• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.33 no.7
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• pp.21-25
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• 2004

생물재료인 식품의 성분 중에서 물은 식품의 주요기능인 영양기능(1차기능), 기호기능(2차기능), 생체 조절기능(3차기능)의 관점에서 무시되는 경우가 많으나 식품의 수송, 보존, 가공 공정에서 직접적으로 제어해야 하는 대상이므로 가장 먼저 고려해야 할 존재이다. 일반적으로 식품의 보존 공정에서 수분활성은 여러 가지의 화학반응, 효소반응, 미생물의 생육속도 등에 영향을 미치게 된다. 특히, 미생물 생육을 위해서는 높은 수분 활성을 필요로 하므로, 수분활성을 제어함으로써 미생물의 제어가 가능하다. 따라서 저온의 이용도 기본적으로는 미생물 및 수분의 활성제어를 위한 공정이라고 말할 수 있다. 최근에는 수분의 활성을 억제하기 위하여 어류의 냉각공정에 사용되는 빙수를 해수나 수도수가 아닌 해양 심층수를 이용함으로써 미생물의 활성을 제어하는 연구가 진행 중이다. (중략)

• Microbiology and Biotechnology Letters
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• v.6 no.1
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• pp.9-16
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• 1978

Effects of the addition of Ginseng extract and it's incubation time on enzyme activity (${\alpha}$-amylase, ${\beta}$-amylase, protease) of Aspergillus app. was investigated. 1. ${\alpha}$-Amylase activity of Asp. oryzae was higher for 48 hours than control, however, the same after 48 hours. ${\beta}$-Amylase activity was stimulated at the concentration of 0.1 to 1.0％, and decreased at the concentration of 3.0 to 5.0％. The acid protease activity was higher than control for 72 hours and in the medium of 120 hours was decreased significantly. The alkaline protease activity was lower than control. However, alkaline protease activity was higher than acid protease activity. 2. ${\alpha}$-Amylase of Asp. niger was increased in proportion to increasing of the extract concentration. ${\beta}$-Amylase was increased at the concentration from 0.5 to 3.0％ and it's activity was depressed in proportion to increasing of the extract concentration for 48 hours and on the contrary it was improved in proportion to increasing of the extract concentration for 72 hours except for 5.0％ concentration with marked decreasing. Alkaline protease activity was increased at lower concentration (0.1∼0.5％) for 24 to 48 hours and it was depressed at higher concentration (1.0 to 5.0), however after 48 hours incubated, it's activity was decreased in preparation to increasing of the extract concentration.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1986.12a
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• pp.517.3-518
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• 1986

국내 염장식품 및 염전으로부터 세균을 분리하여, 호염성 세균의 NaCl 농도에 따른 성장범위, 생리적 및 효소학적 특성을 조사하고자 했다. 염전으로부터 NaCl 20%배지에서 14주와 총 16종류의 젓갈류에서 NaCl 10% 배지로 56균주의 호염성 세균을 분리하여 0, 5, 10, 15, 20, 25% NaCl농도에서 성장률을 조사하고 최적온도 및 배지조성과 함께 동정에 필요한 생리실험을 하였다. 또한 세포의 효소로서 Lactate dehydrogenase, Glucokinase, Glucose-6-phosphate dehydrogenase, Alanine dehydrogenase, Isocitrate dehydrogenase 등의 특성도 조사하였다. 선별한 균주중 Acinetobacter sp, 등이 관찰 조사되었으며 최적 성장 NaCl농도는 10%이고, 최적온도는 3$0^{\circ}C$이며, 25% NaCl, 45$^{\circ}C$에서 자란 Halobacterium sp. 등이 분리되었다. 그중 Acinetobacter strain H6는 단백분해효소와 탄수화물 분해효소의 생성능이 15>10>20% NaCl순이며, 특히 Lactate dehydrogenase 활성은 2>3>1>OM NaCl 순으로 나타났고, NaCl 대신 KCl을 사용했을 때는 3>2>1> OM순으로 활성이 나타났다.

