• KSBB Journal
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• 제27권1호
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• pp.61-66
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• 2012

In the screening process of organic solvent tolerant bacteria showing good growth in media containing several kinds of organic solvents, one strain was isolated and identified as Bacillus sp. BCNU 5006. The strain was able to tolerate many organic solvents including benzene, toluene, xylene, octane, dodecane, butanol and ethylbenzene. Likewise, it could also utilize these solvents as the sole source of carbon with significant enzyme production. The lipolytic enzyme stability of Bacillus sp. BCNU 5006 was studied in the presence of several kinds of solvents at a 25% (v/v) concentration. The highest enzyme stability was observed in the presence of octane (107%), followed by ethylbenzene (88%), decane (86%), and chloroform (85%). Especially, BCNU 5006 lipase was determined to be more stable than immobilized enzyme (Novozyme 435) in the presence of octane, chloroform and xylene. This organic solvent tolerant Bacillus sp. BCNU 5006 could be expected as a potential bioremediation agent and biocatalyst for biodegradation and provide on organic-solvent-based enzymatic synthetic method in industrial chemical processes.

• Korean Chemical Engineering Research
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• 제44권1호
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• pp.92-96
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• 2006

유기용매에서 효소를 이용하면 다양한 선택적 반응을 쉽게 수행할 수 있어 산업적 적용 가능성이 매우 높지만, 효소의 안정성 저하는 아직까지 큰 문제 중의 하나로 남아있다. 유기용매에서 효소 반응시 효소의 실활 원인과 효소의 안정화 방법 연구를 위하여 단백질의 folding에 관여하는 molecular chaperone의 일종인 heat-shock protein Hsp90을 이용하여, 대표적인 유기용매 반응시스템에서의 과산화효소 HRP 안정성 향상 연구를 수행하였다. 그 결과 Hsp90은 30％ DMSO, 30％ 및 50％ dioxane 완충용액에서 HRP의 실활 방지 효과를 보였고, 실활된 효소의 재생에도 탁월한 효과를 보였다. 그리고 형광분석과 CD(circular dichroism)에 의한 구조분석을 수행하여 Hsp90이 유기용매에 의해 unfolding되어 있는 효소를 다시 refolding하는 데 기여함을 알았다.

• 펄프종이기술
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• 제44권6호
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• pp.50-57
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• 2012

In this study, the beeswax extraction methods using organic solvents were examined to develop a optimal dewaxing technology for beeswax-treated Hanji. Thermally-aged beeswax-treated Hanji was dewaxed using four types of extraction methods including dipping, Soxhlet extraction, ultrasonic washing and shaking methods. Then, the aging stability of the dewaxed Hanji was evaluated in terms of variations in paper strength and in the color of the printed area with muk. The experimental results suggested that the dewaxing methods allowing solvent to flow during extraction showed superior extraction efficiency. The dipping method in which the organic solvent does not flow showed the slowest extraction rate of beeswax compared to three other methods. In terms of variations in tensile strength and folding endurance, however, no obvious differences in the aging stability were observed amongst these four extraction methods. Regarding the aging stability in terms of the color of the printed area with muk, Soxhlet extraction method showed the best performance of dewaxing.

• Journal of Microbiology and Biotechnology
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• 제20권5호
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• pp.881-888
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• 2010

solvent-tolerant bacterium strain, MH6, was isolated by hydrophilic organic solvent DMSO enrichment in the medium and identified as Serratia marcescens. The extracellular protease with novel organic-solvent-stable properties from strain MH6 was purified and characterized. The molecular mass of the purified protease was estimated to be 52 kDa on SDS-PAGE. The open reading frame (ORF) of the MH6 protease encoded 504 amino acids with 471 amino acid residues in the mature protease. Based on the inhibitory effects of EDTA and 1,10-phenathroline, the MH6 protease was characterized as a metalloproteinase. The enzyme activity was increased in the presence of $Ni^{2+}$, $Mg^{2+}$, and $Ca^{2+}$. The protease could also be activated by the nonionic surfactants Tween 80 (1.0%) and Triton X-100 (1.0%). The protease showed remarkable solvent stability in the presence of 50% (v/v) solutions of long-chain alkanes and long-chain alcohols. It was also fairly stable in the presence of 25% solutions of hydrophilic organic solvents. Owing to its high stability in solvents and surfactants, the MH6 protease is an ideal candidate for applications in organic catalysis and other related fields.

• 생명과학회지
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• 제26권5호
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• pp.603-607
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• 2016

유기용매 내성 세균 Pseudomonas sp. BCNU 106으로부터 생산된 리파아제 조효소액은 pH 4-10의 넓은 범위의 pH와 37℃에서 매우 안정적이었다. BCNU 106의 리파아제 안정성은 25% xylene, hexane, octane, toluene, chloroform 및 dodecane에서 증가하였으며, 상업적인 고정화 효소와 비교해도 우수한 안정성을 보이고 있다. 그리고 Cu²⁺, Hg²⁺, Zn²⁺ 및 Mn²⁺ 존재 하에서 110% 이상의 상대활성을 나타낸 반면에, Fe²⁺에서는 효소활성이 억제되었다. 게다가 계면활성제인 tween 80과 triton X-100 및 SDS에서도 높은 안정성을 유지됨이 확인되었다. 본 연구에서 유기용매 내성 Pseudomonas sp. BCNU 106의 리파아제는 고정화 효소에 못지않은 효소 활성 및 안정성을 유지함이 밝혀져 다양한 산업공정에서 잠재적인 생물촉매로 적용될 수 있는 가능성을 확인할 수 있었다.

