• KSBB Journal
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• v.8 no.2
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• pp.133-142
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• 1993

The effects of genetic and environmental factors on productivity of a cloned protein were studied in recombinant Saccharomyces cerevisiae. Plasmid stability and copy level were very high for a $REP^+$ system(at ca. 10 generations, stability: 65-90%, plasmid copy number per cell: 40-200), whereas these were very low for a yep- system(at ca. 10 generations, stability: 30%, plasmid copy number per cell 20). In plasmids containing the $2{\mu}m$ circle genome, a $[cir^o]$ strain was a preferred host cell since the plasmid stability and the copy number in a $[cir^o]$ strain were higher than in a $[cir^+]$strain. Cloned gene expression was dependent on plasmid copy number and stability. The inducer (galactose) level played a very important role in cloned lacZ gene expression, showing that a galactose concentration of 0.8% was sufficient for induction of gene expression. Induction rate was very fast in the case of plasmids exhibiting high stability and copy number by a factor of 4 to 25. The time to reach the peak value of gene expression was longer when galactose was added at the start of fermentation (ca. 26 hours) than at the mid-exponential phase (ca. 6 hours). Glucose repression was reduced by a factor of 2 to 5 as the relative inducer level increased.

• Biotechnology and Bioprocess Engineering:BBE
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• v.5 no.4
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• pp.234-241
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• 2000

The Saccharomyces cerevisiae PMR1 gene encodes a Ca2+-ATPase localized in the Golgi. We have investigated the effects of PMR1 disruption in S. cerevisiae on the glycosylation and secretion of three heterologous glycoproteins, human ${\alpha}$1-antitrypsin (${\alpha}$1-AT), human antithrombin III (ATHIII), and Aspergillus niger glucose oxidase (GOD). The pmr1 null mutant strain secreted larger amounts of ATHIII and GOD proteins per a unit cell mass than the wild type strain. Despite a lower growth rate of the pmr1 mutant, two-fold higher level of human ATHIII was detected in the culture supernatant from the pmr1 mutant compared to that of the wild-type strain. The pmr1 mutant strain secreted ${\alpha}$1-AT and the GOD proteins mostly as core-glycosylated forms, in contrast to the hyperglycosylated proteins secreted in the wild-type strain. Furthermore, the core-glycosylated forms secreted in the pmr1 mutant migrated slightly faster on SDS-PAGE than those secreted in the mnn9 deletion mutant and the wild type strains. Analysis of the recombinant GOD with anti-${\alpha}$1,3-mannose antibody revealed that GOD secreted in the pmr1 mutant did not have terminal ${\alpha}$1,3-linked mannose unlike those secreted in the mnn9 mutant and the wild type strains. The present results indicate that the pmr1 mutant, with the super-secretion phenotype, is useful as a host system to produce recombinant glycoproteins lacking high-mannose outer chains.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.6
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• pp.833-838
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• 2015

To develop a value-added product from individually quick-frozen oyster Crassostrea gigas extract (IQFOE), we prepared two types of oyster sauce (OS): bottled OS (BOS) and retort pouched OS (ROS). We investigated processing conditions, quality metrics and flavor compounds in each type of sauce. We found that the most appropriate base formular for both BOS and ROS consisted of 40.0% IQFOE (Brix $30^{\circ}$), 15.0% sugar, 6.0% salt, 4.0% monosodium glutamate, 4.0% soy sauce, 3.5% starch, 3.0% yeast extract, 3.5% wheat flour and 21.0% water. The crude protein, salinity and amino-nitrogen contents of the BOS and ROS were 8.2 and 8.3%, 9.3 and 9.2%, and 539.2 and 535.2 mg/100 g, respectively. In commercial oyster sauces (COS), these values were 4.7-6.5%, 9.7-12.0%, and 244.7-504.2 mg/100 g, respectively. The total free amino acids content of ROS was 7,346.9 mg/100 g, and the main free amino acids were glutamic acid, taurine, proline, glycine and alanine. The inosinic monophosphate (IMP) content of the ROS was 131.6 mg/100 g, and the primary inorganic ions were Na, K, S and P. The present BOS and ROS have favorable organoleptic qualities and storage stability compared with COS, and are suitable for commercialization as high-flavor seasoning sauces.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.6
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• pp.656-661
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• 2017

