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Bafrncová, P.; Šmogrovičová, D.; Sláviková, I.; Pátková, J.; Dömény, Z.

doi:10.1023/a:1005436816047

Cited by 110 publications

(23 citation statements)

References 11 publications

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“…It has been reported that decreases in the growth and viability of yeasts occur as sugar concentrations in the media increase from 12% to 18% (w/v) [9,11,12]; however, when initial glucose concentrations were higher than 18% (w/v), they had a considerable inhibitory effect on yeast cell growth, ethanol concentration and ethanol yield. Our studies showed that the inhibitory effect on yeast cell growth as well as ethanol concentration and ethanol yield was diminished by the fed-batch mode of culture.…”

Section: Discussionmentioning

confidence: 99%

Enhancement of the Efficiency of Bioethanol Production by Saccharomyces cerevisiae via Gradually Batch-Wise and Fed-Batch Increasing the Glucose Concentration

et al. 2018

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High initial glucose concentrations may inhibit glucose utilization and decrease ethanol fermentation efficiency. To minimize substrate inhibition, the effects of feeding yeast with different glucose concentrations on the ethanol production by batch and fed-batch cultures in a 5-L fermentor were investigated. When a batch culture system with Saccharomyces cerevisiae was used for ethanol fermentation with glucose concentrations ranging 10-260 g/L, as a result, 0.2-7.0 g/L biomass and 5.1-115.0 g/L ethanol were obtained. However, substrate inhibition was observed with the initial glucose concentrations greater than 200 g/L in the fermentative media. When a fed-batch culture system (an initial glucose concentration of 180 g/L and total glucose concentration of 260 g/L) was performed, the maximum ethanol concentrations and ethanol yield were significantly higher than those of the batch cultures. The cell biomass, maximum ethanol concentration, and ethanol yields for the fed-batch fermentation cultures were 8.3 g/L, 130.1 g/L and 51% (100% of the theoretical value), respectively. The results indicated that high ethanol concentration and ethanol yield could be achieved by the fed-batch cultures with total glucose concentrations up to 260 g/L.

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Section: Discussionmentioning

confidence: 99%

Enhancement of the Efficiency of Bioethanol Production by Saccharomyces cerevisiae via Gradually Batch-Wise and Fed-Batch Increasing the Glucose Concentration

et al. 2018

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“…Consequently, the addition of adjunct to the wort dilute FAN content and change nutrient balance in wort, which may result in nitrogen limitation during brewing, the modification of physiological characteristics of brewer's yeast, and finally cause modifications in fermentation performance. Nitrogen limitation is a key factor responsible for the decrease of the fermentation performance and viability of brewer's yeast, the extension of fermentation time under VHG fermentation . In order to eliminate the effects of nitrogen limitation on fermentation performance of brewer's yeast, the worts fermentations medium supplemented with nitrogen source is a common industrial practice .…”

Section: Discussionmentioning

confidence: 99%

Peptide (Lys–Leu) and amino acids (Lys and Leu) supplementations improve physiological activity and fermentation performance of brewer's yeast during very high‐gravity (VHG) wort fermentation

Yang

Zong

Cui

et al. 2018

Biotech and App Biochem

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Lys and Leu were generally considered as the key amino acids for brewer's yeast during beer brewing. In the present study, peptide Lys-Leu and a free amino acid (FAA) mixture of Lys and Leu (Lys + Leu) were supplemented in 24 °P wort to examine their effects on physiological activity and fermentation performance of brewer's yeast during very high-gravity (VHG) wort fermentation. Results showed that although both peptide Lys-Leu and their FAA mixture supplementations could increase the growth and viability, intracellular trehalose and glycerol content, wort fermentability, and ethanol content for brewer's yeast during VHG wort fermentation, and peptide was better than their FAA mixture at promoting growth and fermentation for brewer's yeast when the same dose was kept. Moreover, peptide Lys-Leu supplementation significantly increased the assimilation of Asp, but decreased the assimilation of Gly, Ala, Val, (Cys)2, Ile, Leu, Tyr, Phe, Lys, Arg, and Pro. However, the FAA mixture supplementation only promoted the assimilation of Lys and Leu, while reduced the absorption of total amino acids to a greater extent. Thus, the peptide Lys-Leu was more effective than their FAA mixture on the improvement of physiological activity, fermentation performance, and nitrogen metabolism of brewer's yeast during VHG wort fermentation.

