• Journal of the Korean Society for Heat Treatment
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• v.28 no.6
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• pp.300-309
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• 2015

The aim of the present study was to predict the variations in microstructure and deformation occurring during gas carburizing and quenching processes of a SCM420H planetary gear in a real production environment using the finite element method (FEM). The motivation for the present study came from the fact that previous FEM simulations have a limitation of the application to the real heat treatment process because they were performed with material properties provided by commercial programs and heat transfer coefficients (HTC) measured from laboratory conditions. Therefore, for the present simulation, many experimentally measured material properties were employed; phase transformation kinetics, thermal expansion coefficients, heat capacity, heat conductivity and HTC. Particularly, the HTCs were obtained by converting the cooling curves measured with a STS304 gear without phase transformations using an oil bath with an agitator in a real heat treatment factory. The FEM simulation was successfully conducted using the aforementioned material properties and HTC, and then the predicted results were well verified with experimental data, such as the cooling rate, microstructure, hardness profile and distortion.

• Microbiology and Biotechnology Letters
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• v.27 no.6
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• pp.491-499
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• 1999

A great variety of the volatile metabolic by-products was formed in yeast cell during alcohol fermentation. The seibel grape (Vitis labrasca) which was grown in the Southern Korea used for wines. The objective of this research was to identify the volatile flavor compounds during alcohol fermentation and aging at 12$^{\circ}C$. saccharomyces cerevisiae and Schizosaccharomyces pombe were inoculated and fermented in seibel grape must. The volatile flavor compounds of logarithmic, stationary and death phases were extracted, concentrated and identified by gas chromatography/mass spectrometer (GC/MS). The volatile flavor compounds were determined by a Hewlett-Packard 5890 II Plus GC which was equipped with Supelcowax 10 fused silica capillary column (60m$\times$0.32mm$\times$0.25${\mu}{\textrm}{m}$ film thickness) wall coated with polyethyleneglycerol. The scan detection method allowed the comparison of the spectrum from the chromatogram of volatile flavor compounds to those in data Wileynbs base library. Among the volatile compounds collected by ether-hexane extraction method, the evolution of 20 main compounds, such as 9 esters (ethyl butyrate, isoamyl acetate, ethyl caproate, n-hexyl acetate, ethl caprylate, ethyl caprate, diethy succinate, ethyl hexadecanoate, 2-pheneethyl acetate), 4 alcohols (3-methyl-1-butanol, 1-hexanol, 1-heptanol, benzoethanol), 4 ketones and acids (2-octanone, caproic acid, caprylic acid, capric acid), 2 furan and phenol (2,6-bis(1,1-dimethyl ethyl)phenol, 2,3-dihydrobenzofuran) were observed during alcohol fermentation and aging. The production of the esters during alcohol fermentation with S. cerevisiae was higher than those of Sch. pombe. The sensory scores of the aged wine samples in aroma, taste and overall acceptability were not significantly different(p<0.05).

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.5
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• pp.756-762
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• 2006

The objective of this study was to define the effects of various cooking and re-heating methods (pan roasting, steaming, oven grilling and micro-waving) on the cholesterol and formation of cholesterol oxidation products in beef loin during storage at $4^{\circ}C$. Raw samples showed lower total cholesterol content than cooked products sampled during storage for 6 d. The following cholesterol oxidation products (COPs) were separated by gas chromatography: $7{\beta}$-hydroxy cholesterol, $20{\alpha}$-hydroxy cholesterol, 25-hydroxy cholesterol, cholestane-$3{\beta}$, $5{\alpha}$, $6{\beta}$ triol (triol), ${\alpha}$-epoxide and 7-ketocholesterol. Total amounts of COPs/cholesterol at 0 d were 0.74, 0.63, 0.76, 1.23 and 0.83% for the raw sample, pan roasting, steaming, oven grilling and micro waving methods, respectively. After 6 d storage almost of the samples had higher content of total COPs than at 0 and 3 d; the lowest (0.55%) COPs was found in the steaming cooking and re-heating method. The highest (5.96%) of COPs was found in the pan roasting cooking and re-heating method after 6 d storage. In conclusion, the concentration of total cholesterol and cholesterol oxidation of beef loin were increased as a consequence of cooking and re-heating methods. Steaming and micro-waving methods showed the lowest of cholesterol oxidation products under refrigerated storage for 6 d. However, each cooking and re-heating method had its own distinctive cooking effects.

