• KSBB Journal
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• v.9 no.1
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• pp.8-15
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• 1994

The research has been carried out to optimize a recombinant S. cerevisine fermentation process for the production of an anticoagulant hirudin. The structural gene coding for hirudin was combined with the GAL10 promoter for controlled expression, the MFal signal sequence for hirudin secretion, and the GAL7 terminator for transcriptional termination. Growth medium composition and environmental conditions were optimized for maximizing cell growth and final hirudin concentration. The optimized conditions included yeast extract 40g/$\ell$, casamino acid 5g/$\ell$, g1ucose 20g/$\ell$, galactose 30g/$\ell$, DO 50% and temperature $30^{\circ}C$. These conditions yielded the specific cell growth rate of $0.13hr^{-1}$, the final cell density of 30g cell/$\ell$ and the final hirudin concentration of 64mg/$\ell$ in the batch fermentation with a 2.5$\ell$ jar fermentor.

• KSBB Journal
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• v.9 no.4
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• pp.395-399
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• 1994

P. stipitis CBS5776 was cultivated to examine the characteristics of ethanol fermentation for hexoses (mannose, g1ucose, and galactose) and pentoses(xylose and arabinose). Glucose was the best carbon source among the sugars used in terms of ethanol yield. Glucose was used to produce ethanol with an yield coefficient 0.376g ethanol/g glucose, whereas mannose was converted to produce ethanol with an yield coefficient 0.326g ethanol/g mannose. P. stipitis CBS5776 was also grown in a mixture of sugars to study the pattern of carbon utilization. The yeast utilized glucose and mannose firsts and then galastose and xylose as carbon sources. Arabinose was partially used for biomass when it was present as a sole carbon source, but it was not metabolized at all in a mixture of carbon sources. P. stipitis produced $12.2g/\ell$ ethanol with a yield coefficient 0.332 g ethano1/g sugar in a mixture of sugars.

• Applied Chemistry for Engineering
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• v.20 no.3
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• pp.290-295
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• 2009

Red-algae agar, consisting of D-galactose and 3, 6-anhydro-L-galactose, is usable for bio-ethanol production if hydrolyzed to monomer unit. The objective of this study is to produce bio-ethanol from agar using the heat and acid-treatment. Bio-ethanol was produced by Saccharomyces cerevisiae KCCM1129 strains using agar-pretreatment. The optimal condition for reducing sugar conversion by agar was found to be 15 min reaction at a HCl concentration of 0.1 N and $120^{\circ}C$. The optimum concentration for maximum cell growth was 0.1 N NaCl (17.88 g/L). Over 0.1 N NaCl, the cell growth decreased to 6.78~10.76 g/L. At 16% agar concentration, the ethanol production obtained by optimum pretreatment was found to be 10.16 g/L.

• Food Science of Animal Resources
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• v.29 no.2
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• pp.143-150
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• 2009

This study was carried out to investigate the properties of crude exopolysaccaride (CEPS) produced by Streptococcus thermophilus LFG in goat milk. The yields of CEPS from yogurt cultured with Str. thermophilus LFG were greater at higher temperatures $(40-45^{\circ}C)$ than at lower temperatures $(30-35^{\circ}C)$. Goat milk yogurt had lower viscosity values than cow milk yogurt. However, the CEPS yield was higher in goat milk yogurt than in cow milk yogurt. The yields of CEPS from yogurt were also higher in cultured milk containing 3% glucose (14-21%), and 3% sucrose (4-16%) relative to the control yogurt. Antioxidant activities were higher in goat milk yogurt supernatant (21%) and its CEPS (28%) than cow milk yogurt supernatant (11%) and its CEPS (24%). The amino acid contents of CEPS were higher in yogurt using goat milk than that using cow milk. The CEPS extracted from goat milk yogurt produced by Str. thermophilus LFG consists of carbohydrate (37% w/w) and protein (63% w/w). The CEPS consisted of monosaccharides such as glucose 56.45% (w/w), galactose 42.35% (w/w), galactosamine 1.37% (w/w), glucosamine 1.09% (w/w) and fucose 0.27% (w/w).

• Journal of the Korean Society of Food Science and Nutrition
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• v.7 no.2
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• pp.21-24
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• 1978

Fermented ordinary Korean soysauce has been one of the most favored seasonings in Korea. The change of free sugars as taste components during the fermentation were analyzed. The results obtained are summarized as follows. 1. Such free sugars as xylose, arabinose, glucose and galactose were detected in Korean ordinary soysauce during the fermentation and galactose was found to be most abundant free sugars. 2. The content of these free sugars in soysauce were increased until 20-40days of fermentation and then decreased rapidly. But slight increase was observed after 80 days of fermentation. 3. It is estimated that galactose plays most important role as sweet taste component in Korean ordinary soysauce.

