Continuous ethanol production and evaluation of yeast cell lysis and viability loss under very high gravity medium conditions

Bai, Fengwu; Chen, L.J; Zhang, Z; Anderson, William A.; Moo‐Young, Murray

doi:10.1016/j.jbiotec.2004.01.017

Cited by 117 publications

(46 citation statements)

References 9 publications

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“…However, at a sugar concentration of 300 g¨L´1 the ethanol concentration was remarkably decreased, and a large amount of sugar remained in the fermentation broth at both 37˝C and 40˝C. High sugar concentrations have been reported to cause negative effects on cell viability and morphology due to an increase in the osmotic pressure, which leads to a reduction in the cell biomass and ethanol yield [53,55]. The maximum ethanol concentrations produced by S. cerevisiae DBKKU Y-53 and SC90 were achieved at a sugar concentration of 250 g¨L´1.…”

Section: Factors Influencing Ethanol Production When Using Thermotolementioning

confidence: 99%

Ethanol Production from Sweet Sorghum Juice at High Temperatures Using a Newly Isolated Thermotolerant Yeast Saccharomyces cerevisiae DBKKU Y-53

et al. 2016

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Ethanol production at elevated temperatures requires high potential thermotolerant ethanol-producing yeast. In this study, nine isolates of thermotolerant yeasts capable of growth and ethanol production at high temperatures were successfully isolated. Among these isolates, the newly isolated thermotolerant yeast strain, which was designated as Saccharomyces cerevisiae DBKKU Y-53, exhibited great potential for ethanol production from sweet sorghum juice (SSJ) at high temperatures. The maximum ethanol concentrations produced by this newly isolated thermotolerant yeast at 37˝C and 40˝C under the optimum cultural condition were 106.82 g¨L´1 and 85.01 g¨L´1, respectively, which are greater than values reported in the literatures. It should be noted from this study with SSJ at a sugar concentration of 250 g¨L´1 and an initial pH of 5.5 without nitrogen supplementation can be used directly as substrate for ethanol production at high temperatures by thermotolerant yeast S. cerevisiae DBKKU Y-53. Gene expression analysis using real-time RT-PCR clearly indicated that growth and ethanol fermentation activities of the thermotolerant yeast S. cerevisiae DBKKU Y-53 at a high temperature (40˝C) were not only restricted to the expression of genes involved in the heat-shock response, but also to those genes involved in ATP production, trehalose and glycogen metabolism, and protein degradation processes were also involved.

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Section: Factors Influencing Ethanol Production When Using Thermotolementioning

confidence: 99%

Ethanol Production from Sweet Sorghum Juice at High Temperatures Using a Newly Isolated Thermotolerant Yeast Saccharomyces cerevisiae DBKKU Y-53

et al. 2016

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Section: Discussionmentioning

confidence: 99%

“…Although a number of studies have been carried out to determine the viability conditions of the Saccharomyces cerevisiae strains as an alimentary product, [15][16][17][18] very few data are available concerning S. boulardii. 14) It is important to note that despite being a subtype of S. cerevisiae yeast species known as S. cerevisiae Hansen CBS 5926, S. boulardii is clearly distinguishable from S. cerevisiae and possesses strain-specific beneficial properties.…”

Section: Discussionmentioning

confidence: 99%

Formulations for Protecting the Probiotic Saccharomyces boulardii from Degradation in Acidic Condition

