• KSBB Journal
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• 제28권5호
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• pp.332-337
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• 2013

호열성 진정세균인 Thermotoga maritima의 xylose isomerase 유전자를 대장균을 이용하여 클로닝하고 재조합 발현시켰다. 재조합 효소의 최적활성은 $90^{\circ}C$와 pH 8.0에서 관찰되었다. 사포닌을 재조합효소로 처리한 후 사람의 위암 세포주 (AGS)와 대장암 세포주 (HT-29)에 처리한 결과, 효소 무처리 사포닌에 비해 우수한 암세포 생육저해 활성을 나타냈다. 한편, 푸코이단을 재조합효소로 처리한 후 동일 세포주들에 처리한 결과, 효소 무처리 푸코이단과 비슷한 암세포 생육저해 활성을 보였다. 1 ${\mu}g/ml$ 농도의 효소 처리 사포닌은 100 ${\mu}g/ml$ 농도의 효소 무처리 사포닌과 유사하거나 우수한 암세포 생육저해 활성을 보였다. 본 연구결과는 기능성 식품이나 의약품의 개발에 참고가 될 것으로 사료된다.

• Journal of Microbiology and Biotechnology
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• 제22권5호
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• pp.637-641
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• 2012

TPDex, a putative dextranase from Thermoanaerobacter pseudethanolicus, was purified as a single 70 kDa band of 7.37 U/mg. Its optimum pH was 5.2 and the enzyme was stable between pH 3.1 and 8.5 at $70^{\circ}C$. A half-life comparison showed that TPDex was stable for 7.4 h at $70^{\circ}C$, whereas Chaetominum dextranase (CEDex), currently used as a dextranase for sugar milling, was stable at $55^{\circ}C$. TPDex showed broad dextranase activity regardless of dextran types, including dextran T2000, 742CB dextran, and alternan. TPDex showed the highest thermostability among the characterized dextranases, and may be a suitable enzyme for use in sugar manufacture without decreased temperature.

• Journal of Microbiology and Biotechnology
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• 제27권2호
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• pp.271-276
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• 2017

A highly thermostable ${\beta}-(1-4)-glucanase$ (NA23_08975) gene (fig) from Fervidobacterium islandicum AW-1, a native-feather degrading thermophilic eubacterium, was cloned and expressed in Escherichia coli. The recombinant FiG (rFiG) protein showed strong activity toward ${\beta}-{\small{D}}-glucan$ from barley (367.0 IU/mg), galactomannan (174.0 IU/mg), and 4-nitrophenyl-cellobioside (66.1 IU/mg), but relatively weak activity was observed with hydroxyethyl cellulose (5.3 IU/mg), carboxymethyl cellulose (2.4 IU/mg), and xylan from oat spelt (1.4 IU/mg). rFiG exhibited optimal activity at $90^{\circ}C$ and pH 5.0. In addition, this enzyme was extremely thermostable, showing a half-life of 113 h at $85^{\circ}C$. These results indicate that rFiG could be used for hydrolysis of cellulosic and hemicellulosic biomass substrates for biofuel production.

• 생명과학회지
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• 제22권4호
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• pp.472-477
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• 2012

고온성 ${\alpha}$-아밀라제를 생산하는 내열성 $Alicyclobacillus$ $acidocaldarius$ 균을 인도 Tirupati, Andhra Pradesh 지역의 가열한 미강 열수 추출물에서 분리하였다. 분리균인 내열성 $Alicyclobacillus$ $acidocaldarius$가 생산하는 세포 외 ${\alpha}$-아밀라제의 생산과 성장에 미치는 배양조건을 실험실 규모로 조사하였다. 그 결과 ${\alpha}$-amylase의 고생산 최적 조건은 온도 $60^{\circ}C$, pH 6.0 및 배지의 전분농도 1.0%, yeast extract와 tryptone은 0.2%를 나타냈다. Surfactants like Tween-20과 SDS 같은 계면활성제는 0.02%까지 균주의 성장과 효소 생산을 증가 시켰으나, 그 이상의 농도 에서는 ${\alpha}$-amylase 효소의 생산이 현저하게 감소하였다.

• 한국미생물·생명공학회지
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• 제34권4호
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• pp.318-322
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• 2006

알칼리와 고온에 대한 내성을 가진 invertase를 대량생산하기 위하여 호알칼리성이며 고온성 세균인 Bacillus sp. TA-11의 세포내 invertase유전자를 pUC 19벡터를 이용하여 E. coli HB101에 클로닝 시키고 발현시켜 invertase를 강력하게 생산하는 재조합 E. coli (pYC17)를 얻었다. 재조합 E. coli(pYC17)를 이용한 invertase 생산 최적조건을 검토한 결과 E. coil(pYC17)를 0.25% sucrose, 0.5% yeast extract, 0.1% $K_2HPO_4$와 0.1% $KH_2PO_4$을 함유한 SY배지(초기 pH 9.0)에 접종하여 37$^{\circ}C$에서 9시간 배양하였을 때 친주보다도 많은 47.7 U/ml-cell free extract의 invertase가 생산되었다.

