• Korean Journal of Microbiology
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• v.55 no.3
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• pp.242-247
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• 2019

Biological factors (e.g. microorganism activity) in wastewater treatment plant (WWTP) play essential roles for degradation and/or removal of organic matters. In this study, to understand the microbial functional roles in WWTP, we tried to isolate and characterize a bacterial strain from activated sludge sample. Strain S16 was isolated from the activated sludge of a municipal WWTP in Daejeon metropolitan city, the Republic of Korea. The cells were a Gram-stain-positive, non-motile, facultative anaerobe, and rod-shaped. Strain S16 grew at a temperature of $15{\sim}40^{\circ}C$ (optimum, $30^{\circ}C$), with 0~9.0% (w/v) NaCl (optimum, 1.0~2.0%), and at pH 5.5~9.0 (optimum, pH 7.0~7.5). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain S16 was most closely related to the unique species Miniimonas arenae NBRC $106267^T$ (99.79%, 16S rRNA gene sequence similarity) of the genus Miniimonas. The cell wall contained alanine, glutamic acid, serine, and ornithine. Although the isolation source of the type strain NBRC $106267^T$ which considered as a marine microorganism is sea sand, that of strain S16 is terrestrial environment. It might raise an ecological question for habitat transition. Therefore, comparative genome analysis will be valuable investigation for shedding light on their potential metabolic traits and genomic streamlining.

• Korean Journal of Ecology and Environment
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• v.52 no.3
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• pp.192-201
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• 2019

While a fairly large amount of organic matter is produced daily via phytoplankton photosynthesis in Lake Paldang, South Korea, knowledge of the role of algal-derived organic matter (OM) as a refractory OM source is not adequate. To understand the contribution of algal-derived OM to the refractory pool, biodegradation experiment and $KMnO_4$ oxidation experiment were conducted for 60 days using $^{13}C$ and $^{15}N$ labeled natural phytoplankton assemblage. The assemblage was collected from Lake Paldang on May 20, 2010. The photosynthetically produced total organic carbon ($TO^{13}C$), particulate organic carbon ($PO^{13}C$), and particulate nitrogen ($P^{15}N$) remained at 26%, 20%, and 17% of the initial concentrations, respectively, in the form of non-biodegradable organic matter. In addition, 12% and 38% of $PO^{13}C$ remained after $KMnO_4$ treatment on Day 0 and 60, respectively. These results indicate that photosynthetic products could be an important source of refractory organic matter after microbial degradation. Moreover, the microbially transformed algal-derived OM could contribute to the oxidation rate of the chemical oxygen demand.

• Korean Journal of Environmental Agriculture
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• v.40 no.3
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• pp.219-230
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• 2021

BACKGROUND: Biochar is a solid material converted from agricultural biomass such as crop residues and pruning branch through pyrolysis under limited oxygen supply. Biochar consists of non-degradable carbon (C) double bonds and aromatic ring that are not readily broken down by microbial degradation in the soils. Due to the recalcitrancy of C in biochar, biochar application to the soils is of help in enhancing soil carbon sequestration in arable lands that might be a strategy of agricultural sector to mitigate climate change. METHODS AND RESULTS: Data were collected from studies on the effect of biochar application on soil C content conducted in East Asian countries including China, Japan and Korea under different experimental conditions (incubation, column, pot, and field). The magnitude of soil C storage was positively correlated (p < 0.001) with biochar application rate under field conditions, reflecting accumulation of recalcitrant black C in the biochar. However, The changes in soil C contents per C input from biochar (% per t/ha) were 6.80 in field condition, and 12.58 in laboratory condition. The magnitude of increment of soil C was lower in field than in laboratory conditions due to potential loss of C through weathering of biochar under field conditions. Biochar production condition also affected soil C increment; more C increment was found with biochar produced at a high temperature (over 450℃). CONCLUSION: This review suggests that biochar application is a potential measures of C sequestration in agricultural soils. However, as the increment of soil C biochar was affected by biochar types, further studies are necessary to find better biochar types for enhanced soil C storage.

• Korean Journal of Food Science and Technology
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• v.54 no.1
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• pp.94-102
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• 2022

Defatted soybean, larvae of brown mealworm (Tenebrio molitor), and powdered pupae of silkworm (Bombyx mori) were fermented in solid and liquid forms using Aspergillus oryzae and Bacillus subtilis. The protein degradation rate (NDR) through solid fermentation was the highest in the fermented soybean control sample (54.69±6.54%), followed by silkworm pupae (34.82±5.99%) and brown mealworm larvae (30.54±3.80%). When these edible insects were fermented in liquid form, solid extraction yield was 37.73-46.88%, and protein yield was 47.47-63.02%. NDR of fermented liquid form products increased to 58.90, 52.62, and 50.13% for soybean, brown mealworm larvae, and silkworm pupae, respectively. SDS-PAGE of the liquid fermented products confirmed that microbial fermentation decomposed higher-molecular-weight proteins into small polypeptides. In vitro digestibility of liquid forms of edible insects increased by 1.26 to 1.53 times after fermentation. The protein solubility, foaming ability, and foam stability of liquid-fermented edible insects all tended to increase through fermentation.

