• Proceedings of the Korean Society of Life Science Conference
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• 2002.12a
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• pp.48-60
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• 2002

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a cytokine that stimulates the production of granulocytes, macrophages, and white blood cells. The effects of osmotic pressure on secretion of human GM-CSF into the culture medium were investigated in suspension cultures of transgenic tobacco cells. An increase in osmotic pressure caused by the addition of mannitol decreased the cell size index, with the effect being more pronounced when cells were measured wet rather than dry. Increased osmotic pressure enhanced the secretion of hGM-CSF. At 90 g/L mannitol, the maximum concentration tested, hGM-CSF was present in the culture medium at 980 ug/L. As the concentration of mannitol increased, the total amount of protein secreted also increased, but was disproportionately enriched in GM-CSF NaCl, another osmoticum, had very similar effects on cell growth and hGM-CSF production, but did not cause enrichment for hGM-CSF Additionally, protein-stabilizing polymer was added to culture broth to enhance stability of secreted recombinant protein. Finally, above two method were applied together to maximize the productivity.

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.4
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• pp.367-371
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• 2005

About 3,000 bacterial colonies with esterase activities were isolated from soil samples by enrichment culture and halo-size on Luria broth-tributyrin (LT) plates. The colonies were assayed for esterase activity in microtiter plates using enantiomerically pure (R)- and (S)-2-phenylbutyric acid resorufin ester (2PB-O-res) as substrates. Two enantioselective strains (JH2 and JH13) were selected by the ratio of initial rate of hydrolysis of enantiomerically pure (R)- and (S)-2-PB-O-res. When cell pellets were used, both strains showed high apparent enantioselectivity ($E_{app}>100$) for (R)-2PB-O-res and were identified as Exiguobacterium acetylicum. The JH13 strain showed high esterase activity on p-nitrophenyl acetate (pNPA), but showed low lipase activity on p-nitrophenyl palmitate (pNPP). The esterase was located in the soluble fraction of the cell extract. The crude intracellular enzyme preparation was stable at a pH range from 6.0 to 11.0.

• Korean Journal of Microbiology
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• v.29 no.2
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• pp.136-142
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• 1991

The selection of ethanol-tolerant strains was applied to enrichment culture of YPD broth medium containing various concentrations of ethanol. Isolates were identified to be Saccharomyces cerevisiae, the others as S. dairensis, S. exiguus, S. telluris, Saccharomycodes ludwigii, Schwanniomyces occidentalis var. occidentalis and Zygosaccharomyces florentinus. Among isolates S. cerevisiae YO-1 was screened as having the highest ethanol tolerance and produced 18% (v/v) ethanol after 4 days fermentation. The change of fatty-acyl residues represents that a progressive decrease in fatty-acyl unsaturation and a proportional increase in saturation in phospholipids of yeast cells during fermentation affected the yeast viability. Supplementation ethanol to the cultures led to an increase of unsaturated fatty-acyl residues, especially $C_{16}$ or $C_{18}$ residues, along with a decrease in the proportion of saturated residues in cellular phospholipids. Increasing the amount of soy flour led to an increase in the maximum number of viable yeast cells and ethanol production. It was possible in 4 days to reach 21% (v/v) ethanol by adding 4% soy flour as source of unsaturated fatty-acyl residues to the fermentation medium. Soy flour not only increased yeast population but also enhanced the physiological properties of yeast cells to be ethanol tolerant in the anaerobic culture.

• Journal of Microbiology and Biotechnology
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• v.4 no.3
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• pp.215-221
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• 1994

Two strains of yeast (RA-74-2 and RA-912) showing superior fermenting ability at a high temperature were isolated from soils and wastewaters by an enrichment culture method. Based on the morphological and physiological charateristics, the two strains were identified as Saccharomyces cerevisiae and Kluyveromyces marxianus, respectively. RA-74-2 was able to grow upto $43^{\circ}C$ and sustain similar fermenting ability in the temperatures range from 30 to $40^{\circ}C$. In addition, the sugar- and ethanol-tolerance of RA-74-2 were 30% (w/v) glucose and 10% (v/v) ethanol, which appeared to be higher than those of nine other industrial yeast strains currently being used in the alcohol factories. The thermotolerant ethanol fermenting yeast RA-912 showed identical growth in the temperatures range from 35 to $45^{\circ}C$ and was resistant to various heavy metals. The quality and quantity of byproducts of the isolated yeast strains in fermentation broth after fermentation at $40^{\circ}C$ and $45^{\circ}C$ were similiar with those obtained at $30^{\circ}C$. These results show that RA-74-2 can be adopted for the ethanol fermentation process where the expenses for cooling system is significant, and suggest that RA-912 may be applied in either SSF(simultaneous saccharification and fermentation) or Flash-fermentation process and RA-912 may be used as a gene donor for the development of thermotolerant ethanol-fermenting yeasts.

