Continuous ethanol production by cell-holding culture of yeasts

Taniguchi, Masayuki; Wakamiya, Ken; Tsuchiya, Masakazu; Matsuno, Ryuichi; Kamikubo, Tadashi

doi:10.1007/bf00501509

Cited by 10 publications

(3 citation statements)

References 16 publications

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“…In contrast, batch cultivation would be problematic due to initially high inhibitor levels and, as a result, an extended lag phase. Furthermore, continuous cultivation generally has higher average production per volume unit than both batch and fed-batch cultivation (Taniguchi et al, 1983).…”

Section: Introductionmentioning

confidence: 99%

Continuous fermentation of wheat‐supplemented lignocellulose hydrolysate with different types of cell retention

Brandberg¹,

Karimi²,

Taherzadeh³

et al. 2007

Biotech & Bioengineering

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Medium supplementation and process alternatives for fuel ethanol production from dilute acid lignocellulose hydrolysate were investigated. Dilute acid lignocellulose hydrolysate supplemented with enzymatically hydrolysed wheat flour could sustain continuous anaerobic cultivation of Saccharomyces cerevisiae ATCC 96581 if further supplemented with ammonium sulphate and biotin. This medium composition allowed for a hexose utilisation of 73% and an ethanol production of 36 mmol l(-1) h(-1) in chemostat cultivation at dilution rate 0.10 h(-1). Three different methods for cell retention were compared for improved fermentation of supplemented lignocellulose hydrolysate: cell recirculation by filtration, cell recirculation by sedimentation and cell immobilisation in calcium alginate. All three cell retention methods improved the hexose conversion and increased the volumetric ethanol production rate. Recirculation of 75% of the bioreactor outlet flow by filtration improved the hexose utilisation from 76% to 94%. Sedimentation turned out to be an efficient method for cell separation; the cell concentration in the reactor was 32 times higher than in the outflow after 60 h of substrate feeding. However, chemostat and continuous cell recirculation cultures became severely inhibited when the dilution rate was increased to 0.20 h(-1). In contrast, an immobilised system kept producing ethanol at a stable level also at dilution rate 0.30 h(-1).

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Section: Introductionmentioning

confidence: 99%

Continuous fermentation of wheat‐supplemented lignocellulose hydrolysate with different types of cell retention

Brandberg¹,

Karimi²,

Taherzadeh³

et al. 2007

Biotech & Bioengineering

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“…In contrast to the wealth of data on the effects of different nutrient limitation regimes in actively growing cultures, information on aerobic S. cerevisiae cultures grown at near-zero growth rates is scarce. In anaerobic cultures, nitrogen-limited cultivation with biomass recycling has been explored to maximize ethanol yields (19, 20). Brandberg and coauthors (21), who investigated the impact of severe nitrogen limitation on ethanol production by S. cerevisiae , used incomplete cell recycling under anaerobic and micro-aerobic conditions.…”

Section: Introductionmentioning

confidence: 99%

Quantitative physiology of non-energy-limited retentostat cultures ofSaccharomyces cerevisiaeat near-zero specific growth rates

Liu

Masoudi

Pronk

et al. 2019

Preprint

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excess 12 13 14 15 16 17 18 19 20 21 a Current address: Royal Haskoning DHV, George Hintzenweg 85, 3009 AM Rotterdam, The Netherlands.prevent loss of feedstock to biomass production. Establishing S. cerevisiae cultures in which 46 growth is restricted by the limited supply of a non-energy substrate could therefore have a 47 wide range of industrial applications, but remains largely unexplored. In this work we 48 accomplished near-zero growth of S. cerevisiae through limited supply of a non-energy 49 nutrient, namely the nitrogen or phosphorus source and carried out a quantitative 50 physiology study of the cells under these conditions. The possibility to achieve near-zero-51 growth S. cerevisiae cultures through limited supply of a non-energy nutrient may offer 52 interesting prospects to develop novel fermentation processes for high-yield production of 53 bio-based chemicals. 54 Growth and viability in ammonium-and phosphate-limited retentostat cultures130 Retentostat cultures were started by redirecting the effluent of steady-state ammonium-or 131 phosphate-limited chemostat cultures, grown at a dilution rate of 0.025 h -1 , through a 132 membrane filter unit placed inside the reactor (see Materials and Methods). Replicate 133 ammonium-limited retentostats were operated for 220 h with full biomass retention, after 134 which fouling caused the membrane filters to clog. Membrane fouling was not observed in 135 the phosphate-limited retentostats, which were operated with full biomass retention until, 136 after 400 h, the biomass concentration had reached a stable value. 137