To develop a highly value-added product from extract from small and damaged sea mussels Mytilus edulis, we prepared two types of sea mussel sauce (MS): bottled (BMS) and retort pouched (RMS). We investigated the processing conditions, quality metrics and flavor compounds in each type of sauce. We found that the most appropriate base formulation for both BMS and RMS consisted of 40.0% SME (Brix $30^{\circ}$), 15.0% sugar, 6.0% salt, 4.0% monosodium glutamate, 4.0% soy sauce, 3.5% starch, 3.0% yeast extract, 3.5% wheat flour and 21.0% water. The crude protein, salinity, volatile basic nitrogen and amino-nitrogen content of the BMS and RMS were 8.7% and 8.8%, 9.3% and 9.2%, 24.9 and 31.4 mg/100 g, and 468.5 and 455.1 mg/100 g, respectively. For comparison, the ranges of these values in commercial oyster sauces (COS) are 4.7-7.5%, 10.7-12.0%, 8.2-12.5 mg/100 g, and 225.7-448.2 mg/100 g, respectively. The total free amino acid content of RMS and Premium COS was 7,215.7 and 6,160.7 mg/100 g, respectively, and the main free amino acids were glutamic acid, taurine, glycine, alanine, arginine, proline and lysine. These results demonstrate that BMS and RMS have favorable organoleptic qualities and good storage stability compared to COS, and are suitable for commercialization as high-flavor seasoning sauces.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.7
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• pp.1002-1008
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• 2012

For the production of Korea traditional cereal wine makgeolli, a rice fermentation starter nuruk was Rhizopus oryaze CCS01 commercial nuruk. The carbohydrate content of rice nuruk was higher, the levels of moisture, ash, crude protein, and crude fat were lower. In particular, the saccharifying activity of rice nuruk was 2.2 times higher than commercial nuruk. pH, alcohol, and viable yeast cells of makgeolli made rice nuruk were higher than those of makgeolli made commercial nuruk. In contrast, the levels of acidity, $^{\circ}Brix$, viable lactic acid bacteria (LAB) cells, and browning of makgeolli made rice nuruk were lower than those of makgeolli made commercial nuruk, the alcohol content of glutinous rice (GUR) makgeolli made rice nuruk higher other samples. These results suggest that rice nuruk R. oryzae CCS01 make new type cereal makgeolli.

• KSBB Journal
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• v.25 no.1
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• pp.47-54
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• 2010

The mycelial dispersed growth of Cordyceps sinensis was optimized in submerged batch culture at initial pH of 5.0, 150 rpm, and $25^{\circ}C$. The morphological data showed much more dispersed growth of C. sinenesis at initial pH of 5.0. Also, projected area, main hyphal length and number of tips for the mycelial growth of initial pH 5.0 were higher than those of other initial pHs. The industrial medium for mycelial production of C. sinensis was determined to be molasses of 100 g and crushed brewery yeast of 10 g per liter as carbon and nitrogen sources, respectively. With these culture conditions, the maximum production of mycelia was approximately 30.0 g per liter by batch culture in 5-liter jar fermenter with no controlled pH. This result suggests that large-scale mycelia production of C. sinensis may be possible in submerged batch culture. The hot water extract of mycelia from C. sinensis was mainly composed of 83.0% carbohydrate, 11.8% protein, 1.9% lipid, and 2.4% ash and there were present glucose, mannose, galactose, and arabinose as molar ratio of 8.79 : 2.59 : 1.34 : 1.0 in the carbohydrate, respectively. In the experiment using spleen cell and macrophage, the extract showed potent mitogenic and immuno-stimulating activities and among various components, an important factor that contribute to the immunological activities was turned out to be carbohydrate moiety.

• KSBB Journal
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• v.11 no.5
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• pp.543-549
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• 1996

Recombinant Saccharomyces cerevisiae BZ-pJ containing the gene coding for metallothionein, a metalbinding protein was grown in the medium with high cadmium concentrations to study the characteristics of growth and cadmium uptake. High concentrations of cadmium reduced cell growth and final cell density and increased the lag phase periods of the recombinant yeast. Addition of 10 mg $Cd^{2+}$/L to the growth medium remarkably decreased a lag period and enhanced the specific cadmium uptake to 52.6 mg $Cd^{2+}$/g dry cell. The effect of copper addition was further investigated in the medium of 680 mg Cd2+/L. An increase in copper concentration from 11.0 to 33.3 mg/L enhanced the specific cadmium uptake from 17.0 to 42.0 mg Cd2+/g dry cell.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.2
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• pp.117-124
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• 2010

