• Microbiology and Biotechnology Letters
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• v.32 no.2
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• pp.184-189
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• 2004

Rice wine cake (RWC) is the solid waste obtained after rice wine fermentation. For the mass production of the spores of yeast Saccharomyces from RWC, the optimum pretreatment condition of RWC, the optimum composition of culture medium, and the optimum culture condition were examined. For sporulation, yeast cells were grown in the pre sporulation medium (PSM), transferred into sporulation medium (SM) containing 1 % potassium acetate, and incubated in a rotary shaking incubator at $25^{\circ}C$ for 4 days. The supernatant of the mixture of RWC and water was used as the presporulation medium (PSM). The optimum temperature and time for the pre-incubation of the mixture of RWC and water (1:2) to obtain maximum sporulation yield were $V^{\circ}C$ and 24 hr, respectively, and optimum culture time in PSM was 48 hr. Using these optimum conditions, the asci number obtained was 0.72$ 1.06${\times}$10^{8}$$m\ell$. The addition of wheat coat koji into SM increased the final number of asci to beTEX>$10^{8}$ $m\ell$. Spores were formed in the SM with the initial pH of 7-11, but no spores were formed in the SM with the initial pH of 5. To save the time and effort to pretreat the RWC, 2% and 0.5% RWC without any pretreatment were directly added into PSM containing 1 % brown sugar and SM, respectively, and the maximum asci number of $1.27${\times}$10^{8}$ /$m\ell$ was obtained.

• Korean Journal of Food Science and Technology
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• v.31 no.2
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• pp.475-481
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• 1999

Yeast extracts were prepared using either autolysis or enzymatic digestion methods for industrial application of the Saccharomyces cerevisiae B24 strain developed previously to have high RNA content. Extraction ratio of yeast extract from yeast cell reached 65% when autolysis of yeast slurry having 10% solid content was induced at $50^{\circ}C$ and pH 5.0 by agitating with 100 rpm. However, neither 5'-IMP nor 5'-GMP was detected from the autolyzate. In another attempt to prepare a yeast extract S. cerevisiae B24 culture was treated at $90^{\circ}C$ and then treated by various enzymes including ${\beta}-1,3-glucanase$, phosphodiesterase (nuclease P1), adenylic deaminase, and a protease. The yeast extract prepared by the enzymatic digestion method contained 3.2g of 5'-IMP and 5'-GMP/100g dry yeast extract.

• Fisheries and Aquatic Sciences
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• v.9 no.4
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• pp.160-166
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• 2006

We explored the possibilities of using the freshwater rotifer Brachionus angularis as a live food for small fishes cultured in fresh- or brackish waters. Brachionus angularis were collected from a reservoir for isolation and laboratory culture. Length and width of the lorica were $102.3{\mu}m$ and $76.6{\mu}m$, respectively, and those of amictic eggs were $64.4{\mu}m\;and\;47.9{\mu}m$, respectively. When their growth rates were examined at six different temperatures, i.e., 15, 20, 25, 30, 35, and $40^{\circ}C$, the highest daily growth rate of 0.801 was observed at $35^{\circ}C$, and growth was lower with decreasing temperature. Adaptation to salinity change was evaluated with two different modes of salinity increase: step-wise elevation lasting for short durations of 5 to 30 min or a long duration of 24 h. With the short duration modes, no individuals survived salinity higher than 10 psu, and the number of live individuals did not increase throughout the experiment. However, in the 24-h elevation, the number of individuals increased when salinity was elevated by 1 to 2 psu per day for the first 2 or 3 days, while no increase in number occurred at salinity increments higher than 3 psu per day. In addition, to assess the effect of different diets, four single-component diets (Chlorella vulgaris, Nannochloris sp., baker's yeast, or dry yeast) and three combination diets (C. vulgaris + Nannochloris sp. + baker's yeast + dry yeast; C. vulgaris 70% + baker's yeast 30%; C. vulgaris 30% + baker's yeast 70%) were used. The specific growth rates of B. angularis fed combination diets were higher than those of rotifers fed any single-component diet, with the highest rate of 0.648 in B. angularis fed a mixture of C. vulgaris, Nannochloris sp., baker's yeast, and dry yeast, and the lowest rate of 0.200 in those fed dry yeast only. Our results indicate that the freshwater rotifer B. angularis can be used for seedling production of both freshwater and brackish-water fishes that require small (less than about $120{\mu}m$) live food during their early stages.

