefit traditional bio-ethanol production and allow simultaneous saccharification and fermentation (SSF) of starch or lignocellulosic biomass. Results We identified and characterized the physiology of a new thermotolerant strain able to fermentate at 40 °C while producing high yields of ethanol. Our results showed that, in comparison to the industrial yeast CAT-1, our strain was more resistant to various stressors generated during the production of first- and second-generation ethanol, and it also was able to change the pattern of genes involved in sucrose assimilation (SUC2 and AGT1). The formation of secondary products of fermentation was different at 40ºC, with reduced expression of genes involved in the formation of glycerol (GPD2), acetate (ALD6 and ALD4), and acetyl-CoA (ACS2). Conclusion The LBGA-01 strain is a thermotolerant strain that modulates the production of key genes, changing metabolic pathways during high-temperature fermentation, and increasing its tolerance to the high concentration of ethanol, sugar, acetic lactic, acetic acid, furfural and HMF. This indicates that this strain can be used to improve first- and second-generation ethanol production in Brazil.

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Characterisation of a thermotolerant yeast, Kluyveromyces marxianus CBS712

Acta Agraria Debreceniensis ◽

10.34101/actaagrar/35/2804 ◽

2009 ◽

pp. 7-13

Author(s):

Éva Erdei ◽

Mónika Molnár ◽

Gyöngyi Gyémánt ◽

János Harangi ◽

János Nagy ◽

...

Keyword(s):

Ethanol Production ◽

Glucose Concentration ◽

Temperature Limit ◽

Thermotolerant Yeast ◽

Bioethanol Production ◽

Technological Advantage ◽

Different Temperatures ◽

Higher Temperature

Fermentation at high temperature with application of thermotolerant microorganisms is a technological advantage in bioethanol production. Among the yeasts, K. marxianus has outstanding thermotolarance. The industrial application of the IMB3 strain occurs usually at 45C. The final aim of our project is the genetic modification of the K. marxianus CBS712 strain in order to achieve ethanol production at higher temperature than the currently applied. This requires the characterization of the CBS712 strain, with special attention to the determination of the temperature limit of its growth and the amount of the ethanol produced. The temperature limit of growth was 48C in YPD medium. Elevation of the temperature above 45C led to an exponential drop of the cell viability. Ethanol production was tested in shaking flasks, in MYFM medium, under oxigene limited conditions, applying variable concentrations of glucose (12–20%) and different temperatures (45–47 ºC). Preliminary results have revealed that the elevation of glucose concentration increased the amount of ethanol produced. The amount of ethanol (appr. 5%)+ produced at the highest glucose concentration was not different at the tested temperatures (45, 46 and 47 ºC). The observation indicates the potential in raising the thermotolerance of the strain.

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Rumen disappearance kinetics and chemical characterization of by-products from cellulosic ethanol production

Animal Feed Science and Technology ◽

10.1016/j.anifeedsci.2010.11.020 ◽

2011 ◽

Vol 165 (3-4) ◽

pp. 151-160 ◽

Cited By ~ 3

Author(s):

S.L. Scott ◽

R.S. Mbifo ◽

J. Chiquette ◽

P. Savoie ◽

G. Turcotte

Keyword(s):

Ethanol Production ◽

Cellulosic Ethanol ◽

Chemical Characterization ◽

By Products ◽

Disappearance Kinetics

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Characterization of persistent colors and decolorization of effluent from biologically treated cellulosic ethanol production wastewater

Environmental Science and Pollution Research ◽

10.1007/s11356-016-6220-5 ◽

2016 ◽

Vol 23 (10) ◽

pp. 10215-10222 ◽

Cited By ~ 14

Author(s):

Lili Shan ◽

Junfeng Liu ◽

Yanling Yu ◽

John J. Ambuchi ◽

Yujie Feng

Keyword(s):

Ethanol Production ◽

Cellulosic Ethanol

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Physiological characterization of a new thermotolerant yeast strain isolated during Brazilian ethanol production, and its application in high-temperature fermentation

Biotechnology for Biofuels ◽

10.1186/s13068-020-01817-6 ◽

2020 ◽

Vol 13 (1) ◽

Author(s):

Cleiton D. Prado ◽

Gustavo P. L. Mandrujano ◽

Jonas. P. Souza ◽

Flávia B. Sgobbi ◽

Hosana R. Novaes ◽

...

Keyword(s):

Acetic Acid ◽

Lactic Acid ◽

High Temperature ◽

Ethanol Production ◽

Thermotolerant Yeast ◽

Secondary Products ◽

High Concentration ◽

Physiological Characterization ◽

Expression Of Genes ◽

Thermotolerant Strain

Abstract Background The use of thermotolerant yeast strains can improve the efficiency of ethanol fermentation, allowing fermentation to occur at temperatures higher than 40 °C. This characteristic could benefit traditional bio-ethanol production and allow simultaneous saccharification and fermentation (SSF) of starch or lignocellulosic biomass. Results We identified and characterized the physiology of a new thermotolerant strain (LBGA-01) able to ferment at 40 °C, which is more resistant to stressors as sucrose, furfural and ethanol than CAT-1 industrial strain. Furthermore, this strain showed similar CAT-1 resistance to acetic acid and lactic acid, and it was also able to change the pattern of genes involved in sucrose assimilation (SUC2 and AGT1). Genes related to the production of proteins involved in secondary products of fermentation were also differentially regulated at 40 °C, with reduced expression of genes involved in the formation of glycerol (GPD2), acetate (ALD6 and ALD4), and acetyl-coenzyme A synthetase 2 (ACS2). Fermentation tests using chemostats showed that LBGA-01 had an excellent performance in ethanol production in high temperature. Conclusion The thermotolerant LBGA-01 strain modulates the production of key genes, changing metabolic pathways during high-temperature fermentation, and increasing its resistance to high concentration of ethanol, sugar, lactic acid, acetic acid, and furfural. Results indicate that this strain can be used to improve first- and second-generation ethanol production in Brazil.

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