• Korean Chemical Engineering Research
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• v.50 no.1
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• pp.141-148
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• 2012

In order to study the utilization of brown seaweed Laminaria japonica as an alternative renewable feedstock for bioethanol production, the properties of acid hydrolysis and ethanol fermentation were investigated. The acid hydrolysis enhanced the final yield of fermentable sugars, which led great increase of ethanol productivity. The maximum yield of reducing sugars reached 135 mg/g-dry Laminaria japonica after 1.0N sulfuric acid-hydrolysis at $130^{\circ}C$ for 6 h. The Saccharomyces cerevisiae (ATCC 24858) could ferment $C_6$-sugars like glucose, galactose and mannose into ethanol, but not $C_5$-sugars like arabinose and xylose. Optimal fermentation time varied with sugars; 48 h for glucose, 72 h for galactose, and 96 h for mannose. Nevertheless, the ethanol yield from the hydrolysate reached 242 mg/g-dry Laminaria japonica after fermentation by the S. cerevisiae at $35^{\circ}C$ for 96 h, which corresponds to approximately 4 times more than the theoretical yield from total reducing sugars in the hydrolysates. It indicates that the non-reducing sugars or oligosaccharides dissolved in the hydrolysate played an important role in producing bioethanol. The ethanol concentration linearly increased from 2.4 to 9.2 g/L, while the ethanol yield per dry weight of biomass decreased from 242 to 185 mg/g, with increasing the ratio of biomass to acid solution from 1 to 5% (w/v). The bioethanol yield estimated was approximately 7,400~9,600 kg/ha/year, and indicated that Laminaria japonica is a promissing feedstock for bioethanol production.

• Korean Journal of Food Science and Technology
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• v.26 no.3
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• pp.195-198
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• 1994

A bubble counter was designed and fabricated for the measurement of gas production rate on the basis of number of bubbles produced from yeast fermentor. The sensor was consisted of bubble forming device and electronic signal processing circuitry. The bubble forming device was built with bubble collector and liquid cell to form uniform size of bubble. Bubbles were counted by pulses formed by photo-interrupter circuitry having 8-bit binary latch counter. The gas production rate curves on the basis of bubble counted showed a good agreement to that of growth curves obtained by the optical measurement method. The sensor was succesfully applied to monitoring of the nutrient utilization test with glucose and galactose media.

• Korean Journal of Food Science and Technology
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• v.29 no.2
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• pp.362-368
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• 1997

As a preliminary study for the development of cancer-preventing functional food using Korean mistletoe, the cytotoxic effects of Korean mistletoe on between non-tumorigenic A3l cell and tumorigenic MSV cell derived from mouse 3T3 fibroblast cell line were investigated. While the raw extract, of which $ID_{50}$, value was $3.94\;{\mu}g/mL$, showed strong cytotoxic effect, its heat-treated extract was not cytotoxic up to $30\;{\mu}g/mL$. On the other hand, the heat-treated extract with law concentration showed an accelerative effect on the proliferation of non-tumorigenic A3l cell and an inhibitory effect on that of tumorigenic MSV cell. In addition, the influences of the addition of carbohydrates, such as galactose, lactose, glucose, mannose, fructose, sucrose and starch, to mistletoe extract were studied. There were not any significant changes with raw extract plus carbohydrate treatment, but the accelerative and inhibitory effects of heat-treated extract on each A3l and MSV cell were increased further by the treatment with sugars such as lactose, galactose, glucose, fructose. In order to investigate the changes of cytotoxicity of fermented Korean mistletoe according to fermentation periods, the raw and heat-treated extract were inoculated with Lactobacillus plantarum. During 1, 3, 5 and 7 fermentation days, the fermented raw mistletoe extract showed gradual accelerative effect on A31 cell proliferation without any changes of cytotoxicity on MSV cell. In case of the fermented heat-treated extract, however, the accelerative effect of heat-treated extract on A31 cell proliferation in early stage was disappeared during the fermentation.

• Korean Journal of Food Science and Technology
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• v.27 no.6
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• pp.878-884
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• 1995

In order to use whey lactose in alcohol fermentation, we investigated fermentation conditions of Saccharomyces cerevisiae and Kluyveromyces fragilis in lactose-hydrolyzed whey with ${\beta}-D-galactosidase$. and optimum conditions of the above two yeasts through oxygen regulation by Pasteur effect which is the characteristic of the yeasts were determined. In addition, optimum condition for application of fermented whey in Tak-ju process was also examined. With 0.7% ${\beta}-D-galactosidase$, 93% lactose was hydrolyzed at pH 6.5 in 30 minutes. Because S. cerevisiae is unable to ferment galactose, the production of ethanol by S. cerevisiae was lower than that of K. fragilis in lactose-hydrolyzed whey. But ethanol productivity by S. cerevisiae was higher than that by K. fragilis in glucose added whey. In fermentation with oxygen regulation and addition of 60 g/l glucose, the ethanol productivity of K. fragilis and S. cerevisiae were 18.9 g/l (11.8% increase) and 43.5 g/l (22.1% increase), respectively. It appeared that the ethanol productivity of S. cerevisiae was higher than thst of K. fragilis under the above conditions. In ethanol fermentation added rice starch, Aspegillus oryzae hydrolyzed 80% of starch in 60 hours, and the production of ethanol was 80.2 g/l

• Korean Journal of Food Science and Technology
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• v.22 no.2
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• pp.129-133
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• 1990

The strain of Nuruk yeat No. 15 (NY-15) which ferments lactose in milk was Isolated from Nuruk and identified as Saccharomyces marxianus according to the API 20C profile index. The lactose hydrolysing ability of NY-15 was similar to that Saccharomyces fragilis ATCC 8583 which has ${\beta}-galactosidase$ activity. Its optimum growth temperature, pH and time for the production of maximum enzyme activity showed $28^{\circ}C$, 4.5 and 28hr, respectively. Galactose as well as sucrose as carbon sources, and urea as nitrogen source Increased the production of enzyme. In order to test the production of alcohol, NY-15 was inoculated in whey medium and whey medium added with sugar. In the former, NY-15 produced 2% alcohol and in the latter, it showed 12% alcohol production. The optimal medium pH for lactose hydrolysis of NY-15 is 4.5, whereas that of Saccharomyces fragilis ATCC 8583 is 3.5