• Economic and Environmental Geology
• /
• v.28 no.3
• /
• pp.243-249
• /
• 1995

In order to investigate the origin of sulfate in rain waters and to evaluate the feasibility of using sulfur isotope method as a tracer of atmospheric pollutants, the sulfur isotopic ratio of sulfate in rain waters collected in Chonju city from October 1994 to March 1995 was monitored and was compared with those of possible sources proposed by previous works. The pH of rain waters shows an intermediate acidic range from 4.45 to 6.88 and their daily variation appears to be well correlated with to the amount of precipitation. The sulfur isotopic ratios of sulfate in rain waters show a highly restricted range from 0.0 to + 1.8‰. The ${\delta}^{34}S$ values are similar to those of soil and pine tree surrounding Chonju city, but largely deviate from those of China. D-parameter($d={\delta}D-8{\delta}^{18}O$) of rain waters varies from 9.4 to 28.8. The values indicate that the rain waters in Chonju city are originated from the rainy front of China continent. All data obtained from this study suggested that sulfate in the rain waters collected in Chonju city was mainly derived from the sulfur dioxide gas emitted by the petroleum combustion. Therefore, sulfur isotopic study for the precipitation provided an excellent tool for environmental assessment in this region and for tracing the source of atmospheric pollutants.

• Microbiology and Biotechnology Letters
• /
• v.10 no.2
• /
• pp.145-154
• /
• 1982

To maximize the production of glucose oxidase by Aspergillus niger KUF-04 isolated from a soil, the cultivation conditions and nutrient sources for the enzyme production were studied. The results obtained were as fellows: 1. The optimum temperature, pH of the medium, and cultivation time for the enzyme formation were found to be 28-34$^{\circ}C$, 7.0-8.0 and 40 hours, respectively. 2. The best carbon source was proved to be glucose and its most effective concentration was 15 percent. 3. Ammonium sulfate was the best nitrogen source as compared with the other inorganic and organic nitrogen sources tested. Its optimum concentration for the glucose oxidase production was 0.02 percent. 4. As mineral sources, 0.05% of Mag cesium sulfate 7-hydrate and 0.02% of Potassium phosphate, monobasic seemed to be necessary to further increase the level of the enzyme production.

• Journal of Korean Society of Environmental Engineers
• /
• v.27 no.11
• /
• pp.1198-1204
• /
• 2005

The objectives of this study were to isolate and culture methanotrophs and to apply them for biological removal of nitrogen and phosphorous. Methanotrophs (dominant species: Methylomonas methanica) were isolated from a landfill cover soil, cultured in a NMS medium, and analyzed to reveal their characteristics of growth and nutrient removal. The methanotrophs themselves can produce substantial amount of organic substances(as COD) including methanol, formaldehyde, and formate, as carbon sources required for denitrification. For instance, the production rate for methanol was $8\;mg/L{\cdot}hr$. Moreover, the analysis of nitrogen and phosphorous in the sludge suggested that the methanotrophs assimilate nitrogen and phosphorous as growth substances.

• Journal of Environmental Impact Assessment
• /
• v.16 no.4
• /
• pp.241-250
• /
• 2007

A study was carried out on the level of heavy metals, total coliform and benzo(a)pyrene that may be introduced through by-product fertilizers or air pollution to turfgrass in natural turfgrass playground in elementary schools around the western coast and eastern mountain areas in Jeollabuk-do, Korea. The level of heavy metals found in turfgrass was in the order of Cu > Zn > Pb > Cd. The majority of heavy metals was found in the roots. It is presumed that the absorption of some air pollutants and by-product fertilizers or chemical fertilizers. The level of benzo(a)pyrene showed an average of 0.05ng/g with a range between 0.02 to 0.08ng/g in the leaves. In the meantime, none was detected in the stems, while the average for roots was 0.02ng/g with a range between 0.01 and 0.03ng/g. The level detected is that found background level, however, benzo(a)pyrene can be introduced partly from the unstable combustion of fossil fuel or through vehicle emissions. Total coliform distributed in grass showed an average of 12MPN/100ml with a range between 2 and 36MPN/100ml. The density of total coliform displayed no regional predominance. However, in some urban areas, the density was slightly higher. The feces of pets or by-product fertilizers may have contributed to the input of pathogenic micro-organism. Yet the level was found to be negligible.

• Microbiology and Biotechnology Letters
• /
• v.31 no.4
• /
• pp.383-388
• /
• 2003

A bacterium producing the extracellular xylanase and CMCase was isolated from soil and has been identified as Bacillus sp. The isolate, named Bacillus sp. A-7, was shown to be very similar to Bacillus licheniformis on the basis of its biochemical and physiological properties. The maximum xylanase and CMCase production were obtained when 2.0% (w/v) glucose and 0.3% (w/v) yeast extract were used as carbon source and nitrogen source, respectively. The best mineral conditions for xylanase and CMCase production were 0.1%(w/v) $CaC1_2$. Among the various feedstuffs, 1.0%(w/v) soybean meal was selected for the best xylanase and CMCase production.

