• Microbiology and Biotechnology Letters
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• v.24 no.6
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• pp.743-748
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• 1996

For the biological treatment of phenolic resin wastewater containing phenol and formaldehyde, a phenol-degrading yeast was isolated from the papermill sludge, and then identified as Candida tropicalis PW-51 according to morphological, physiological and biochemical properties. The strain was able to degrade high phenol concentrations up to 2,000mg/l within 58 hours in batch cultures. Phenol-degrading efficiency by the strain was maximum at the culture conditions of a final concentration of 9 $\times$ 10$^{6}$ cells/ml, 30$\circ$C and pH 7.0. The mean degradation rate of phenol was highest at 45.5mg/l/h in 1,000mg/l phenol from 500mg/l to 2,000mg/l phenol. Because the enzyme activity of catechol 1,2-dioxygenase increased in the course of degradation of phenol, it seems that this strain degrades phenol via the ortho-cleavage of benzene ring. The isolate C. tropicalis PW-51 could be effectively used for the biological treatment of phenolic resin wastewater.

• Journal of Microbiology and Biotechnology
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• v.12 no.5
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• pp.849-853
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• 2002

Metal ions have an adverse effect on anaerobic digestion. In an acetate degradation test of upflow of anaerobic sludge blanket granules with $Cu^{2+}$, not all of the acetate that disappeared was stoichiometrically converted to methane. In the presence of 400 mg/g-VSS (volatile suspended solids) $Cu^{2+}$, only 26% of the acetate consumed was converted to methane. To study acetate conversion by other anaerobic microorganisms, sulfate and nitrate reductions were investigated in the presence of $Cu^{2+}$ Sulfate and nitrate reductions exhibited more resistance to $Cu^{2+}$than methanogenesis, and the granules reduced 2.2 mM and 5.4 mM of nitrate and sulfate, respectively, in the presence of 400 mg/g-VSS copper ion. However, the acetate degraded by sulfate and nitrate reductions was only 24% of the missing acetate that could have been stoichiometrically converted to $CO_2$. Accordingly, 76% of the acetate consumed appeared to have been converted to other unknown compounds.

• Journal of Applied Biological Chemistry
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• v.55 no.1
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• pp.27-34
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• 2012

Soy protein isolate (SPI)-based edible coating, with and without carboxymethyl cellulose (CMC), were used to reduce oxidative degradation of cut pork stored at $4^{\circ}C$ for 5 days. The SPI coating reduced (p<0.05) thiobarbituric acid-reactive substances (TBARS) and peroxide value (PV), compared with controls. The inhibition of TBARS and PV for SPI-coated porks with and without CMC, compared with the control was 19.1 and 23.9, and 25.7 and 37.7%, respectively. The SPI coating prevented loss of $L^*$ and $a^*$ values of porks compared to the control. The ability of the SPI coating to provide a moisture barrier for the porks was reduced (p<0.05). The SPI-coated porks with and without CMC reduced moisture loss by 37.3 and 44.6%, respectively, over the control. However, SPI coating of porks did not inhibit the growth of either total plate counts or L. monocytogenes. The result revealed that SPI can effectively be used as a natural antioxidative coating to extend quality and shelf life of pork.

• Biotechnology and Bioprocess Engineering:BBE
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• v.7 no.2
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• pp.105-111
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• 2002

The biological removal of 2,4,6-trinitrotoluene (TNT) was studied in a bench-scale bioreactor using a bacterial culture of strain OK-5 originally Isolated from soil samples contaminated with TNT. The TNT was completely removed within 4 days of incubation in a 2.5 L bench-scale bioreactor containing a newly developed medium. The TNT was catabolized in the presence of different supplemented carbons. Only minimal growth was observed in the killed controls and cultures that only received TNT during the incubation period. This catabolism was affected by the concentration ratio of the substrate to the biomass. The addition of various nitrogen sources produced a delayed effect for the TNT degradation. Tween 80 enhanced the degradation of TNT under these conditions. Two metabolic intermediates were detected and identified as 2-amino-4, 6-dinitrotoluene and 4-amino-2, 6-dinitrotoluene based on HPLC and GC-MS analyses, respectively. Strain OK-5 was characterized using the BIOLOG system and fatty acid profile produced by a microbial identification system equipped with a Hewlett Packard HP 5890 II gas chromatograph. As such, the bacterium was identified as a Stenotrophomonas species and designated as Stenotrophomonas sp. OK-5.

• Animal cells and systems
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• v.16 no.6
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• pp.488-497
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• 2012

A DNA barcode based on 648 bp of cytochrome c oxidase I (COI) gene aims to build species-specific libraries for animal groups. However, it is hard to recover full-length (648 bp) barcode gene from environmental fecal samples due to DNA degradation. In this study, we designed a new primer set (K_Bird), which amplifies a 226 bp fragment targeted an inner position of full-length COI barcode based on 102 species of Korean birds to improve amplification success, and we attempted to identify bird species from 39 avian fecal samples collected during 4 months from Jinan, South Korea. Simultaneously, we conducted a dietary analysis using a universal DNA mini-barcode (Uni_Minibar) from same fecal samples. In silico analysis on newly designed mini-barcode represented that genetic distances were 0.5% in species and 9.1% in genera. Intraspecific variations of 149 species out of 174 species (86%) between Korea and North America were within the threshold (5.3% threshold in this study). From environmental fecal samples collected in Jinan, we identified seven avian species, which have high similarity (99-100%) with registered COI sequences in GenBank. Eight kinds of prey species, such as moth, spider, fly, and dragonfly, were identified in dietary analysis. We suppose that our strategy applying mini-barcode for environmental fecal samples, might be a useful and convenient tool for species identification and dietary analysis for birds.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.3
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• pp.362-370
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• 1995

