• Korean Journal of Food Science and Technology
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• v.22 no.2
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• pp.145-149
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• 1990

Extraction and analysis conditions of di-(2-ethylhexyl) adipate (DOA) and its migration contents into foods wrapped with plasticized polyvinyl chloride (PVC) film during storage and cooking with microwave were examined using gas chromatography. Experiments on the extraction solvent and method showed that the method of reflux using carbon tetrachloride for longer than one hour allowed the highest extraction of DOA. Analysis of four PVC wrap films from different factories in domestic market showed the DOA contents of 18.9% for home-use and 24.6% for retail-use on the average. The highest migration during storage was observed in pork belly, which were 21% and 26% after one and three days respectively. During microwave cooking; smaller than 5.5% of DOA were migrated into foods when the film was not contacted with foods, whereas about 49% migration was observed in pork belly contacted with film directly.

• Journal of Microbiology and Biotechnology
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• v.30 no.4
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• pp.622-632
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• 2020

Phenylalanine ammonia-lyase (PAL) catalyzes the reversible deamination of phenylalanine to cinnamic acid and ammonia. Algae have been considered as biofactories for PAL production, however, biochemical characterization of PAL and its potency for myristicin biotransformation into MMDA (3-methoxy-4, 5-methylenedioxyamphetamine) has not been studied yet. Thus, PAL from Anabaena flos-aquae and Spirulina platensis has been purified, comparatively characterized and its affinity to transform myristicin was assessed. The specific activity of purified PAL from S. platensis (73.9 μmol/mg/min) and A. flos-aquae (30.5 μmol/mg/min) was increased by about 2.9 and 2.4 folds by gel-filtration comparing to their corresponding crude enzymes. Under denaturing-PAGE, a single proteineous band with a molecular mass of 64 kDa appeared for A. flos-aquae and S. platensis PAL. The biochemical properties of the purified PAL from both algal isolates were determined comparatively. The optimum temperature of S. platensis and A. flos-aquae PAL for forward or reverse activity was reported at 30℃, while the optimum pH for PAL enzyme isolated from A. flos-aquae was 8.9 for forward and reverse activities, and S. platensis PAL had maximum activities at pH 8.9 and 8 for forward and reverse reactions, respectively. Luckily, the purified PALs have the affinity to hydroaminate the myristicin to MMDA successfully in one step. Furthermore, a successful method for synthesis of MMDA from myristicin in two steps was also established. Gas chromatography-mass spectrometry (GC-MS) analysis was conducted to track the product formation.

• Asian Journal of Atmospheric Environment
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• v.11 no.3
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• pp.202-216
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• 2017

Nitrogen (N) is an essential macronutrient. Thus, evaluating its flows and stocks in rice paddy ecosystems provides important insights into the sustainability and environmental loads of rice production. Among the N sources of paddy fields, atmospheric deposition and irrigation inputs remain poorly understood. In particular, insufficient information is available for atmosphere-rice paddy exchange of gaseous and particulate reactive N (Nr, all N species other than molecular N) which represents the net input or output through dry deposition and emission. In this study, we assessed the N inputs via atmospheric deposition and irrigation to a Japanese rice paddy area by weekly monitoring for 2 years with special emphasis on gas and particle exchange. The rice paddy during the cropping season acted as a net emitter of ammonia ($NH_3$) to the atmosphere regardless of the N fertilizer applications, which reduced the effects of dry deposition to the N input. Dry N deposition was quantitatively similar to wet N deposition, when subtracting the rice paddy $NH_3$ emissions from N exchange. The annual N inputs to the rice paddy were 3.2 to $3.6\;kg\;N\;ha^{-1}\;yr^{-1}$ for exchange, 8.1 to $9.8\;kg\;N\;ha^{-1}\;yr^{-1}$ for wet deposition, and 11.1 to $14.5\;kg\;N\;ha^{-1}\;yr^{-1}$ for irrigation. The total N input, 22.8 to $27.5\;kg\;N\;ha^{-1}\;yr^{-1}$, corresponded to 38% to 55% of the N fertilizer application rate and 53% to 67% of the brown rice N uptake. Monitoring of atmospheric deposition and irrigation as N sources for rice paddies will therefore be necessary for adequate N management.