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“…pHs of the EP media during fermentation were slightly decreased and were not different among the treatments (Figure 1d). Bafrncová et al (1999) found that yeast extract had a protective effect either on growth and fermentation or on viability during VGH ethanol fermentation from a synthetic medium containing 300 g l -1 of glucose, leading to an increase in the fermentation rate and ethanol production. In addition, Stewart et al (1988) reported that when the concentrations of peptone and yeast extract in the VHG medium were increased, yeast could better tolerate to osmotic pressure and high temperature.…”

Section: Effects Of Nitrogen Sources On Ethanol Productionmentioning

confidence: 99%

“…pH adjustment was not required, only nitrogen supplementation was essential under VHG fermentation to improve ethanol production efficiency (Laopaiboon et al 2009;Nuanpeng et al 2011). Nitrogen sources that are widely used to stimulate fuel alcohol, brewing, or winery fermentations are yeast extract and peptone (Bafrncová et al 1999;Bvochorá et al 2000;Reddy and Reddy, 2006;Laopaiboon et al 2009), ammonium (Laopaiboon et al 2007;Srichuwong et al 2009) and urea (Yue et al 2010). They are employed to increase yeast growth or viability and the rate of sugar utilization, and to reduce the fermentation time.…”

Section: Introductionmentioning

confidence: 99%

The use of dried spent yeast as a low-cost nitrogen supplement in ethanol fermentation from sweet sorghum juice under very high gravity conditions

Sridee

Laopaiboon

Jaisil

et al. 2011

Electro Journal of Biotech

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Dried spent yeast (DSY) was used as a low-cost nitrogen supplement for ethanol fermentation from sweet sorghum juice under very high gravity (VHG) conditions by Saccharomyces cerevisiae NP 01. The fermentation was carried out at 30ºC in a 5-litre bioreactor. The results showed that DSY promoted ethanol production efficiencies. The ethanol concentration (P), productivity (Qp) and yield (Yp/s) of the sterile juice (total sugar of 280 g l -1 ) supplemented with 8 g l -1 of DSY were not different from those supplemented with yeast extract and/or peptone at the same amount. The initial yeast cell concentration of 5 x 10 7 cells ml -1 was found to be optimal for scale-up ethanol production. In addition, an increase in sugar concentration in inoculum preparation medium (from 10 to 100 g l -1 ) improved the ability of the inoculum to produce ethanol under the VHG conditions. When S. cerevisiae NP 01 grown in the juice containing 100 g l -1 of total sugar was used as the inoculum for ethanol fermentation, the P, Qp and Yp/s obtained were 108.98 ± 1.16 g l -1 , 2.27 ± 0.06 g l -1 h -1 and 0.47 ± 0.01 g g -1 , respectively. Similar results were also observed when the ethanol fermentation was scaled up to a 50-litre bioreactor under the same conditions. The cost of the sweet sorghum for ethanol production was US$ 0.63 per litre of ethanol. These results clearly indicate the high potential of using sweet sorghum juice supplemented with DSY under VHG fermentation for ethanol production in industrial applications.

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Cited by 110 publications

References 11 publications

Enhancement of the Efficiency of Bioethanol Production by Saccharomyces cerevisiae via Gradually Batch-Wise and Fed-Batch Increasing the Glucose Concentration

Enhancement of the Efficiency of Bioethanol Production by Saccharomyces cerevisiae via Gradually Batch-Wise and Fed-Batch Increasing the Glucose Concentration

Peptide (Lys–Leu) and amino acids (Lys and Leu) supplementations improve physiological activity and fermentation performance of brewer's yeast during very high‐gravity (VHG) wort fermentation

The use of dried spent yeast as a low-cost nitrogen supplement in ethanol fermentation from sweet sorghum juice under very high gravity conditions

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