Graff

Chaumeil

Boy

et al. 2008

Biological & Pharmaceutical Bulletin

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Saccharomyces boulardii is a nonpathogenic yeast with proven health benefits, some of them depending on its viability. However, the living yeast is sensitive to environmental conditions and its viability is less than 1% in the faeces after oral administration. Therefore, we assessed the survival conditions of S. boulardii in aqueous suspension and in its freeze-dried form and we formulated microspheres with the former and tablets with the latter in order to preserve the viability of the probiotic. While the viability of the yeast in aqueous suspension could be maintained for one year at ؊20°C and ؉5°C, increasing the temperature led to almost total mortality within 14 d at ؉40°C and 4 d at ؉60°C. The viability of the freeze-dried yeast was preserved for one year at ؉25°C without moisture. With 75% relative humidity, the mortality was significant at 28 d at ؉25°C and almost total within 1 d at ؉60°C. In vitro, whereas less than 1% of non-encapsulated or non-tabletted S. boulardii survived after 120 min at pH 1.1, both formulations in microspheres and direct compression enabled to protect the yeast from degradation in HCl and to release it viable at pH 6.8. However, despite a similar release profile from both dosage forms, the compression led to a significant decrease in the viability of the freeze-dried yeast. In conclusion, although both formulations are efficient in protecting S. boulardii in acidic condition, microspheres provide a higher entrapment efficiency and a faster release of the viable probiotic in intestinal condition than matrix tablets.Key words microsphere; tablet; Saccharomyces boulardii; viability conditions; probiotic Biol. Pharm. Bull. 31(2) 266-272 (2008) © 2008 Pharmaceutical Society of Japan * To whom correspondence should be addressed. e-mail: sandrine.graff@univ-paris5.ft Assessment of the Survival of S. boulardii under Different Handling/Storage Conditions Samples of freeze-dried yeast (batch 4) were stored at ϩ25 or ϩ60°C either under aerobic conditions with 75% humidity or with no relative humidity, respectively (using saturated NaCl solution to maintain a constant humidity within the enclosure, or silicate gel to maintain the enclosure without humidity) or anaerobic conditions (nitrogen) for one year. A control sample was stored in ambient conditions for one year (temperature between ϩ15 and ϩ35°C and relative humidity from 35 to 90%). At 0,1,4,7,14,28, 90, 180 d and one year, the freezedried yeast was sampled to evaluate its viability.Samples of the aqueous suspension (batch 1) were stored at Ϫ20, ϩ5, ϩ25, ϩ40 and ϩ60°C under aerobic or anaerobic conditions for one year. At the times cited above, the aqueous suspension was sampled to assess the yeast viability. All the experiments were carried out in triplicate.Determination of Viable Yeasts The viability of the yeast has been defined as the proportion of the cells that are capable of multiplication after incubation in standard microbiological conditions. It was evaluated after serial 10-fold dilutions by a plate culture method u...

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“…Moreover, a novel strain capable of producing large amounts of n-butanol called ACKKO-adhE2 was obtained via advanced metabolic engineering and synthetic biology technologies (Zhou et al, 2016;Jiang et al, 2009;Yu et al, 2011). In terms of sweet sorghum industrialization, fermentation process development has been very important for efficient ethanol production (Bai et al, 2004;Laopaiboon, 2007). At present, Saccharomyces cerevisiae is widely used in industrial ethanol production (Zhao & Bai, 2009).…”

Section: Improvmentioning

confidence: 99%

Recent Progresses on Industrialization of Sweet Sorghum at IMP

XiCun¹,

Li²,

Liu³

et al. 2017

JAS

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Sweet sorghum [Sorghum bicolor (L.) Moench] is not only an efficient and highly productive bioenergy crop that may help alleviate potential food-fuel tension caused by over-reliance on corn grain ethanol because of its outstanding features, including large amounts of fermentable carbohydrates in its juice-rich stalks, drought-tolerance, saline-alkaline resistance but also has considerable potential as food, forage crop owing to the limited availability of arable land. In this review, we have provided a brief overview of the progress that has been made in sweet sorghum industrialization at IMP range from research motivation, breeding, planting scale to products development. A conclusion is drawn that sweet sorghum industry is a systematic project, involving many key points, such as breeding, planting, production process and products sale. From a strategic and sustainability point of view, sweet sorghum is one of the most promising plants, particularly for ethanol, silage and liquor production.

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Continuous ethanol production and evaluation of yeast cell lysis and viability loss under very high gravity medium conditions

Cited by 117 publications

References 9 publications

Ethanol Production from Sweet Sorghum Juice at High Temperatures Using a Newly Isolated Thermotolerant Yeast Saccharomyces cerevisiae DBKKU Y-53

Ethanol Production from Sweet Sorghum Juice at High Temperatures Using a Newly Isolated Thermotolerant Yeast Saccharomyces cerevisiae DBKKU Y-53

Formulations for Protecting the Probiotic Saccharomyces boulardii from Degradation in Acidic Condition

Recent Progresses on Industrialization of Sweet Sorghum at IMP

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