• Journal of Microbiology and Biotechnology
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• 제24권1호
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• pp.19-25
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• 2014

An extracellular agarase was purified from Bacillus sp. BI-3, a thermophilic agar-degrading bacterium isolated from a hot spring in Indonesia. The purified agarase revealed a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, with an apparent molecular mass of 58 kDa. The optimum pH and temperature of the agarase were 6.4 and $70^{\circ}C$, respectively. The activity of the agarase was stable at high temperatures, and more than 50% activity was retained at $80^{\circ}C$ for 15 min. Furthermore, the enzyme was stable in the pH range of 5.8-8.0, and more than 60% of the residual activity was retained. Significant activation of the agarase was observed in the presence of $K^+$, $Na^+$, $Ca^{2+}$, $Mg^{2+}$, and $Sr^{2+}$; on the other hand, $Ba^{2+}$, $Zn^{2+}$, $Cu^{2+}$, $Mn^{2+}$, $Co^{2+}$, $Fe^{2+}$, and EDTA inhibited or inactivated the enzyme activity. The components of the hydrolytic product analyzed by thin-layer chromatography showed that the agarase mainly produced neoagarobiose. This study is the first to present evidence of agarolytic activity in aerobic thermophilic bacteria.

• 농업과학연구
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• 제9권1호
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• pp.377-386
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• 1982

고온균(高溫菌)의 생리적(生理的) 특성(特性)과 내열기구(耐熱機構)에 관한 기초자료(基礎資料)를 얻고자 온천토양(溫泉土壤)에서 ${\beta}$-galactosidase를 생산(生産)하는 고온균(高溫菌)을 분리(分離)하여 동정(同定)하고, 몇가지 주요(主要)한 생리적(生理的) 특성(特性)을 검토(檢討)하였으며, 그의 균체지방산(菌體脂肪酸) 조성(組成)을 gas chromatography로 분석(分析)하여 다음과 같은 결과(結果)를 얻었다. 1. ${\beta}$-galactosidase를 생산(生産)하는 공시(供試) 균주(菌株)는 Thermus속(屬)으로 동정(同定)되었다. 2. 분리선정(分離選定)한 균주(菌株)의 최적(最適) 생육온도(生育溫度)는 $65^{\circ}C$이었고, $37^{\circ}C$에서 생육(生育)하지 않는 절대(絶對) 고온균(高溫菌)이었으며 최적(最適) pH는 6.5내외(內外)이었다. 3. NaCl에 대(對)한 내성(耐性)은 NaCl 1% 이상(以上)에서 생육(生育)하지 못했다. 4. 공시균주(供試菌株)의 항생물질(抗生物質) 내성(耐性)은 Penicillin G는 $10{\mu}g/m{\ell}$, Chloramphenicol은 $0.5{\mu}g/m{\ell}$이었다. 5. Vitamin 요구성(要求性)은 Ca-pantothenate와 pyridoxine-HCl을 절대적(絶對的) 생육인자(生育因子)로 요구(要求)하였고 niacin을 자극적(刺戟的) 생육인자(生育因子)로 요구(要求)하였다. 6. 공시균주(供試菌株)는 최대(最大) 흡수파장(吸收波長)이 420nm 부근(附近)의 색소(色素)를 생성(生成)하였고 그의 생성능(生成能)은 약(弱)하였다. 7. 공시균주(供試菌株)의 균체 지방산(脂肪酸) 조성(組成)은 palmitic acid 60.20%, lauric acid 11.80%, myristic acid 7.56%, behenic acid 4.25%, capric acid 1.77%, stearic acid 2.13%, arachidic acid 1.53%이었다.

