• KSBB Journal
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• v.27 no.1
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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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• v.44 no.1
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• pp.92-96
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• 2006

Enzymes in organic media afford many advantages such as chiral synthesis and resolution, modification of fats and oils and production of biodegradable polymers. However, the nature of solvents influences the activity and stability of enzymes, and the presence of organic solvents always constitute a risk of enzyme inactivation. Heat-shock protein Hsp90, one of the molecular chaperone, was applied for understanding of enzyme inactivation and for increasing of enzyme stability in water-miscible organic solvent. Hsp90 showed stabilization effect on HRP in the 30％ of DMSO, in the 30％ and 50％ of dioxane. Hsp90 also showed reactivation effect on the inactivated HRP by water-miscible organic solvent such as dioxane and DMSO. In addition, structural analysis using fluorescence spectrophotometry and circular dichroism showed that exposure of HRP in water-miscible organic solvent caused appreciable conformational changes and enzyme inactivation, and the unfolded HRP by water-miscible organic solvent was refolded by Hsp90.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.44 no.6
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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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• v.20 no.5
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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.

• Journal of Life Science
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• v.26 no.5
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• pp.603-607
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• 2016

A crude extracellular lipase from solvent-tolerant bacterium Pseudomonas sp. BCNU 106 was highly stable in the broad pH range of 4-10 and at temperature of 37℃. Crude lipase of BCNU 106 exhibited enhanced stability in 25% organic solvents such as xylene (121.85%), hexane (120.35%), octane (120.41 %), toluene (118.14%), chloroform (103.66%) and dodecane (102.94%) and showed excellent stability comparable with the commercial immobilized enzyme. In addition, the stability of BCNU 106 lipase retained above 110% of its enzyme activity in the presence of Cu²⁺, Hg²⁺, Zn²⁺ and Mn²⁺, whereas Fe²⁺ strongly inhibited its stability. The detergents including tween 80, triton X-100 and SDS were positive signals for lipase stability. Because of its stability in multiple organic solvents, cations and surfactants, the Pseudomonas sp. BCNU 106 lipase could be considered as a potential biocatalyst in the industrial chemical processes without using immobilization.

• BMB Reports
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• v.44 no.10
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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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• v.23 no.4
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• pp.340-344
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• 2008

Coprinus cinereus peroxidase (CiP) was often used as a catalyst for oxidative polymerization of a variety of phenol derivatives to produce a new class of polyphenols. Economical point of view, to know the mechanism of enzyme deactivation is significantly important because cost of enzyme is critically high. Hydrogen peroxide being used as oxidizing agent induced deactivation of peroxidase by destruction of heme structure. In the presence of hydrogen peroxide the stability of peroxidase was unexpectedly improved by adding organic solvent. Especially 2-propanol significantly improved enzyme stability among tested solvents. Radical scavenging by organic solvents may play a major role in protecting peroxidase from the oxidation of oxidizing radicals.

• YAKHAK HOEJI
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• v.28 no.6
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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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• v.15 no.3
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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.

• Journal of Life Science
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• v.25 no.3
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• pp.345-348
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• 2015

An organic solvent stable lipase from solvent-tolerant Pseudomonas sp. BCNU 171 had an optimal pH of 8 and an optimal temperature of 37℃. This crude extracellular lipase from BCNU 171 exhibited increased stability in the presence of various types of solvents at high concentrations (25%, v/v). The lipase stability was found to be highest in the presence of xylene (137%), followed by toluene (131%), octane (130%), and butanol (104%). Overall, BCNU 171 lipase tended to be more stable than immobilized commercial lipase (Novozyme435) in the presence of organic solvents. Furthermore, BCNU 171 lipase maintained about 90% of its enzyme original activity in the presence of NH₄⁺, Na⁺, Ba²⁺, Hg²⁺, Ni²⁺, Cu²⁺, and Ca²⁺ion and significantly increased its enzyme activity in the presence of various emulsifying agents. Thus, the organic solvent stable lipase from Pseudomonas sp. BCNU 171 could be usable as a potential whole cell biocatalyst and for synthetic applications of enzymes for industrial chemical processes in organic solvents without using immobilization.