• Journal of the Korean Geotechnical Society
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• v.39 no.8
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• pp.7-16
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• 2023

This study aimed to evaluate the sulfate removal capacity of the enzyme-induced carbonate precipitation (EICP) technique through the chemical precipitation of sulfate with calcium ions. The optimal EICP recipe was obtained to retain the excess calcium cations in the solution for the generation of a sufficient amount of calcium carbonate (CaCO₃) mineral. The effect of gypsum precipitation on the EICP-treated sand specimen was investigated by measuring the shear wave velocity and by visual inspection via scanning electron microscopy. The EICP solution using soybean crude urease, as an alternative to laboratory-grade purified urease, exhibited a lower sulfate removal efficiency at a similar CaCO₃ production rate compared with the optimal EICP recipe because of soybean impurities.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.6
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• pp.409-414
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• 2006

Sulfur-oxidizing bacteria were enumerated and isolated from a steady-state anaerobic master culture reactor (MCR) operated for over six months under a semi-continuous mode and nitrate-limiting conditions using thiosulfate as an electron donor. Most are Gram-negative bacteria, which have sizes up to 12 m. Strains AD1 and AD2 were isolated from the plate count agar (PCA), and strains BD1 and BD2 from the solid thiosulfate/nitrate medium. Based on the morphological, physiological, FAME and 16S rDNA sequence analyses, the two dominant strains, AD1 and AD2, were identified as Paracoccus denitrificans and Paracoccus versutus (formerly Thiobacillus versutus), respectively. From the physiological results, glucose was assimilated by both strains AD1 and AD2. Heterotrophic growth of strains AD1 and AD2 could be a more efficient way of obtaining a greater amount of biomass for use as an inoculum. Even though facultative autotrophic bacteria grow under heterotrophic conditions, autotrophic denitrification would not be reduced.

• Journal of the Korea Organic Resources Recycling Association
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• v.4 no.1
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• pp.13-21
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• 1996

For treating tannery wastewater containing high sulfate and heavy metals, test was performed to assess their performance, competition between SRB (sulfate reducing bacteria) and MPB (methane producing bacteria), and the activity of MPB according to change of chromium concentrations. COD removal efficiency was above 70% at VLR (volumetric loading rate) of 2.0 gCOD/I.day and HRT (hydraulic retention time) of 18hrs at $35^{\circ}C$. In the competition between SRB and MPB, about 15% of the removed COD was utilized by SRB in the begining, but it became 43% at the end. It indicated that MPB was strongly suppressed by the occurrence of significant sulfate reduction since a large electron flow was uptaken by SRB. For the entire experiment, removal efficiencies of chromium concentration were more than 90%. Despite high removal efficiencies of chromium concentration, performance of reactor did not change significantly during the experimental periods. Expecially, chromium (III) is tannery wastewater is less toxic than chromium (VI).

• Journal of Life Science
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• v.17 no.12
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• pp.1616-1621
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• 2007

Off-flavors and odors in fermented cucumbers result from the growth of undesirable microorganisms during the secondary fermentation. Under laboratory conditions using a sterile fermented cucumber slurry medium, the spoilage fermentations were reproduced. Using this system the salt and pH conditions that allow the spoilage to occur were determined by varying the NaCl concentration and pH of the slurry medium. At pH 3, no spoilage was observed, regardless of the salt concentration, while at pH 3.5, pH 4, and pH 4.5, spoilage occurred in the 0 and 2% NaCl samples. For pH 5.0 samples, spoilage products were seen for all NaCl treatments. Based on these results the Preservation Prediction Chart was developed. The Chart may be used for selection of proper pH value and salt concentration for long term storage of fermented cucumber.

• Journal of Life Science
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• v.13 no.5
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• pp.658-667
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• 2003

