• KSBB Journal
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• v.4 no.2
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• pp.134-142
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• 1989

In exopolysaccharide fermentation by Aureobasidium pulluans, the effects culture conditions (concentration of nitrogen, potassium phosphate, dissolved oxygen, and initial pH) on the production of exopolysaccharide and the appearance of melanin pigment were investigated. The results are as follows. (1) The specific growth rate and the specific production rate of exopolysaccharide were inhibited by substrate when the carbon source concentration higher than $50g\;/\;{\ell}$ and the cell growth increased with increases of nitrogen source but exopolysaccharide production decreased with the nitrogen concentration when it become greater than $1\;g\;/\;{\ell}$. (2) The maximum cell growth and the maximum exopolysaccharide production were obtained at initial pH values of 3.0 and 7.5 respectively. As the initial pH increased, the yeast-like cells increased and the increased of dissolved oxygen increased the cell growth and exopolysaccharide production. (3) As the concentration of dissolved oxygen is increased or the concentration of nitrogen source is decreased, the period of melanin pigment appearance becomes shorter and the melanin pigment never appeared when the initial pH was less than 3.0 or the potassium phosphate was not added.

• KSBB Journal
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• v.14 no.4
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• pp.503-510
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• 1999

In order to analyze nutritional factors affecting in situ bioremediation of diesel degradation and cell viability were studied by varying nutritional conditions. In column experiments packed with diesel-contaminated soil, nitrogen was found to be the major limiting nutrient. When nitrogen was added to soil at four different levels of C : N (100 : 5, 100 : 10, 100 : 15, and 100 : 20 mg N/kg dry soil), the greatest simulation of microbial activity occurred at the lowest, rather than the highest nitrogen addition. However, no significant effects was observed when phosphorus and air were added. No matter how the incubation mode varied, less than 50% of the diesel was remained after 7 days of treatment, presumably because the residual hydrocarbons were adsorbed on soil particles, adsorption

• KSBB Journal
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• v.5 no.1
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• pp.75-80
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• 1990

The investigations of specific growth rate, specific alcohol production rate, cell yield, alcohol yield of K. marxianus LG were performed according to the sugar concentrations, 50, 80, 110, 190, and 250g/l of extracted solution of Jerusalem Artichoke. The functipnal relationship between specific growth rate, specific alcohol production rate, and alcohol concentrations were devoted study to. In case of low concentration of alcohol, the fuctions were linear relationships. But in the region of high concentration of alcohol, they expressed the exponential relationships. The growth rate of K. marxianus was prohibited at higher than 50g/l of alcohol concentrations regardless of concentration of residual sugar. Cell and alcohol yield showed the maximum values around 25g/l of alcohol concentraton without being related to initial sugar concentrations.

• Korean Journal of Microbiology
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• v.8 no.1
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• pp.41-51
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• 1970

In previous paper, it was reported that antibiotic substance such as tetracycline and streptomycin were produced by S'. albus subsp. and S'. globosus. And increase of mycelial growth of two strains, antibiotic production, and changes of pH range are extended to approximately 110-130 hrs in fermenting medium, there-after they decreased with culture period exception of pH range. Two Streptomyces spp. required commonly 4-5% starch as carbon sources and 1.5-2.0% soybean meal as nitrogen sources. However, 0.005-0.01M potassium phosphate dibasic, calcium carbonate (6mg/ml in S.albus subsp. and 2mg/ml in S. globosus), 0.01-0.03M, magnesium sulgate and 0.01M ferric chloride showed as optimal concentration for the growth of 2 strains. Mineral compoments such as zinc, manganese, cobalt, sodium and copper at the level of 10$^{-4}$ -10$^{-6}$ M were observed. Especially, zinc ion showed toxicity to the growth of 2 strains at 0.005M. In relation with pH, there is a little difference in mycelial growth with cultural initial pH.

• Journal of Life Science
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• v.20 no.11
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• pp.1729-1737
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• 2010

This study was conducted to establish the optimal medium condition for the animal probiotic Lactobacillus plantarum by using onion juice. Cell yield and antioxidant activity increased in proportion to high additive levels of onion juice in medium. Onion juice, sucrose and yeast extract were selected as media ingredient factors and the effects of their mixed ratio in medium were evaluated. The full factorial design consisted of 24 experimental runs and was employed to estimate the main effects of the factors and their interactions. Significant positive effects on cell yield and antioxidant activity was shown with yeast extract and onion juice, respectively. Significant interaction was found only between sucrose and yeast extract in antioxidant activity. Finally, we selected an optimal medium that was composed of (g/l) onion juice, 600; sucrose, 15; yeast extract, 5. The efficiency of this optimum medium was estimated by using a 5 l jar fermenter. As a result, the maximum cell yield was $9.7\;{\log}_{10}$ (CFU/ml) at 12 hr. Cell yield at the end of incubation (20 hr) was $8.9\;{\log}_{10}$ (CFU/ml) and it was very similar with the predicted value, $9.0\;{\log}_{10}$ (CFU/ml). Antioxidant activity of culture was maintained at about 60~65% during all incubation time, resulting in a higher-than-predicted activity of 47.1%.

