• Journal of Microbiology and Biotechnology
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• 제23권9호
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• pp.1221-1228
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• 2013

Two lipase genes (bpl1 and bpl3) from Antarctic Bacillus pumilus strains were expressed in Bacillus subtilis. Both recombinant lipases BPL1 and BPL2 were secreted to the culture medium and their activities reached 3.5 U/ml and 5.0 U/ml, respectively. Their molecular masses apparent using SDS-PAGE were 23 kDa for BPL1 and 19 kDa for BPL3. Both lipases were purified to homogeneity using ammonium sulfate precipitation and HiTrap SP FF column and Superose 12 column chromatographies. The final specific activities were estimated to be 328 U/mg for BPL1 and 310 U/mg for BPL3. Both lipases displayed an optimum temperature of $35^{\circ}C$, similar to other mesophilic enzymes. However, they maintained as much as 70% and 80% of the maximum activities at $10^{\circ}C$. Accordingly, their calculated activation energy at a temperature range of $10-35^{\circ}C$ was 5.32 kcal/mol for BPL1 and 4.26 kcal/mol for BPL3, typical of cold-adapted enzymes. The optimum pH of BPL1 and BPL3 was 8.5 and 8.0, respectively, and they were quite stable at pH 7.0-11.0, showing their strong alkaline tolerance. Both lipases had a preference toward medium chain length ($C_6-C_{10}$) fatty acid substrates. These results indicate the potential for the two Antarctic B. pumilus lipases as catalysts in bioorganic synthesis, food, and detergent industries.

• 한국미생물·생명공학회지
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• 제25권2호
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• pp.166-172
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• 1997

Aspergillus niger was selected as a strain producing the potent raw starch hydorlyzing enzyme. These experiments were conducted to investigate the conditions of the glucoa- mylase production, the purification of the enzyme, some characteristics of the purified enzyme and hydrolysis rate on various raw starches such as com, rice, potato, glutinous rice, sweet potato, wheat and barley. The optimum cultural temperature and time for the enzyme production on wheat bran medium were $30^{\circ}C$ and 96hrs, respectively. The respective addition of yeast extract and nutrient broth on wheat bran medium increased slightly the enzyme production. The enzyme was purified by ammonium sulfate fractionation and DEAE-cellulose column chromatography. The specific activity of the purified enzyme was 30.7u/mg-protein and the yield of enzyme activity was 25.8%. The purified enzyme showed a single band on polyacrylamide disc gel electrophoresis and its molecular weight was estimated to be 56,000 by SDS-polyacrylamide disc gel electrophoresis. The isoelectric point for the purified enzyme was pH3.7. The optimum temperature and pH were $65^{\circ}C$ and pH 4.0, respectively. The purified enzyme was stable in the pH range of pH 3.0-9.5 and below $45^{\circ}C$, and its thermal stability was slightly increased by the addition of $Ca^{2+}$. The purified enzyme was activated by $Co^{2+},\;Sr^{2+},\;Mn^{2+},\;Fe^{2+},\;Cu^{2+}$. Raw rice starch, raw corn starch, raw glutinous rice starch, raw sweet potato starch, raw wheat starch and raw barley starch showed more than 90% hydrolysis rate in 48hrs incubation. Even raw potato starch, most difficult to be hydrolyzed, showed 80% hydrolysis rate. The purified enzyme was identified as glucoamylase.

• 한국환경농학회지
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• 제26권1호
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• pp.36-41
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• 2007

PDA-calcium phosphate 평판배지를 이용하여 경상남북도 일대의 토양으로부터 인산가용화능이 우수한 사상균을 분리하고 배양특성을 조사하였다. 최종적으로 분리한 인산가용화능이 우수한 사상균 PS-104 균주를 선발하여 형태적 특성을 조사한 결과 이 균주의 분생자는 비가지형으로 끝이 돌출되어 있으며, 균사가 격막으로 형성되는 등의 특징을 갖는 Aspergillus sp. PS-104 균주로 동정되었다. 이 균주의 인광석 분해능이 최대가 되는 최적 배양온도와 pH는 각각 $30^{\circ}C$와 pH 7.0이었다. 이와 같은 배양조건에서 tricalcium phosphate, aluminium phosphate, hydroxyapatite, 인광석 등의 난용성 인산염에 대한 이 균주의 인산가용화능을 살펴보면 최대 인산가용화능은 tricalcium-phosphate 처리구(1,900 ppm)에서, 최소 인산가용화능은 hydroxyapatite 처리구(320 ppm)에서 확인되었다. 또한 이 균주의 인산가용화능은 질소원으로 첨가한 ammonium 염보다 nitrate 염에서 높게 나타났다.