• Korean Journal of Microbiology
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• v.32 no.4
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• pp.297-300
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• 1994

About thirty bacterial strains of actinomycete isolated from the soil were examined for the presence of restriction endonuclease activity. Streptomyces diastatochromogenes, which was identified previously, was found to contain restriction endonuclease activity. The purification of this enzyme, SdiI, was carried out via streptomycin sulfate precipitation and ammonium sulfate fractionation followed by hydroxylapatite column chromatography. Sephacryl S-200 HR column chromatography and second hydroxylapatite column chromatography. SDS-polyacrylamide gel electrophoresis of the active protein (purified from various column chromatography) resulted in 35,000 Da protein.

• Korean Journal of Microbiology
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• v.26 no.3
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• pp.215-222
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• 1988

The effect of ammonia and glutamine on nitrogenase activity of Rhodopseudomonas sphaeroides was examined. The nitrogenase activity of this strain was inhibited by ammonia and glutamine. When ammonia and glutamine were exhausted, nitrogenase activity promptly resumed at its original rate. Methionine sulfoximine (MSX), irreversible glutamine synthetase (GS) inhibitor, is a structural analogue of glutamate. MSX was used in order to know whether the nitrogenase activity was inhibited by ammonia and glutamine directly or not. The ability of MSX to prevent nitrogenase switch-off by ammonia was found to be dependent upon the phase of culture. When the cells were sampled after 12 hour culture, $500{\mu}M$ MSX would not prevent the nitrogenase switch-off by ammonia. Twenty one percents of GS actibity was inhibited by $500{\mu}M$ of MSX and concentration of released ammonia decreased. But nitrogenase activiy was still inhibited by ammonia. However, nitrogenase switch-off after 20 hours would be prevented by $100{\mu}M$ of MSX. On the other hand, GS activity was ingibited completely by $100{\mu}M$ MSX and concentration of released ammonia somewhat increased. But nitrogenase activity was not inhibited. The data indicated that the inhibition of in vivo nitrogenase actibity of Rp. sphaeroides by ammonia seemed to be mediated by products of ammonia assimilation rather than by ammonia itself.

• Microbiology and Biotechnology Letters
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• v.16 no.3
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• pp.193-198
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• 1988

Catalase from Aspergillus niger KUF-04 was purified by five steps including gel filtration. The overall purification gave 64-fold purified preparation, a yield of about nine percent. The enzyme showed its maximum absorption at 406 nm. The optimum pH and temperature for the enzyme activity were around pH 7.0 and 6$0^{\circ}C$, respectively. The catalase was found to be stable in the range of pH 4.0 to pH 8.3 and temperature 2$0^{\circ}C$ to 6$0^{\circ}C$. However, it lost nearly all of the activity by heating at 8$0^{\circ}C$ for 20 min. The activity was markedly inhibited by hydroxylamine, potassium cyanide and sodium azide.

• Microbiology and Biotechnology Letters
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• v.26 no.1
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• pp.15-22
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• 1998

The dnrF gene, responsible for conversion of aklavinone to $\varepsilon$-rhodomycinone via C-11 hydroxylation, was mapped in the daunorubicin gene cluster of Streptomyces peucetius subsp. caesius ATCC 27952, close to drrAB, one of the anthracycline resistance genes. To characterize the enzymatic properties of the aklavinone 11-hydroxylase, the dnrF gene was overexpressed in Escherchia coli. The pET-22(+) plasmid which has the T7 promoter under the control of lacUV5 gene was used for the overexpression of the dnrF gene, and the recombinant plasmid pET213 that contains the dnrF gene linked to the T7 promoter of pET-22b(+) was introduced into the E. coli BL2l. When the expression of the dnrF gene was induced by IPTG at the final concentration of 1 mM, the induced protein could be detected in SDS-PAGE only in insoluble precipitate. The insoluble protein was electroeluted from the gel and used for the preparation of antiserum in mice. Various culture conditions were tested to maximize the expression of the aklavinone 11-hydroxylase in soluble form. The enzymatic activity was checked by the bioconversion experiment, and the protein was confirmed by the SDS-PAGE and the Western blot analysis. From the analysis of the data, it was concluded that the culture induced with IPTG at the final concentration of 0.02 mM at 37$^{\circ}C$ yielded the best productivity of active form of enzyme.

