• Applied Chemistry for Engineering
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• v.33 no.3
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• pp.322-327
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• 2022

Fucoidans were degraded by hydrogen peroxide under the electron beam (2.5 MeV) with various radiation doses (5 kGy, 10 kGy, 15 kGy, and 20 kGy) at room temperature. The degradation property was analyzed with a gel permeation chromatography (GPC-MALLS) method. An average molecular weight of fucoidan decreased from 99,956 at the irradiation dose of 0 kGy to 6,725 at the irradiation dose of 20 kGy. The solution viscosity of fucoidans showed a similar pattern to the molecular weight change. The number of chain breaks per molecule (N) increased with increasing the irradiation dose and concentration of hydrogen peroxide. The radiation yield of scission value markedly increased with increasing the irradiation dose up to 15 kGy. Also a 10% hydrogen peroxide concentration was more efficient than that of 5%. The structures of degraded fucoidan samples were studied with Fourier transform infrared spectroscopy (FT-IR). The results showed that the degradation process did not significantly change the chemical structure or the content of sulfate group. The sulfur content of each sample was determined with an Elemental Analyzer. With increasing the concentration of hydrogen peroxide, the ratios of sulfur/carbon, hydrogen/carbon, and nitrogen/carbon slightly decreased. The antioxidant activities of fucoidans were investigated based on hydroxyl radical scavenging activities. The ability of fucoidan to inhibit the hydroxyl radical scavenging activity was depended on its molecular weight.

• Food Science of Animal Resources
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• v.43 no.4
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• pp.625-638
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• 2023

Among various biological agents, bacteriocins are important candidates to control Listeria monocytogenes which is a foodborne pathogen. In this study, a novel bacteriocin, named agilicin C7, was isolated from Ligilactobacillus agilis C7 showing inhibitory activity against L. monocytogenes. Agilicin C7 biosynthesis gene was characterized by bioinformatics analyses and heterologously expressed in Escherichia coli for further study. The anti-listeria activity of recombinant agilicin C7 (r-agilicin C7) was lost by proteases and α-amylase, suggesting that agilicin C7 is a glycoprotein. r-Agilicin C7 has wide pH and thermal stability and is also stable in various organic solvents. It destroyed L. monocytogenes by damaging the integrity of the cell envelope. These properties of r-agilicin C7 indicate that agilicin C7 is a novel amylase-sensitive anti-listerial Class IId bacteriocin. Physicochemical stability and inhibitory activity against L. monocytogenes of r-agilicin C7 suggest that it can be applied to control L. monocytogenes in the food industry, including dairy and meat products.

• Genomics & Informatics
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• v.20 no.4
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• pp.41.1-41.9
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• 2022

The pathogen Gallibacterium anatis has caused heavy economic losses for commercial poultry farms around the world. However, despite its importance, the functions of its hypothetical proteins (HPs) have been poorly characterized. The present study analyzed the functions and structures of HPs obtained from Gallibacterium anatis (NCTC11413) using various bioinformatics tools. Initially, all the functions of HPs were predicted using the VICMpred tool, and the physicochemical properties of the identified virulence proteins were then analyzed using Expasy's ProtParam server. A virulence protein (WP_013745346.1) that can act as a potential drug target was further analyzed for its secondary structure, followed by homology modeling and three-dimensional (3D) structure determination using the Swiss-Model and Phyre2 servers. The quality assessment and validation of the 3D model were conducted using ERRAT, Verify3D, and PROCHECK programs. The functional and phylogenetic analysis was conducted using ProFunc, STRING, KEGG servers, and MEGA software. The bioinformatics analysis revealed 201 HPs related to cellular processes (n = 119), metabolism (n = 61), virulence (n = 11), and information/storage molecules (n = 10). Among the virulence proteins, three were detected as drug targets and six as vaccine targets. The characterized virulence protein WP_013745346.1 is proven to be stable, a drug target, and an enzyme related to the citrate cycle in the present pathogen. This enzyme was also found to facilitate other metabolic pathways, the biosynthesis of secondary metabolites, and the biosynthesis of amino acids.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.22 no.2
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• pp.173-183
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• 2024

Vitrification, one of the most promising solidification processes for various materials, has been applied to radioactive waste to improve its disposal stability and reduce its volume. Because the thermal decomposition of dry active waste (DAW) significantly reduces its volume, the volume reduction factor of DAW vitrification is high. The KHNP developed the optimal glass composition for the vitrification of DAW. Since vitrification offers a high-volume reduction ratio, it is expected that disposal costs could be greatly reduced by the use of such technology. The DG-2 glass composition was developed to vitrify DAW. During the maintenance of nuclear power plants, metals containing paper, clothes, and wood are generated. ZrO₂ and HfO₂ are generally considered to be network-formers in borosilicate-based glasses. In this study, a feasibility study of vitrification for DAW that contains metal particulates is conducted to understand the applicability of this process under various conditions. The physicochemical properties are characterized to assess the applicability of candidate glass compositions.