• 유기물자원화
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• 제3권1호
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• pp.21-34
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• 1995

음식물 쓰레기 퇴비화 장치에 사용하기 위한 미생물제제 개발을 목적으로 토양, 퇴비 등으로부터 고온균을 분리하여 그 생육 특성을 조사하였다. 분리한 81주 중에서 음식물 쓰레기를 분해시키는 전분 분해효소, 단백 분해효소, 지방 분해효소 및 섬유소 분해효소의 활성이 높은 20주를 분리하여 형태 및 생리적 특성을 조사한 결과 모두 그람 양성의 간균으로 카탈라제를 가지고 있었으며 17주는 포자 형성균으로 밝혀졌다. 이 균주들은 대부분 pH 5에서 pH 10까지 생육할 수 있었으며 8% NaCl이 함유된 배지에서도 성장하였다. 또한 각 효소의 생산 균주 그룹별로 생육에 미치는 영향을 조사한 결과 통기에 의해 생육이 크게 증가하였으며, $50^{\circ}C$ 이상 온도가 올라갈수록 생육이 저하되었다.

• Journal of Microbiology and Biotechnology
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• 제21권3호
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• pp.284-292
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• 2011

An endocellulase-free multienzyme complex was produced by a thermophilic anaerobic bacterium, Thermoanaerobacterium thermosaccharolyticum strain NOI-1, when grown on xylan. The temperature and pH optima for growth were $60^{\circ}C$ and 6.0, respectively. The bacterial cells were found to adhere to insoluble xylan and Avicel. A scanning electron microscopy analysis showed the adhesion of xylan to the cells. An endocellulase-free multienzyme complex was isolated from the crude enzyme of strain NOI-1 by affinity purification on cellulose and Sephacryl S-300 gel filtration. The molecular mass of the multienzyme complex was estimated to be about 1,200 kDa. The multienzyme complex showed one protein on native PAGE, one xylanase on a native zymogram, 21 proteins on SDS-PAGE, and 5 xylanases on a SDS zymogram. The multienzyme complex consisted of xylanase, ${\beta}$-xylosidase, ${\alpha}$-L-arabinofuranosidase, ${\beta}$-glucosidase, and cellobiohydrolase. The multienzyme complex was effective in hydrolyzing xylan and corn hulls. This is the first report of an endocellulase-free multienzyme complex produced by a thermophilic anaerobic bacterium, T. thermosaccharolyticum strain NOI-1.

• 미생물학회지
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• 제28권4호
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• pp.311-317
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• 1990

Intraspecific and interspecific protoplast fusions in/between C. thermocellum and C. thermohydrosulfuricum were studied. Protoplast fusions were well induced in 30-40% PEG solution, however, their fusion frequencies were low level of 1.2*10$^{-7}$ for intraspecific fusion of C. thermocellum, $6.7*10^{-7}$ for C. thermohydrosulfuricum, and 4.2*10$^{-7}$ for interspecific fusion between above two Clostridia, respectively. Most fusants were unstable and segregated after 3 subcultures. Relatively stable intraspecific C. thermocellum fusant FTT17, intraspecific C. thermohydrosulfurecum fusant FSS22 and interspecific fusant FTS3, which were stable after several subcultures, were selected and properties of fusants were further investigated, Phenotypes of the fusants were similar with wild types mostly in cellular morphology, carbon source assimilation and enzyme activities. However they were differed in assimilation of pyruvic acid and sorbitol as carbon source. The DNA contents of fusants were slightly increased compared with wild types. Ethanol production by intraspecific and/or interspecific fusants was not increased, however, acetic acid production as byproduct was decreased or not detected, which indicates that industrial thermophilic anaerobes can be improved by means of protoplast fusion of two strains.

• 한국미생물·생명공학회지
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• 제20권1호
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• pp.46-52
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• 1992

농축유청으로부터 유청음료 제조를 위한 최적조건을 조사하기 위해 역삼투장치(reverse osmosis system)를 사용하여 치즈유청 속의 유당을 농축한 수 $\beta$-D-glactosidase로 가수분해시켜 그 분해정도를 HPLC(high performance liquid chromatography)로 측정하였다. 유당의 가수분해 정도는 농축적 유청, 2배 농축 유청과 3배 농축 유청 순으로 가수분해되었고 일정량의 효소첨가에 의해 농축된 염이 $\beta$-D-Galactosidase에 대한 약간의 저해작용을 일으켰다.

• Journal of Microbiology and Biotechnology
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• 제16권2호
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• pp.272-279
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• 2006

The gene encoding Thermus sp. T351 alkaline phosphatase (T351 APase) was cloned and sequenced. The gene consisted of 1,503 bp coding for a protein with 500 amino acid residues including a signal peptide. The deduced amino acid sequence of T351 APase showed relatively low similarity to other Thermus APases. The T351 APase gene was expressed under the control of the T7lac promoter on the expression vector pET-22b(+) in Escherichia coli BL21 (DE3). The expressed enzyme was purified by heat treatment, and $UNO^{TM}$ Q and $HiTrap^{TM}$ Heparin HP column chromatographies. The purified enzyme exhibited high activity at extremely alkaline pHs, reaching a maximum at pH 12.0. The optimum temperature of the enzyme was $80^{\circ}C$, and the half-life at $85^{\circ}C$ was approximately 103 min. The enzyme activity was found to be dependent on metal ions: the addition of $Mg^{2+}$ and $CO^{2+}$ increased the activity, whereas EDTA inhibited it. With p-nitrophenyl phosphate as the substrate, T351 APase had a Michaelis constant ($K_{m}$) of $3.9{\times}10^{-5}M$. The enzyme catalyzed the hydrolysis of a wide variety of phosphorylated compounds.