• KSBB Journal
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• v.15 no.1
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• pp.100-105
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• 2000

Optimal medium composition, culture conditions, characteristics of phase variation and activity of insecticidal toxin by Xenorhabdus nematophilus isolated and identified from Korean entomopathogenic nematode Steinernema carpocapsae were examined. Optimal medium composition of this strain was 50-70 g/L yeast extract, 3 g/L $K_{2}HPO_{4}$, 1g/L $NH_{4}H_{2}PO_{4}$, 2g/L ${MgSO}_4$$\cdot$${7H}_{2}O$, 10g/L NaCl and, these, yeast extract was found as a limiting nutrient for cell growth. When Monod equation was applied, maxmum specific growth rate and Monod constant were estimated as 0.13 $hr^{-1}$ and 20g/L, respectively. The pH of culture medium increased up to 8.5-9.5 regardless of initial pH 6-7 as the cells continued to grow. The specific growth rate in a 7 L fermentor was 0.18 $hr^{-1}$, which was enhancement 1.4 fold compared to a flask culture. In case of phase variation, phase I fraction was maintained above 90% at the stationary phase for both flask and fermentor cultures. According to oral toxicity test of Gallena mellonella by Xenorhabdus nematophilus, the addition of cell pellets into feed inhibited normal growth of insect larvae and killed completely then after 20 days cultivation. When culture supernatant of this strain was injected into hemolymph of insect larva, the toxicity was strongest at 24hr cultivation in the early exponential phase and gradually decreased as the culture time proceeded.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.390-393
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• 2001

The optimal temperature, pH and aeration rate for spore production by Bacillus polyfermenticus SCD in 500 ml shake flask and 5-1 jar fermenter were found to be $32^{\circ}C$, 7.0 and 1.0 vvm. respectively. When batch culture processes was performed under optimized culture conditions. viable cells were $3.3{\times}10^{10}$ CFU/ml and spore cells were $3.3{\times}10^{10}$ CFU/ml. Fed-batch culture processes were also examined with regard to higer maximum viable cell and spore production. The highe viable cells and spores were obtained in 5-1 jar fermenter at 72 h cultivation time by strategy in an intermediate feeding mode with 60% glucose solution 150 ml and 5% soybean flour solution 150 ml fed to the fermenter twice, and the productivity of spore cells was significantly increased. Finally. volumetric productivity of spore cells on fed-batch culture indicated $9.9{\times}10^8$ CFU/ml/h, which was approximately 2 times higher than batch culture. Thus, fed-batch culture show a promise as an industrial production method.

• The Korean Journal of Mycology
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• v.45 no.4
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• pp.319-327
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• 2017

In this study, we investigated the culture conditions of four ectomycorrhizal fungi, namely, Amanita spissacea NIFoS 2719, Pisolithus arhizus NIFoS 2784, Suillus spraguei NIFoS 2848, and Xanthoconium affine NIFoS 2716, in solid and liquid culture media. In addition, we attempted to induce in vitro mycorrhization of the fungi with Pinus densiflora. Prior to liquid culture, we determined the optimal culture conditions for each species in solid media. The results revealed that all species examined are capable of growth in potato dextrose agar (PDA), malt extract agar (MEA), and modified Melin-Norkran's medium (MMN), although their preferred growth media were different. Liquid culture experiments showed that inorganic nitrogen did not enhance the mycelial growth of all four species. Therefore, we used MMN-based liquid inocula to promote the growth of ectomycorrhizal fungi in our symbiosis culture system. Mycorrhization was observed in Xanthoconium affine NIFoS 2716. Morphological analysis revealed that fungi-inoculated roots of P. densiflora form simple and dichotomous lateral roots with dense mycelia. In addition, inoculation with X. affine NIFoS 2716 promoted root and shoot developments.

