• Microbiology and Biotechnology Letters
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• v.36 no.3
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• pp.182-188
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• 2008

A hyperthermophilic bacteria (strain HJ6) was isolated from a hot springs located in the Arima-cho, Hyogo, Japan. The cells were long-rod type ($2-4{\mu}m$), about $0.4{\mu}m$ in diameter. The pH and temperature for optimal growth were 6.5 and $80^{\circ}C$, respectively. Phylogenetic analysis based on the 16S rDNA sequence and biochemical studies indicated that HJ6 belonged to the genus Thermus thermophilus (Tt). The gene encoding the Trehalose synthase (TS) was cloned and sequenced. The open reading frame (ORF) of the TtTS gene was composed of 2,898 nucleotides and encoded a protein (975 amino acids) with a predicted molecular weight of 110.56 kDa. The deduced amino acid sequence of TtTS showed 99% and 83% identities to the Thermus caldophilus TS and Meiothermus ruber TS, respectively. TtTS gene was expressed in Escherichia coli cells, and the recombinant protein was purified to homogeneity. The optimal temperature and pH for Trehalose synthase activity were found to be $80^{\circ}C$ and 7.5, respectively. The half-life of heat inactivation was about 40 min at $90^{\circ}C$. The maximum trehalose conversion rate of maltose into trehalose by the enzyme increased as the substrate concentration increased, and reached 55.7% at the maltose concentration of 500 mM, implying that the enzyme conversion was dependent of the substrate concentration.

• Microbiology and Biotechnology Letters
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• v.11 no.1
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• pp.5-13
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• 1983

This experiment was carried out to elucidate the thermotolerant properties of a thermophilic bacterium which isolated from soils of the hot springs area and selected for the $\beta$-galactosidase production. Biochemical and physiological characteristics of this strain were studied, including the investigation on the fatty acid composition for its neutral fats. The results obtained were summarized as follows. 1. This bacterium was identified as a strain belong to the genus Thermus. 2. Optimal temperature and pH for growth of this strain were $65^{\circ}C$ and pH 6.5 respectively, and it was found to be an absolute thermophilic bacterium which could not grow at 37$^{\circ}C$. 3. No growth was obtained in the medium which contained more than 1.0% of sodium chloride. 4. The tolerable concentration of antobiotics were 10$\mu\textrm{g}$ of penicillin G per $m\ell$ of medium and 0.5$\mu\textrm{g}$ of chloramphenicol per $m\ell$ respectively 5. This strain had autotrophilic requirements for calcium-pantothenate and pyridoxine-HCO as an-essential factor and for niacin as a stimulative factor. 6. Fatty acid composition of neutral fats of the strain was palmitic acid. 60.20%; lauric acid, 11.8%; myristic acid, 7.56%, behenic acid, 4.25%; capric acid, 1.77%; stearic acid, 2.13%; arachidic acid, 1.53%; and others unidentified, 10.7%.

• Journal of the Korean Institute of Landscape Architecture
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• v.43 no.6
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• pp.25-40
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• 2015

Korean tourist areas are designated/managed in accordance with the Tourism Promotion Act. Since Taejongdae was designated as a tourist area in 1969, a total of 230 tourist areas have been designated/built/operated. It has been 46 years since the first tourist area was designated. According to the Tourism Area Life Cycle by Butler, it is estimated that the flow of the life cycle will be reflected in ups and downs over time. Thus, this study aimed to provide basic data for suggesting the direction of changes and development of the future tourist areas after analyzing the life cycle stage of domestic tourist areas, by applying the Tourism Area Life Cycle by Butler. The research method was based on the tourist areas by year, the number of visitors, and data of the target to derive the change transition curve, obtained by dividing the life cycle stages of the tourist areas based on the visitor rate of change. In the analysis results, more than 1/3 of domestic tourist areas are reaching the stagnation/decline stage, and tourist areas such as hot springs and seaside/beach resources show a particularly high ratio of stagnation/decline. The tourist areas that already have reached the stagnation/decline stage will need to analyze the causes for the decline, seek for resolution measures, and introduce new innovative elements. Even though the results of this study are not sufficient to be used as an absolute standard to decide the life cycle stage of domestic tourist areas, it is considered to be adequate for phenomenologically understanding the life cycle stage of Korean tourist areas. Based on this study, the causes for the stagnation/decline of tourist areas can be revealed while it can be also used as basic research to establish revitalization measures for tourist areas by introducing new innovation.

