• Journal of Institute of Control, Robotics and Systems
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• v.11 no.10
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• pp.857-863
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• 2005

A yeast strain utilizing styrene epoxide as a sole carbon and energy source was isolated from soil samples for the production of enantiopure of styrene epoxide by kinetic resolution. The strain, identified as a Rhodosporidium toruloides SJ-4, expressed an epoxide hydrolase which preferentially converted (R)-styrene epoxide into the corresponding diol. A maximum activity of 135 U/L was observed when biomass (dry cell mass) reached 6.7 g/L at 21 h of batch culture. Under the partially optimized reaction conditions ($35^{\circ}C$ and pH 8.0), the optically pure (S)-styrene epoxide was obtained with the yield of 21% when the initial substrate concentration was 100 mM. The reaction was completed at 9 h.

• Korean Journal of Poultry Science
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• v.18 no.3
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• pp.167-181
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• 1991

In order to study the effects of dietary yeast (Saccharomyces cerevisiae) products on the performance of broiler chickens, tow feeding trial using Arbor Acres strain were conducted. In experiment 1, 200 hatched male broiler chickens were divided into groups of 10 birds each and four groups were given each of the five dietary treatments : control, 0.25% yeast culture supplemented (YC-0.25%), 2.5% yeast culture supplemented(YC-2.5%), 0.05% live yeast supplemented(LY-0.05%) and 0.1% live yeast supplemented(LY-0.1%) . In experiment 2, 240 hatched broiler chickens(120 birds in each sex) were assigned to 2$\times$3(sex$\times$feed) factorial design Dietary treatments were control, 0.1% live yeast supplementation in finisher diet(LY-Finisher) , and 0.1% live yeast supplementation in whole period (LY-Whole). Results of experiment 1 showed that weight gain, feed intake and mortality were not significantly different among treatments. However, weight .gain of YC-0.25% and LY-0.1% tended to be greater than other treatments after 3wks of age Feed efficiency of LY-0.05% was poorer than those of control, YC-0.25% and LY-0.1% . Although nutrients availabilities were not significantly different among treatments, availiabilities of Ca and P were greater in yeast products supplemented groups than in control group. The number of Lactobacillus spp., Streptococcus spp . and yeast in small intestine tended to be greater in supplemented groups while that of Coliforms bacteria tended to be greafter in control group. In experiment 2, there were significant effects of factors (feed and sex) and interaction on growth rate. LY-Whole groups showed best weight gain in male while LY-Finisher groups did best in female broiler chickens. Feed intake and mortality were significantly higher in male broiler chickens. Feed$\times$sex interaction had a significant effect on feed efficiency. LY-Whole groups showed best feed efficiency in male while LY-Finisher did best in female broiler chickens. Availabilities of dry matter, Ca and P were higher in male than in female broiler chickens. Availabilities of Ca and P were higher in live yeast supplemented groups than in control groups. Live yeast supplemented groups tended to have greater number of Lactobacillus spp . and yeast in the small intestine and Stre))tococcu spp. in the small intestine and cecum, and lesser number of Coliforms bacteria in the small intestine The pH of small intestinal contents tended to be higher in live yeast supplemented groups.

• Korean Journal of Food Science and Technology
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• v.34 no.2
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• pp.249-254
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• 2002

To determine the abilities as both lactic starter and probiotics for fermented foods, we investigated the potency of acid production, proteolytic activity and lactose metabolism of Lactobacillus amylovorus IMC-1. And the strain was cultured with lactococci in 10% skim milk medium. It was also examined the bactericidal action of antibacterial substance, produced by the strain IMC-1, against pathogenic bacteria. L. amylovorus IMC-1 showed excellent production of acid in 10% skim milk supplemented with yeast extract, and produced 0.8 and 2.7% of acid at 12 and 72 h incubation, respectively. It was found that the activity of ${\beta}-galactosidase$, about $39\;{\mu}M/minute/dry$ cell weight (mg), was stronger than that of $phospho-{\beta}-galactosidase$ in the strain IMC-1. The strain showed weak proteolytic activity in 10% skim milk, thus it produced 6 and $69\;{\mu}g/mL$ of free tyrosine at 12 and 72 h cultivation, respectively. It was known that the strain utilized mainly ${\alpha}-casein$ than ${\beta}-casein$ from patterns of SDS-PAGE. Mixed culture produced more acid than single cultures of L. amylovorus IMC-1 and Streptococcus thermophilus NIAI 510. Single culture of Str. thermophilus and mixed culture showed increasing cheese flavor with incubation times. Optimal fermentation time of mixed culture for the acid production and flora of lactic starter was 16 and 12 h by adding 0.1 and 0.5% of yeast extract to 10% skim milk, respectively. Antibacterial substance produced by the strain IMC-1 reduced about 2 log of the viable cell counts of both Escherichia coli O157 and Shigella flexneri after 24 and 4 h incubation, and they were not detected after 48 and 6 h incubation, respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.2
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• pp.254-260
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• 2012