• Journal of Microbiology and Biotechnology
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• v.8 no.1
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• pp.61-66
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• 1998

A microorganism which degrades phenol and co-metabolizes trichloroethylene (TCE) was isolated from Yangsan stream after enrichment in a medium containing phenol as the sole carbon source. The isolate EL-43P was identified as the genus Rhodococcus by its morphological, cultural and physiological characteristics. Phenol-induced cells of Rhodococcus sp. EL-43P degraded TCE. Toluene and nutrient broth could not replace the phenol requirement. The optimal conditions of initial pH and temperature of media for growth were 7.0~9.0 and $30~50^{\circ}C$, respectively. Rhodococcus sp. EL-43P could grow with phenol up to 1,000 ppm. Growth was inhibited by phenol at a concentration above 1,500 ppm. It was observed that Rhodococcus sp. EL-43P was able to degrade 90% of phenol (1,000 ppm) after 40 h in a culture. Phenol-induced cells of Rhodococcus sp. EL-43P degraded 95% of $5{\mu}M$ TCE in 6 h. Rhodococcus sp. EL-43P hardly degraded TCE above $100{\mu}M$.

• Korean Journal of Environmental Agriculture
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• v.30 no.2
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• pp.202-208
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• 2011

BACKGROUD: ${\alpha}$- and ${\beta}$- Endosulfan isomers of endosulfan, an endocrine disrupting chemical, are widely used cyclodiene organochlorine pesticide in worldwide, and it has widespread application in agriculture and can contaminate river-system as runoff from soil or aerial deposition METHOD AND RESULTS: In this study, an attempt was made to isolate an endosulfan degrading fungus from endosulfan-polluted agricultural soil. Through repetitive enrichment and successive subculture in media containing endosulfan and its metabolites as the sole carbon source, a fungus designated KEF-1 was isolated. Based on phylogenetic analysis, strain KEF-1 was assigned to the genus Eutypella. Also, the ITS (internal transcribed spacer) sequences of KEF-1 were submitted to GenBank under accession number EF581006. In potato dextrose broth containing 8 ${\mu}g$/mL endosulfan, strain KEF-1 completely degraded the endosulfanin 12 days. CONCLUSION: These results suggested that Eutypella sp. KEF-1 has potential as a biocatalyst for endosulfan bioremediation

• Journal of Microbiology and Biotechnology
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• v.33 no.2
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• pp.228-234
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• 2023

In this study, the performance of a gold biosensor combined with light microscope imaging system (GB-LMIS) was comparatively evaluated against enzyme-linked immunosorbent assay (ELISA) for detecting Salmonella under simulated chilling condition. The optimum concentration of antiSalmonella polyclonal antibodies (pAbs) was determined to be 12.5 and 100 ㎍/ml for ELISA and GBLMIS, respectively. GB-LMIS exhibited a sufficient and competitive specificity toward three tested Salmonella among only. To mimic a real-world situation, chicken was inoculated with Salmonella cocktail and stored under chilling condition for 48 h. The overall growth of Salmonella under chilling condition was significantly lower than that under non-exposure to the chilling condition (p < 0.05). No significant differences in bacterial growth were observed between brain heart infusion and brilliant green broth during the enrichment period (p > 0.05). Finally, both GB-LMIS and ELISA were employed to detect Salmonella at every 2-h interval. GB-LMIS detected Salmonella with a competitive specificity by the direct observation of bacteria on the sensor using a charge-coupled device camera within a detection time of ~2.5 h. GB-LMIS is a feasible, novel, and rapid method for detecting Salmonella in poultry facilities.

• The Plant Pathology Journal
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• v.40 no.3
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• pp.282-289
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• 2024

Fire blight is a bacterial disease caused by Erwinia amylovora. In Korea, fire blight was first reported in 2015 in an orchard. If the infection is confirmed, all trees in the orchard must be removed and the orchard must remain closed for 3 years. Since 2020, if the number of trees infected with fire blight is less than 5% of the total trees in the orchard, only the infected tree and adjacent trees are removed in Korea. Three years after removal, the trees can be replanted after confirming that the orchard soil is free from E. amylovora. In this study, a protocol was established for detecting E. amylovora in soil via selective enrichment, using tryptic soy broth with 0.05% bile salts and 50 ㎍/ml cycloheximide, and real-time polymerase chain reaction. This protocol resulted in a 1,000-times improved detection limit for E. amylovora in soil samples compared to that in unenriched samples. Soil monitoring was performed for orchards where fire blight-infected trees had been removed 3-27 months prior; the selected orchards were monitored every 3 months. Monitoring confirmed that E. amylovora was not present in the soil at any site in any of the orchards. A new detection protocol facilitates the monitoring of E. amylovora in soil and could help permit the replanting of trees in orchards. Also monitoring results provide evidence that trees can be planted earlier.

