• Applied Biological Chemistry
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• v.50 no.1
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• pp.82-85
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• 2007

내염성 조건에서 phytase를 생성하는 효모 균주를 개발하기 위하여 phytase를 생산하는 효모인 S. cerevisiae CY 균주와 내염성 효모인 Z. rouxii Y-80 균주 사이의 전기적 세포융합을 실시하였다. S. cerevisiae CY 균주의 Z. rouxii Y-80 균주의 배양된 세포를 1.0%의 ${\beta}$-mercaptoethanol로 전처리하고 Tunicase로 세포벽을 분해시킨 후 원형질체를 얻었다. 각 균주의 원형질체는 electrofusion 완충액에 1:1의 비율로 현탁한 후 AC 13V에서 30초간 처리하고 고전압(DC 500 V/100 ${\mu}sec$)을 가하여 전기적 세포융합을 실시하였다. 선별된 융합균주는 NaCl이 10% 첨가된 배지에서 친주들과 비교한 결과 Z. rouxii Y-80 균주보다는 생육면에서 25% 이상 증가하였으며, phytase 활성도는 친주인 S. cerevisiae CY 균주 대비 53%의 생성도를 확인하였다.

• The Microorganisms and Industry
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• v.16 no.3
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• pp.15-19
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• 1990

본 연구에서는 lignin 분해시 lignin peroxidase와 glucose oxidase의 역할을 규명하기 위하여 백색부후균의 일종인 Pleurotus ostreatus를 실험 재료로 하여 glucose oxidase와 세포의 peroxidase를 분리하여 그 특성을 규명하여 이미 분리된 타 균주의 효소와 비교 분석하고, .betha.-O-4 linkage를 지닌 이합체 모델화합물에 작용시켜 그 산물을 분석함으로서 간접적이나마 두 효소의 역할및 분해기작을 추정하여 보았다.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1993.04a
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• pp.57-57
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• 1993

단백질 분해효소는 염증주변에 축적된 파괴조직이나 변성단백질등을 분해하여 염증, 특히 만성염증의 순환을 정상화함으로써 소염제로서 사용되어 왔으며 현재, Chymotrypsin, Trypsin, Promelain, Papain, Serrathiopeptidase, Pronase 등이 소염효소제로써 사용되고 있다. 이들은 주로 미생물 배양액에서 통상적인 방법으로 정제하여 사용하며, 유전자 재조합기술을 사용하여 재조합 균주에서 생산할 경우 그 생산성을 증대시킬수 있을 것이라 기대된다.

• Korean Journal of Microbiology
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• v.54 no.4
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• pp.343-353
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• 2018

Our previous research demonstrated the essential role of the xenB gene in stress response to RDX by using Pseudomonas sp. HK-6 xenB knockout. We have extended this work to examine the cellular responses and altered proteomic profiles of the HK-6 xenA knockout mutant under RDX stress. The xenA mutant degraded RDX about 2-fold more slowly and its growth and survival rates were several-fold lower than the wild-type HK-6 strain. SEM revealed more severe morphological damages on the surface of the xenA mutant cells under RDX stress. The wild-type cells expressed proportionally-increased two stress shock proteins, DnaK and GroEL from the initial incubation time point or the relatively low RDX concentrations, but slightly less expressed at prolonged incubation period or higher RDX. However the xenA mutant did not produced DnaK and GroEL as RDX concentrations were gradually increased. The wild-type cells well maintained transcription levels of dnaA and groEL under increased RDX stress while those in the xenA mutant were decreased and eventually disappeared. The altered proteome profiles of xenA mutant cells under RDX stress also observed so that the 27 down-regulated plus the 3 up-regulated expression proteins were detected in 2-DE PAGE. These all results indicated that the intact xenA gene is necessary for maintaining cell integrity under the xenobiotic stress as well as performing an efficient RDX degradation process.

• The Korean Journal of Pesticide Science
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• v.10 no.2
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• pp.138-148
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• 2006

Two bacteria were isolated from the continuously pesticide-used soil under plastic film house and upland condition. The degradation test of several pesticides by the selected bacteria, B59 and B71, were conducted. The degradation rates for 6 pesticides, procymidone, chlorothalonil, ethoprophos parathior, alachlor and pendimethalin, in medium by the isolates were 21.1% to 53.2% higher than non-inoculated medium. Under shaking culture condition, 90% to 95% of procymidone was degraded after 21 days treatment. Parathion was degraded in the range of 60% to 100% by B71 and B59, respectively. Otherwise 70% of alachlor was degraded by the two isolated bacteria during same period. The pH was not significantly affected for degradation of pesticides. The bacterial strains, B59 and B71 was identified as Acinetobacter sp. and as Pseudomonas sp. based on morphological, biochemical and physiological characteristics, and identity and similarity of automatic identification system, Biolog and MIDI.

