• Journal of Photoscience
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• v.12 no.1
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• pp.17-23
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• 2005

Application of a new photocatalyst has been attempted to improve the efficiency and rates of photocatalytic degradation of azo dyes by using a model dye such as Methyl Orange. As a new photocatalyst, $TiO_2$ encapsulated EFAL-removed zeolite Y ($TiO_2$ /EFAL-removed zeolite Y) has been synthesized by ion-exchange in the mixture of EFAL-removed zeolite Y with 0.05 M aqueous [$(NH_4)_2 TiO(C_2O_4)_2.H_2O$] [$TiO(C_2O_4)_2.H_2O$]. This new photocatalyst has been characterized by measuring XRD, IR and reflectance absorption spectra as well as ICP analysis, and it was found that the framework structure of $TiO_2$ /EFAL-removed zeolite Y is not changed by removing the extra-framework aluminum (EFAL) from the normal zeolite Y and the $TiO_2$ inside the photocatalyst exists in the form of $(TiO^{2+})_n$ nanoclusters. Based on the ICP analysis, the Si/Al ratio of the $TiO_2$ /EFAL-removed zeolite Y and the weight of $TiO_2$ were determined to be 23 and 0.061g in 1.0g photocatalyst, respectively. It was also found that adsorption of the azo dye in the $TiO_2$ /EFAL-removed zeolite is very effective (about 80 % of the substrate used). This efficient adsorption contributes to the synergistic photocatalytic activities of the $TiO_2$ /EFAL-removed zeolite by minimizing the required flux diffusion of the substrate. Thus, the photocatalytic reduction of methyl orange (MO) was found to be 8 times more effective in the presence of $TiO_2$ /EFAL-removed zeolite Y than in the presence of $TiO_2$ /normal zeolite Y. Furthermore, the photocatalytic reduction of MO by using 1.0 g of the $TiO_2$ /EFAL-removed zeolite Y containing 0.061g of $TiO_2$ is much faster than that carried out by using 1.0 g of Degussa P-25.

• Applied Biological Chemistry
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• v.43 no.4
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• pp.260-265
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• 2000

To determine the quality change of the irradiated eggs during storage, fresh shell eggs were irradiated using $^{60}Co$ at 0, 1, 5, 10, 30 kGy and stored for 30 days. The york index, color, pH, viscosity, egg weight, and SDS-PAGE profile of the irradiated eggs were examined. During storage, york index values of the irradiated eggs and the control were decreased and the increase of dose decreased yolk index. However, the yolk index values were increased temporarily at 10 kGy and 30 kGy. The yolk color had a bright yellow with increases in dose level and there was no significant change during storage. The albumen viscosities were decreased with increases in dosage and were decreased during storage. Also, the albumen pH values of the irradiated eggs were higher than that of the control and were increased during storage. The weight losses of eggs were increased during storage and there were no significant changes by dose level. SDS-PAGE profile of the egg white proteins of the shell eggs showed the change in molecular weight distribution and had aggregation pattern as well as degradation. CD and fluorescence spectroscopy study showed changes in the secondary and tertiary structure of egg white proteins by ${\gamma}-irradiation$. Therefore, this study clearly indicates that irradiation dose of eggs should be appropriate to prevent the loss of egg qualities.

• Korean Journal of Agricultural Science
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• v.36 no.1
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• pp.1-10
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• 2009

The characteristics of fruit ripening and cell wall modifications of two oriental pear fruits were compared during storage. The loss of fresh weight was lower in 'Pingguoli' than 'Niitaka', probably due to the difference in wax accumulation and skin structure. 'Pingguoli' produced much higher amount of ethylene and showed climacteric ripening pattern, but this response was not found in 'Niitaka'. A significant difference in soluble pectin contents was found, thus, the amount of water soluble pectins were much higher in 'Niitaka' at harvest but this difference was not significant at later stage of storage. A severe loss of water soluble pectins in 'Niitaka' was confirmed whereas a similar tendency was not found in CDTA soluble ones. Even the amount of $Na_2CO_3$ soluble pectins was relatively low, 'Pingguoli' contained approximately 2 times higher than 'Niitaka' and both cultivars showed an increasing tendency in $Na_2CO_3$ soluble polymers at later stage of storage. No significant difference in alkali soluble polysaccharides (hemicelluloses fraction) was found between both cultivars. There was a significant change in gel filtration profiles regardless of cultivars, especially in water soluble pectins resulting from severe depolymerization probably due to degradation of higher molecular weight pectins and loss of their side chains. In gel filtration profiles of $Na_2CO_3$ soluble pectins, neutral sugars were evenly distributed regardless of molecular size of pectic polymers but the decrease of high molecular weight fraction was found. In comparison of alkali soluble polymers, a similar trend was found, that is, there was no difference in gel filtration profiles but 'Niitaka' seemed to have longer side chains in alkali soluble polysaccharides in both 4% and 24% of KOH soluble fractions.