• Korean Journal of Agricultural Science
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• v.9 no.1
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• pp.377-386
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• 1982

This experiment was carried out to elucidate the thermotolerant properties of a thermophilic bacterium which was isolated from soils of the hot springs area and selected for the ${\beta}$-galactosidase production. This bacterium was identified as a strain belong to the genus Thermus. Biochemical and physiological characteristics of this strain were studied, including the investigation of the fatty acid composition of its neutral fats. The results obtained were summarized as follows. 1. Optimal temperature and pH for growth of this strain were $65^{\circ}C$ and pH 6.5 respectively, and it was found to be an absolute thermophilic bacterium which could not grow at the temperature below $43^{\circ}C$. 2. No growth was obtained in the medium which contained more than 1.0% of sodium chloride. 3. The tolerable concentration of antibiotics were 10mg of penicillin G per ml of medium and 0.5mg of chloramphenicol per ml respectively. 4. This strain had auxotrophilic requirements for calcium-pantothenate and pyridoxin-HCl as an essential factor and for niacin as a stimulative factor. 5. Yellow pigment was released into the liquid culture of this strain, which showed maximum absorption at 420 nm. 6. Fatty acid composition of neutral fats of the strain was palmitic acid, 60.20%; lauric acid, 11.80%; myristic acid, 7.56%; behenic acid, 4.25%; capric acid, 1.77%; stearic acid, 2.13%; arachidic acid, 1.53%; and others unidentified, 10.7%.

• Microbiology and Biotechnology Letters
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• v.31 no.2
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• pp.95-102
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• 2003

Microalgae are a diverse group of photosynthetic organisms and abundant in every ecosystem in the biosphere. They are common in aqueous environments including marine, brackish and fresh waters and in some habitats that lack eukaryotic life such as some hot springs and highly alkaline lakes. Microalgal biotechnology that is focused on the microalgae-based production of a variety of useful materials such as pharmaceutical comfounds, health foods, natural pigments, and biofuels is considered as an important discipline with the development of biotechnology. In addition, the mass cultivation of microalgae can also contribute to improving the environmental quality by reducing the concentration of $CO_2$ which is one of major gases lead to global warming. Consequently, it seems that the microalgae can be used as an efficient, renewable, environmentally friendly source of high-value biomaterials such as chemicals, pigments, energy, etc. and the microalgal biotechnology will most likely represent a larger portion of modern biotechnology.

• Journal of Life Science
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• v.23 no.1
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• pp.110-115
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• 2013

A microorganism (strain AR1) producing an extracellular lipolytic enzyme was isolated from hot springs located in Beppu, Japan. Phylogenetic analysis based on the 16S rDNA sequence and biochemical studies indicated that AR1 belongs to the genus Geobacillus. This study focused on novel strategies to increase extracellular lipolytic enzyme production by this novel Geobacillus sp. AR1. Cultures of the AR1 strain grew within a wide temperature range (from 35 to $75^{\circ}C$); the optimum temperature was $65^{\circ}C$. The pH for optimal growth was 6.5, whereas the optimum pH for lipolytic enzyme production was 8.5. The presence of oils in the culture medium led to improvements in lipolytic enzyme activity. Soybean oil was the most efficient inducer, and it yielded better results when added in the exponential phase. On the other hand, the addition of chemical surfactants led to lipolytic enzyme production. Their addition to the culture could affect the location of the enzyme activity. The addition of Tween 20 in the stationary phase significantly increased the proportion of the extracellular enzyme activity. According to the results, following the addition of soybean oil and Tween 20 in the exponential and stationary phases, the extracellular lipolytic activity was increased 2.4-fold compared with that of a control.

• Journal of Wetlands Research
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• v.23 no.1
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• pp.1-6
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• 2021

The average annual rainfall in Busan to increase, and in case of Oncheon-Chen in Busan, frequent flooding occurred frequently. The middle and lower reaches of the Oncheon-Chen are relatively flat and urban areas are developed. Therefore, due to the frequent flooding of rivers and the large flood damage, a method of effectively eliminating the flow rate of Oncheon-Chen in the event of heavy rain is needed. In this study, underground waterway was established in the east of Hoedong-Reservoir as a measure to reduce floods in hot springs and simulated with EPA-SWMM. The information needed to construct the basin was utilized by GIS. In middle part of the Suyeong-Gang, there is a Hoedong-Reservoir and a dam is installed and has better conditions than the Nakdong-Gang. It also analyzed the effect of the Oncheon-Chen flow through the underground waterway on the Suyeong-Gang when it was transferred to the Hoedong-Reservoir. It was analyzed that the flood reduction rate at the flood risk points set up in this study was reduced by 24.64% on average when the underground waterway was installed, and the inflow of the water into the Suyeong-Gang increased by 1% on average when the flow rate was excluded by the Suyeong-Gang.