• Journal of Microbiology and Biotechnology
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• v.24 no.9
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• pp.1280-1290
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• 2014

In order to obtain the cellulolytic bacterial consortia, sediments from Great Basin hot springs (Nevada, USA) were sampled and enriched with cellulosic biomass as the sole carbon source. The bacterial composition of the resulting anaerobic ethanol-producing celluloytic bacterial consortium, named SV79, was analyzed. With methods of the full-length 16S rRNA library-based analysis and denaturing gradient gel electrophoresis, 21 bacteria belonging to eight genera were detected from this consortium. Clones with closest relation to the genera Acetivibrio, Clostridium, Cellulosilyticum, Ruminococcus, and Sporomusa were predominant. The cellulase activities and ethanol productions of consortium SV79 using different agricultural residues (sugarcane bagasse and spent mushroom substrate) and energy crops (Spartina anglica, Miscanthus floridulus, and Pennisetum sinese Roxb) were studied. During cultivation, consortium SV79 produced the maximum filter paper activity (FPase, 9.41 U/ml), carboxymethylcellulase activity (CMCase, 6.35 U/ml), and xylanase activity (4.28 U/ml) with sugarcane bagasse, spent mushroom substrate, and S. anglica, respectively. The ethanol production using M. floridulus as substrate was up to 2.63 mM ethanol/g using gas chromatography analysis. It has high potential to be a new candidate for producing ethanol with cellulosic biomass under anoxic conditions in natural environments.

• 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-Australasian Journal of Animal Sciences
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• v.31 no.2
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• pp.263-269
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• 2018

Objective: Heat stress (HS) triggers oxidative stress and respiratory alkalosis in pigs. The objective of this experiment was to study whether a short-term supranutritional amount of dietary vitamin E (VE) can mitigate oxidative stress and respiratory alkalosis in heat-stressed pigs. Methods: A total of 24 pigs were given either a control diet (17 IU/kg VE) or a high VE (200 IU/kg VE; HiVE) diet for 14 d, then exposed to thermoneutral (TN; $20^{\circ}C$, 45% humidity) or HS ($35^{\circ}C$, 35% to 45% humidity, 8 h daily) conditions for 7 d. Respiration rate and rectal temperature were measured three times daily during the thermal exposure. Blood gas variables and oxidative stress markers were studied in blood samples collected on d 7. Results: Although HiVE diet did not affect the elevated rectal temperature or respiration rate observed during HS, it alleviated (all p<0.05 for diet${\times}$temperature) the loss of blood $CO_2$ partial pressure and bicarbonate, as well as the increase in blood pH in the heat-stressed pigs. The HS reduced (p = 0.003) plasma biological antioxidant potential (BAP) and tended to increase (p = 0.067) advanced oxidized protein products (AOPP) in the heat-stressed pigs, suggesting HS triggers oxidative stress. The HiVE diet did not affect plasma BAP or AOPP. Only under TN conditions the HiVE diet reduced the plasma reactive oxygen metabolites (p<0.05 for diet${\times}$temperature). Conclusion: A short-term supplementation with 200 IU/kg VE partially alleviated respiratory alkalosis but did not reduce oxidative stress in heat-stressed pigs.

• 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.