• Journal of Life Science
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• v.23 no.1
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• pp.110-115
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• 2013

A microorganism (strain AR1) producing an extracellular lipolytic enzyme was isolated from hot springs located in Beppu, Japan. Phylogenetic analysis based on the 16S rDNA sequence and biochemical studies indicated that AR1 belongs to the genus Geobacillus. This study focused on novel strategies to increase extracellular lipolytic enzyme production by this novel Geobacillus sp. AR1. Cultures of the AR1 strain grew within a wide temperature range (from 35 to $75^{\circ}C$); the optimum temperature was $65^{\circ}C$. The pH for optimal growth was 6.5, whereas the optimum pH for lipolytic enzyme production was 8.5. The presence of oils in the culture medium led to improvements in lipolytic enzyme activity. Soybean oil was the most efficient inducer, and it yielded better results when added in the exponential phase. On the other hand, the addition of chemical surfactants led to lipolytic enzyme production. Their addition to the culture could affect the location of the enzyme activity. The addition of Tween 20 in the stationary phase significantly increased the proportion of the extracellular enzyme activity. According to the results, following the addition of soybean oil and Tween 20 in the exponential and stationary phases, the extracellular lipolytic activity was increased 2.4-fold compared with that of a control.

• Journal of Life Science
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• v.18 no.1
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• pp.103-108
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• 2008

An agar-degrading marine bacterium, strain AS-1 was isolated from the seawater. The strain AS-1 was identified as Sphingomonas paucimobilis (90% probability) by VITEK. The optimum medium for agarase activity of the isolated strain was determined to be marine medium, marine broth 2216 containing 0.1% agar as carbon source. An extracellular agarase was purified 104-fold from the culture supernatant by ammonium sulfate precipitation, ion exchange chromatography and gel filtration methods. The molecular weight of the purified enzyme was estimated to be 80 kDa by SDS-PAGE. The optimum pH and temperature for activity were 7.0 and $40^{\circ}C$, respectively. Antioxidative activity of the strain AS- was 72% in the supernatant cultured for 12 h. The culture supernatant of the strain AS-1 showed antibacterial activity against bacteria causing putrefaction and food poisoning such as Escherichia coli, Staphylococcus aureus and Proteus vulgaris. However, the cell growth of the lactic aicd forming strain, Lactobacillus plantarium was promoted by the treatment of 10% culture supernatant of an agar-degrading strain.

• Food Engineering Progress
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• v.21 no.1
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• pp.88-92
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• 2017

We attempted to investigate antibacterial and proteolytic activities of bacteria isolated from three ethnic fermented seafoods in the east coast of South Korea, gajami sikhae, squid jeotgal, and fermented jinuari (Grateloupia filicina). Bacillus cereus ATCC 14579, Listeria monocytogenes ATCC 15313, Staphylococcus aureus KCTC 1916, Escherichia coli O157:H7 ATCC 43895, and Salmonella enterica serovar Typhimurium ATCC 4931 were selected to determine the antibacterial activity of the bacterial isolates. Among 233 isolates from the three foods, 36 isolates (15.5%) showed antibacterial activity against B. cereus ATCC 14579, the highest incidence of inhibition, followed by S. aureus KCTC 1916 (7.7%) and L. monocytogenes ATCC 15313 (6.0%). However, only five and three strains among the isolates exhibited inhibitory activity against Gram-negative indicators, E. coli ATCC 43895 and Sal. enterica ATCC 4931, respectively. The proteolytic activity of the isolates was determined via hydrolysis of skim milk after 24, 48, and 72 h incubation. After 72 h incubation, 72 out of 233 isolates (30.9%) showed proteolytic activity, and the isolates of fermented jinuari exhibited the highest incidence of proteolytic activity (60%, 36 isolates). These results suggest that ethnic fermented seafoods in the east coast of South Korea might be a promising source of bacterial strains producing antibacterial and proteolytic compounds.

• Journal of Life Science
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• v.32 no.4
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• pp.285-289
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• 2022

In this study, the growth characteristics of an agar-degrading bacterium isolated from seawater samples collected from Yeongheungdo, Incheon, and the characteristics of its agarase were analyzed. The 16S rRNA gene sequence of the isolated strain was 95% similar to that of the genus Agarivorans, and thus the isolated strain was named Agarivorans sp. HY-1. When Agarivorans sp. HY-1 was cultured in a marine broth 2216 medium at 27℃ and 250 rpm, it showed maximum growth on day 1 and showed maximum enzymatic activity on day 2. A crude enzyme solution was prepared from secreted agarase in the culture medium. The extracellular agarase of the Agarivorans sp. HY-1 strain showed maximal activity at 40℃ and pH 7.0 (20 mM Tris-HCl) with 591.91 U/l. The agarase exhibited relative activities of 64, 91, 100, 97, 89, and 60% at 20, 30, 40, 50, 60, and 70℃, respectively. At pH 5, 6, 7, and 8, the relative activities were 79, 95, 100, and 55%, respectively. Furthermore, the agarase exhibited >86% residual activity at 20, 30, and 40℃ for 2 hr and >44% residual activity at 50℃ after 2 hr. A TLC analysis confirmed that Agarivorans sp. HY-1 produced α-agarase. As the degradation products of α-agarase have anticancer and antioxidant effects, Agarivorans sp. HY-1 and its agarase may well prove useful.

• Microbiology and Biotechnology Letters
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• v.30 no.3
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• pp.210-215
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• 2002

A bacterium degrading soy protein was isolated from Korean traditional fermented foods. The isolated strain was identified as Bacillus subtilis, and named as B. subtilis EB464. The optimum pH and temperature of the protease produced by 5. subtilis EB464 were pH 9.0 and $50^{\circ}C$, respectively. The protease was stable in the range of pH 6~10 and below $40^{\circ}C$. The content of water-soluble protein and free amino acid of the medium were increased from 4.2% to 20.6% and ken 1.9% to 22.0%, respectively, by solid-state fermentation of soybean meal with B. subtilis EB464 for 72 h.