• KSBB Journal
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• v.15 no.2
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• pp.134-138
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• 2000

Addition of carbon and nitrogen source to an alcohol distillery wastewater was tried to increase the cell concentration of a b baker's yeast cultivated in that wastewater. Carbon was found to be primary limiting nutrient and nitrogen secondary limiting o one. Glucose addition increased the cell concentration 1.3 times higher than no addition, and both glucose and $(NH_4)_2S0_4$ a addition did 5.8 times. A fed-batch cultivation by the automatic addition of glucose and ammonium was executed. Added g glu$\infty$se was automatically controlled to low concentration by a method using DO as control parameter. Ammonium was a automatically added as NH40H used as pH $\infty$ntrol agent after initiating glucose addition. By this simple cultivation method t the cell concentration $\infty$내d be efficiently increased from 2.6g/L to 12.0g/L, and maximum specific growth rate and biomass y yield to glu$\infty$se were $0.18hr^{-1}$ and about 0.54g/g respectively. By increasing cell concentration, COD of the wastewater m media could be additionally reduced by about 22%.

• Microbiology and Biotechnology Letters
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• v.36 no.2
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• pp.158-164
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• 2008

The fusants which contain starch utilizing ability and alcohol fermenting ability were developed by protoplast fusion of Saccharomyces cerevisiae KOY-1 and Saccharomyces diastaticus KCTC 1804. Sacharomyces cerevisiae KH-12 was obtained by haploid induction from Saccharomyces cerevisiae KOY-1. The auxotropic mutants of yeast were obtained by using an ethylmethane sulfonate (EMS). The frequency of protoplast formation in Saccharomyces cerevisiae KOY-1 $(Met^-)$ and Saccharomyces diastaticus KCTC 1804 $(Trp^-)$ were 90.5% and 97.7%, respectively. The frequency of fusant formation was $1.79{\times}10^{-4 }$ for the regenerated protoplast and the 1,000 fusants were obtained. Fusant FA 776 was selected as a potential yeast which contain an alcohol fermenting ability in the starch medium. The genetic stability was 4.64% for 10 passages of generation. Fusant FA 776 produced 13mg/ml of alcohol in 24% starch medium and showed 1.86-fold higher alcohol fermenting ability than Saccharomyces diastaticus KCTC 1804.

• The Korean Journal of Mycology
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• v.45 no.2
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• pp.153-159
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• 2017

We isolated 120 strains of wild yeasts from the water and riverside soils of Daejeoncheon and Gapcheon in Daejeon, Korea. We identified Debaryomyces udenii JSF601, Kazachstania telluris JSF602, Trichosporon faecale JSF614, Candida infanticola WJSL0039, Candida palmioleophila WJSL0048, Pichia spartinae WJSL0087, and Trichosporon coprophilum WJSL0093 from Daejeoncheon, and Leucosporidium golubevii WJSL0108 and Ustilentyloma graminis WJSL0118 from Gapcheon, as newly recorded yeast strains in Korea and investigated their microbiological characteristics. All of these previously unrecorded yeasts were oval- or ellipsoidal-shaped with ascospores, except C. infanticola WJSL0039, C. palmioleophila WJSL0048, and D. udenii JSF601. L. golubevii WJSL0108 and U. graminis WJSL0118 grew in vitamin-free medium, and C. infanticola WJSL0039 was halotolerant and grew in 10% NaCl-containing YPD broth. K. telluris JSF602 and P. spartinae WJSL0087 were thermophilic yeasts, which grew at $37^{\circ}C$.

• Korean Journal of Food Science and Technology
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• v.15 no.2
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• pp.177-182
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• 1983

Direct conversion of starchy materials to single cell protein of Sporobolomyces holsaticus FRI Y-5 was investigated. Effect of yeast extract concentration on its cell growth showed that it could utilize more of starch in the medium containing 2.5 g/l of yeast extract. In case of jar fermentor culture, the specific growth rate and cell yield of Sp. holsaticus on soluble starch were calculated to be $0.14\;hr^{-1}$ and 0.425, respectively and its maximum cell concentration was 13.4 g/l. After 80 hr of incubation time, 45.96% of starch was consumed and 45.1% of relative blue value was decreased. Reducing sugars in the starch medium seemed to increase from 4.06 g/l to 6.08 g/l and then to decrease. During fermentor culture, pH of medium was almost not changed in the range of $pH\;7.0{\pm}0.5$. The optimal temperature and pH of Sp. holsaticus amylase activity were $40^{\circ}C$ and pH 7.5, respectively. It was shown from the effect of Tapioca starch concentration on the cell growth that the optimal concentration of Tapioca starch for Sp. holsaticus was lower than that of soluble starch. FRI Y-5 cells settled much slower than Sp. holsaticus IFO 1032 cells and the viscosity vs cell concentration relationship was related to be linear.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.5
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• pp.660-665
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• 2008