• Journal of Microbiology and Biotechnology
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• v.20 no.7
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• pp.1053-1060
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• 2010

Cordyceps militaris, an entomopathogenic fungus belonging to the class Ascomycetes, has been reported to have beneficial biological activities such as hypoglycemic, anti-inflammatory, antitumor, antimetastatic, hypolipidemic, immunomodulatory, and antioxidant effects. In this study, the crude water-soluble polysaccharide CMP, which was obtained from the fruiting body of C. militaris by hot water extraction and ethanol precipitation, was fractionated by DEAE-cellulose and Sepharose CL-6B column chromatographies. This process resulted in three polysaccharide fractions, termed CMP Fr I, CMP Fr II, and CMP Fr III. Of these fractions, CMP Fr II, with an average molecular mass of 127 kDa, was able to upregulate effectively the phenotypic functions of macrophages such as NO production and cytokine expression. The chemical property of the stimulatory polysaccharide, CMP Fr II, was determined based on its monosaccharide composition, which consisted of glucose (56.4%), galactose (26.4%), and mannose (17.2%). Its structural characteristics were investigated by a combination of chemical and instrumental analyses, including methylation, reductive cleavage, acetylation, Fourier transform infrared spectroscopy (FTIR), and gas chromatography-mass spectrometry (GCMS). Results indicated that CMP Fr II consisted of the (1${\rightarrow}$4) or (1${\rightarrow}$2) linked glucopyranosyl or galactopyranosyl residue with a (1${\rightarrow}$2) or (1${\rightarrow}$6) linked mannopyranosyl, glucopyranosyl, or galactopyranosyl residue as a side chain. The configuration of the ${\beta}$-linkage and random coil conformation of CMP Fr II were confirmed using a Fungi-Fluor kit and Congo red reagent, respectively.

• Journal of Microbiology and Biotechnology
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• v.22 no.9
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• pp.1185-1192
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• 2012

This study investigated the hydrocarbonoclastic microbial community present on weathered crude oil and their ability to degrade weathered oil in seawater obtained from the Gulf St. Vincent (SA, Australia). Examination of the native seawater communities capable of utilizing hydrocarbon as the sole carbon source identified a maximum recovery of just $6.6{\times}10^1\;CFU/ml$, with these values dramatically increased in the weathered oil, reaching $4.1{\times}10^4\;CFU/ml$. The weathered oil (dominated by > $C_{30}$ fractions; $750,000{\pm}150,000mg/l$) was subject to an 8 week laboratory-based degradation microcosm study. By day 56, the natural inoculums degraded the soluble hydrocarbons (initial concentrations $3,400{\pm}700mg/l$ and $1,700{\pm}340mg/l$ for the control and seawater, respectively) to below detectable levels, and biodegradation of the residual oil reached 62% ($254,000{\pm}40,000mg/l$) and 66% ($285,000{\pm}45,000mg/l$) in the control and seawater sources, respectively. In addition, the residual oil gas chromatogram profiles changed with the presence of short and intermediate hydrocarbon chains. 16S rDNA DGGE sequence analysis revealed species affiliated with the genera Roseobacter, Alteromonas, Yeosuana aromativorans, and Pseudomonas, renowned oil-degrading organisms previously thought to be associated with the environment where the oil contaminated rather than also being present in the contaminating oil. This study highlights the importance of microbiological techniques for isolation and characterisation, coupled with molecular techniques for identification, in understanding the role and function of native oil communities.

• Bulletin of the Korean Chemical Society
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• v.34 no.12
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• pp.3817-3824
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• 2013

Various separation modes in HPLC, such as anion exchange (AE), reversed-phase (RP), and affinity (AF) chromatography were examined for the separation of selenium species in human blood serum and urine. While RP- and AE-HPLC were mainly used for the separation of small molecular selenium species, double column AF-HPLC achieved the separation of selenoproteins in blood serum efficiently. Further, the effluent of AF-HPLC was enzymatically hydrolyzed and then analyzed with RP HPLC for selenoamino acid study. The versatility of the hybrid technique makes the in-depth study of selenium species possible. For quantification, post column isotope dilution (ID) with $^{78}Se$ spike was performed. ORC ICP/MS (octapole reaction cell inductively coupled plasma/mass spectrometry) was used with 4 mL $min^{-1}$ Hydrogen as reaction gas. In urine sample, inorganic selenium and SeCys were identified. In blood serum, selenoproteins GPx, SelP and SeAlb were detected and quantified. The concentration for GPx, SelP and SeAlb was $22.8{\pm}3.4\;ng\;g^{-1}$, $45.2{\pm}1.7\;ng\;g^{-1}$, and $16.1{\pm}2.2\;ng\;g^{-1}$, respectively when $^{80}Se/^{78}Se$ was used. The sum of these selenoproteins ($84.1{\pm}4.4\;ng\;g^{-1}$) agrees well with the total selenium concentration measured with the ID method of $87.0{\pm}3.0\;ng\;g^{-1}$. Enzymatic hydrolysis of each selenium proteins revealed that SeCys is the major amino acid for all three proteins and SeMet is contained in SeAlb only.