• 한국수소및신에너지학회논문집
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• 제22권4호
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• pp.432-442
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• 2011

Anodized tubular $TiO_2$ electrodes (ATTEs) with three noticeably different lengths are prepared to determine their optimum length for the photo-driven activity in the reaction of Cr(VI) reduction and hydrogen evolution. The ATTEs with ethylene glycol have longer $TiO_2$ tubes (7-15.6 ${\mu}m$) than those with hydrfluoric acid (0.6-0.8 ${\mu}m$). These samples, which differ only in the length of the tubes, with a wall thickness of ca. 20 nm, consist mainly of an anatase crystalline phase after heat treatment at $650^{\circ}C$, since the anatase crystallites at the tube walls do not undergo transformation into rutile phase, due to the constraints imposed by the wall thickness. Among them, the medium size (ca. 8 ${\mu}m$) tubes provide the optimum conditions, irrespective of the light intensity, which is explained in terms of the correlation between the amount of photons and the adsorbed electron acceptors and their location. Photocatalytic Cr(VI) reduction leads to ca. 60% reduction of Cr(VI) even under 1 sun irradiation with the medium-sized anodized $TiO_2$ tubes, but only ca. 20% with the short- and long-sized tubes. For hydrogen evolution, tubes longer than 8 ${\mu}m$ do not exhibit better performance with any light intensity.

• KSBB Journal
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• 제25권1호
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• pp.79-84
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• 2010

In the present study, we isolated a new bacterial strain producing invertase (EC 3.2.1.26) and determined optimized culture condition in flask culture. The strain was identified as Bacilus flexus determined by the 16S rDNA sequencing method. The invertase was produced only in the sucrose medium as the sole carbon source. Potassium nitrate was an adequate nitrogen source for enzyme production, whereas meat peptone showed the highest bacterial growth. Enzyme production was increased about 2-fold when $MgSO_4\cdot7H_2O$ was supplemented to the growth media. The optimum temperature was found to be $30^{\circ}C$ for both enzyme production and bacterial growth. Invertase exhibited pH optima in the range 5.0-6.0 and have a temperature optimum at $40^{\circ}C$, similarly to other invertases found from different microbial sources. Several mineral ions (K and Fe) stimulated the invertase activity, whereas some bioelements (Ag, Mg, and Mn) inhibited enzyme activity. Under the optimized culture condition, the maximum enzyme production (over 250 units/mL) was achieved at 20 h. To the best of our knowledge, this is the first time to report on invertase production by Bacilus flexus.

• Journal of Microbiology and Biotechnology
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• 제1권2호
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• pp.136-141
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• 1991

Optimum culture conditions for the formation of nitrile hydratase by Brevibacterium sp. CH2 were investigated. Addition of ferric and ferrous ions greatly increased the nitrile hydratase formation. The effects of nitriles, amides, and acids as an inducer on the formation of nitrile hydratase were investigated. Isobutyramide was the best inducer among the tested compounds. When Brevibacterium sp. CH2 was cultivated for 23 h at $30^{\circ}C$ in a optimized medium containing 15 g of glucose, 5 g of bacto peptone, 3 g of yeast extract, 3 g of malt extract, 1 g of $KH_2$$PO_4$, 1 g of $K_2$$HPO_4$, 1 g of NaCl, 0.5 g of isobutyramide, 0.2 g of MgSO$_4$ㆍ7$H_2O$, and 0.02g of $FeSO_4$ㆍ$7H_2$O per liter of distilled water with pH controlled at 7.1, the maximum total activity was 665 units/ml of the culture broth and the specific activity was 70 units/mg of the dry cells. The medium optimization increased the specific activity of Brevibacterium sp. CH2 2.2 times.