• Journal of Korean Society of Water and Wastewater
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• v.12 no.4
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• pp.78-85
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• 1998

Strains degrading and decolorizing reactive dyes, Procion blue HEGN and Procion red HE7B were isolated from water system, are named as RBK1 and RRK, the growth characteristics of which were investigated. Decolorization efficiencies after 42 hrs in batch culture were 95% and 77%, respectively. and the optimal culture condition of temperature and pH were $30^{\circ}C$, 7.0. Decolorization efficiencies in condition of aerobic shaking culture by strains RBK1 and RRK conspicuously increased, and culture by strain RBK1 was found as 95% after 42 hrs, while standing culture was 64%, Optimum nitrogen source was peptone, and It was found that decolorization efficiencies by strains RBK1 and RRK increased up to 4,000mg/l of peptone concentration as nitrogen source, but peptone concentration did' nt influence the decolorization efficiency in above 4,000mg/l. When the concentration of dyes were more than 800 mg/l and 400 mg/l respectively, the strains RBK1 and RRK, which degrade Procion bule HEGN and Procion red HE7B, showed a sharply decreased decolorization efficiencies; then the specific growth rate were $0.25hr^{-1}$ and $0.09hr^{-1}$.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.1
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• pp.17-22
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• 2004

A bacterial strain WJ-98 found to produce active extracellular keratinase was isolated from the soil of a poultry factory. It was identified as Paracoccus sp. based on its 16S rRNA sequence analysis, morphological and physiological characteristics. The optimal culture conditions for the production of keratinase by Paracoccus sp. WJ-98 were investigated. The optimal medium composition for keratinase production was determined to be 1.0% keratin, 0.05% urea and NaCl, 0.03% K$_2$HPO$_4$, 0.04% KH$_2$PO$_4$, and 0.01% MgCl$_2$$.$6H$_2$O. Optimal initial pH and temperature for the production of keratinase were 7.5 and 37$^{\circ}C$, respectively. The maximum keratinase production of 90 U/mL was reached after 84 h of cultivation under the optimal culturing conditions. The keratinase from Paracoccus sp. WJ-98 was partially purified from a culture broth by using ammonium sulfate precipitation, ion-exchange chromatography on DEAE-cellulose, followed by gel filtration chromatography on Sephadex G-75. Optimum pH and temperature for the enzyme reaction were pH 6.8 and 50$^{\circ}C$, respectively and the enzymes were stable in the pH range from 6.0 to 8.0 and below 50$^{\circ}C$. The enzyme activity was significantly inhibited by EDTA, Zn$\^$2+/ and Hg$\^$2+/. Inquiry into the characteristics of keratinase production from these bacteria may yield useful agricultural feed processing applications.

• Korean Journal of Microbiology
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• v.43 no.1
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• pp.59-65
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• 2007

The optimal conditions for Monascus pigments production of Monascus sp. KM 1001, pigment overproducing mutant, in submerged culture was investigated. The optimal medium for the production of pigment from KM 1001 mutant is determined to be composed of 4% rice powder, 0.15% Bacto-peptone, 0.1% glycine, 0.01% $FeSO_{4}{\cdot}7H_{2}O,\;0.1%\;MgSO_{4}{\cdot}7H_{2}O,\;0.25%\;KH_{2}PO_{4},\;pH4.5$. On optimal conditions,10.0 g/L of the cell mass was obtained at $30^{\circ}C$ for 5 days. Yellow, orange and red pigment of Monascus sp. KM 1001 were produced 3.25 units, 1.59 units and 0.88 units in extracellular part, and 84.96 units, 78.84 units and 91.80 units in intracellular part, respectively.

• Journal of Embryo Transfer
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• v.25 no.4
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• pp.259-262
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• 2010

Optimization of the preimplantation mammalian embryo culture condition was widely focused on refining medium composition under the name of chemically defined media. However, recent research revealed that the alteration of physical environment can be a crucial factor to a successful embryo development. In this study, under the same embryo density, a novel culture device named oil-free micro tube culture (MTC) system was evaluated using porcine parthenogenetic embryos. The activated oocytes were placed into the 0.2 ml thin-wall flat cap PCR tube and cultured to the blastocyst stage. As a preliminary step, embryo density and culture medium volume were optimized under a standard drop culture system. The optimal embryo density range for in vitro culture was 0.5 embryos per ${\mu}l$ in $20\;{\mu}l$ drop (20.5%) and 1.0 embryos per ${\mu}l$ in $10\;{\mu}l$ drop (20.6%). Based on these results, we compared drop culture system and 'MTC' system in terms of the developmental rate to the blastocyst stage. In $20\;{\mu}l$ medium volume, the 'MTC' system showed similar blastocyst formation rate when compared with drop culture system (20.2% versus 20.5%, respectively) while the 'MTC' system showed lower blastocyst formation rate than drop culture system in $10\;{\mu}l$ one (12.7% versus 20.0%, respectively). Therefore the $20\;{\mu}l$ MTC system may be an alternative incubation system for short-distance embryo transport without carrying the $CO_2$ incubator and this provides novel embryo culture device to clinical veterinary embryologists.

