• Bulletin of the Korean Chemical Society
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• v.33 no.12
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• pp.4122-4126
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• 2012

Cellulose-graft-poly (L-lactide) (cellulose-g-PLLA) was successfully prepared via ring-opening polymerization (ROP) by using 4-dimethylaminopyridine (DMAP) as an organic catalyst in an ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl). The structure and morphology of the polymer was characterized by nuclear magnetic resonance (NMR) and transmission electron microscope (TEM). From wide-angle X-ray powder diffraction (WAXD) and degradation test (by acid, alkaline, PBS and enzyme solution), changes in the crystalline structure as a result of degradation was also investigated. The results indicated that materials which have low degree of crystallinity showing higher degradability, however, in acid liquor, enzyme solution, alkaline liquor and PBS system, the degradation rate of the polymer decreased by the above sequence. Moreover, with the further increase of graft degree of this material, its degradation degree decreased.

• Molecular & Cellular Toxicology
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• v.1 no.3
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• pp.189-195
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• 2005

Industrial development has increase consumption of crude oil and environmental pollution. A large number of microbial lipolytic enzymes have been identified and characterized to date. To development for a new lipase with catalytic activity in degradation of crude oil as a microbial enzyme, Acinetobactor sp. B2 was isolated from soil samples that were contaminated with oil in Daejon area. Acinetobactor sp. B2 showed high resistance up to 10 mg/mL unit to heavy metals such as Ba, Li, Al, Cr, Pb and Mn. Optimal growth condition of Acinetobactor sp. B2 was confirmed $30^{\circ}C$. Lipase was purified from the supernatant by Acinetobactor sp. B2. Its molecular mass was determined to the 60 kDa and the optimal activity was shown at $40^{\circ}C$ and pH 10. The activation energies for the hydrolysis of p-nitrophenyl palmitate were determined to be 2.7 kcal/mol in the temperature range 4 to $37^{\circ}C$. The enzyme was unstable at temperatures higher than $60^{\circ}C$. The Michaelis constant $(K_{m})\;and\;V_{max}$ for p-nitrophenyl palmitate were $21.8{\mu}M\;and\;270.3{\mu}M\;min^{-1}mg\;of\;protein^{-1}$, respectively. The enzyme was strongly inhibited by $Cd{2+},\;Co^{2+},\;Fe^{2+},\;Hg^{2+},\;EDTA$, 2-Mercaptoethalol. From these results, we suggested that lipase purified from Acinetobactor sp. B2 should be able to be used as a new enzyme for degradation of crude oil, one of the environmental contaminants.

• Journal of the Korean Wood Science and Technology
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• v.23 no.4
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• pp.108-116
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• 1995

This experiment was conducted to screen a superior wood-rotting fungi for lignin degradation and ligninolytic enzyme production by evaluation of red colored zone width on potato-dextrose agar medium and oak woodmeal medium complimented guaiacol. Relationship between the red colored zone width on GU-WA medium and klason lignin loss on woodmeal medium showed the positive correlation. Thus, the potential ligninolytic activity of wood rotting fungi which are not elucidated yet may be estimated to some extent by the evaluation of the red colored zone width on GU-WA medium. Of the isolates screened from fruit bodies and decayed woods. LKY-12, LKY-7 and C. versicolor-13 isolates having preferential lignin degradation and laccase activity were selected. These isolates exhibited characteristics of superior wood-rotting fungi as Klason lignin loss ranged from 30% to 35% and ligninolytic enzyme activity of these isolates on glucose-peptone broth was higher than that of other isolates. And then, these isolates were considered to be able to use in biological pulping and bleaching and ligninolytic enzyme production.

