• KSBB Journal
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• v.14 no.5
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• pp.585-592
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• 1999

This study was aimed to enhance the Fe(II) oxidation rate using immobilized cells of Thiobacillus ferroxidans. For this purpose, a medium for the minimization of jarosite formation was developed first. Secondly, cell immobilization in celite beads was carried out. And then, repeated-batch and continuous operatons of Fe(II) oxidation by using immobilization cells were performed. In a series of flask cultures, three types of media were tested: media with a much lower salt concentration than that of the 9K medium; media which contained different nitrogen sources from that of the 9K medium, that is $(NH_4)_2HPO_4$, $NH_4Cl and HNO$_3$; media which contained $(NH_4)_2HPO_4$ as nitrogen and phosphate source, but without $K_2HPO_4$ as nitrogen and phosphate source in the 9K medium. As a result, the M16 medium which contained 3 g/L of $(NH_4)_2HPO_4$ as nitrogen and phosphate source was found to be the optimal one. It sustained good cell growth allowing no jarosite formation. In the repeated-batch operations, the rate of Fe(II) oxidation gradually increased to reach a maximum value as the batch was repeated. As a result of repeated-batch operations. a maximum Fe(II) oxidation rate was 2.33 g/L . h. In the continuous operations, the iron oxidation rate could be increased to 2.14 g/L .h at a dilution rate of 0.25 $h^{-1}$ which is greater than the maximum specific growth rate (0.12 $h^{-1}$) of the bacteria.

• Microbiology and Biotechnology Letters
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• v.23 no.6
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• pp.687-694
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• 1995

Alkalophilic Bacillus sp. HJ-12 producing $\beta $-1, 4-D-arabinogalactanase was isolated from soil in the alkalic condition, pH 10.0. $\beta $-1, 4-D-arabinogalactanase was maximaly produced in the medium consisting of 2% soybean arabinogalactan (SAG), 0.5% yeast extract, 0.5% polypeptone, 0.5% NaCl, 0.1% K$_{2}$HPO$_{4}$, 0.02% MgSO$_{4}$$\cdot $7H$_{2}$O, 0.1% Na$_{2}$CO$_{3}$ under the aerobic condition (pH 8.2). $\beta $-1, 4-D-arabinogalactanase is inducible enzyme so that its activity has been increased 10 fold in the SAG medium than in the glucose medium. Through the ammonium sulfate precipitation, DEAE- Sephadex A-50 ion chromatography, and Sephadex G-75 gel chromatography procedures, this enzyme was purified with a single protein of 11% vield and 110 fold's purity. $\beta $-1, 4-D-arabinogalactanase is endo type enzyme producing ollgosaccharide from SAG.

• YAKHAK HOEJI
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• v.36 no.5
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• pp.455-459
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• 1992

Haemophilus K-12 producing novel sulfotransferase was isolated from mouce intestinal flora. The enzyme catalyzed the transfer of sulfate group from p-nitrophenylsulfate to phenolic compounds. The optimum medium condition for the sulfotransferase production was 0.2% sucrose, 1% yeast extract, $Na_{2}HPO_4$ and 0.5% NaCl. The enzyme production was induced by donor substrate, but was not by accepters. When p-nitrophenylsulfate was used as a donor substrate, 1-naphthol was best substrate, followed by phenol, p-acetaminophenol and tyramine.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.257-257
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• 1994