• Korean Journal of Food Science and Technology
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• v.48 no.2
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• pp.97-103
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• 2016

This study was conducted for the production of water-soluble dietary fiber (SDF) from buckwheat hulls by using Celluclast or Viscozyme. The functionality of this SDF, including antioxidant activity, glucose- and bile acid-retardation effects in vitro, was measured. SDF yields from cellulose and hemicellulose fractions were 60.5 and 123.7 g/kg dry matter, respectively. Analysis of molecular weight distribution of SDF by using gel chromatography showed that SDF degradation increased with increase in reaction time. The antioxidant activity of SDF obtained by enzymatic hydrolysis was higher than that of dietary fiber without enzyme treatment. SDF showed higher retardation effects on glucose and bile acid than the sample without dietary fiber did. The results of this study suggested that SDF produced from buckwheat hull by enzymatic hydrolysis is a good source of functional food material because of its high antioxidant activity and glucose- and bile acid-retardation effects.

• Korean Journal of Food Science and Technology
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• v.47 no.1
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• pp.6-12
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• 2015

This study was performed to determine the optimal hydrolysis conditions for the production of hydrolysates, including water-soluble dietary fiber from Chinese cabbage, with commercial enzymes. The optimal pH and temperature for hydrolysis of the hemicellulose fraction were pH 5.0 and $40^{\circ}C$, and optimal enzyme concentrations were 45 units and 21 units for Shearzyme plus and Viscozyme L, respectively. The yields of the hydrolysate including the water-soluble dietary fiber from the hemicellulose fraction by Shearzyme plus and Viscozyme L were 22.64 and 24.73%, respectively, after a 72 h reaction. The molecular weight distribution of alcohol-insoluble fiber was characterized by gel chromatography; degradation of hemicellulose increased with increasing reaction time. Our results indicate that the hemicellulose fraction was degraded to water-soluble dietary fiber by enzymatic hydrolysis, and its hydrolysate could be utilized as new watersoluble food materials.

• Microbiology and Biotechnology Letters
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• v.25 no.1
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• pp.89-95
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• 1997

The current processer of the textile wastewater treatment are mostly consisted of a combination of a physico-chemical and a biological treatment. The overall efficiency of these processes is, however, assessed to be fairly low. It is even worse during the summer season when temperature of the wastewater rises above 40$\circ $C. Therefore, a feasible process of the textile wastewater treatment which can work efficiently at higher temperatures was investigated in this work. We used a bench scale reactor consisted of one 4 liter anaerobic and one 8 liter aerobic tank, and the thermophilic symbiotic PVA degraders, Pasteruella hemolytica KMG1 and Pseudomonas sp. KMG6 that had been isolated in our laboratory. In the preliminary flask experiments, we observed that the thermophilic symbiotic PVA degraders could not grow in the wastewater substrate. Then, we isolated the mutant strains by acclimating the KMG1and KMG6 strains to the wastewater medium. The mutant symbionts (KMG1-1 and KMG6-1) were isolated through 6 times successive transfers into the fresh wastewater medium after 5 days culture for each. The mutant strains obtained grew well in the mixed medium composed of 75% wastewater and 25% synthetic medium, and supplemented with 0.5% PVA as a sole carbon source. During the culture for 14 days at pH 7.0 and 40$\CIRC $C, the bacteria assimilated about 89% of the added PVA. The symbionts degraded equally well all the PVA substrates of different molecular weight (nd=500~30000). In contrast to the flask experiments, in the reactor system the mutant strains showed very low levels of the PVA and COD removal rates. However, the new reactor system with an additional aerobic tank attained 82% removal rate of COD, 94% of PVA degradation and 71% of color index under the conditions of 5% inoculm on the tank 2, incubation temperature of 40$\circ $C, dissolved oxygen level of 2~3 mg/l and retention time of 30 hours. This result ensures that the process described above could be an efficient and feasible treatment for the PVA contained textile wastewater at higher temperatures.