• Journal of Microbiology and Biotechnology
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• v.33 no.1
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• pp.127-134
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• 2023

Laccase activity is influenced by copper (Cu) as an inducer. In this study, laccase was immobilized on Cu and Cu-magnetic (Cu/Fe₂O₄) nanoparticles (NPs) to improve enzyme stability and potential applications. The Cu/Fe₂O₄ NPs functionally activated by 3-aminopropyltriethoxysilane and glutaraldehyde exhibited an immobilization yield and relative activity (RA) of 93.1 and 140%, respectively. Under optimized conditions, Cu/Fe₂O₄ NPs showed high loading of laccase up to 285 mg/g of support and maximum RA of 140% at a pH 5.0 after 24 h of incubation (4℃). Immobilized laccase, as Cu/Fe₂O₄-laccase, had a higher optimum pH (4.0) and temperature (45℃) than those of a free enzyme. The pH and temperature profiles were significantly improved through immobilization. Cu/Fe₂O₄-laccase exhibited 25-fold higher thermal stability at 65℃ and retained residual activity of 91.8% after 10 cycles of reuse. The degradation of bisphenols was 3.9-fold higher with Cu/Fe₂O₄-laccase than that with the free enzyme. To the best of our knowledge, Rhus vernicifera laccase immobilization on Cu or Cu/Fe₂O₄ NPs has not yet been reported. This investigation revealed that laccase immobilization on Cu/Fe₂O₄ NPs is desirable for efficient enzyme loading and high relative activity, with remarkable bisphenol A degradation potential.

• Korean Journal of Food Science and Technology
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• v.49 no.2
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• pp.141-145
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• 2017

In this study, we evaluated the alcohol degradation ability of fig enzyme in the production of cheese using Lactobacillus kitasatonis, Lactobacillus amylophillus, and Leuconostoc mesenteroides sub. The strains were highly resistant to ethanol, acid, and bile acid. When 10% of fig enzyme was added, the alcohol dehydrogenase and aldehyde dehydrogenase activities in each strain were approximately 170, 270, and 190% higher, respectively, than in samples without fig enzyme. The addition of 10% of fig enzyme to produce cheese with the L. amylophillus strain showed an approximately 250% increase in alcohol dehydrogenase and aldehyde dehydrogenase degradation. In conclusion, when fig enzyme was added to produce cheese using L. amylophillus, high alcohol degradation ability was observed. The applicability of fig enzyme addition was confirmed for the production of functional food.

• KSBB Journal
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• v.8 no.1
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• pp.42-48
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• 1993

Continuous degradation of formaldehyde by using a rotating disc contactor was investigated in this study. Peudomonas putida H-5K was selected as a mutant using N-methyl N'-nitro N-nitrosoguandine (250$\mu\textrm{g}$/$m\ell$), which showed 1.5 times higher ability of formaldehyde degradation than that of the parent strain. Enzyme activity for formaldehyde degradation released form Peudomonas putida H-5K showed the highest level of 6.2mo1/min/mg protein in the 2% glucose mineral medium containing 0.02% formaldehyde. Degradation of formaldehyde from the first stage in rotating disc contactor was 95% and 5% from the 4th stage when the reactor was fed with 0.02% or 0.04% formaldehyde solution at a rate of 20$m\ell$ per hour. Continuous degradation of formaldehyde using rotating disc contactor was above 95%o in the medium containing 0.04% formalchyde, at the medium feed ratc of 20$m\ell$ per hour.

• Microbiology and Biotechnology Letters
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• v.28 no.1
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• pp.52-58
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• 2000

The effect of fivrinolytic enzyme produced from Bacillus subtilis K-54 on the thrombosis and stress in vivo was investigated. Each partially purified fibrinolytic enzyme of 4 protein casein unit was administered orally for 3 days before intravenously injection with collagen and epinephrine. In the mice group administered with the enzyme and increased life span of mice was observed in comparison with that of control. The result suggest that the enzyme may prevent the formation of thrombos in vivo. Administration of the enzyme did not influence to stress itself because 5-hydroxyindoleacetatic acid concentration of brain in the mice group with stress did not decreased after the administration of the enzyme. The value of lipid peroxide (LPO) of the liver and brain cells in the group treted with the enzyme was lower than that of control. However, protein degradation (PDP value showed no significant difference between treatment and control groups. In addition, the value of activated partial thromboplastin time (APTT), protrombin time (PT0 and antiplasmin in blood were higher in the stress group than that of the enzyme treated group.