생쥐의 장내세균으로 부터 황산전이 반응을 촉매하는 효소인 sulfotransferase를 생산하는 균주를 분리하였으며 동정결과 Haemophilus속 균주로 확인되어 Haemophilus K-12라 명명하였다. 균의 성장과 효소활성과의 관계를 보면 균은 10시간에서 완전히 성장하였으며 효소활성도 이와 비례하였다. Haemophilus K-12의 배지조성에 따른 sulfotransferase의 생산성을 Brain Heart Infusion 배지에서의 생산성과 비교해보면 탄소원으로는 sucrose가 0.2%농도에서 584%로 가장 좋았으며 질소원으로는 yeast extract가 266%로 가장 좋았다. 공여체로 PNS를 최종농도 1mM로 하여 배지에 첨가하였을때 212%로 가장 높은 효소증가를 보였다. 2가금속이온에 의한 효소증가는 현저하지 않았으며 $Mn^{2+}$이 107%로 가장 높았고$Zn^{2+}$와 EDTA에 의해서는 저해를 받았다. 이상의 결과를 종합하여 균배양을 위한 이상적인 배지조성을 sucrose 0.2%, yeast extract 1%, $Na_2$HPO$_4$ 0.25%, NaCl 0.5%로 결정하였다. 결정된 최적배지에 균을 10L 배양하여 초음파 처리, 원심분리한 것을 70 % ammonium sulfate fractionation, DEAE-cellulose column chromatography를 2회, Hydroxyapatite column chromatography, chromatdfocusing column chromatography, Silica PAE column chromatography, Sephacryl S-300 superfine column chromatography를 행한결과 specific activity가 6.76 umoie/min/mg protein인 효소액을 얻었으며 homogeneous enzyme였다. 이렇게 해서 얻은 효소를 이용하여 수용체 기질 특이성을 측정한 결과 1-naphthol이 phenol을 100%로 하였을 때 233%로 가장 좋았으며 Eubacterium A-44 sulfotransferase의 좋은 기질이었던 p-acetaminophenol, tyramine, 9-phenanthrol은 좋은 기질이 되지 못했다. 이상의 결과로 미루어 보아Haemophilus K-12 sulfotransferase는 지금까지 보고된 bacterial sulfotrasferase와는 다른 효소로 사려되며 효소반응기전의 규명이 이루어지면 산업적 응용이 가능할것으로 사료된다.

• Microbiology and Biotechnology Letters
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• v.30 no.4
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• pp.367-372
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• 2002

Cytosine deaminase (cytosine aminohydrolase, EC 3.5.4.1) stoichiometrically catalyzes the hydrolytic deamination of cytosine and 5-fluorocytosine to uracil and 5-fluorouracil, respectively. Optimal medium compositions for production of cytosine deaminase from Chromobacterium violaceum YK 391 were 0.75% soluble starch, 1.5% peptone, 0.1% meat extract, 0.1% yeast extract, 0.01% NaCl, 0.01% $MgCl_2{\cdot}7H_2O$ and 0.05% $K_2HPO_4$. The optimal pH of medium and incubation temperature were 7.0 and $30^{\circ}C$, respectively. C. violaceum reached stationary phase after 30 hr, and produced a maximum cytosine deaminase (120 units/ml) after 72 h in batch culture.

• KSBB Journal
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• v.27 no.2
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• pp.97-102
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• 2012

In the present study, the biomass productivity of two green microalgae (Chlorella sp. and Dunaliella salina DCCBC2) were assessed in a 12 L tubular photobioreactor under optimum culture conditions. In the batch culture optimization process, the Chlorella sp. biomass was obtained as 1.2 g/L under atmospheric air as a sole $CO_2$ source and other culture conditions as follows: light intensity, temperature, pH, $NH_4Cl$ and $K_2HPO_4$ were 100 ${\mu}E/m^2/s$, $27^{\circ}C$, 7.0, 20.0 mM and 2.0 mM, respectively. On the other hand, 2.9 g/L of D. salina DCCBC2 biomass production was observed under the following conditions: light intensity, temperature, pH, $KNO_3$ and $K_2HPO_4$were 80 ${\mu}E/m^2/s$, $27^{\circ}C$, 8.0, 3.0 mM and 0.025 mM, respectively. At 1% $CO_2$ supply to the reactor, the Chlorella sp. production was reached 1.53 g/L with 25% increment under the same operating conditions. In addition, the maximum D. salina DCCBC2 biomass was observed as 3.40 g/L at 3% $CO_2$ concentration. Based on the aforementioned optimized conditions, the dilution rate and maximal biomass productivity of Chlorella sp. and D. salina DCCBC2 in the continuous cultivation were 0.4/d and 0.6 g/L/d and 0.6/d and 1.5 g/L/d, respectively.

