• Applied Biological Chemistry
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• v.27 no.4
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• pp.217-224
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• 1984

Effect of a thermophilic yeast (strain T-71) on the ethanol fermentation of raw starchy materials was investigated. The maximum temperature of the thermophilic yeast for the growing and fermentation was a little higher than that of ordinary yeasts and their resistance to ethanol was also high. Even though the optimum temperature of the thermophilic yeast for fermenting ethanol of several raw starchy materials was different depending upon the concentration of mashing, their optimum fermentation temperature was higher than the ordinary yeasts in all cases studied, and their fermentation efficiency was good enough to use. It was also found from the study that the period of fermentation could be shortened for about one to two days by using the thermophilic yeast.

• KSBB Journal
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• v.11 no.4
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• pp.445-452
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• 1996

To investigate the promoter effect on heterologous gene expression in S. cerevisiae, the recombinant plasmids pYI11, pYI12, pYI10-2, and pYIGP were constructed to contain the inulinase gene (INUI) as a reporter under the control of GAL10, GAL7, GAL1, and GAP promoters, respectively. When the yeasts transformants were cultivated on galactose-containing rich media, the cell growth reached to 36-39 OD600 at 72 hours of cultivation. The specific growth rates of the cells harboring the four different plasmids decreased similarly : they dropped from $0.24 h^{-1}$ during the glucose-consuming period to 0.04 -$0.10 h^{-1}$ during the galactose-consuming period (gene expression phase for GAL promoter system). After the depletion of glucose, the expression of inulinase gene was started and reached to maximal levels of 4.3(GAL1 promoter), 4.0(GAL10 promoter), 3.8(GAL7 promoter), and 1.6(GAP promoter) unit/mL at 72 hours of cultivation. Based on the maximal expression level and activity staining on the plate, the promoter strength was in the order of GAL1, GAL10, GAL7 and GAP promoter. While the GAL-promoter systems showed a high plasmid stabilities of more than 78%, the GAP-promoter plasmid revealed a lower plasmid stability of 55%. Most of inulinase activity (98%) was found in the extracellular medium, indicating that the secretion efficiency of inulinase is independent on the type of promoter.

• Applied Biological Chemistry
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• v.40 no.6
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• pp.472-477
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• 1997

The effects of roasting Cassia tora L. were investigated for proximate composition, color, volatile flavor profile, microbial growth and alcohol fermentation. While moisture, protein and fat contents decreased with increasing roasting temperature, fiber and ash contents increased. The L, a and b values of Cassia tora L. extracts decreased with increasing temperature, and only a small difference in total color difference$({\Delta}E)$ was observed. A little difference in major flavor components between raw and roasted treatment was found during roasting. Furfuryl alcohol, a major component of coffee flavor, was separated from Cassia tora L. extracts extracted with ethyl ether. The yeast growth was the highest on the water-extract of Cassia tora L. roasted at $160^{\circ}C$. With increased levels of water-extract at $160^{\circ}C$, S. cerevisiae grew rapidly for 24 hr incubation and the growth rate was higher than the unroasted control group. The growth rate of Bacillus subtilis was the highest in a treatment of 0.5% concentration. Little differences in ${\alpha}-amylase$ produced from Bacillus subtilis were observed among the treatment groups. The total alcohol content increased with increasing roasting temperature during alcohol fermentation.

• Korean Journal of Food Science and Technology
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• v.9 no.4
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• pp.306-312
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• 1977

A mixed culture of Candida tropicalis and Trichosporon cutaneum was carried out using a n-paraffin medium. The growth of C. tropicalis was markedly enhanced by the mixed culture with T. cutaneum which did not grow on n-paraffin. C. tropicalis extracellularly excreted free fatty acids as metabolic products of n-paraffin in the culture medium. T. cutaneum appeared to assimilate these free fatty acids which were growth inhibitors for C. tropicalis, threreby enhancing the growth of C. tropicalis.

• Microbiology and Biotechnology Letters
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• v.20 no.1
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• pp.85-90
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• 1992

Rice bran was employed as a main medium component for ethanol fermentation by Saccharomyces species. Among the several strains of .Saccharomyces yeasts. S. cerevisiae IF0 2346 was selected as the hest strain in view of the interest in the production of ethanol and amino acids. It was found that S. cerevisiae IF0 2346 showed $3\times 10^8$cells/d and 4.7% (v/v) ethanol production after 72 hr cultivation. Although total amount of free amino acids was decreased from 1.099 mg/l to 829 mg/l during the fermentation, glutamic acid. histidine, and isoleucine were increased considerably. With the supplement of 5% glucose to the ferrnentation medium, both ethanol and amino acid production were increased up to 134% and 264%, respectively. compared to the control case. Glutamic. acid, leucine, alanine. phenylalanint:, and valine were the major amino acids in the fermentation broth.

