• Korean Chemical Engineering Research
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• v.49 no.5
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• pp.516-520
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• 2011

Sodium borohydride, $NaBH_4$, shows a number of advantages as hydrogen source for portable proton exchange membrane fuel cells (PEMFCs). The hydrogen yield of sodium borohydride hydrolysis reaction was studied. The effect of temperature, $NaBH_4$ concentration, NaOH concentration and catalyst type on the hydrogen yield from $NaBH_4$ hydrolysis reaction were measured. The catalysts of Co-P/Cu, Co-B/Cu and Co-P-B/Cu were used in this study and there was no different effect of these catalysts on the hydrogen yield from $NaBH_4$. Under the temperature of $60^{\circ}C$, the hydrogen yield decreased as $NaBH_4$ concentration increased due to formation of gel with by-products and reactants. The gel formed during $NaBH_4$ hydrolysis reaction diminished the hydrogen evolution rate and total volume of hydrogen. Addition of NaOH stabilizer enhanced the formation of gel and then decreased the hydrogen yield.

• 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%.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.2
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• pp.166-171
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• 2007

The objective of this study was to assess the association of polymorphisms in ${\kappa}$-cn, ${\beta}$-lg, ${\beta}$-lg 5′ flanking region, CSN1S2, and IGFBP-3 genes with milk production traits and mastitis-related traits in Chinese Holstein. Traits analyzed were 305 day standard milk yield, protein percentage, fat percentage, the ratio of fat percentage and protein percentage, pre-somatic cell count, somatic cell count, and somatic cell score, respectively. CSN1S2 locus was uninformative because only one genotype BB was found in Chinese Holstein. Allele frequencies of A and B in IGFBP-3 gene were 0.5738 and 0.4262 in Chinese Holstein population, which was different from reported Qinchuan cattle population. The genotypes of animals at IGFBP-3 locus significantly affected 305 day standard milk yield, protein percentage, and somatic cell score. The ${\beta}$-lg genotypes had a significant effect on protein percentage and the ratio of fat percentage and protein percentage. Polymorphism in ${\beta}$-lg 5′ flanking region was associated with 305 day standard milk yield, protein percentage, fat percentage, pre-somatic cell count, and somatic cell count. No significant associations of the polymorphism in ${\kappa}$-cn gene were observed for any trait.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.4
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• pp.479-484
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• 2004

The study was conducted to assess the effect of milk production, parity, stage of lactation, season and individual milk components themselves on milk urea nitrogen (MUN) concentration and other milk components of 3,219 Holstein dairy cows in Korean dairy farms. The MUN concentrations in Korean dairy cows were estimated to 16.68$\pm$5.87 mg/dl. Milk yield was negatively correlated with fat and protein contents and somatic cell counts (SCC) in milk (p<0.01). The increasing MUN concentration has positive correlation with yield and fat content. By increasing somatic cell, milk yield was reduced and MUN level was increased. Cows in spring and winter produced more milk over 1.43 and 0.93 kg/day, respectively, than cows in summer (p<0.01). Milk urea nitrogen concentrations of milk produced in summer and fall were significantly lower (p<0.01) than those in spring and winter. Both MUN concentration and somatic cell counts were highest in winter. Milk yield was lower (p<0.01) in the first calving than other calving time and was tended to increase until the fifth parity and then decrease. Milk urea nitrogen and SCC were not related to parity of cows in this study. Milk yield and SCC were positively related to lactation period while MUN concentrations and milk fat and protein contents were negatively influenced by stage of lactation. In the present study, the relationship between MUN and reproduction of dairy cows was also investigated. Cow produced milk in high MUN concentrations (greater than 18 mg/dl) had more open days than cows in MUN concentrations less than 18 mg/dl. However, no significant difference between MUN concentration levels and frequency of artificial insemination was found in this study. It is suggested that although MUN values for nutritional management and measures of production or reproduction are used, non-nutritional factors should be considered.

• Journal of Microbiology and Biotechnology
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• v.4 no.1
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• pp.56-62
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• 1994

A yeast strain, BT001, which can directly ferment D-xylose to ethanol was isolated from forest soils, and then identified as Candida sp. Cultural conditions for the optimum ethanol production, along with the effects of aeration on cell growth and ethanol production were investigated. Aeration stimulated the cell growth and the volumetric rate of ethanol production, but decreased the ethanol yield. Optimum temperature and initial pH for the ethanol production were $33{\circ}^C$ and 6.0, respectively. In a shake flask culture, this strain produced 52.3 g ethanol per liter from 12%(w/v) D-xylose after incubation for 96 hours. Ethanol yield was 0.436 g per g D-xylose consumed. This corresponds to 85.8% of theoretical yield. Also, this yeast strain produced ethanol from D-galactose, D-glucose and D-mannose, but not from L-arabinose and L-rhamnose. Among these sugars, D-glucose was the fastest in being converted to ethanol sugars.

• KSBB Journal
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• v.4 no.3
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• pp.271-275
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• 1989

Batch growth of plant cell suspension cultures of Thalictrum rugosum was studied to clarify the kinetic behaviors. It was found that the product formation was growth associated. The specific growth rate was $0.20-0.25\;day\;^{-1}$/TEX> at the growth phase and the FW/DCW ratio was an interesting parameter which represented the status of the cells or the status of sugar concentration. The cell yield was 0.36 g cells/g sugar. The maximum berberine level was 139 mg/L of which 120 mg/L was intracellular. In terms of the specific content of berberine, the product was 1.10% of dry cell weight. At the growth phase, the relationship between the specific growth rate and sugar concentration was described well by Monod kinetics.