• The Journal of Korean Medicine
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• v.44 no.2
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• pp.119-131
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• 2023

Objectives: Betula Platyphylla(BP) has been used as a analgesic, anti-microbial, anti-oxidant drug in Eastern Asia. However, it is still unknown whether BP ethanol extract could exhibit the inhibitory activities against ultraviolet B(UVB)-induced skin injury on human keratinocytes, HaCaT cells. This study was aimed to investigate the protective activity of BP ethanol extract on UVB-irradiated skin injury in HaCaT cells. Methods: The skin injury model of HaCaT cells was established under UVB stimulation. HaCaT keratinocyte cells were pre-treated with BP ethanol extract for 1 h, and then stimulated with UVB. Then, the cells were harvested to measure the cell viability, production of reactive oxygen species(ROS), pro-inflammatory cytokines such as interleukin(IL) 1-beta, IL-6, and tumor necrosis factor(TNF)-𝛼, hyaluronidase, type 1 collagen, matrix metalloproteinase(MMP)s. In addition, we examined the mitogen activated protein kinases(MAPKs) and inhibitory kappa B alpha(I𝜅;-B𝛼) as inhibitory mechanisms of BP ethanol extract. Results: The treatment of BP ethanol extract inhibited the UVBinduced cell death and ROS production in HaCaT cells. BP ethanol extract treatment inhibited the UVB-induced increase of IL-1beta, IL-6, and TNF-𝛼. BP ethanol extract treatment inhibited the increase of hyaluronidase, MMP and decrease of collagen. BP ethanol extract treatment inhibited the activation of MAPKs and the degradation of I𝜅-B𝛼. Conclusions: Our result suggest that treatment of BP ethanol extract could inhibit the UVB-induced skin injury via deactivation of MAPKs and nuclear factor kappa B(NF-𝜅B) in HaCaT cells. This study could suggest that BP ethanol extract could be a beneficial agent to prevent skin damage or inflammation.

• Journal of Applied Biological Chemistry
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• v.66
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• pp.213-220
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• 2023

The most common skin disease, acne, often occurs in adolescence, but it is also detected/observed in adults due to air pollution and drug abuse. One of the causative agents of acne, Cutibacterium acnes (C. acnes) plays a role in the development of skin acne by inducing inflammatory mediators. Torreya nucifera (TN) is an evergreen tree of the family Taxaceae, having well reported antioxidant, anti-proliferative, liver protection, and nerve protection properties. Improvement of these bioactive properties of natural products is one of the purposes of natural product chemistry and pharmaceuticals. We believe biorenovation could be one improvement strategy that utilizes microbial metabolism to produce unique derivatives having enhanced bioactivity. Therefore, in this study, the C. acnes-induced RAW264.7 inflammation model was used to evaluate the anti-inflammatory activity of the biorenovated Torreya nucifera product (TNB). The results showed improved viability of TNB-treated cells compared to TN-treated cells in the concentration range of 50, 100, and 200 ㎍/mL. At non-toxic concentrations, TNB inhibited the production of nitric oxide and prostaglandin E2 by suppression of inducible nitric oxide synthase and cyclooxygenase-2 protein expression. TNB also attenuated the expression of interleukin-1β, interleukin-6, interleukin-8, and tumor necrosis factor-α induced by C. acnes. Furthermore, TNB inhibited the nuclear factor-κB signaling pathway, a transcription factor known to regulate inflammatory mediators. Based on these results, this study suggests the potential of using TNB as natural material for the treatment of acnes and thus, supporting our postulation of biorenovation as an bioactivity improvement strategy.

• Tunnel and Underground Space
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• v.34 no.2
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• pp.89-103
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• 2024

In the disposal environment, gases can be generated at the interface between canister and buffer due to various factors such as anaerobic corrosion, radiolysis, and microbial degradation. If the gas generation rate exceeds the diffusion rate, the gas within the buffer may compress, resulting in physical damage to the buffer due to the increased pore pressure. In particular, the rapid movement of gases, known as gas breakthroughs, through the dilatancy pathway formed during this process may lead to releasing radionuclide. Therefore, understanding these gas generation and movement mechanism is essential for the safety assessment of the disposal systems. In this study, an experimental apparatus for investigating gas migration within buffer was constructed based on a literature review. Subsequently, a gas injection experiment was conducted on a compacted bentonite block made of Bentonile WRK (Clariant Ltd.) powder. The results clearly demonstrated a sharp increase in stress and pressure typically observed at the onset of gas breakthrough within the buffer. Additionally, the range of stresses induced by the swelling phenomenon of the buffer, was 4.7 to 9.1 MPa. The apparent gas entry pressure was determined to be approximately 7.8 MPa. The equipment established in this study is expected to be utilized for various experiments aimed at building a database on the initial properties of buffer and the conditions during gas injection, contributing to understanding the gas migration phenomena.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.4
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• pp.362-371
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• 2016