• Analytical Science and Technology
• /
• v.12 no.1
• /
• pp.53-60
• /
• 1999

Dissolution properties for the 6 inorganic pollutants (As, Cd, Cu, Pb, Zn, Cr) in soils have been studied. These 6 inorganic pollutants were spiked to 3 kinds of fresh soils which were sand, clay, and loam. The dissolution properties of the prepared samples were investigated under the various extracting conditions such as extracting time, acid concentration, particle size, etc. in order to obtain basic information about the process of extraction test and improvement of related analytical methods. As the results, dissolution properties were affected mainly by acid concentration in extracting procedure and mineral composition of soils. On the other hand, extracting time, sort of acids and particle size of soils had a little influence on the dissolution properties. Cd revealed very high dissolving efficiency and As was very low in whole extracting test.

• Journal of Microbiology and Biotechnology
• /
• v.30 no.7
• /
• pp.1005-1012
• /
• 2020

Acid mine drainage (AMD) has been a serious environmental issue that threatens soil and aquatic ecosystems. In this study, an acid-tolerant sulfate-reducing bacterium, strain S4, was isolated from the mud of an AMD storage pond in Vietnam via enrichment in anoxic mineral medium at pH 5. Comparative analyses of sequences of the 16S rRNA gene and dsrB gene involved in sulfate reduction revealed that the isolate belonged to the genus Desulfovibrio, and is most closely related to Desulfovibrio oxamicus (with 99% homology in 16S rDNA sequence and 98% homology in dsrB gene sequence). Denaturing gradient gel electrophoresis (DGGE) analyses of dsrB gene showed that strain S4 represented one of the two most abundant groups developed in the enrichment culture. Notably, strain S4 was capable of reducing sulfate in low pH environments (from 2 and above), and resistance to extremely high concentration of heavy metals (Fe 3,000 mg/l, Zn 100 mg/l, Cu 100 mg/l). In a batch incubation experiment in synthetic AMD with pH 3.5, strain S4 showed strong effects in facilitating growth of a neutrophilic, metal sensitive Desulfovibrio sp. strain SR4H, which was not capable of growing alone in such an environment. Thus, it is postulated that under extreme conditions such as an AMD environment, acid- and metal-tolerant sulfate-reducing bacteria (SRB)-like strain S4 would facilitate the growth of other widely distributed SRB by starting to reduce sulfate at low pH, thus increasing pH and lowering the metal concentration in the environment. Owing to such unique physiological characteristics, strain S4 shows great potential for application in sustainable remediation of AMD.

• Journal of Korean Society of Environmental Engineers
• /
• v.34 no.2
• /
• pp.136-142
• /
• 2012

Various factors affecting on the bioassay were investigated. Experiments with a low mixture ratio (cell to toxicant solution) of 0.5 : 9.5 (v/v) produced observable bioluminescence intensity for assay. Both sodium lactate and potassium nitrate stimulate bioluminescence activity; 2.6~4.0 times of control. Distilled water and MSM, which gave non significant effects on the bioluminescence activity, were determined as proper diluent or extract solutions. A wide range of toxic responses of metals and organics were observed. In general, organics were much less sensitive than metals. Samples collected from eleven sites showed the bioluminescence activity ranging from 29 to 111% of the control. Significant correlation between toxicity and total metal contents was not observed, but the toxicity of two groups, sorted based on the contaminated arsenic concentration in soils, was 44% and 20%, showing considerable differences.

• Journal of Species Research
• /
• v.6 no.2
• /
• pp.141-153
• /
• 2017

During an investigation of the biodiversity of bacterial species in Korea, we discovered many indigenous prokaryotic species. A total of 39 bacterial strains in the class Alphaproteobacteria were isolated from various environmental samples collected from marine organisms, sea water, fresh water, tap water, mud flats, activated sludge, mineral water, tidal flats, soil and decayed plants. From the high 16S rRNA gene sequence similarity (>98.7%) and formation of robust phylogenetic clades with the most closely related species, it was determined that each strain belonged to each independent and predefined bacterial species. There is no official report that any of these 39 Alphaproteobacteria species have been described in Korea. Specifically, 18 species in 11 genera in the order Sphingomonadales, 11 species in 10 genera in the order Rhizobiales, two species in two genera in the order Caulobacterales, six species in six genera in the order Rhodobacterales and two species in two genera in the order Rhodospirillales were found in Korea. Gram reaction, colony and cell morphology, basic biochemical characteristics, isolation source, and strain IDs are described in the species description section.

• Korean Journal of Microbiology
• /
• v.23 no.1
• /
• pp.1-8
• /
• 1985

Three strains (JC1, JC2, and HY1) of aerobic carbon monoxide (CO)-utilizing Acinetobacter were isolated from soil through CO-enrichment culture technique. All of them were Gram-negative, nonmotile, and rod-shated but they were changed to spherical form at the end of logarithmic phase. They were resistant to penicillin and able to frow at $42^{\circ}C$. The guanine plus cytosine contents of the DNAs ranged from 43 to 44.5 mol%. Oxidase was not present in all cells. The colonies were smooth and whitish yellow. Heterotrophic growth occurred on several sugars, organic acids, amino acids, and alcohols. The doubling times under and atmosphere of 30% CO and 70% air at $30^{\circ}C$ were 19h, 25h, and 35h, respectively, for JC1, JC2, and HY1, JC1 was studied in more detail. The cells were grown optimally in a mineral medium (pH 6.8) under a gas mixture of 30% CO and 70% air at $30^{\circ}C$. Growth of the cells with CO did not depend on molybdenum. It was able to grow with 100 ppm of CO in air as a sole source of carbon and energy.