• Microbiology and Biotechnology Letters
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• v.20 no.4
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• pp.390-394
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• 1992

Some enzymatic characteristics of the aflatoxin degrading factor produced extraceIlularly by Aspergillus awamori var. fumeus were investigated. When aflatoxin B1 was incubated with the culture filtrate of A. awamori var. fumeus. 60% of it was degraded within an hour. The degradation rate decreased with time and there was virtually no degradation after one hour. The apparent Michaelis constant ($K_m$) determined by Lineweaver-Burk plot was $10.2{\mu}M$. The optimum degradation was observed at $30^{\circ}C$ and pH 5. For the degradation, molecular oxygen seemed to be required. The degradation was enhanced by the $Co^{2+}$. but was inhibited by many other ions like $Fe^{2+}$, $Ca^{2+}$. $Mg^{2+}$, $Zn^{2+}$,$Cu^{2+}$, and $Ba^{2+}$, The presence of either KeN or metyrapone inhibited the reaction while that of $NaI0_4$ cytochrome C or NADPH showed no effect.

• Journal of Microbiology and Biotechnology
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• v.28 no.7
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• pp.1147-1155
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• 2018

The degradation efficiency and catabolism pathways of the different methylxanthines (MXs) in isolated caffeine-tolerant strain Pseudomonas putida CT25 were comprehensively studied. The results showed that the degradation efficiency of various MXs varied with the number and position of the methyl groups on the molecule (i.e., xanthine > 7-methylxanthine ${\approx}$ theobromine > caffeine > theophylline > 1-methylxanthine). Multiple MX catabolism pathways coexisted in strain CT25, and a different pathway would be triggered by various MXs. Demethylation dominated in the degradation of N-7-methylated MXs (such as 7-methylxanthine, theobromine, and caffeine), where C-8 oxidation was the major pathway in the catabolism of 1-methylxanthine, whereas demethylation and C-8 oxidation are likely both involved in the degradation of theophylline. Enzymes responsible for MX degradation were located inside the cell. Both cell culture and cell-free enzyme assays revealed that N-1 demethylation might be a rate-limiting step for the catabolism of the MXs. Surprisingly, accumulation of uric acid was observed in a cell-free reaction system, which might be attributed to the lack of activity of uricase, a cytochrome c-coupled membrane integral enzyme.

• Journal of Environmental Health Sciences
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• v.26 no.3
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• pp.86-91
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• 2000

The purpose of this was to investigate the degradation efficiency of phenol compounds(catechol, ferulic acid, protocatechuic acid, syringic acid, vanillic acid) by Streptomyces halstedii scabies SAI-36, Streptomyces avendulas SA2-14, and Strptomyces badius(ATCC 39117, control group). The results were as follows: Catechol showed the degradation efficiency that is lower than 50% in three strains. Ferulic acid and vanillic acid showed high degradation efficiency of 98.8% and 94.5% respectively by Streptomyces lavendulas SA2-14. protocatechuic acid and syringicacid showed high degradation efficiency of 89.6% and 77.9%. The degradation efficiency of catechol by Streptomyces halstedii scabies SAI-36, Streptomyces lavendulas SA2-14 and Streptomyces badius(ATCC 39117) was low as 49.2%, 40.2% and 20.2% respectively. But the degradation of other phenolic compoumds except catechol by Streptomyces laven-dulas SA2-36 and Streptomyces badius(ATCC 39117). The results demonstrated that two experimental strains are superior ability to control group in degradation of phenol compounds and Streptomyces lavendulas SA2-14 was superior of two experimental strain. This results were consistent with previous research results that Streptomyces lavendulas SA2-14 was the best strain in degradation ability for lignin, decoloration abilities for variousdyes, and various enzyme production abilities. Therefore, it is suggested that lignin can be used as a indicator when selecting Actinomycetes for degradation of non-degradable materials such as phenol compounds.