• Microbiology and Biotechnology Letters
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• v.30 no.3
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• pp.287-292
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• 2002

Lignin-peroxidase (LiP) has been considered as one of the most important industrial enzymes for biodegradation of various recalcitrant toxic compounds such as chlorinated aromatic hydrocarbons and azo-dyes. Recently, several soil actinomycetes have been reported to secrete a functionally-similar lignin-peroxidase called actinomycetes lig-nin-peroxidase (ALiP). In this manuscript, we isolated over 100 morphologically distinct actinomycetes from the contaminated soils around 10 different gas stations located nearby the Kyung-An river. Among these actinomycetes screened based on the congo-red dye-decolorization activities, one newly-isolated actinomycetes named SMA-2 showed the most significant dye-decoloring activity on the congo-red plate as well as a significant ALiP activity in a yeast-extract-malt-extract liquid media supplemented with starch. The optimum SMA-2 culture condition fur ALiP production was determined and the kinetic parameters fur the SMA-2 AkIP activity were characterized. The optimally-cultured SMA-2 also exhibited the oxidation activities toward various recalcitrant aromatic compounds including phenol, 2- chlorophenol, 4- chlorophenol, 2,4- dichlorophenol ,2,6- dichlorophenol, and 2,4, f-trichlorophe - not, suggesting a potential application of SMA-2 for contaminated soil bioremediation.

• Journal of Microbiology and Biotechnology
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• v.25 no.12
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• pp.2049-2057
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• 2015

Various salt concentrations (1.0%, 1.3%, 1.6%, 1.9%, and 2.1% labeled as sample A, B, C, D, and E, respectively) were investigated for microbial diversity, identification of Lactic Acid Bacteria (LAB) in salted kimchi cabbage, prepared under laboratory conditions. These samples were stored at 4°C for 5 weeks in proper aluminum-metalized pouch packaging with calcium hydroxide gas absorber. A culture-independent method known as polymerase chain reaction - denaturing gradient gel electrophoresis was carried out to identify LAB distributions among various salt concentration samples that had identified 2 Weissella (W. confusa and W. soli), 1 Lactobacillus (Lb. sakei), and 3 Leuconostoc (Lc. mesenteroides, Lc. lactis, and Lc. gelidum) in the overall kimchi samples. The pH, titratable acidity, viable cell counts, and coliform counts were not affected by salt variations. In order to assess sensory acceptance, the conducted sensory evaluation using a 9-point hedonic scale had revealed that samples with 1.3% salt concentration (lower than the manufacturer's regular salt concentration) was more preferred, indicating that the use of 1.3% salt concentration was acceptable in normal kimchi fermentation for its quality and safety. Despite similarities in pH, titratable acidity, viable cell counts, coliform counts, and LAB distributions among the various salt concentrations of kimchi samples, the sample with 1.3% salt concentration was shown to be the most preferred, indicating that this salt concentration was suitable in kimchi production in order to reduce salt intake through kimchi consumptions.

• Journal of Microbiology and Biotechnology
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• v.19 no.9
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• pp.951-959
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• 2009

Most, if not all, Basidiomycetes mushrooms have biologically active polysaccharides showing potent antitumor activity with immunomodulating properties. These polysaccharides have various chemical compositions and belong primarily to the $\beta$-glucan group. In this study, the crude water-soluble polysaccharide HEF-P, which was obtained from the fruiting body of Hericium erinaceus by hot water extraction and ethanol precipitation, was fractionated by DEAE-cellulose and Sepharose CL-6B column chromatographies. This process resulted in four polysaccharide fractions, named HEF-NP Fr I, HEF-NP Fr II, HEF-AP Fr I, and HEF-AP Fr II. Of these fractions, HEF-AP Fr II was able to upregulate the functional events mediated by activated macrophages, such as production of nitric oxide and expression ofcytokines (IL-1${\beta}$ and TNF-${\alpha}$). The molecular mass of HEF-AP Fr II was estimated by gel filtration to be 13 kDa. Its structural characteristics were investigated by a combination of chemical and instrumental analyses, including methylation, reductive cleavage, acetylation, Fourier transform infrared spectroscopy (FT-IR), and gas chromatography-mass spectrometry (GC-MS). Results indicate that HEF-AP Fr II is a low-molecular-mass polysaccharide with a laminarin-like triple helix conformation of a ${\beta}$-1,3-branched-${\beta}$-1,6-glucan.