• Korean Journal of Veterinary Service
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• v.22 no.3
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• pp.221-237
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• 1999

To investigate the specificity of rapid slide agglutination test for pullorum-gallinarum diseases and to obtain a basic data for avian salmonellosis control, salmonella isolation was peformed for the layer chickens positively reacted in pullonlm-typhoid agglutination test. The biochemical, serological and antimicrobial properties of the isolates were examined. The results obtained through this study were summarized as follows; 1. Of 2,384 chickens tested by the agglutination test, 606 chickens (25.4%) were positive reactors. 154 of 606 reactors and 49 of the non-reacting chickens were investigated for salmonella isolation, resulting in isolation of 68 strains of salmonellae from 27 chickens. 2. By organs, the isolation frequency from liver, cecum, spleen, ovary and gall bladder showed 8.9% (18 strains), 8.9% (18 strains), 7.4% (15 strains), 4.4% (9 strains) and 3.9% (8 strains), respectively. 3. By culture medium the combination of selenite broth and MacConkey agar revealed the highest isolation rate and the enrichment culture by delayed secondary enrichment culture method was found the most effective for salmonella isolation. 4. The serotypes of 68 salmonella isolates were identified as 3 strains of S pullorum, 24 strains of S gallinarum, 15 strains of S typhimurium, 8 strains of S enteritidis, 7 strains of S paratyphi A, 5 strains of S typhimurium and 6 strains of the other salmonellae. 5. The serotypes of 8 salmonella strains isolated from 49 chickens non-reacting in pullorum-typhoid agglutination test were identified as 3 strains of S typhimurium and 5 strains of S infantis. 6. When 24 chickens of which 68 strains of salmonellae isolated were examined by microplate agglutination test, the average antibody titer for pullorum antigen was $2^{5.25}$. The chickens at antibody titer between $2^3$ and $2^5$ showed the higher frequency of isolation as compared with the chickens at the other titers. 7. When salmonella isolates were tested the antimicrobial drug sensitivity by disk diffusion method, S paratyphi A were highly sensitive by 100% to ATM and GM, S typhimurium, by 88% to AM, CIP, IMP and TN, S infantis, by 100% to AM, CRO, ENR and PIP, S enteritidis,by 100% to IMP and PIP, S pullorum, by 100% to ATM, CRO, ENR and PIP and S gallinarum, by 92% to CRO, CIP and PIP.

• Food Science of Animal Resources
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• v.36 no.6
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• pp.779-786
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• 2016

This study aimed to evaluate the prevalence of Listeria monocytogenes on livestock farms in Korea and determine their serotypes and genetic correlations. Twenty-five livestock farms in Korea (central: 15, south west: 7, south east: 3) were visited 2-3 times, and 2,018 samples (feces: 677, soil: 680, silage: 647, sludge: 14) were collected. Samples were enriched in LEB (Listeria enrichment broth) and Fraser broth media, and then plated on Palcam agar. The isolates were identified by PCR and 16S rRNA gene sequencing. Then, the sero-types, presence of virulence genes (actA, inlA, inlB, plcB, and hlyA), and antibiotic resistance were determined. Genetic correlations among the isolates were evaluated by analyzing the restriction digest pattern with AscI. Of the 2,018 samples, only 3 (0.15%) soil samples (FI-1-FI-3) from 1 farm in the south east region were positive for L. monocytogenes. Based on biochemical tests and multiplex PCR, the serotype of the isolates were 4ab (FI-1 and FI-3) and 3a (FI-2), which are not common in foodborne L. monocytogenes. The 3a sero-type isolate was positive for all tested virulence genes, whereas the 4ab serotype isolates were only positive for hlyA, actA, and inlA. The isolates were resistant to all 12 tested antibiotics, especially FI-3. The genetic correlations among the isolates were 100% for those of the same serotype and 26.3% for those of different serotypes. These results indicate that the prevalence of L. monocytogenes on livestock farms in Korea is low; however, the isolates are pathogenic and antibiotic resistant.