• Analytical Science and Technology
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• v.37 no.5
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• pp.295-305
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• 2024

5-Hydroxymethyl-2-furaldehyde (5-HMF) is considered one of the main quality indexes of various food products. Its metabolism in humans can potentially lead to carcinogenic compounds. Metallic ions such as Zn, Mg, Mn, and Fe have been reported to enhance 5-HMF formation. Recently, studies on adsorbents that can extract specific organic and inorganic substances with one adsorbent have been conducted. However, simultaneous analysis of organic and inorganic materials typically requires distinct pre-treatment and analytical methods, which increase a lot of labor and cost. In this study, hybrid imprinted polymer (HIP) by mixing 5-HMF imprinted polymer (FIP) and zinc ion imprinted polymer (ZIIP) were generated to extract two analytes, Zn ion and 5-HMF, simultaneously. Physicochemical characterization of HIP was conducted by Fourier-transform infrared spectroscopy, scanning electron microscopy, and sorption tests. Extraction conditions including adsorbent mixing ratio, adsorbate mixing range, and equilibrium time were optimized. Freundlich adsorption model was as the best-fitting isotherm model to elucidate the adsorption mechanism. Affinity of Zn ion and 5-HMF on HIP was superior to non-HIP. In conclusion, HIP showed reasonable feasibility that could be used as an adsorbent to be used for simultaneous extraction of organic and inorganic compounds present in the sample.

• Korean Journal of Food Science and Technology
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• v.40 no.5
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• pp.551-557
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• 2008

In order to investigate the effect of different ingredients on the quality of Korean rice wines, 30% of rice were substituted by malt, corn, potato, soybean, glutinous millet, unpolished rice, glutinous rice, or non-glutinous rice, when rice wines were prepared. Physicochemical and sensory characteristics of the rice wines from the varying ingredients were evaluated. Sample rice wines were analyzed for ethanol, pH, total acid, amino acid, soluble solid, coloring degree, UV absorbance, reducing sugar, organic acids, and free sugars. After fermentation for 16 days, the ethanol contents ranged from 13.28 to 16.23%, while the total acid levels were within the range of 0.27 to 0.32%. The amino acid contents in eight samples ranged from 0.18 to 0.36%, while the soluble solid contents were within the range of 8.35 to $11.1^{\circ}$Bx. Among the eight samples tested, rice wine prepared with malt showed the highest level of coloring degree, UV absorbance, and reducing sugar levels, while rice wine prepared with potato showed the lowest value. Organic acid contents of rice wines prepared with soybean, glutinous rice, and non-glutinous rice showed the highest levels of succinic acid followed by acetic acid, citric acid, malic acid, and pyroglutamic acid. Free sugar contents of all rice wines showed the higher levels of glucose followed by fructose and maltose. Rice wines prepared with unpolished rice and corn showed the same highest overall sensory preference. By descriptive analysis, the overall mean sensory intensities of samples prepared with glutinous rice and non-glutinous rice, showed similar levels of 'sweetness', 'fruitiness', and 'freshness of aroma', while those samples prepared with soybean, glutinous millet, and potato showed stronger intensities of 'nuruk', 'grain aroma', and 'yellowness'. Rice wine prepared with corn showed middle ranges in all sensory attributes tested.