This study was conduced to ferment high quality wine by using Omija fruit. Dry Omija farmed and dried in the Moonkyung area was used in this study. The Omija was soaked in 10~40 folds of distilled water to extract water-soluble components and the fluid was filtered after soaking for 6 hours at $50^{\circ}C$. Strains of alcoholic yeast were isolated respectively from spoiled Omija extract. Isolated alcoholic yeasts, OM-1 and OM-2, showed a round to ellipsoidal shape and formed white or milky white colonies on a solid YM medium. Two yeasts produced 10.33~11.23% alcohol from Omija extract adjusted to $10^{\circ}Brix$ with sugar. Their abilities to ferment alcohol were higher than those of other yeast strains belonging to Saccharomyces cerevisiae such as KCTC 7296 (standard strain of Korean Biological Resources Center), Makgeolli yeast, or beer yeast. The isolates OM-1 and OM-2 showed similar abilities in alcohol fermentation. However, the wine fermented by OM-2 got a better sensory score especially with color. Growth of OM-2 was significantly accelerated by addition of a 0.1% urea and 0.02% mineral mixture. A vitamin mixture was effective for the growth only when urea was added as well.

• Food Science and Biotechnology
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• v.16 no.1
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• pp.133-137
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• 2007

The Strain TFM-7, Which has an antitumor effect, was isolated from Kefir and identified based on analysis using the API 50 CHL kit and 265 rDNA sequencing. Strain TFM-7 was confirmed to belong to the genus Kluyveromyces. Analysis of the 265 rDNA nucleotide sequences found strain TFM-7 to be related to Kluyveromyces marxianus. NRRL Y-828IT. K. marxianus. TFM-7 was cultured with potato dektrose broth medium at $27^{\circ}C$ for 72 hr, and its inhibition effects on the proliferation of seven tumor cell lines and a normal cell line were assessed using the MTT assay. The antitumor effects and growth characteristics of K. marxianus TFM-7 were investigated during a culture period of 7 days. By the $3^{rd}\;day$, K. marxianus TFM-7 showed a dry cell weight 2.39 g/L, a pH of 4.39, an ethanol content of 0.89%, and an inhibition effect on the proliferation of seven tumor cell lines above 50%, except for A-549 tumor cell line. K. marxianus TFM-7 was the most effective at inhibiting the growth of Hep-2 cell line among all tumor cell lines tested. Growth inhibition of a normal cell line, NIH/3T3, was less than 35%, suggesting a decreased level of cytotoxicity toward normal cells. These results indicate that K. marxianus TFM-7 may have used as a yeast strain with antitumor activity.

• Journal of Microbiology and Biotechnology
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• v.34 no.3
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• pp.710-724
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• 2024

Flavobacterium can synthesize xanthophyll, particularly the pigment zeaxanthin, which has significant economic value in nutrition and pharmaceuticals. Recently, the use of carotenoid biosynthesis by bacteria and yeast fermentation technology has shown to be very efficient and offers significant advantages in large-scale production, cost-effectiveness, and safety. In the present study, JSWR-1 strain capable of producing xanthophyll pigment was isolated from a freshwater reservoir in Wanju-gun, Republic of Korea. Based on the morphological, physiological, and molecular characteristics, JSWR-1 classified as belonging to the Flavobacterium species. The bacterium is strictly aerobic, Gram-negative, rod-shaped, and psychrophilic. The completed genome sequence of the strain Flavobacterium sp. JSWR-1 is predicted to be a single circular 3,425,829-bp chromosome with a G+C content of 35.2% and 2,941 protein-coding genes. The optimization of carotenoid production was achieved by small-scale cultivation, resulting in zeaxanthin being identified as the predominant carotenoid pigment. The enhancement of zeaxanthin biosynthesis by applying different light-irradiation, variations in pH and temperature, and adding carbon and nitrogen supplies to the growth medium. A significant increase in intracellular zeaxanthin concentrations was also recorded during fed-batch fermentation achieving a maximum of 16.69 ± 0.71 mg/l, corresponding to a product yield of 4.05 ± 0.15 mg zeaxanthin per gram cell dry weight. Batch and fed-batch culture extracts exhibit significant antioxidant activity. The results demonstrated that the JSWR-1 strain can potentially serve as a source for zeaxanthin biosynthesis.