• Microbiology and Biotechnology Letters
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• v.14 no.2
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• pp.125-131
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• 1986

In order to obtain the optimum conditions for intact yeast cell transformation in the various yeast host-vector systems, 3 yeast plasmid vectors, YRp7, YEpl3 and YIp5 were introduced into 5 yeast hosts, Saccaromyces cervisiae Dl3-1A, DKD-5D, DBY-746, MC-16 and S2022D with various transformation conditions, and plasmid stabilities in all the transformants were also observed. The highest transformation frequencies in all the host-vector system were obtained in the 16 hour Cultured cell (5.4 $\times$ 10$^6$ - 2.4 $\times$ 10$^8$cells/$m{\ell}$) treated with 0.1-0.2 M lithium chloride in 0.1 M tris-HCl (pH 7.6), 35% polyethylene glycol 4000, and heat-shocked at 42$^{\circ}C$ for 5 minutes after 60 minutes of induction. The intact cell transformation got more transformation frequency in DKD-5D (YRp7) and DBY-746 (YEpl3) than protoplast transformation, but reverse tendency was observed in DKD-5D (YEp13) and Dl3-lA (YRp7). The transformants, D13-1A (YRp7) and DKD-5D (YRp7) were very unstable in selective medium, with 80 to 85% of the transformants losing the plasmid after 70 generations, but the transformants, DKD-5D (YEpl3) and DBY-746 (YEpl3) were quite stable, with 35% of the transformants losing the plasmid.

• Applied Biological Chemistry
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• v.46 no.4
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• pp.348-352
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• 2003

In this study, strain of high-producing intracellular glutathione was isolated from Korean traditional rice wine. The isolated strain was identified as Saccharomyces cerevisiae based on the morphological, physiological and biochemical characteristics, and was designated as FF-8. The optimal condition for glutathione production by Saccharomyces cerevisiae FF-8 was obtained after cultivation with shaking for 72 hours in the YM medium. The optimal temperature, shaking rate and initial pH for the glutathione production were $30^{\circ}C$, 100 rpm and pH 6.0, respectively. The dry cell weight and glutathione concentration produced by Saccharomyces cerevisiae FF-8 were 5.2 g/l and 72.0 mg/l, respectively, under the optimal culture condition.

• Korean Journal of Food Science and Technology
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• v.2 no.2
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• pp.56-59
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• 1970

Although there are no oil wells in Korea, yet more than 900 strains of petroleum hydrocarbon utilizing microorganisms have been isolated from 357 soil and sewage samples collected from oil depots and other sources there. From these samples 7 strains of yeast were selected on the basis of their superior cell yields. Five of them were identified as Candida tropicalis, the other being Candida lipolitica and Torulopis sp. Of the selected strains the mass doubling time is $2.9{\sim}4.5$ hrs., the yield is $6.5{\sim}16.3\;g/l$; the conversion rate of crude petroleum substrate into the microbial mass is $7.8{\sim}19.3%$; and protein content of dried cells is $48.8{\sim}59.8%$.

• Applied Biological Chemistry
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• v.29 no.1
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• pp.36-43
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• 1986

In order to produce cellulosic single cell protein from the cellulose, 163 strains of cellulose assimilating bacteria were isolated from 95 sources and one of them was screened by its strong cellulose assimilating activity. and was identified as Sporocytophaga congregate A-7. The optimum temperature and pH for cellulase production were $30^{\circ}C$ and 6.0, and the optimum temperature, pH and heat stability of the enzyme were $50^{\circ}C$, 7.0 and below $55^{\circ}C$. When the bacteria was cultured in fermentor, the specific growth rate was $0.034hr^{-1}$ and when the bacteria was mixed cultured with Candida guilliermondii var. guilliermondii, the specific growth rate of the bacteria and yeast were $0.06hr^{-1}$ and $0.08hr^{-1}$ respectively and total cell dry weight was $4{\sim}5g/l$.

• Applied Biological Chemistry
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• v.30 no.1
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• pp.31-39
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• 1987

This study has been investigated the effect of Ganordema lucidum extract on Saccharomyces cerevisiae growth and physiology. Sacch. cerevisiae was inoculated in Hayduck solution medium which were added 0, 0.1, 0.5, 1.0% extracts of G. lucidum and fermented at $30^{\circ}C$ for 5 days respectively. Some results about cell number, alcohol content and carbon dioxide products during fermentation are as follows: $CO_2$ evolution of yeasts by addition of extract of G. lucidum was more increased than control after the fermentation for 120 hours. It was the most abundant by addition of 1.0% extract of pot-culture G. lucidum. The cell number of yeasts during the fermentation w as more increased than control by addition of extract of G. lucidum. It was by addition of extract of pot-culture G. lucidum that the cell number of yeasts was more increased than by each addition of extract of wood-culture G. lucidum and G. lucidum. Dry weight of yeasts was systematically increased in addition of extract of pot 0.5%>pot 1.0%>wild 1.0%>wood 1.0%=wood 0.5%>wild 0.5%>wild 0.1%>pot 0.1%>wood 0.1%>control in order. It was by addition of extract of pot-culture G. lucidum that. the dry weight of yeasts was more increased than by addition of woodculture G. lucidum and wild G. lucidum. Alcohol quantity by addition of extract of G. lucidum was increased more than 3 times after the fermentation for 72 hours compared with control but there was no any difference among them after the fermentation for 120 hours. The rate of sugar-consumption and fermentation of yeast by addition of extract of G. lucidum was highly increased during the early fermentation. As times went, there was no difference among them during the subsequent fermentation.