Antioxidative enzymes (superoxide dismutase; SOD, ascorbate peroxidase; APX, glutathione reductase; GR) play major roles in scavenging mechanism of reactive oxygen species which were involved in various stress conditions including salt. In order to investigate the relation between their growth responses (dry weight) and the changes of antioxidative enzymes activity, salt-tolerant spinach beet having 15cm of shoot length were treated with various salt levels (0, 50, 200, 1000 mM NaCl) for 24 hours. Spinach beet exhibited an increase in the activity of antioxidative enzymes by salt, the maximal activity at 200 mM NaCl and the lowest activity at 50 mM NaCl in 2 hrs. after treatments. As a result of PAGE, it has been confirmed that spinach beet contained 3 isoforms (Fe-SOD, CuZn-SOD and Mn-SOD) of SOD and main isoform was CuZn- SOD form. In case of APX, isoforms of the low molecular weight(No. 7, 8) were showed strong expression especially at 200 and 400 mM NaCl treatment. Meanwhile, GR did not show specific pattern of isoforms among the salt treatments. Especially, in case of 50 mM treatment, plant showed the lowest activity of SOD with the best growth, a low enzyme activity was induced by inactivation of the Mn-SOD. Therefore, we suggested that the decrease of SOD activity at a low salt level (50 mM NaCl) or the increase of enzyme activity at a high salt level (200 mM NaCl) may be related to expression of the Mn-SOD isoform. These antioxidative enzymes showed the increase of activity in a short time by salt addition. So, it is considered that spinach beet copes effectively with a stressful condition such as salt by operating effective antioxidative defense mechanism rapidly under high salt level.

• Journal of Bio-Environment Control
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• v.21 no.4
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• pp.478-484
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• 2012

This study was carried out to investigate the plant growth and ion absorbance balance of various native plants affected by the NaCl concentration (0, 100, 200, 300 mM). Carex blepharicarpa, Carex lenta, Carex matsumarae, Carex sendaica, Iris pseudacorus L., Sedum oryzifolium Makino, Sedum polytrichoides Hemsl., and Typha angustifolia L. were used in this experiment. Carex blepharicarpa, Carex lenta, Carex matsumarae, and Iris pseudacorus L. were tolerant of salinity at the NaCl concentration of 200 mM. The root growth of Carex sendaica and Typha angustifolia L. was suppressed at the NaCl concentration of 100 mM, expecially the root growth responded more sensitively than the upper growth to salinity. The K absorbance of Carex sendaica decreased according to the NaCl application, and the Na/K rate value was 3 at the NaCl concentration of 300 mM. The K, Ca, and Mg absorbance of Typha angustifolia L. decreased at the NaCl concentration of 200~300 mM, and the Na/K rate value was 0.8 at the NaCl concentration of 300 mM. The plant growth of Sedum oryzifolium Makino and Sedum polytrichoides Hemsl. was suppressed at the NaCl concentration of 100~200 mM. The K, Ca, and Mg absorbance of Sedum oryzifolium Makino decreased at the NaCl concentration of 200~300 mM, and Sedum polytrichoides Hemsl. was unaffected by the NaCl application. The Na/K value was 1 in both plants. Therefore, Carex blepharicarpa, Carex lenta, Carex matsumarae, and Iris pseudacorus L. were tolerant plants of salinity at the NaCl concentration of 200 mM considering the plant growth and ion absorbance balance. Especially, the Carex plants were expected to expanding use by the proven tolerance of salinity. The root growth of Carex sendaica, Sedum oryzifolium Makino, Sedum polytrichoides Hemsl., and Typha angustifolia L., was suppressed at the NaCl concentration of 100 mM, but there was no distinct tendency of ion absorbance in leaves according to the NaCl application.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.10
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• pp.1567-1575
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• 2013

Anti-inflammatory effects of sulfur-fed duck extract on colitis induced by 2.5% dextran sulfate sodium (DSS) were examined in male Balb/c mice. Animals were divided into eight groups: normal (0.1 mL of PBS without 2.5% DSS), control (0.1 mL of PBS with 2.5% DSS), SD-H (3 mL/kg of high sulfur-fed duck extract), SD-L (1 mL/kg of low sulfur-fed duck extract), GD-H (3 mL/kg of high general duck extract), GD-L (1 mL/kg of low general duck extract), GC-H (3 mL/kg of high general chicken extract), and GC-L (1 mL/kg of low general chicken extract). Mice were fed PBS or six different doses of extracts (sulfur-fed duck, general duck, and chicken), once daily for 14 days. Colitis was induced from day 7 to 14 via the administration of 2.5% DSS in drinking water. The colon length was significantly shortened in mice compared to the control group. The administration of SD-H, SD-L, and GD-L increased colon length and decreased histological colon injury from DSS-induced colitis. However, chicken extracts did not recover any clinical sign of the colitis. SD-L significantly suppressed not only the concentrations of IL-$1{\beta}$, IL-6, TNF-${\alpha}$, IL-17A, and IL-12 in serum but also the mRNA expressions of IL-6, TNF-${\alpha}$, iNOS and COX-2 in DSS-treated colon tissues (P<0.05). The administration of SD-H suppressed the concentrations of IL-6 in serum and the mRNA expressions of IL-6, iNOS, and COX-2 in colon tissues. Administration of GD-L suppressed the concentrations of IL-6, TNF-${\alpha}$, and IL-17A in serum and the mRNA expressions of IL-6, iNOS, and COX-2 in colon tissues. The inhibitory effects of sulfur-fed duck extracts were effective at a dose of 1 mL/kg. Our results indicate that sulfur-fed duck extracts may possess anti-inflammatory effects on DSS-induced colitis mice.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.425-428
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• 2000