• Journal of Microbiology and Biotechnology
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• v.17 no.12
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• pp.1996-2004
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• 2007

In this study, the optimization of culture medium using a Sterigmatomyces elviae mutant was investigated using statistical analysis to increase the cell mass and lactosucrose ($^4G-{\beta}$-D-galactosylsucrose) production. In basal medium, the cell mass and lactosucrose production were 4.12 g/l and 140.91 g/l, respectively. However, because of the low cell mass and lactosucrose production, optimization of culture medium was carried out to increase the cell mass and lactosucrose production. Culture media were optimized by the S. elviae mutant using analysis of variance (ANOVA) and response surface methodology (RSM). Central composite designs using RSM were utilized in this investigation. Quadratic models were obtained for cell mass and lactosucrose production. In the case of cell mass, optimal components of the medium were as follows: sucrose 1.13%, yeast extract 0.99%, bactopeptone 2.96%, and ammonium sulfate 0.40%. The predicted maximum value of cell mass was about 5.20 g/l and its experimental value was 5.08 g/l. In the case of lactosucrose production, optimal components of the medium were as follows: sucrose 0.96%, yeast extract 1.2%, bactopeptone 3.0%, and ammonium sulfate 0.48%. Then, the predicted maximum value of lactosucrose production was about 194.12 g/l and the corresponding experimental value was about 183.78 g/l. Therefore, by culturing using predicted conditions, the real cell mass and lactosucrose production increased to 23.3% and 30.42%, respectively.

• Journal of Life Science
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• v.11 no.1
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• pp.7-10
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• 2001

Nonactin is the parent compound of a group of ionophore antibiotics, that known as the macrotetrolides. In previous report, in th course of screening superoxide radical-generating compounds from microbial sources, we first screened Streptomyces viridochromogenes JM-4151 that produces nonactin. It was proved that nonactin is superoxide radical-producing compound. In present study, we examined the optimal culture conditions of nonacin. Th optimal culture conditions for nonactin production were as follows: 1% soluble starch, 1% yeast extract, 0.2% ammonium nitrate, 0.06% magnesium sulfate, 0.2% calcium carbonate, initial pH 7.0 at 28$^{\circ}C$ for 96 h. The highest nonactin production was achieved in the production medium of initial pH7.0 at 28$^{\circ}C$ for 96h. The threshold level of dissolved oxygen was found to be above 33.2% at 28$^{\circ}C$ when 1% soluble starch was used as a carbon source. These results suggest that S. viridochromogenes JM-4151 might be a possible strain for industrial nonactin producer.

• Biotechnology and Bioprocess Engineering:BBE
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• v.11 no.5
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• pp.408-413
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• 2006

We assessed the ability of a Pseudonocardia sp. from soil samples to bioconvert vitamin $D_3$. The optimal culture conditions for the bioconversion of vitamin $D_3$ to active $1{\alpha}$,25-dihydroxyvitamin $D_3$ were investigated by varying the carbon and nitrogen sources, the metal salt concentrations, the initial pH, and the temperature. Microbial transformations were carried out with the addition of vitamin $D_3$ dissolved in ethanol. They were sampled by extraction with methanol-dichloromethane and the samples were examined by HPLC. Optimum culture conditions were found to be 0.4% yeast extract, 1% glucose, 3% starch, 1% fish meal, 0.2% NaCl, 0.01% $K_2HPO_4$, 0.2% $CaCO_3$, 0.01% NaF, and pH 7.0 at $28^{\circ}C$. The optimal timing of the addition of vitamin $D_3$ for the production of calcitriol by Pseudonocardia autotrophica ID9302 was concurrent with the inoculation of seed culture broth. Maximum calcitriol productivity and the yield of bioconversion reached a value of 10.4mg/L and 10.4% respectively on the 7th day in a 75L fementer jar under the above conditions.