• Microbiology and Biotechnology Letters
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• v.30 no.1
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• pp.26-32
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• 2002

For commercial production of Korean fermented anchovy sauce through rapid fermentation, a bacterial strain which showed the high protease activity was isolated from a commercially fermented anchovy sauce. The isolate was Bacillus amyloliquefaciens, and named as B. amyloliquefaciens HTP-8. The incubation temperature, initial pH, and cultivation time for optimal production of protease by B. amyloliquefaciens HTP-8 were $30^{\circ}C$, 7.0, and 3 days, respectively. In jar fermenter, B. amyloliquefaciens HTP-8 showed higher protease activity when grown at pH 7.0. The protease was partially purified by 80% ammonium sulfate precipitation and CM-Sephadex C-50 ion exchange chromatography. The partially purified enzyme had specific activity of 103.3 units/mg, yield of 0.4%, and purification fold of 43.0. The optimal pH and temperature for the protease activity were 10.0 and $50^{\circ}C$, respectively. The protease was relatively stable at the pH range of 7.0~12.0 and at the temperatures below 4$0^{\circ}C$. The activity of the enzyme was inhibited by $Ag^{＋}$ /, $Ba^{2＋}$ and selectively inhibited by PMSF, suggesting that it is a serine protease.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2005.05a
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• pp.375-379
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• 2005

본 연구는 ${\beta}-galactosidase$와 phytase활성이 높은 균주의 선발을 목적으로 수각 미생물들을 Kefir와 자연환경에서 분리하여 효소활성을 측정하였다. 배양한 유산균과 효모 균체액을 French pressure cell press로 세포를 파쇄하였을 때, 각 미생물의 단백질농도는 효모보다 유산균이 높은 것으로 나타났다. ${\beta}-galcactosidase$의 비활성은 Kluyveromyces maxiranus와 Candida utilis를 제외하고는 대부분 $0.80{\sim}0.89\;umol/min/mg$ 사이였다. 체적활성의 경우는 Lactobacillus paracasei 및 Lactobacillus rahmnosus, Enterococcus faecium이 각각 15.9 및 14.5, 14.5 umol/ml를 기록하여 ${\beta}-galcactosidase$의 추출재료로 우수하였다. phytase의 비활성은 Lactobacillus paracasei 와 Enterococcus faecium이 0.032와 0.038 umol/min/mg로 가장 높았다. 체적활성의 경우는 Lactobacillus paracasei가 35.12 umol/ml로 가장 높았다. 결론적으로 ${\beta}-galactosidase$와 phytase의 생산측면에서 이용한 미생물중에서는 Lactobacillus paracasei가 가장 우수한 것으로 사료되었다.

• Journal of Life Science
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• v.15 no.1 s.68
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• pp.136-140
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• 2005

Microbial cell-based UV spectrometric assay for the quantitative measurement of epoxide hydrolase activity was evaluated and optimized for the efficient screening of whole cell activity of novel epoxide hydrolase. Epoxide hydrolase activity was determined by measuring the increase of the oxidized product, benzaldehyde. The effects of the concentrations of phenyl-1,2-ethanediol, sodium metaperiodate and cells were optimized for epoxide hydrolase-catalyzed hydrolysis of styrene oxide. The relevant kinetic parameters of Km and $V_{max}$ for the hydrolysis of (R)-styrene oxide by Rhodotorula glutinis were determined from Lineweaver-Burk plot as 41.2 nmol/min$\cdot$mg dcw and 7.5 mM respectively, and coincided well with those from GC analysis.