• Journal of Microbiology and Biotechnology
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• v.25 no.11
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• pp.1856-1862
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• 2015

In order to improve the stability of endoglucanase under thermal and acidic conditions, the endoglucanase gene was fused to the N-terminus of the Saccharomyces cerevisiae pir gene, encoding the cell wall protein PIR. The fusion gene was transformed into Pichia pastoris GS115 for expression. A resulting strain with high expression and high activity was identified by examining resistance to Geneticin 418, Congo red staining, and quantitative analysis of enzyme activity. SDS-PAGE analysis revealed that the endoglucanase was successfully displayed on the yeast cell surface. The displayed endoglucanase (DEG) showed maximum activity towards sodium carboxyl methyl cellulose at approximately 275 IU/g cell dry weight. DEG exhibited greater than 60% residual activity in the pH range 2.5-8.5, higher than free endoglucanase (FEG), which had 40% residual activity at the same pH range. The highest tolerated temperature for DEG was 70℃, much higher than that of FEG, which was approximately 50℃. Moreover, DEG showed 91.1% activity at 65℃ for 120 min, while FEG only kept 77.8% residual activity over the same period. The half-life of DEG was 270 min at 65℃, compared with only 150 min for FEG. DEG could be used repeatedly at least three times. These results suggest that the DEG has broad applications as a yeast whole-cell biocatalyst, due to its novel properties of high catalytic efficiency, acid-thermal stabilities, and reusability.

• Microbiology and Biotechnology Letters
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• v.16 no.2
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• pp.105-110
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• 1988

The production of single cell protein using the amylolytic fusant obtained from cell fusion between Hansenula anomala and Saccharomyces cerevisiae was studied. The fusant12 strain was selected for single cell protein production from starchy materials among five fusants. Optimum nitrogen source and its concentration for the growth of fusant12 were ammonium sulfate and 0.1%, respectively. Optimum concentration of soluble starch and optimum pH of the basal medium were lord and pH 5.6, respectively. Autolysis of fusant12 was effectively carried out by addition of 5% (v/v) ethyl acetate to the cell suspension and liquidization for 30 min before incubation for 24 hr at 3$0^{\circ}C$. Coculture of fusant12 and non-amylolytic yeast, Torulopsis candida YA-l5, resulted in the increase of the mass as compared to the monoculture of fusant12. The cell mass on tapioca medium was increased about 2.5 times as on soluble starch medium. The content of crude protein and nucleic acid of the dry cell were 39% and 5.8%, respectively.

• Journal of Life Science
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• v.26 no.5
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• pp.571-583
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• 2016

Biogenic amines are produced primarily by microorganisms found in fermented foods and are often implicated in poisoning incidents in humans. In this study, 620 strains of microorganisms were isolated from traditional Korean fermented food in Sunchang in order to screen for non-biogenicamine-producing microorganisms present in these foods. One strain was identified and named Bacillus subtilis SCJ1, by using 16S rRNA sequencing and biochemical characterization. We investigated the cell growth of this organism in order to understand its potential for industrial application. To this end, we optimized the culture medium constituents by using the response surface methodology. The Plackett-Burman experimental design was used for screening of the medium constituents, such as molasses, yeast extract and peptone, for improving cell growth. In order to determine the optimal concentration of each constituent, we used a central composite design. Consequently, the optimized concentrations of molasses, yeast extract and peptone were predicted to be 27.5 g/l, 7.5 g/l and 17.5 g/l, respectively. By model verification, we confirmed that a 1.49-fold increase in dry cell weight compared to the basal medium-from 1.32 g/l, to 1.9722 g/l-was achieved.

• Korean Journal of Food Science and Technology
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• v.19 no.4
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• pp.324-330
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• 1987

A large number of methanol-assimilating yeasts and bacteria were isolated from samples of soil, sewage, decomposed milk and spoiled sweet-radish pickles. Among the yeasts, one strain was selected and identified as a strain of Candida boidinii. In 1% (v/v) methanol Candida boidinii YF-3 grew well and could grow in as much as 5%. This yeast required boitin for grwoth. Maximum growth was observed at $30^{\circ}C$ and pH 6 in a semisynthetic medium. The productivity was 2.72g dry cells per liter in batch culture with 1%(v/v) methanol and the cell yield for methanol was $0.39\;gg^{-1}$. The specific growth rate was $0.11\;h^{-1}$ and the generation time was 6.4 hours. The protein content of the cell was 45.5% and total nucleic acid content was 5.9%. The amino acid profile was as good as FAO standard for food protein.