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“…In contrast to the wealth of data on the effects of different nutrient limitation regimes in actively growing cultures, information on aerobic S. cerevisiae cultures grown at near-zero growth rates is scarce. In anaerobic cultures, nitrogen-limited cultivation with biomass recycling has been explored to maximize ethanol yields (19,20). Brandberg and coauthors (21), who investigated the impact of severe nitrogen limitation on ethanol production by S. cerevisiae, used incomplete cell recycling under anaerobic and microaerobic conditions.…”

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confidence: 99%

Quantitative Physiology of Non-Energy-Limited Retentostat Cultures of Saccharomyces cerevisiae at Near-Zero Specific Growth Rates

Liu

Masoudi

Pronk

et al. 2019

Appl Environ Microbiol

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So far, the physiology of Saccharomyces cerevisiae at near-zero growth rates has been studied in retentostat cultures with a growth-limiting supply of the carbon and energy source. Despite its relevance in nature and industry, the near-zero growth physiology of S. cerevisiae under conditions where growth is limited by the supply of non-energy substrates remains largely unexplored. This study analyzes the physiology of S. cerevisiae in aerobic chemostat and retentostat cultures grown under either ammonium or phosphate limitation. To compensate for loss of extracellular nitrogen- or phosphorus-containing compounds, establishing near-zero growth rates (μ < 0.002 h−1) in these retentostats required addition of low concentrations of ammonium or phosphate to reservoir media. In chemostats as well as in retentostats, strongly reduced cellular contents of the growth-limiting element (nitrogen or phosphorus) and high accumulation levels of storage carbohydrates were observed. Even at near-zero growth rates, culture viability in non-energy-limited retentostats remained above 80% and ATP synthesis was still sufficient to maintain an adequate energy status and keep cells in a metabolically active state. Compared to similar glucose-limited retentostat cultures, the nitrogen- and phosphate-limited cultures showed aerobic fermentation and a partial uncoupling of catabolism and anabolism. The possibility to achieve stable, near-zero growth cultures of S. cerevisiae under nitrogen or phosphorus limitation offers interesting prospects for high-yield production of bio-based chemicals. IMPORTANCE The yeast Saccharomyces cerevisiae is a commonly used microbial host for production of various biochemical compounds. From a physiological perspective, biosynthesis of these compounds competes with biomass formation in terms of carbon and/or energy equivalents. Fermentation processes functioning at extremely low or near-zero growth rates would prevent loss of feedstock to biomass production. Establishing S. cerevisiae cultures in which growth is restricted by the limited supply of a non-energy substrate therefore could have a wide range of industrial applications but remains largely unexplored. In this work we accomplished near-zero growth of S. cerevisiae through limited supply of a non-energy nutrient, namely, the nitrogen or phosphorus source, and carried out a quantitative physiological study of the cells under these conditions. The possibility to achieve near-zero-growth S. cerevisiae cultures through limited supply of a non-energy nutrient may offer interesting prospects to develop novel fermentation processes for high-yield production of bio-based chemicals.

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Continuous ethanol production by cell-holding culture of yeasts

Cited by 10 publications

References 16 publications

Continuous fermentation of wheat‐supplemented lignocellulose hydrolysate with different types of cell retention

Continuous fermentation of wheat‐supplemented lignocellulose hydrolysate with different types of cell retention

Quantitative physiology of non-energy-limited retentostat cultures ofSaccharomyces cerevisiaeat near-zero specific growth rates

Quantitative Physiology of Non-Energy-Limited Retentostat Cultures of Saccharomyces cerevisiae at Near-Zero Specific Growth Rates

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