To enhance the productivity of recombinant protein, ${\beta} -glucuronidase(GUS)$, by transgenic Nicotiana suspensions, perfusion culture was carried out in a 5-L stirred tank bioreactor. Maximum cell density of 20.0 gDCW/L was obtained and GUS activity was noticeably affected by medium composition, such as salt concentration. Effect of headspace purging by $CO_2-enriched$ air was also investigated. Aeration of $CO_2(5%)-enriched$ air with 0.2 vvm significantly promoted the cell growth in lag pahse and increased volumetric GUS activity from 0.69 U/mL to 5.76 U/mL. In contrast, aeration of $CO_2(5%)-enriched$ air with 0.1 vvm did not affect the cell growth but enhanced the GUS acitivity from 3.24 to 5.25 U/mL at the 4th day.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.8 no.1
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• pp.37-45
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• 1975

The present study was ,conducted to evaluate the effects of condensed phosphates on the refeezing damage of Alaska pollack muscle. The fillets were dipped in such solution as 5 and $10\%$ sodium polyphosphate, 1 and $5\%$ mixture of sodium polyphosphate and sodium pyrophosphate (1:1, w/w) for 1 and 5 minutes, respectively, before refreezing. And fillets were frozen at $27^{\circ}C\~28^{\circ}C$ and stored for 15 days at $-18^{\circ}\~-20^{\circ}$. The degree of denaturation was estimated by determining amounts of drip relased, content of total solids, nitrogen, and DNA in the drip an cooking-weight-loss. Phosphorus absorbed in the muscle was also determined. Phosphorus absorbed in the fillets treated with loft solution of sodium polyphosphate for 5 minutes amounted to 101 mg/100g muscle as $P_2O_5$. The absorption was dependent on tile concentration of treating solution rather than on the dipping time. The increase of phosphorus absorption seemed to affect to reduction of drip. Among the treating conditions, $10\%$, 5 minutes and $10\%$ 1 minute with sodium polyphosphate appeared most effective ones on drip reduction. The effect of $5\%$, minutes with the mixture of sodium polyphosphate and sodium pyrophosphate did not show so benefitable effect in refrozen fillets. As a tendency total solids, nitrogen, and DNA in tile drip varied proportionally to the amount of drip released. And the content of DNA was lower than the amount. Treatment, at higher the concentration and longer the dipping time, resulted in the lower cooking-weight-loss and the better quality on organoleptic test of thawed fillets.

• Resources Recycling
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• v.28 no.3
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• pp.15-20
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• 2019

The recovery of struvite using nitrogen and phosphorus in wastewaters is useful for prevention of eutrophication and use as fertilizer, but there are theoretical and technical issues to be resolved. Through the detailed literature review, this study discusses the possible reasonable prediction of struvite formation reaction by setting a feasible reaction equation with some theoretical considerations. In a technical aspect, the purity of struvite in solid precipitates can be promoted by excluding Ca in an effective way. As for the struvite reaction prediction issue, selection of proper equilibrium reaction as well as its reaction equilibrium coefficient is significant in the neutral and basic pH regions. The equilibrium reaction agrees well with the experimental batch test results. Considering the charge balance of the ions, the pH drop along struvite formation in a diluted solution can be predicted. Also, improvement of struvite purity through elimination of Ca can be expected by providing a highly concentrated ${NH_4}^+-N$ relative to ${HPO_4}^{2-}-P$ because ${NH_4}^+$ can enhance the thermodynamic driving force toward favorable struvite formation. Even though the phosphate reacts rapidly with Ca to form a solid precipitate, the thermodynamic driving force due to the high ${NH_4}^+$ activity can dissociate the phosphate-calcium precipitates and produce struvite.