To examine the effective use of seaweeds, sea tangle (Laminaria japonica) was extracted with water and the resultant extracts were fermented with Saccharomyces cerevisiae. Four strains of S. cerevisiae were cultured in aqueous extracts from sea tangle. S. cerevisiae SC-2, which was isolated from a traditional Korean fermented food (Meju), was selected for further study based on the results of a sensory evaluation. No significant differences in proximate compositions, such as moisture, crude protein, crude fat, and crude ash, of the sea tangle extracts before and after fermentation were observed. The reducing sugar decreased as the fermentation period increased, and the contents of some free amino acids were also affected by S. cerevisiae SC-2 fermentation. However, the content of glutamic acid, which is a major taste compound in sea tangle extract, was not affected by fermentation for up to 36 hr by the SC-2 strain. To determine the antioxidant activity of fermented sea tangle extract (fermented for 36 hr by SC-2 strain), the radical scavenging activities of 1,1-diphenyl-2-picrylhydrazyl (DPPH), superoxide, and nitric oxide were investigated and xanthin oxidase inhibition assay was performed. The antioxidant activity increased by 8 to 35%. The greatest enhancement of antioxidant activity was seen in the superoxide radical scavenging assay with $100\;{\mu}g/mL$ of raw and fermented sea tangle extract. The anti-inflammatory activity of fermented sea tangle extract was also enhanced. The fermented sea tangle extract showed 34.2% inhibitory activity against nitric oxide synthesis versus 11.9% for raw sea tangle extract at $100\;{\mu}g/mL$ concentration. These results suggest that fermented aqueous extracts from sea tangle are a useful resources.

• Korean Journal of Poultry Science
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• v.28 no.1
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• pp.15-25
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• 2001

This experiment was conducted to investigate the effect of feeding two strains of Lactobacillus and virginiamycin on performance, nutrients digestibility and intestinal microflora of broiler chicks(Abor acres$\times$Abor Acres) were randomly allocated into six treatments with four replications for five weeks. Control(no supplement), 0.05% virginiamycin(VM), Lactobacillus crispatus avibro1(LC), Lactobacillus reuteri avibro2(LR), LC+0.05% VM(LC+VM), LR+0.05% VM(LR+VM) were supplemented into basal diets, which contained ME 3,100kcal/kg and CP 22.0, 20.0% for starting and finishing period, respectively. Weight gain, feed intake and feed conversion(FC) were weekly measured. Nutrients digestibility, intestinal microflora and fecal noxious gas were examined at the end of experiment. Weight gains of chicks fed Lactobacillus or VM was significantly higher than control(P〈0.05). Feed intake increased significantly in those supplemental groups(P〈0.05). FC of chicks fed Lactobacillus or VM significantly lower than control(P〈0.05). Degestibility of crude protein, calcium, and phosphorus improved significantly in alone or combined Lactobacillus treatments(P〈0.05). Whereas DM, crude fat and ash digestibility were not statistically different. Feeding Lactobacilli tended to increase the total Lactobacillus spp. in ileum at one and three weeks of age(WOA) and showed significantly higher in cecum than control at 5 WOA. Total yeast were not shown difference at 1 and 3 WOA, but significantly increased at 5 WOA(P〈0.05). The ileal and cecal anaerobes were started to increase from the first WOA. Fecal NH$_3$gas tended to decrease in Lactobacillus treatments compared to that of other treatments.

• Journal of The Korean Society of Grassland and Forage Science
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• v.34 no.3
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• pp.163-168
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• 2014

This study was conducted to investigate the effects of bacterial inoculation (Lactobacillus plantarum) and cutting height on the chemical composition, fermentation characteristics and in vitro dry matter digestibility (IVDMD) in whole crop barley silage. Barley forage (Youngyang hybrid) was harvested at about 27% of dry matter (DM) level at two different cutting height (5 vs. 15 cm). And it was chopped to 5 cm length and treated with or without L. plantarum. Four replicates of each treatment were ensiled into 10 L mini silo (3 kg) for 100 days. After 100 days, bacterial inoculation decreased (p=0.001) DM content, while increased cutting height increased (p=0.002) DM in uninoculated silage. Crude protein (CP) concentration was decreased by increasing height in uninoculated silage (8.84 vs. 8.16) but increased in inoculated silage (8.19 vs. 8.99). Both neutral detergent fiber (NDF) (p<0.011) and acid detergent fiber (ADF) (p<0.004) were decreased by increasing cutting height of forage at harvest. The IVDMD and ammonia-N was increased (p=0.001) by increasing cutting height and inoculation, respectively. Lactic acid bacteria (LAB) was increased (p=0.002) in inoculated silage, but yeast count was decreased (p=0.026) in uninoculated silages. It is concluded that increased cutting height of forage at harvest could be useful to make a fibrous portion with increase of dry matter digestibility of silages.