The aim of this work was to investigate the microbiological and physicochemical properties of the rice sourdough for Jeungpyun prepared by mixed culture of Saccharomyces cerevisiae (S. cerevisiae) and Leuconostoc mesenteroides (L. mesenteroides) strains. The rice sourdough was fermented with S. cerevisiae and L. mesenteroides strains in rice dough for 24 hours at $30^{\circ}C$. Growth of L. mesenteroides strain was decreased after inoculation, however, it increased again after 18 hours of dough fermentation, and the growth of S. cerevisiae showed a typical growth pattern. Also, total aerobic microorganisms counts in rice sourdough were decreased due to the produced organic acids and ethanol during dough fermentation. These products led to a favorable fermentative quotient (FQ; molar ratio between lactic to acetic acid) value of $1.9{\sim}3.2$ and more stable fermentation for rice sourdough formation. The expansion ratio and viscosity were considerably increased by mixed cultivation of S. cerevisiae and L. mesenteroides strains. Addition of the brown rice at 10% (w/w) to dough preparation increased the relative expansion ratio to the highest value.

• Applied Biological Chemistry
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• v.13 no.1
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• pp.43-50
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• 1970

To study the productivity of single cell protein from the petroleum hydrocarbon utilizing yeasts, 242 soil samples, such as oil soaked soil of gas stations and garage, coal, farm soil, and sewage, from 135 places in Korea were collected. From these samples 468 yeast strains which utilize petroleum hydrocarbon as a sole organic carbon source were isolated and identified by observing the growth rates. For the identified strains optimum culture conditions were determined and analysis of cell components were performed. 1. 90.8% of petroleum hydrocarbon utilizing yeast strains were found from oil soaked soil and about 10% from coal, farm soil and sewage etc. 2. The yeast strain of the highest cell productivity was isolated from oil soaked soil and was identified as Candida curvata HY-69-19. 3. The optimum culture conditions for the selected yeast strain were found to be pH 5.0, $28^{\circ}C$ and affluent aerated state. 4. Candida curvata HY-69-19 was found to utilize favorably the heavy gas oil fractionated at above $268.9^{\circ}C$ as carbon source and urea as inorganic nitrogen source. 5. The growth curve of this strain on heavy gas oil medium showed that the yeast has a lag phase up to 18 hours and logarithmic growth phase between 24 to 42 hours. Generation time was found to be between 3.8 and 4.5 hours during the logarithmic growth phase. 6. About 300 mg dried cells per heavy gas oil was harvested under the culture conditions of adjusted pH to 5.0 at time intervals of 6 hours for 54 hours and heavy gas oil urea for shaking culture medium. 7. Chemical composition of the yeast cell was found to be 40.25%, 14.81%, 24.32% and 10.63% for crude protein, crude lipid, carbohydrate and ashes, respectively.

• Korean Journal of Food Science and Technology
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• v.11 no.4
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• pp.242-248
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• 1979

To detect proper lytic assay conditions of the crude zumolyase from Arthrobacter luteus, effets of the various factors involved in the lytic system of Sacchromyces sake cultured with shaking in the malt extracts medium were investigated. The results are summarized as follows : 1. The susceptibilities of viable cells of S. sake from logarithmic growth phase to the lytic enzmye were much greater than those of the cells in lag and stationary phases. The cells cultured for 18 hr were the most susceptible to the enzyme. 2. Lytic activity of the enzyme toward the viable cells of S. sake was very low. It was, however, enhanced 4 folds of more by the pretreatment of the cells with 0.05 M sodium sulfite. 3. Lytic activity of the enzyme toward commercial baker's yeast cells was negligible, and the effect of sodium sulfite on the lysis of the cells also was nothing but a little. 4. The lyophilized cells of the baker's yeast showed more susceptibility to the lytic enzyme than viable cells of the yeast. No definite effect of sodium sulfite on the lysis of the lyophilized cells, however, was observed either baker's yeast of S. sake. 5. It appeared that the relationship between the reaction rate and the enzyme concentration on the lysis of the yeast cell walls followed enzyme kinetic theory, but one between the reaction rate and concentration of the yeast cells as substrates showed different pattern from that in enzyme kinetic theory. 6. After the preparation of crude zymolyase was kept at $7^[\circ}C$ for 10 days in the 0.05 M phosphate buffer, pH 7.5, the remainning lytic activity was about 80 %.