• The Journal of the Petrological Society of Korea
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• v.21 no.1
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• pp.1-12
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• 2012

The Baegdusan volcano is one of the most active volcanoes in northeastern Asia, and the 10th century eruption was the most voluminous eruption in the world in recent 2,000 years. During the period from 2002 to 2005, volcanic earthquakes and abnormal surface distortions by suspected subsurface magma intrusion beneath the volcano were observed in the Baegdusan area. Seismic activity has gradually increased with earthquake swarms during 2002-2003 and hundreds of seismic event in a day, especially annual peak of 2,100 in 2003. Then the number of seismic activity has declined since 2006 to the background level in 1999-2001. According to the typical frequency of volcanic earthquakes in the Baegdusan volcano, the frequency distribution of typical volcanic earthquakes between 2002 and 2005 indicates that all the main frequency of the earthquakes basically falls down less than 5 Hz and 5-10 Hz. These events are all the VT-B and LP events caused by the shallow localized fracture and intrusion of magma. The horizontal displacement measurement by GPS during the period from 2000 to 2007 of the Baegdusan stratovolcano area indicates that an inflated process has been centered at the summit caldera since 2002. The displacement between 2002 and 2003 reached at a maximum value of 4 cm. After 2003, the deformation rate of the volcano continued to decrease with unusual variation during the period from 2006 to 2007. After 2003 the vertical displacement uplift rate falls down gradually but still keeps in an uplift trend in northern slope. It is generally believed that when $^3He/^4He(R)$ in a gas sample from a hot spring exceeds $^3He/^4He(R)$ in the atmosphere, it can be concluded that mantle-source. And temperatures of hot springs are rising steadily to $83^{\circ}C$. It is unrest signals at the Baegdusan, which is potentially active. The Baegdusan volcano is now in unrest status, there is eruption threat in the near future. Intensified monitoring and emergency response plan for volcanic risk mitigation are urgent for the volcano.

• Korean Journal of Soil Science and Fertilizer
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• v.51 no.1
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• pp.16-27
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• 2018

To predict the influence of volcano eruption on agriculture in South Korea we evaluated the dispersal ranges of the volcanic ashes toward the South Korea based on the possibilities of volcano eruption in Mt. Baekdu. The possibilities of volcano eruption in Mt. Baekdu have been still being intensified by the signals including magmatic unrest of the volcano and the frequency of volcanic earthquakes swarm, the horizontal displacement and vertical uplift around the Mt. Baekdu, the temperature rises of hot springs, high ratios of $N_2/O_2$ and $_3He/_4He$ in volcanic gases. The dispersal direction and ranges and the predicted amount of volcanic ash can be significantly influenced by Volcanic Explosivity Index (VEI) and the trend of seasonal wind. The prediction of volcanic ash dispersion by the model showed that the ash cloud extended to Ulleung Island and Japan within 9 hours and 24 hours by the northwestern monsoon wind in winter while the ash cloud extended to northern side by the south-east monsoon wind during June and September. However, the ash cloud may extent to Seoul and southwest coast within 9 hours and 15 hours by northern wind in winter, leading to severe ash deposits over the whole area of South Korea, although the thickness of the ash deposits generally decreases exponentially with increasing distance from a volcano. In case of VEI 7, the ash deposits of Daejeon and Gangneung are $1.31{\times}10^4g\;m^{-2}$ and $1.80{\times}10^5g\;m^{-2}$, respectively. In addition, ash particles may compact close together after they fall to the ground, resulting in increase of the bulk density that can alter the soil physical and chemical properties detrimental to agricultural practices and crop growth.

• The Journal of Engineering Geology
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• v.13 no.3
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• pp.293-308
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• 2003

New results about the crustal structure down to a depth of 60 km beneath North Korea were obtained using the seismic tomography method. About 1013 P- and S-wave travel times from local earthquakes recorded by the Korean stations and the vicinity were used in the research. All earthquakes were relocated on the basis of an algorithm proposed in this study. Parameterization of the velocity structure is realized with a set of nodes distributed in the study volume according to the ray density. 120 nodes located at four depth levels were used to obtain the resulting P- and S-wave velocity structures. As a result, it is found that P- and S-wave velocity anomalies of the Rangnim Massif at depth of 8 km are high and low, respectively, whereas those of the Pyongnam Basin are low up to 24 km. It indicates that the Rangnim Massif contains Archean-early Lower Proterozoic Massif foldings with many faults and fractures which may be saturated with underground water and/or hot springs. On the other hand, the Pyongyang-Sariwon in the Pyongnam Basin is an intraplatform depression which was filled with sediments for the motion of the Upper Proterozoic, Silurian and Upper Paleozoic, and Lower Mesozoic origin. In particular, the high P- and S-wave velocity anomalies are observed at depth of 8, 16, and 24 km beneath Mt. Backdu, indicating that they may be the shallow conduits of the solidified magma bodies, while the low P-and S-wave velocity anomalies at depth of 38 km must be related with the magma chamber of low velocity bodies with partial melting. We also found the Moho discontinuities beneath the Origin Basin including Sari won to be about 55 km deep, whereas those of Mt. Backdu is found to be about 38 km. The high ratio of P-wave velocity/S-wave velocity at Moho suggests that there must be a partial melting body near the boundary of the crust and mantle. Consequently we may well consider Mt. Backdu as a dormant volcano which is holding the intermediate magma chamber near the Moho discontinuity. This study also brought interesting and important findings that there exist some materials with very high P- and S-wave velocity annomoalies at depth of about 40 km near Mt. Myohyang area at the edge of the Rangnim Massif shield.