• Korean Journal of Clinical Laboratory Science
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• v.45 no.1
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• pp.37-42
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• 2013

The cells are concentrated approximately 20-fold by cytocentrifugation. This study evaluated the nucleated cell number for cells recovered on slide by using Cytospin-3 (Thermo Shandon Ltd. UK) and Cytopro-7620 (Wescor Inc., USA) cytocentrifuges to hematocytometer cell count of $0{\sim}5WBCs/{\mu}L$ of hematocytometer in the cerebrospinal fluid cell count. One hundred forty eight samples of $0{\sim}5WBCs/{\mu}L$ on hematocytometer, were cytocentrifuged by Cytospin-3 and Cytopro-7620 instruments. The nucleated cell number for cells recovered on slide was counted after Wright stain. The nucleated cell number for cells recovered on slide was 0~40 cells in the 44 samples of $0WBC/{\mu}L$, and 3~95 cells in the 31 samples of $1WBC/{\mu}L$. It was observed that the nucleated cell number for cells recovered on slide was 13~100 cells in the 44 samples of $2WBCs/{\mu}L$, and more than 100 cells in the 29 samples of $3{\sim}5WBCs/{\mu}L$, respectively. In addition, extremely normal lymphocyte, monocyte and polymorphonuclear neutrophil were observed in the 143 samples of $0{\sim}5WBCs/{\mu}L$. Macrophage and eosinophil were also rarely observed. The nucleated cell number for cells recovered on slide was 20 cells, which were regarded as $1WBC/{\mu}L$ in body fluid cell count. However, in this study, we made alterations to report nucleated cell percentage as 0% without preparing the cytocentrifuged slide at $0WBC/{\mu}L$ by using the cell yield in a comparison between the value of $0{\sim}5WBCs/{\mu}L$ and nucleated cell number for cells recovered on slide.

• Preventive Nutrition and Food Science
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• v.2 no.1
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• pp.66-70
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• 1997

A mixed-culture of Gluconobacter suboxydans IFO 3172 and Saccharomyces uvarum IFO 0751 was per-formed in a synthetic medium. the optimal inculum ratio of G. suboydans and S. uvarum for mixed-culture fermentation was 150:1. The optimum pH, incubation temperature and aeration rate for mixed-culture fer- mentation were 5.0, 3$0^{\circ}C$ and 2.25vvm, reapectively. As a result of batch pure-and mixed-culture fer-mentation, specific growth rate in pure-culture of both strain was lower than that in mixed-culture. The yield of cell mass from S. uvarum exclusively decreased. The growth rate of the mixed-culture was very similar to the pure-culture in the begining of culture, but it has been decreased after 16hrs. In the mean time, S. uvarum in mixed-culture fermentation could grow due to fructose converted, but it could not row in pure-culture fermentation. Thus, the relationship was a sort of commensalism. The kinetic parameters cal-culated through steady-state results during continuous fermentations are as follows :{TEX}$$\mu$_{max1}${/TEX}=0.118({TEX}$h^{-1}${/TEX}), {TEX}$Ks_{1}${/TEX}=0.330(g/L),:{TEX}$$\mu$_{max2}${/TEX}=0.162({TEX}$h^{-1}${/TEX}), {TEX}$Ks_{2}${/TEX}=0.038(g/L). The yield of bacterial cell mass relatively constant, but yield of yest cell mass was gradually decreased.

• Journal of Embryo Transfer
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• v.23 no.4
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• pp.291-298
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• 2008

We separately cultured follicular oocytes collected from individual ovaries of slaughtered Korean native cows and examined both the embryonic development rate and pregnancy rate after embryo transplantation according to the meat yield and quality grades of the source beef carcass. Oocytes from meat yield grade B cows exhibited a higher fertilization rate and embryonic developmental rate to the eight-cell stage than oocytes from grade A or C animals (p<0.05), but there was no significant difference in rate of development to the blastocyst stage among meat yield grades A, Band C. The oocyte cleavage rate and development rate to the eight-cell stage from meat quality grade 3 cattle was higher than grades 1++, 1+, 1 and 2 (p<0.05). Embryos derived from grade animals displayed a development rate to the blastocyst stage of 19.4%, which was also higher than all other meat quality grades (p<0.05). Transplantation of in vitro-cultured oocytes from meat yield grade A ovaries led to a higher pregnancy rate (64.2%) than in vitro-cultured oocytes from meat yield grade B ovaries (56.5%), but there was no significant difference between the two groups in pregnancy or abortion rates. In conclusion, embryonic development rate and pregnancy rate has a close relation to meat quality grades of the source beef carcass, this results is to give information for the Korean native cows improvement of breed.

• Journal of Microbiology and Biotechnology
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• v.11 no.4
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• pp.564-569
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• 2001

This study was carried out in order to investigate the characteristics of xylitol fermentation by a xylitol dehydrogenase defective mutant PXM-4 of P stipitis CBS 5776 and to determime optimum conditions for the high yield ofxylitol production from xylose. Gluconic acid was selected as a co substrate for the xylitol fermentation, since gluconic acid neither blocked xylose transport nor repressed xylose reductase expression. An increase of gluconic acid concentration reduced the rates of xylitol production and cell growth by decreasing medium pH, and the optimal concentration of gluconic acid was determined to be 20 gll with approximately 100% xylitol conversion yield. A fed-batch cell culture resulted in a 44.8 g/l xylitol concentration with 100% yield, based on the amount of xylose consumed.