• Journal of Microbiology and Biotechnology
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• 제25권9호
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• pp.1476-1484
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• 2015

Three endoxylanase-encoding genes from the moderately themophilic chemoorganotrophic bacterium Melioribacter roseus were cloned and expressed in Escherichia coli. Genes xyl2091 (Mros_2091) and xyl2495 (Mros_2495) encode GH10 family hydrolases, whereas xyl2090 (Mros_2090) represents the GH30 family. In addition to catalytic domains, Xyl2090 and Xyl2091 contain carbohydrate-binding modules that could facilitate their binding to xylans and Por sorting domains associated with the sorting of proteins from the periplasm to the outer membrane, where they are covalently attached. Recombinant endoxylanase Xyl2495 exhibited a high specific activity of 1,920 U/mg on birchwood xylan at 40℃. It is active at low temperatures, exhibiting more than 30% of the maximal activity even at 0℃. Endoxylanases Xyl2090 and Xyl2091 have lower specific activities but higher temperature optima at 80℃ and 65℃, respectively. Analysis of xylan hydrolysis products revealed that Xyl2090 generates xylo-oligosaccharides longer than xylopentaose. Xylose and xylobiose are the major products of xylan hydrolysis by the recombinant Xyl2091 and Xyl2495. No activity against cellulose was observed for all enzymes. The presence of three xylanases ensures efficient xylan hydrolysis by M. roseus. The highly processive "free" endoxylanase Xyl2495 could hydrolyze xylan under moderate temperatures. Xylan hydrolysis at elevated temperatures could be accomplished by concerted action of two cell-bound xylanases; Xyl2090 that probably degrades xylans to long xylo-oligosaccharides, and Xyl2091 hydrolyzing them to xylose and xylobiose. The new endoxylanases could be useful for saccharification of lignocellulosic biomass in biofuels production, bleaching of paper pulp, and obtaining low molecular weight xylooligosaccharides.

• 한국미생물·생명공학회지
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• 제23권3호
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• pp.304-310
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• 1995

A thermophilic bacterium producing the extracellular cellulase-free xylanase was isolated from soil and has been identified as Bacillus sp. The optimal growth temperature was 50$\circ$C and the optimal pH, 7.0. Under the optimal growth condition, maximal xylanase production was 2.2 units/ml in the flask culture. The enzyme production was induced by xylan and xylose, but was repressed by sucrose or trehalose. The partially purified xylanase was most active at 70$\circ$C. It was found that the enzyme was stable at 65$\circ$C for 10 hours with over 75% of the activity. The enzyme was most active at pH 7.0 and retained 90% of its maximum activity between pH 5.0 and pH 9.0 though Bacillus sp. was not grown on alkaline conditions (>pH 8.0). In addition, the activity of xylanase was over 60% at pH 10.0. At the ambient temperature, the enzyme was stable over a pH range of 5.0 to 9.0 for 10 h, indicating that the enzyme is thermostable and alkalotolerant. The activity of xylanase was completely inhibited by metal ions including Hg$^{2+}$ and Fe$^{2+}$, while EDTA, phenylmethylsulfonyl fluoride (PMSF), $\beta$-mercaptoethanol and SDS didn't affect its activity. The enzyme was also identified to exert no activity on carboxymethylcellulose, laminarin, galactomannan, and soluble starch.

• 자연과학논문집
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• 제5권1호
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• pp.47-52
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• 1992

$\beta$-galactosidase를 강력하게 생산하는 호알칼리성, 고온성 세균 TA-11를 부엽토에서 분리하여 Bacillus sp. TA-11로 동정 하였다. Bacillus sp. TA-11에 의한 $\beta$-galactosidase 생산은 lactose 1.5%, peptone과 yeast ext. 각각 0.4%, $MgSO_4$ 0.2%, $NH_4$CL 0.05% 및 NaCl 0.2% 등을 함유한 배지의 pH를 10.0으로 하여 시험균을 접종한후 $50^{\circ}C$에서 2일간 진탕배양 하였을 때 가장 좋았다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVII)
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• pp.200-200
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• 2005

• 한국미생물·생명공학회지
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• 제11권1호
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• pp.5-13
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• 1983