• International Journal of Industrial Entomology and Biomaterials
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• v.6 no.1
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• pp.33-44
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• 2003

The arylphorin was purified from the pupal haemolymph of the Chinese oak silkmoth, Antheraea pernyi, and characterized physiologically and biochemically, The protein was purified by a simple preparative polyacrylamide gel electrophoresis (PAGE) and subsequent diffusive elution. The preparation was shown to be homogeneous by 7.5% native-PAGE. The native molecular weight of arylphorin was 450 kDa with a 80 kDa single subunit, suggesting hexamer, The protein contained high amounts (18.3%) of aromatic amino acids, phenylalanine (9.7%) and tyrosine (8.6%). Therefore, the protein was identified as a kind of a storage protein referred to as an arylphorin. The protein was stained by Schiff's reagent, suggesting a glycoprotein. The protein contained 4.9% (w/w) sugar and mannose and N-acetylglucosamine were major components. Also, degradation of the protein was begun by heat treatment at 90 for 20 minutes. These results showed that the A. pernyi arylphorin in the study is hexamer associated with the six subunits consisting of a 80kDa single subunit, and is different from that of Kajiura et al. (1998) in the subunit composition.

• Microbiology and Biotechnology Letters
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• v.2 no.1
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• pp.45-50
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• 1974

1 With cysteinedesulfhydrase (E. C.4.4.1.1.) from Aerobactor aerogenes, an enzyme which catalyzes the stoichiometric conversion of L-cysteine to pyruvate, ammonia and sulfide, reversibility of the degradation of L-cysteine was investigated. It was found that the enzyme also catalized the reverse reaction of $\alpha$, $\beta$-elimination to synthesize L-cysteine derivatives from pyruvate, ammonia and sulfides when large amounts of substrates were added to the reaction mixtures. 2. The synthetic reaction by cysteinedesulfhydrase proceeded linearly with incubation time and enzyme concentrations. The optimal pH for the synthetic reaction was 10.0. 3. The results of the isolation and identification of the products showed that the L-cysteine derivatives synthesized by this enzymatic method were identical with S-methyl-L-cysteine and S-ethyl-L-cysteine respectively.

• Applied Biological Chemistry
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• v.33 no.1
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• pp.79-86
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• 1990

Cyclodextrin hydrolase from Bacillus stearothermophilus KFCC 21203 was purified and the properties of the purified enzyme were investigated. The enzyme was purified 15 folds with 77 % recovery by ammonium sulfate fractionation, DEAE-cellulose chromatography, and Ultro AcA 34 gel filtration. The specific activity and the molecular weight of the enzyme were 1.30 units/mg protein and about 29,500, respectively, The maximum activity of the enzyme was shown at $55^{\circ}C$ and pH 5.5. However, stable temperature and pH were $40^{\circ}C$ and $5.0{\sim}8.0$, respectively. The Km value for ${\gamma}-cyclodextrin$ was $3.78{\times}10^{-3}$ M. The degradation activity of the enzyme was selectively high for ${\gamma}-cyclodextrin$, and very low for ${\beta}-cyclodextrin$, but not for ${\alpha}-cyclodextrin$. The decomposed products of ${\gamma}-cyclodextrin$ were mainly glucose and maltose, and a little mlatotriose. The activity of the enzyme was very high for amylose, potato starch, corn starch, amylopectin and maltooligomer, and relatively high for glycogen and dextrin. The decomposed products of them were mainly glucose and maltose.

• Elastomers and Composites
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• v.35 no.4
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• pp.272-280
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• 2000

The experimental kinetics was analyzed for commercial rubbers such as NR, IR, BR, SBR 1500, and SBR 1700. Kinetic analysis for the commercial rubbers was performed using a thermogravimetric method, which the activation energies of NR obtained by Kissinger, Friedman, ana Ozawa's method were 195.0, 198.3, and 186.3 kJ/mol, respectively. whereas that of SBR 1500 were 246.4, 247.5, and 254.8 kJ/mol, respectively. It was shown that the yield of pyrolytic oil was generally increased with increasing the final temperature. Considering the effect of heating rate. it was found that the yield of pyrolytic oil was not consistent for each sample. The number average molecular weight of pyrolitic oil of SBR 1500 was in the range of 740-2486. The calorific value of SBR 1500 was 39-40 kJ/g, and it might be a considerable energy potential although it was lower than the conventional fuel such as kerosene, diesel, light fuel, and heavy fuel.