• BMB Reports
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• 제44권10호
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• pp.665-668
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• 2011

In order to clarify the impact of Ca-binding sites (Ca1 and 2) on the conformational stability of neutral proteases (NPs), we have analyzed the thermal, pH and organic solvent stability of a NP variant, V189P/A195E/G203D/A268E (Q-mutant), from Salinovibrio proteolyticus. This mutant has shown to bind calcium more tightly than the wild-type (WT) at Ca1 and to possess Ca2. Q-mutant was resisted against autolysis, thermoinactivation and pH denaturation in a Ca-dependent manner and exhibited better activity in organic solvents compared to the WT enzyme. These results imply that Ca1 and Ca2 are important for the conformational stability of NPs.

• KSBB Journal
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• 제23권4호
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• pp.340-344
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• 2008

CiP를 이용한 유기합성은 주로 유기용매와 완충용액을 섞어서 반응을 한다. 하지만 단순히 유기용매 상에서 효소의 활성도를 측정한 것이 아니라, 과산화수소가 있을 경우에 효소의 활성도를 측정한 결과는 예상과는 다르게 순수한 완충용액에서 보다 유기용매를 포함하고 있는 것이 더 높게 나타났다. 또한 유기용매의 비율을 증가가 될수록 효소의 활성도가 더 높게 나타났으며, 특히 2-propanol이 33%가 포함이 된 경우에는 순수한 완충용액보다 효소의 활성도가 크게 증가가 되는 것을 관찰을 할 수가 있었다. 이러한 효소의 활성도가 유기용매가 포함이 된 조건에서 높게 나는 이유는 유기용매가 CiP에 의해 생성된 반응성이 높은 라디칼을 포집을 하여서, CiP의 활성 부위인 heme의 파괴를 막는 것에 크게 기여하는 것으로 판단이 되었다.

• 약학회지
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• 제28권6호
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• pp.299-303
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• 1984

In order to eluciate the effect of humidity and organic solvent on the decomposition of carbamide peroxide, the kinetic study was carried out. The carbamide peroxide was prepared from urea and 30%-hydrogen peroxide. The accelerated stability analysis for carbamide peroxide crystal in various relative humidity, and for 10%-carbamide peroxide solution of organic solvents were investigated. Both humidity and temperature were important factors influencing the decomposition rate of carbamide peroxide crystal. The higher the humidity and temperature, the greater was the reaction rate. The breakdown rate of crystal was observed as an apparent zero-order, and was faster than the rate of decomposition in dilute propylene glycol, glycerine or sorbitol solutioos which were measured as an apparent first-order reaction. The more dilute to 10% the organic solvents of 10%-carbamide peroxide, the slower was breakdown rate. It is, therefore, useful in the aspects of stability and economics to substitute solvent of carbamide peroxide topical solution (USP XXI) with 10%-propylene glycol or glycerine instead of anhydrous glycerine.

• Carbon letters
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• 제15권3호
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• pp.187-191
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• 2014

This study reports on the influence of N-butyl-N-methylpyrrolidinium tetrafluoroborate ($PYR_{14}BF_4$) ionic liquid additive on the conducting and interfacial properties of organic solvent based electrolytes against a carbon electrode. We used the mixture of ethylene carbonate/dimethoxyethane (1:1) as an organic solvent electrolyte and tetraethylammonium tetrafluoroborate ($TEABF_4$) as a common salt. Using the $PYR_{14}BF$ ionic liquid as additive produced higher ionic conductivity in the electrolyte and lower interface resistance between carbon and electrolyte, resulting in improved capacitance. The chemical and electrochemical stability of the electrolyte was measured by ionic conductivity meter and linear sweep voltammetry. The electrochemical analysis between electrolyte and carbon electrode was examined by cyclic voltammetry and electrochemical impedance spectroscopy.

• 생명과학회지
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• 제25권3호
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• pp.345-348
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• 2015

유기용매 내성 Pseudomonas sp. BCNU 171 균주가 생산하는 유기용매 내성 리파아제의 최적활성은 pH 8과 37℃로 나타났다. BCNU 171 균주가 생산하는 세포외 리파아제는 고농도의 다양한 유기용매하에서 안정성이 증가하는 것으로 나타났다. 리파아제의 안정성은 xylene (137%) 첨가시 가장 높은 것으로 확인되었고, toluene (131%), octane (130%) 그리고 butanol (104%) 순으로 안정성이 높은 것으로 나타났다. 전체적으로 대부분의 용매에서, 상용 고정화 효소(Novozyme 435)와 비교하여 효소안정성이 높은 것으로 나타났다. 나아가 NH₄⁺, Na⁺, Ba²⁺, Hg²⁺, Ni²⁺, Cu²⁺및 Ca²⁺의 존재하에서 약 90%로 효소 안정성을 유지하였으며 다양한 유화제 첨가시에는 현저하게 안정성이 증가하였다. 그러므로 Pseudomonas sp. BCNU 171의 유기용매 내성 리파아제는 잠재성이 높은 whole cell 생물촉매로서 사용가능 할 것이며, 고정화 하지 않고도 유기용매에서의 공업적인 화학공정에서 효소를 이용한 합성에 유용하게 사용될 수 있을 것이다.