고온균의 생리적 특성자 내열기구에 관한 기초 자료를 얻고자 온천토양에서 $\beta$-galactosidase를 생산하는 고온균을 분리하여 동정하고 몇가지 주요한 생리적 특성을 검토하였으며 그의 균체 지방산 조성을 gas chromatography로 분석하여 다음과 같은 결과를 얻었다. 1. $\beta$-galactosidase를 생산하는 공시균주는 Thermus sp. 으로 동정되었다. 2. 분리선정한 균주의 최적 생육온도는 $65^{\circ}C$이었고, 37$^{\circ}C$에서 생육하지 않는 절대고온균 이었으며 최적pH는 6.5내외이었고 pH에 민감하였다. 3. NaCl에 대한 내성은 NaCl 1% 이상에서는 생육하지 못했다. 4. 항생물질에 대한 내성은 penicillin G는 10$\mu\textrm{g}$/$m\ell$, chloramphenicol은 0.5$\mu\textrm{g}$/$m\ell$ 이었다. 5. Vitamin 요구성은 Ca-pantothenate와 pyridoxine-HCI를 절대적 생육인자로 요구하였고niacin을 자극적 생육인자로 요구하였다. 6. 공시균주의 균체 지방산 조성은 palmitic acid 60.20%, lauric acid 11.80%, myristic acid 7.56%. behenic acid 4.25%, Capric acid 1.77%, stearic acid 2.13%, arachidic acid 1.53% 이었다.

• 한국미생물·생명공학회지
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• 제22권4호
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• pp.407-414
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• 1994

Anaerobic fermentative bacteria were isolated from the acidogenic reactor of a labora- tory scale 2-stage anaerobic digestor. The isolate 1-6 was selected for its ablity to produce more fatty acids from distillery wastewater than others, and was identified as a strain of Clostridium. The isolate Clostridium sp. 1-6 is a thermophilic bacterium growing at 55$\circ$c , and grew best at pH 5.5. An acidogenic reactor using immobilized cells of the isolate Clostridium sp. 1-6 removed about 15% of COD from distillery wastwater as hydrogen, producing about 50 mM butyrate and about 10 mM acetate, when the reactor was operated at the hydraulic retention time(HRT) of 0.8 hr. It is proposed that this system can be used to convert the distillery wastewater to hydrogen and butyrate. More than 90% of COD was removed from the wastewater by anaerobic digestion using a 2-stage digestor consisting of a UASB methanogenic reactor and an acidogenic reactor of the immobilized cells of isolate Clostridium sp. 1-6.

• 한국광물학회지
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• 제14권2호
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• pp.111-118
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• 2001

미생물을 이용한 광물 합성은 현재 초기 연구 단계에 있으나 신소재 개발 측면에서 다양한 활용 가능성을 보이고 있다. 이 연구의 목적은 철 환원 박테리아를 이용한 코발트로 치환된 자철석의 합성 및 이의 광물학적 특성을 알아보는데 있다. 호열성 철 환원 박테리아인 TOR-39는 65에서 비정질 철 수화물과 코발트 이온 ($Co^{2+}$ 와 $Co^{3+}$ )을 환원 및 침전시켜 자철석을 합성하였다. EPMA 분석과 X-선회절분석 결과에 의하면 호열성 박테리아가 철수화물을 환원시켜 자철석을 합성시킬 때, 코발트 이온도 동시에 환원 및 침전시켜 코발트로 치환된 자철석을 형성시킨다. 미생물에 의한 코발트로 치환된 자철석의 합성은 나노미터 크기로 생성되기 때문에 산업적으로 많은 이용 가치가 있을 것으로 본다.

• Journal of Microbiology and Biotechnology
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• 제17권1호
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• pp.162-167
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• 2007

A genetic transfer system for introducing foreign genes to biomining microorganisms is urgently needed. Thus, a conjugative gene transfer system was investigated for a moderately thermophilic, extremely acidophilic biomining bacterium, Acidithiobacillus caldus MTH-04. The broad-hostrange IncP plasmids RP4 and R68.45 were transferred directly into A. caldus MTH-04 from Escherichia coli by conjugation at relatively high frequencies. Additionally the broad-hostrange IncQ plasmids pJRD215, pVLT33, and pVLT35 were also transferred into A. caldus MTH-04 with the help of plasmid RP4 or strains with plasmid RP4 integrated into their chromosome, such as E. coli SM10. The $Km^r\;and\;Sm^r$ selectable markers from these plasmids were successfully expressed in A. caldus MTH-04. Futhermore, the IncP and IncQ plasmids were transferred back into E. coli cells from A. caldus MTH-04, thereby confirming the initial transfer of these plasmids from E. coli to A. caldus MTH-04. All the IncP and IncQ plasmids studied were stable in A. caldus MTH-04. Consequently, this development of a conjugational system for A. caldus MTH-04 will greatly facilitate its genetic study.