The distribution patterns of Chromophoric Dissolved Organic Matter (CDOM) and the chemical characteristics of CDOM in the Seomjin river estuary were investigated in March, June and July 2012 in order to determine the spatial and temporal variability of CDOM along the salinity gradient considering the effects of mixing, nutrients and Chl a. The average CDOM values were $1.0{\pm}0.3m^{-1}$, $1.3{\pm}0.4m^{-1}$, and $1.4{\pm}0.3m^{-1}$ in March, June and July, respectively. A high concentration of CDOM (greater than $1.5m^{-1}$) was found at the head of the river which decreased towards the river mouth to as low as less than $0.5m^{-1}$. The average concentrations of CDOM increased from the dry season (March and June) to the wet season (July), and the average slope values ($S_{300-500}$), which were used as indicators of CDOM characteristics and sources, were in the range of $0.013-0.018m^{-1}$. The CDOM and $S_{300-50}$ values showed that not only the concentration of CDOM but also the chemical properties of DOM clearly changed between upstream and downstream in the Seomjin river. CDOM and FDOM showed a negative correlation with salinity ($R^2$ > 0.8), and CDOM was positively correlated with FDOM. Furthermore, the mixing pattern of CDOM was confirmed as conservative for all seasons. The main environmental factors influencing the concentration of CDOM was confirmed as conservative for all seasons. The main environmental factors influencing the concentration of CDOM were salinity (mixing) and water temperature, which meant the dilution of low CDOM seawater, was the controlling factor for the spatial distribution of CDOM. Increases in water temperature seemed to induce the production of CDOM during summer (June and July) through the biological degradation of DOM either by microbial activity or photo-degradation.

• Journal of Animal Science and Technology
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• v.44 no.5
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• pp.549-560
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• 2002

This study, including two in vitro experiments and an in vivo experiment were conducted to evaluate effects of Passtein$^{(R)}$ on crude protein degradability, ruminal fermentation characteristics and nutrient digestibility. In in vitro experiment protein degradability was examined using borate-phosphate buffer and neutral detergent, and using protease from Stroptomyces griseus at 39$^{\circ}C$ for 0, 2, 4, 8, 12, and 48 h. In addition, an in vivo experiment was conducted in a switch back design and ruminal fermentation and nutrient digestibility were determined. Four ruminal-fistulated Holstein cows weighing 300kg in mean body weight randomly allotted to 2 treatments (control and Passtein$^{(R)}$ supplementation). Although there was no significant difference on protein fraction between treatments, it appears that Passtein$^{(R)}$ supplementation decreased buffer soluble protein fraction compared to control. Protein degradability was not affected by Passtein$^{(R)}$ from 0 h to 4 h, but decreased at 12 h and 48 h compared to control. Degradation of immediately degradable fraction was higher in Passtein$^{(R)}$ treatment, but degradation of fermentable fraction was lower in Passtein$^{(R)}$ treatment compared to control. The pH and $NH_3$-N concentration tended to increase in Passtein$^{(R)}$ treatment, but VFA production, microbial counts and enzyme activity tended to decrease in Passtein$^{(R)}$ treatment compared to control. In addition, nutrient digestibility in the total tract tended to increase in Passtein$^{(R)}$ treatment compared to control.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.9 no.2
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• pp.64-72
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• 2004

We measured the vertical profiles of $O_2$, H$_2$S, and pH in sediment pore water beneath marine cage fish farms using a microsensor with a 25 ${\mu}{\textrm}{m}$ sensor tip size. The sediments are characterized by high organic material load. The oxygen consumption, hydrogen sulfide oxidation, and sulfate reduction rates in the microzonations (derived from the vertical distribution of chemical species concentration) were estimated by adapting a simple one-dimensional diffusion-reaction model. The oxygen penetration depth was 0.75 mm. The oxic microzonations were divided into upper and lower layers. Due to hydrogen sulfide oxidation within the oxic zone, the oxygen consumption rate was higher in the lower layer. The total oxygen consumption rate integrated with reaction zone depth was estimated to be 0.092 $\mu$mol $O_2$cm$^{-2}$ hr$^{-1}$ . The total hydrogen sulfide oxidation rate occurring within 0.7 mm thickness was estimated to be 0.030 $\mu$mo1 H$_2$S cm$^{-2}$ hr$^{-1}$ , and its turnover time in the oxic sediment layer was estimated to be about 2 minutes. This suggests that hydrogen sulfide was oxidized by both chemical and microbial processes in this zone. The molar consumption ratio, calculated to be 0.84, indicates that either other electron accepters exit on hydrogen sulfide oxidation, or elemental sulfur precipitation occurs near the $O_2$- H$_2$S interface. Total sulfate reduction flux was estimated to be 0.029 $\mu$mol cm$^{-2}$ hr$^{-1}$ , which accounted for more than 60% of total $O_2$ consumption flux. This result implied that the degradation of organic matter in the anoxic layer was larger than in the oxic layer.