• 생명과학회지
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• 제18권6호
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• pp.871-877
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• 2008

이 연구는 양파즙을 이용한 알코올 음료의 개발을 위해 수행되었다. 양파는 당, 아미노산과 다양한 영양분을 기인하여 알코올 음료 개발을 위해 적절한 원료로 고려된다. 양파에서 알코올 발효를 위한 효모를 선별하기 위해 시판중인 효모를 양파배지에서 순화시켰다. 양파배지에서 성장하는 19 균주를 사용하여 알코올 생성능을 확인해 본 결과 OJ-8이 가장 높은 것으로 나타났다. 양파의 특이 냄새를 제거하기 위해 여러 가지 방법으로 냄새를 제거한 결과 열을 가하거나 활성탄을 처리하면 효과가 있는 것으로 나타났다. 그래서 액량에 대해 20% 활성탄을 30 분간 처리하고 $100^{\circ}C$ 40분간 열처리를 하면 효과적으로 냄새를 제거하는 것으로 나타났다. 양파즙을 이용하여 효과적으로 발효를 수행할 수 있는 조건의 검사 결과는 5% 접종량으로 $25^{\circ}C$ 5일 동안 정치배양하면 최대의 수율을 얻을 수 있었다.

• 한국미생물·생명공학회지
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• 제42권3호
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• pp.225-231
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• 2014

마늘낙엽버섯(Marasmius scorodonius)에 대하여 리그닌 분해 여부를 조사한 결과, 본 균주는 laccase를 생산하는 백색부후균으로 확인되었다. 마늘낙엽버섯 균사체로부터 laccase를 생산하기 위한 최적배지조건을 조사한 결과, 다양한 합성 배지 중에서 YM (1% dextrose, 0.5% malt extract, 0.3% yeast extract) 배지가 가장 높은 laccase 활성을 나타내었다. 또한 YM 배지의 조성 중에서 탄소원과 질소원을 각각 1% galactose와 0.4% yeast extract로 대체하였을 때 가장 높은 효소활성을 나타내었다. 본 균주는 최적배지조건에서 $25^{\circ}C$로 15일 동안 배양하였을 때 효소의 활성이 최대치에 도달함을 확인하였다. 균사체 배양 상등액을 Native-PAGE로 전기영동한 후 활성염색을 수행한 결과, 분자량 약 60-70 kDa 사이에서 laccase 활성을 가지는 2개의 밴드를 확인하였으며, 효소의 최적 pH와 온도는 각각 pH 3.4과 $75^{\circ}C$이었다.

• 농업과학연구
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• 제21권1호
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• pp.11-21
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• 1994

RNase를 강하게 분비하는 균을 젓갈류서 분리하여 호염성 Micrococcus sp.로 동정하였다. 선정균은 NaCl을 2M 함유하는 pH 7.0의 CM배지에서 $35^{\circ}C$로 2일간 배양할 때 생육이 가장 양호하였으며 yeast extract 2.0%, casamino acid 1.5%, NaCl 2.0M, pH 8.5의 배지에서 $35^{\circ}C$로 2일간 배양할 때 효소 생산이 최대였다. 조효소액을 유안 염석과 이온교환 크로마토그라피, gel 여과 등으로 정제한 결과 비활성이 98.8 units/mg, 정제도는 39.4배, 수율은 0.9% 이었다. 정제 효소의 작용 최적 pH는 8.0, 온도는 $55^{\circ}C$이었으며 RNA를 기질로 한 Km값은 5mg/ml이었다. NaCI농도에 따른 효소활성은 무첨가조건에서 가장 높았고 1.25M에서 활성이 소설되었다가 다시 증가되어 2.5M에서는 무첨가구의 45% 활성을 보였다.

• 한국버섯학회지
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• 제11권3호
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• pp.124-130
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• 2013

The effects of environmental and nutritional requirement such as temperature, pH, different media, carbon, nitrogen, and carbon-to-nitrogen ratio on the mycelial growth of Cordyceps militaris strain 'Yedang 3' were studied. The optimum temperature and pH for the growth of mycelium were $20-25^{\circ}C$ and pH 6-7, respectively. Out of ten media tested, mushroom complete media (MCM) was the best medium for fast mycelial growth, and Sabouraud's dextrose agar yeast extract (SDAY), malt extract yeast extract agar (YMA) also were favored. The color and shape of colonies varied in different media. The best carbon sources for mycelial growth were fructose, mannitol, and sucrose, whereas the best nitrogen sources were tryptone and peptone. However, mycelia grew slowly in inorganic nitrogen compounds such as $NH_4Cl$, $(NH_4)_2SO_4$, $NH_4NO_3$, and $NaNO_3$. The optimum C:N ratio observed on the culture media was 30-40 range. These results provided basic information on cultural characteristics of vegetative growth and might be useful for spawn production in Cordyceps militaris.