• Korean Journal of Mineralogy and Petrology
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• v.35 no.2
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• pp.111-123
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• 2022

Carbonate green rust (CGR) and sulfate green rust (SGR) commonly occur in nature. In this study, CGR and SGR were synthesized through co-precipitation, and their formation mechanisms and physicochemical properties were investigated. X-ray diffraction (XRD) and Rietveld refinement showed both CGR and SGR with layered double hydroxide structure were successfully synthesized without any secondary phases under each synthetic condition. Refined structural parameters (unit cell) for two green rusts were a (=b) = 3.17 Å and c = 22.52 Å for CGR and a (=b) = 5.50 Å and c = 10.97 Å for SGR with the crystallite size 57.8 nm in diameter from (003) reflection and 40.1 nm from (001) reflections, respectively. Scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS) results showed that both CGR and SGR had typical hexagonal plate-like crystal morphologies but their chemical composition is different in the content of C and S. In addition, Fourier transform infrared (FT-IR) spectroscopy analysis revealed that carbonate (CO₃^2-) and sulfate (SO₄^2-) molecules were occupied as interlayer anions of CGR and SGR, respectively. These SEM/EDS and FT-IR results were in good agreement with XRD results. Changes in the solution chemistry (i.e., pH, Eh and residual iron concentrations (Fe(II):Fe(III)) of the mixed solution) were observed as a function of the injection time of hydroxyl ion (OH^-) into the iron solution. Three different stages were observed in the formation of both CGR and SGR; precursor, intermediator, and green rust in the formation of both CGR and SGR. This study provides co-precipitation methods for CGR and SGR in a way of the stable synthesis. In addition, our findings for the formation mechanisms of the two green rusts and their physicochemical properties will provide crucial information with researches and industrials in utilizing green rust.

• The Journal of Engineering Geology
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• v.23 no.1
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• pp.37-46
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• 2013

Leakage of leachate from animal carcass disposal is a significant issue because disease can easily spread to humans and other livestock. In this study, we analyzed the physicochemical properties of leachate and tested for the presence of aerobic bacteria in leachate using molecular biology methods, for 16 animal carcass disposals in the first stage (after burial for 5 months). Leachate physicochemical analysis revealed higher total coliforms, TOC, $NH^{4+}$, and $NO^{3-}$ concentrations compared with previously published data. In most leachate samples, the concentrations of $NH^{4+}$ and $NO^{3-}$ exceeded the Korean guideline values for drinking water. In 16S rRNA sequence analysis of the distribution of leachate under aerobic conditions, Bacillus pumilus, Lysinibacillus sphaericus, and B. sphaericus were observed with high frequency, whereas no food-poisoning-related bacteria such as B. cereus or Salmonella were detected. The present findings improve our knowledge of the transport of leachate from animal carcass disposal sites through geologic media, and are useful in risk analysis and for subsequent studies.

• Journal of Food Hygiene and Safety
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• v.28 no.1
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• pp.1-6
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• 2013

Ten commercially available red pepper powders were investigated for their hygienic quality (total aerobic count, yeasts and molds, and coliforms) and physicochemical properties (moisture content, pH, Hunter's color values, American Spice Trade Association (ASTA) color and particle size). Microbial analysis resulted in $10^3-10^6$ CFU/g of total aerobic count and same of yeasts & molds, where 2 samples were positive ($10^3$ CFU/g) for coliforms. The moisture contents (7.25% to 12.73%) were with in the range as described in the Korean Food Standards Codex. Noteworthy variations were observed in pH (4.97 to 5.15), Hunter's ${\Delta}E$ values (47.19 to 58.04) and ASTA color values (89.31 to 98.61). Although the color differences were evident among the samples, but the Hunter values were not in good correlations with ASTA color values. The average particle sizes of the all samples were comparable ranging from $605{\mu}m$ to $1251{\mu}m$ with few exceptions. There was a great variation in the key quality attributes of commercially available red pepper powders that should be considered for their various uses in food products.

• Economic and Environmental Geology
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• v.46 no.4
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• pp.345-350
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• 2013

In this study, the physicochemical properties of leachate and the bacteria existence in leachate using molecular biology methods for 4 animal carcass disposals on the disposal lapse time was analyzed. The result of leachate physicochemical analysis in the middle stage (been buried 20 months) showed higher EC, DO, $HCO_3{^-}$, TOC, T-N and $SO_4{^{2-}}$ concentration compared to the first stage data (been buried 5 months). For identification of leachate using 16S rRNA method, Lysinibacillus sphaericus, Bacillus pumilus, Pseudoclavibacter helvolus, Pseudochrobactrum saccharolyticum and Corynebacterium callunae in the first stage, Bacillus cereus, Lysinibacillus sphaericus, Bacillus circulans and Corynebacterium glutamicum in the middle stage was observed, while there were detections of pathogenicity bacteria such as B. cereus and L. sphaericus. This study improves our knowledge of the fate and transport in geologic media, treatment, risk analysis on the leachate from animal carcass disposal sites.