Human plasma low density lipoprotein(LDL) is the main carrier for cholesterol, and recent studies suggest the normal LDL can be readily oxidized by free radical and not interact with LDL receptor. Lipoprotein pariticles are consisted of lipid andprotein, and fatty acids of lipoproteins are prone to oxidation. LDL particles readily undergo oxidative modification by copper. From the results, oxidized LDL altered its biological properties. A marked increase in the electrophoretic mobility of LDl on agarose gel indicated that negative surface charge of the LDL particles was increased. Also, the results from the HPLC showed that oxidized LDL was degraded into several polypeptides nonenzymatically. Degradation tests which measured the amount of 5-IAF labelled oxidized LDL were carried out by monocyte and hepatocyte cell culture. Hepatocyte cell culture of modified LDL did not show consistent pattern. However, binding rate of modified LDL with HMDM(human monocyte derived macrophage) was enhanced with oxidation, but was retarded by addition of antioxidants(hyaluronic acid, vitamin A, vitamin E). Also comparisons of oxidized-LDL, acetyl-LDL and MDA-LDL showed significant differences in the chemical properteis and binding affinity to HMDM. Thus, modificaition of normal LDL altered its biological properties.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.19 no.4
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• pp.81-89
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• 2016

This study aims to understand the relationship between visitors and the degradation of natural resources in Bukhansan national park. We analyzed the trend of the number of visitors, destruction of natural resources and decrease of biodiversity per year. We further compared three types of trails, heavily-used trails and rarely-used trails and a trail with limited access, regarding the degree of destruction in the National Park through a field survey. Our result showed that increasing number of visitors had direct and indirect impact on the destruction of natural resources in the National Park. The direct impact came from visitors' excessive use of trails. Naturally, increasing number of visitors caused an immoderate use of natural resources. Physical degradation such as exposure of tree root, poor drainage of trails, trail erosion was more severe than other types of trails. Decreasing biodiversity or mild disturbance around trails is the indirect impact such as broken bough, worn-bark in rarely-used trails. Destruction scale greatly increased as the number of visitors increased. Real-named reservation system helped to prevent trails from degradation. Our result calls for the need of controlling the number of visitors to Bukhansan National Park to mitigate the degradation. We recommend dispersing visitors from the heavily-used trails to other trails and implementing real-named reservation system in the rarely-used trails for the effective management of the national park.

• Korean Journal of Environmental Agriculture
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• v.2 no.2
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• pp.65-72
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• 1983

The effects of soil factors, pesticide application levels and environmental factors on the degradation of two carbamate insecticides, BPMC and carbofuran, in soil were studied under flooded and non-flooded conditions. The degradation patterns of BPMC or carbofuran were similar in flooded and non-flooded soils. It was also found that carbofuran was more persistent than BPMC in the test soil. Regards to organic contents of soils, high contents of organic matter reduced degradation of either BPMC or carbofuran and high soil pH accelerated degradation of both insecticides. Soil microorganisms seem to play an important role in the degradation of BPMC and carbofuran. Both chemical and biological degradations appear to contribute transformation of BPMC and carbofuran in the flooded soil.

• Journal of Radiation Industry
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• v.18 no.1
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• pp.53-61
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• 2024

This study explores the effects of X-ray irradiation for biological control and high-temperature degradation on dye stability in dyed textiles with Gardenia. To evaluate this study, optimal extraction solvents for these textiles were identified by comparing them with a crocin standard solution. Extraction using pyridine closely matched crocin. The study then assessed the stability of X-ray irradiation and high-temperature degradation on these textiles. Transparent yellow dyes were observed in all samples. Color differences were found to increase at higher irradiation doses and longer degradation periods. While UV spectroscopy spectra showed broadening and lowering trends with higher irradiation doses and longer degradation periods, suggesting a reduction in colorant transition, mass spectrometry revealed minimal chemical changes. In conclusion, both X-ray irradiation and high-temperature degradation induced spectral changes without complete dye decomposition. Major colorants were consistently detected.

• Clean Technology
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• v.14 no.1
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• pp.61-68
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• 2008

There have been great attentions on polymer electrolyte membrane fuel cell (PEMFC) due to their advantageous characteristics such as zero emission of hazardous pollutant and high energy density. In this work, we evaluated degradation phenomena and stability of single cell performance via one dimensional single cell modeling. Here, CO poisoning on anode on anode was considered for cell performance degradation. Modeling results showed that the performance and stability were highly degraded with CO concentration in fuel gas. In addition, cell performance was reduced by slow oxygen reduction on cathode in long term operation. In order to overcome, it is required to increase ratio o#hydrogen in the fuel gas of anode and high Pt loading contained in the cathodic catalyst layer.