• Food Science and Preservation
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• v.24 no.7
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• pp.1043-1051
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• 2017

Wild yeasts were isolated from domestic non-sterilized Makgeolli and their fermentation characteristics were analyzed to select the best fermentation seed culture. A total of 65 yeast strains isolated yeasts from non-sterilized Makgeolli and Nuruk. In order to select fermentable strains, hydrogen sulfide, $CO_2$ production ability, alcohol tolerance and aroma component production ability were analyzed. To screen the aromatic strains of isolates, media containing cerulenin, 5,5,5-trifluor-DL-leucine (TFL) and API ZYM kit were used. There were 36 strains resistance to cerulenin and all strains produced esterase and demonstrated tolerance against TFL. Hydrogen sulfide, which could degrade the quality of the fermented beverage, was not produced in 34 yeast. The correlation between alcohol tolerance of yeast and carbon dioxide production was analyzed by principal component analysis. YM22, YM31, YM32 and YM37 produced a total of 0.14-0.18 g/72 h of $CO_2$ indicating high fermentability. Alcohol tolerance was measured by alcohol concentration. YM32, YM37 yeast had 20% alcohol tolerance. As a result, alcohol and flavor characteristics of wild yeast isolated from non-sterilized Makgeolli were analyzed and it was confirmed that yeast was suitable for the production of alcohol.

• Journal of Microbiology and Biotechnology
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• v.17 no.12
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• pp.1996-2004
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• 2007

In this study, the optimization of culture medium using a Sterigmatomyces elviae mutant was investigated using statistical analysis to increase the cell mass and lactosucrose ($^4G-{\beta}$-D-galactosylsucrose) production. In basal medium, the cell mass and lactosucrose production were 4.12 g/l and 140.91 g/l, respectively. However, because of the low cell mass and lactosucrose production, optimization of culture medium was carried out to increase the cell mass and lactosucrose production. Culture media were optimized by the S. elviae mutant using analysis of variance (ANOVA) and response surface methodology (RSM). Central composite designs using RSM were utilized in this investigation. Quadratic models were obtained for cell mass and lactosucrose production. In the case of cell mass, optimal components of the medium were as follows: sucrose 1.13%, yeast extract 0.99%, bactopeptone 2.96%, and ammonium sulfate 0.40%. The predicted maximum value of cell mass was about 5.20 g/l and its experimental value was 5.08 g/l. In the case of lactosucrose production, optimal components of the medium were as follows: sucrose 0.96%, yeast extract 1.2%, bactopeptone 3.0%, and ammonium sulfate 0.48%. Then, the predicted maximum value of lactosucrose production was about 194.12 g/l and the corresponding experimental value was about 183.78 g/l. Therefore, by culturing using predicted conditions, the real cell mass and lactosucrose production increased to 23.3% and 30.42%, respectively.

• KSBB Journal
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• v.7 no.2
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• pp.149-153
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• 1992

Pseudomanas fluorescens was selected from mushroom and studied in both batch and continuous culture in order to find out optimum conditions for cultivation. P. fluorescens is an aerobic bacterium and antagonistic to Pseudomonas tolaasii which causes blotch disease on the mushroom cap. Cells of P. fluorescens were grown well on medium containing 30g/L of glucose, whereas the growth was inhibited with the glucose concentration at higher than 30g/L. The highest value of specific growth rate and productivity were obtained when using 10g/L of yeast extract. Optimum concentrations of $NH_4Cl$ and $(NH_4)_2SO_4$ for culture were found to be 1.0g/L and 0.1g/L respectively. Optimum concentration of $MgSO_4{\cdot}7H_2O$ used as a sulfur source was 1.0g/L. It was also found that the cell concentrations were at the maximum level when grown on the medium containing 1.0g/L of $KH_2PO_4$ and 0.1g/L of $CaCl_2$. Also, the optimum culture conditions were $30^{\circ}C$ and pH 6.0. Cultivation of P.fluorescens at high initial dissolved oxygen (D.O) value led to a decrease of bacterial productivity in batch culture. Maximum productivity was achieved at 68 for the initial D.O value.