• The Korean Journal of Mycology
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• v.26 no.4 s.87
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• pp.458-465
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• 1998

The strain DGUM 5051, an antagonistic bacterium against apple-bitter rot causing Glomerella cingulata, was isolated from soil in Kyongju. Based on the morphological and physiological characteristics, the bacterium was identified as Pseudomonas sp. and named as Pseudomonas sp. DGUM 5051. The optimal pH and temperature for cell growth were pH 6.0 and $30^{\circ}C$, whereas those for antifungal activity were pH 7.0 and $24^{\circ}C$, respectively. Among the complex media tested, brucella medium, brain heart infusion medium and Luria-Bertani medium were good for both cell growth and antifungal activity. The high antifungal activity was found in the mineral salts medium, in which sucrose, $KNO_3$ and $K_2HPO_4$ were used as sources of carbon, nitrogen and phosphorus, respectively.

• Microbiology and Biotechnology Letters
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• v.34 no.3
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• pp.250-256
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• 2006

The optimum cultural conditions for production of Monascus natural pigment by Monascus purpureus MK2 were investigated in submerged culture. This strain was showed the maximum production of monascus natural pigment in the optimal medium of 3.0% wheat flour, 0.15% $NaNO_3$, 0.2% $K_{2}HPO_4$ and 0.05% $MgSO_4{\cdot}7H_{2}O$, at pH 7.0. The maximum production of this pigment was achieved at $30^{\circ}C$ for 7 day cultivation under 130 rpm shaking. At optimal condition, Monascus purpureus MK2 produced 29.10, 36.84 and 48.92 units of yellow, orange and red pigment, respectively.

• Microbiology and Biotechnology Letters
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• v.17 no.4
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• pp.358-364
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• 1989

A crystalline alkaline pretense- producing Streptomyce sp. YSA-130 was isolated from soil in alkaline medium(pH 10.5). The optimum culture condition of Streptomyce sp. YSA-130 for the production of alkaline protease was as follows; 2.0% soluble starch, 1.0% soytone, 0.3% $K_2$HPO$_4$, 0.02% MgSO$_4$.7$H_2O$, 0.8% Na$_2$CO$_3$, pH 10.5, 3$0^{\circ}C$, and 12 hr. The alkaline pretense from the culture broth of Streptomyce sp. YSA-130 was purified about 24 folds by ammonium sulfate precipitation , dialysis, DEAE-cellulose ion exchange chromatography, gel filtration on Sephadex G-15 and crystallization. Optimum temperature and pH of purified enzyme were 6$0^{\circ}C$, and 11.5. Temperature and pH stability of purified enzyme were 5$0^{\circ}C$, and 5.5-12.0. Calcium ion was effective to stabilize the enzyme at higher temperature. The molecular weight of the purified enzyme was approximately 30,000. The purified enzyme was inactivated by diisopropyl flurophosphate(DFP) but not affected by metal ion, EDTA, sulfhydryl reagent and stable detergent.

• Microbiology and Biotechnology Letters
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• v.34 no.1
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• pp.7-14
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• 2006

Feather, generated in large quantities as a byproduct of commercial poultry processing, is almost pure keratin, which is not easily degradable by common professes. Four strains, SMMJ-2, FL-3, NO-4 and RM-12 were isolated from soil for production of extracellular keratinolytic protease. They were identified as Bacillus sp. based on their morphological and physiological characteristics. They shown high protease activity on 5.0% skim milk agar medium and produced a substrate like mucoid on keratin agar medium. Bacillus sp. SMMJ-2 had a faster production time for producing keratinolytic protease than other strains. This strain did not completely degrade whole chicken feather for five days in basal medium but completely degraded whole chicken feather when supplied with nitrogen source for 40hours in keratinolytic producing medium ($0.7%\;K_{2}HPO_{4},\;0.2%\;KH_{2}PO_{4},\;0.1%$ fructose, 1.2% whole chicken feather, $0.01%\;Na_{2}CO_3$, pH 7.0). When supplied with chicken feather as nitrogen source, keratinolytic protease activity was 89 units/ml/min. When soybean meal was used as nitrogen source, the keratinolytic protease production reached a maximum of 106 units/ml/min after 48 hours under $30^{\circ}C$, 180 agitation. To isolate the keratinolytic protease, the culture filtrate was precipitated with $(NH_4)_{2}SO_4$ and acetone. The recovery rate of keratinolytic protease was about 96% after treatment with 50% acetone. The enzyme was stable in the range of $30{\sim}50^{\circ}C$ and pH $6.0{\sim}12.0$.