• Microbiology and Biotechnology Letters
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• v.3 no.3
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• pp.135-140
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• 1975

For the purpose of producing single cell protein out of an agricultural waste, chestnut-bur was hydrolyzed with 4％ H$_2$SO$_4$, solution for 30 min under the steam pressure of 1.5kg/$\textrm{cm}^2$, and 21％ saccharification of the original carbon source was obtained. When Candida tropicalis was grown in the hydrolyzate the cell yield remained only 21％ of the original sugar suggesting a necessity of further treatments.

• Korean Journal of Food Science and Technology
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• v.25 no.2
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• pp.154-159
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• 1993

This present study was carried out particulary focusing on rapid fermentation of soy sauce by using column type reactor $(30\;cm{\times}5\;cm)$ packed each immobilized cells of Pediococcus halophilus R-22, Saccharomyces rouxii R-60 and Candida etchellsii H-50. When immobilized P. halophilus R-22 by column type reactor was performed continuously fermentation, lactic acid was produced $0.62{\sim}0.64%$ during 25 days and then decreased gradually after 30 days. S. rouxii R-60 was Produced the $2.1{\sim}2.5%$ ethylalcohol constantly for 35 days and also C. etchellsii H-50 was produced $14{\sim}16\;mg/l$ 4-ethylguaiacol for 35 days and then this products were decreased gradually after fermentation of 40 days. Final Products of fish sauce contained 1,721.6 mg% total nitrogen, 1,584.1 mg% amino-nitrogen, 0.75% lactic acid, 2.7% ethylalcohol and 18.2 mg/l 4-ethylguaiacol.

• Korean Journal of Microbiology
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• v.35 no.4
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• pp.302-306
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• 1999

Production of biomass by fed-batch culture of Saccharomyces cerevisiae Hansen CBS5926, which is used to treat intestinal disorders, was investigated using ethanol as the sole carbon source. Ethanol was a better carbon source than glucose for high cell density culture of the st-rain since it could decrease the frequency of contamination while increasing the efficiency and final productivity of the fermentation process. Under optimal conditions, 38 g/ℓ of dry cell weight with $2.2{\times}10^{9}$ cfu/㎖ of maximum viable cell count was achieved after 72h cultivation. Freeze-drying of the cultured yeast cells resulted in severe reduction of viability. Of the freeze-drying protectants tested, 20% sucrose and 30% lactose were most effective for the preservation of yeast cells with a viability level of 16.3%. A combination of skim milk and lactose with 20% sucrose(w/v) exerted no synergistic influence upo the viability of the cells during cryopreservation by freeze-drying.

• Korean Journal of Agricultural Science
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• v.3 no.2
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• pp.244-250
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• 1976

Candida brumptii was one of the best isolates which could grow on alcohol distillation slops (reported in the previous paper). Attempts were made to investigate the cultural conditions for cell mass production by this strain, and the results obtained were as follow. The supernatant of the alcohol distillation slops without dilution support ed better growth of the strain than diluted ones. The addition of ammonium sulfate (0.2%), ammonium phosphate (0.1-0.2%), potassium phosphate (0.2%) to the supernatant resulted in positive effects for the growth, among the various inorganic nitrogen and other salts supplements. BOD and COD of the supernatant were reduced approximately 30% and 20%, respectively in 3 days culture. Cell production was maximized when grown at $35^{\circ}C$ and pH 5.0. The yield of cell mass was 1.03% by dry weight and its crude protein content was about 52.65%

• KSBB Journal
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• v.4 no.2
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• pp.191-196
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• 1989

Functional relationship between the Fermentation characteristics of Functional relationship between the Fermentation characteristics of S. cerevisiae SIV-89 and the fermentation time was investigated. According to the increase in the initial sugar cone. from 50g/L to 80 g/L, maximum specific growth rate and maximum specific alcohol production rate were increased until 0.35 and 1.98. But the two values were decreased with increase of initial sugar cone. in the region of more that 80 g/L. Maximum alcohol yield and biomass yield were 0.45 and 0.15 respectively. However those vlaue were found to be reduced with the argument of initial sugar concentration. Sugar conversion was decreased with sugar concentration. When the sugar concentration was more than 190 g/L, the conversion was dropped below 70%. The increase of alcohol concentration in the fermentation broth induced the phenomenon of decline of metabolism. In case of more than 80 g/L of alcohol conc., biomass growth and alcohol production were completely stopped regardless of remaining sugar concentration.