• Food Science and Preservation
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• v.6 no.2
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• pp.221-227
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• 1999

The immobilized culture system of Saccharomyces cerevisiae was examined to improve the efficiency of vinegar production from persimmon juice. Optimum concentration of Na-alginate for the immobilization was 2%. When the 1eakage of yeast from get beads was checked by turbidity of culture medium with varying concentration of Na-alginate from 1 to 4%, turbidity of culture medium increased from 8 hrs of cultivation with 1% Na-alginate concentration showing optical density of 0.82 at 20 hrs. However, the increase in turbidity of culture medium was slow with 2-4% Na-alginate showing optical density of 0.55-0.58 at 20 hrs. Microscopical analysis of gel matrix showed that the immobilized yeast was grown well regardless of Na-alginate concentration. Optimum size of gel bead and amount of inoculation were 2-3 m and 33mg, respectively. For ethanol production aerobic cultivation for 121hrs using cohen plug followed by anaerobic cultivation using silicon plug equipped with a check valve was the most effective.

• KSBB Journal
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• v.22 no.1
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• pp.1-6
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• 2007

The optimum liquid culture conditions were investigated for cell growth and polysaccharide production from liquid culture of Lentinus edodes. In flask culture, the optimal medium compositions for the polysaccharide production contained glucose 60 g/L, yeast extract 10 g/L, $KH_2PO_4$ 2.0 g/L, and $MgSO_4{\cdot}7H_2O$ 1.0 g/L. The maximum mycelial growth and polysaccharide production were 11.01 g/L and 1.64 g/L, respectively. In bioreactor, through the variation of aeration in order to increase mycelial growth and polysaccharide production, the maximum mycelial growth and polysaccharide production were 55.9 g/L at 8th day and 7.34 g/L at 7th day of cultivation with 1.5 vvm, respectively.

• Microbiology and Biotechnology Letters
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• v.28 no.2
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• pp.111-116
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• 2000

Cultural conditions for the production of water-soluble pigment from mycelial culture of Cordyceps scarabaeicola KEFC-C252 and antimutagenic activity of the pigment were investigated. To obtain the maximum productivity of the pigment from mycelial culture of C. scarabaeicola KEFC-C252, the optimized medium was made with 1.5% sucrose, 2.5% yeast extract and initial pH 5.5. C. scarabaeicola KEFC-C252 was cultivated to reach the maximum concentration of the pigment at $26^{\circ}C$ for 108 hrs. C. scarabaeicola KEFC-C252 produced about 1.2 g/liter pigment under the optimized condition. The pigment was isolated from the culture filtrate by ethylacetate extraction, acidic precipitation and crystallization. The isolated pigment was scarlet hexagonal column crystal, and the color of the pigment was changed according to pH of the solution. The pigment showed violet in the alkaline water but showed red color in the acidic water. The pigment showed inhibitory activity against mutagenic activity induced by 4-nitroquinoline N-oxide. Furthermore, the pigment showed inhibitory activity against spontaneous mutation on Salmonella typhimurium TA98 and TAlOO.

• Applied Biological Chemistry
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• v.35 no.6
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• pp.443-448
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• 1992

To investigate the production of monoterpenoids by Mentha pipperita cells in suspension culture, effects of media formulation, plant growth hormones, initial pH of the media, and cold stress on the production of essential oil and menthol were analyzed. Among the media employed, Lin-Staba medium resulted in the best essential oil production. Addition of 100 mg/l of yeast extract to the Lin-Staba medium induced the cells to produce large amount of essential oil and high content of menthol (0.39 g/l and 19.6%, respectively). In the effect of plant growth hormone, auxine were more effective than cytokinins. At initial pH of 4.7, oil production was good but menthol content was low. However at pH 5.7 the trend was reversed. When the culture temperature was lowered from $27^{\circ}$ to $10^{\circ}$ during 6 hour-dark period, growth was not changed much but essential oil production and menthol content was increased and reached to 528 mg/l and 21%, respectively.