• Applied Biological Chemistry
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• v.14 no.2
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• pp.121-129
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• 1971

During the Brewing of Soy Sauce on an industrial scale, Saccharomyces rouxii $T_9$ was cultured and added to the soy sauce mash. The comparative experiments of soy sauce mash in non-addition and addition group of yeast were examined in this report. The yeast flora and chemical composition of Soy sauce mash through out the brewing were observed and the results obtained were as follows. (1) The number of Osmophilic yeast in one ml of soy sauce mash showed $185{\times}10^3$ 1 month after mashing and $750{\times}10^3$ 4 months after mashing in case of yeast group, while presented as $98{\times}10^3$ 1 month after mashing and $394{\times}10^3$ 4 months after mashing in case of non-yeast group. And the number of Osmphilic yeast in yeast group was twice of that in non-yeast group. (2) The number of ordinary yeast of TTC red group was shown as $2132{\times}10^3\;to\;3252 ×10^3$ 5 to 6 months after mashing in case of yeast group, while presented $752{\times}10^3\;to\;1251{\times}10^3$ in case of non-yeast group. And the yeast group was shown more than non-yeast group in ordinary, red pink and pink yeast number. (3) TTC red yeast were strongly appeared in both addition and non-addition group of yeast from 1 month after mashing to 6 months after mashing. (4) Though total nitrogen, pure extract, pH and buffer action contents of soy sauce showed similiar tendency in yeast and non-yeast group, alcohol and color density contents were highly appeared in yeast group and reducing sugar content was in non-yeast group respectively. (5) By the results of Organic function test of soy sauce mash, the difference of taste quality in yeast and non-yeast group were not evidently appeared, however, the appearance and flavour of the soy sauce were better in yeast group than in non-yeast group.

• Food Science and Preservation
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• v.18 no.4
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• pp.604-611
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• 2011

Several wild yeasts were isolated from Korean grape varieties before and during spontaneous fermentation. Among them, four strains were isolated based on the alcohol content and flavor production in wine after fermentation of apple juice. In this study, the four yeast strains were identified and characterized. PCR-restriction fragment length polymorphism analysis of ITS I-5.8S-ITS II region with restriction endonuclease Hae III and Hinf I resulted in that all the strains showed a typical pattern of Saccharomyces cerevisiae. Pulse field gel electrophoresis showed three different chromosome patterns with a same band between strains SS89 and SS812. When ITS I-5.8S-ITS II sequences of the four strains were compared with one another, they were similar to those of Saccharomyces cerevisiae CBS 4054 type strain. Identity of the sequences was higher than 97% with those of the type strain. Phylogenetic analysis showed based on the sequences showed they were genetically closed to the type strain. The four identified strains were tested in a medium containing 200 ppm potassium metabisulfite, and the MM10 and WW108 inhibition rates resulted at up to 24 h. The four strains were tested at an incubation temperature of $30^{\circ}C$. The 30% sugar concentration in the medium (w/v) showed the highest growth in 36 h, especially in the case of SS89, which was close to growth 40. The four strains were tested in an 8% ethanol medium (v/v). Alcohol tolerance was initially kept in the incubation process. The strains began to adapt, however, to the exceeded resistance. The four strains showed the lowest inhibition rate at 24 h.

• Journal of Life Science
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• v.6 no.1
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• pp.56-65
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• 1996

Black tea extractbsupplemented with 10% sucrose was fermented by fungus at 30$\circ$C. A pellicle thick as 7$\sim$8 mm covered entire surface of the medium and the wxtract converted to acidic beverage(abbreviated below as fermented black tea) by 14 days of fermentation. It was a kind of acetic acid fermentation depending on symbiotic microorganisms. During the fermentation strains of yeasts(Saccharomyces cerevisiae and Eeniella sp.)and bacteria(Bacillus subtilis, Kurthia zopfii, Gluconobacter oxydans and Deinicoccus sp.) were isolated from aqueous layer. Contrastly to it, a bacterial strain(Acetobacter aceti) was isolated from thick pellicle. The bacteria grew as a viscouse cluster on solid agar medium differently from usual strains of A. aceti. Fermented black tea had sweet-sour taste and sweet smell.