• Journal of Environmental Science International
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• v.14 no.1
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• pp.23-32
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• 2005

Surface sediments (0$\~$4 cm) were sampled at 40 stations from Ulsan Bay and its adjacent areas of Korea, to evaluate the contamination by sewage-derived organic matters using fecal sterols. Some sterols were quantified by gas chromatography coupled to mass spectrometry (GC/MS). Total concentrations of eight sterols (co­prostanol, cholesterol, cholestanol, epicholestanol, epicoprostanol, ${\beta}-sitosterol,$ brassicasterol, and stigmasterol) in the sediments from Ulsan Bay and its vicinity varied from 929 to 23,444 ng/g dry weight. The most predom­inant sterols were cholesterol and coprostanol, accounting for $33\~72{\%}$ of total sterols. The concentration of coprostanol known as the indicator of human feces ranged from 141 to 8,257 ng/g dry weight. In particular, the coprostanol concentrations in the sediments from Jansaengpo Harbor and Taehwa River exceeded the value of 1,000 ng/g dry weight, suggesting that these areas could be considered as the hot-spot zones by municipal sewage contamination. Some molecular indices and multivariate data analysis were used to assess the origin of these sterols in the sediments. Results showed that the major routes of sewage contamination in Ulsan Bay and its vicinity were the input through Jansaengpo Harbor and Taehwa River.

• Journal of Environmental Science International
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• v.5 no.5
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• pp.593-603
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• 1996

A dual-porosity filmed agglomerate model for the porous cathode of the molten carbonate fuel has been investigated to predict the cell performance. A phenomenological treatment of molecular, kinetic and electrode parameters has been given. The major physical and chemical phenomena being modeled include mass transfer, ohmic losses and reaction kinetics at the electrode- electrolyte interface. The model predicts steady-state cell performance, given the above conditions that characterize the state of the electrode. Quasi-linearization and finite difference techniques are used to solve the coupled nonlinear differential equations. Also, the effective surface area of electrode pore was obtained by mercury porosimeter. The results of the investigation are presented in the form of plots of overpotential vs. current density with varied the electrode material, gas composition and mechanism. The predicted polarization curves are compared with the empirical data from 1 c$m^2$ cell. A fair correspondence is observed.

• Journal of Environmental Science International
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• v.6 no.1
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• pp.75-88
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• 1997

The rates of photodegradation, reactivities, and mechanisms of photooxidation for the aqueous solution containing with halogen derivatives of aliphatic hydrocarbons have been discussed with respect to the kinds of photocatalysts, concentration of photocatalytlc suspensions, strength of radiant power, time of illumination, changes of pH of substrate solution, wavelength of radiation, and pressure of oxygen gas saturated In the solution. These aqueous solutions suspended with 0.5 $gL^{-1}$ $TiO_2$ powder have been photodecomposed in the range of 100 and 93.8% per 1 hour if it is illuminated with wavelength (λ $\geq$ 300nm) produced from Xe-lamp(450W). The photocatalytic abilities have been increased In the order of $Fe_2O_3$ < CdS < $CeO_2$ < Y_2O_3$ <$TiO_2$, and rates of photodegradation for the solution have maldmum values in the condition of pH 6 ~ 8 and 3 psi-$O_2$ gL^{-1}$. These rates for the Photoolddation Per 1 hour were dependent on the size of molecular weight and chemical bonding for organic halogen compounds and the rates of photodegadation were increased in the order of $C_2H_5Br$ < CH_2Br_2$ < C_5H_11Cl C_2H_4Cl_2$ < tracts-$C_2H_2Cl_2$ < cis-C_2H_2Cl_2$ The T_{1/2}$ and t99% for these solutions were 5~21 and 40~90 minutes. respectively, and these values were coincided with Initial reaction kinetics(ro). It was found that reaction of photodegradation has the pseudo first-order kinetics controlled by the amount of $h^+_{VB}$ diffused from a surface of photocatalysts.

• Particle and aerosol research
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• v.9 no.3
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• pp.187-197
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• 2013

To understand the characteristics of organic aerosol(OA) at the background atmosphere of Korea, an observation of atmospheric PM10 was conducted at a Global Atmospheric Watch(GAW) station operated by the Korean Meteorological Administration at Anmyon Island during 2010. Various organic compounds were analyzed from 26 samples by using a gas chromatography-mass spectrometer. Water soluble organic carbon(WSOC) was also analyzed by using a total organic carbon(TOC) analyzer. Among 6 classes with 68 target compounds detected, the classes of n-alkanoic and alkenoic acids ($326.67{\pm}75.40ngm^{-3}$) and dicarboxylic acids ($323.74{\pm}361.89ngm^{-3}$) were found to be major compound classes in the atmosphere of Anmyon Island. Compared to the previous results reported for 2005 spring samples at Gosan site, the concentrations of organic compounds at Anmyon Island were 3-10 times higher than Gosan site due to the difference of location and sampling period. The concentrations of organic compounds were varied with the atmospheric conditions. Significant increase of the concentrations of dicarboxylic and carboxylic acids in the smog episode indicated that secondary oxidation of organic compounds was major factor to increase OA concentration during smog episode in the Anmyon Island. It was found that the compositions of the OA measured at Anmyon Island were dependent on the air parcel trajectories.