• Journal of Korean Society of Environmental Engineers
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• v.28 no.3
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• pp.240-248
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• 2006

In this study, a retrofitting BNR process that was modified for the economical applicability was proposed and evaluated in the pilot plant($50m^3/d$). At the same time the bacterial community structure was investigated in the pilot plant by using FISH(fluorescent in situ hybridization) method. Economically 16% of the initial construction cost for the proposed process(introduction of a biological nutrient removal process of $60,000m^3/d$ scale basis) was reduced due to the absence of a bioreactor. Water treatment efficiencies and maintenance facilities of the modified process were satisfied with the strengthened discharge permits in Korea throughout a long term pilot plant operating including a winter season. Bacterial populations in the pilot plant and in the control plant(A2/O process, B SIP(Sewage Treatment Plant)) were remained uniformly during the test period, but bacterial structure in the bioreactor was changed drastically. Proportions of ${\beta}$-proteobacteria group including soil bacteria which play a important role in wastewater treatment increased $25{\sim}607%$ in population.

• Korean Journal of Environmental Biology
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• v.34 no.4
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• pp.233-239
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• 2016

The purpose of this study is to investigate the response of the soil mesofauna and ground-dwelling arthropods to vegetation structure and composition in a mountain pasture. The pasture mainly comprised five types of plant communities; Agrostis alba - Phleum pratense community, Poa pratensis community, Festuca ovina community, Rumex acetosella community, and the shrub assemblage comprised Spiraea miyabei-Spiraea salicifolia community. Soil chemical properties including the pH, EC and nutrient levels were influenced by plant communities. Plant-specific responses were observed for bacteria-feeding and plant-feeding soil nematodes. Collembola and Oribatida having the same feeding habit were influenced differently by plants. nMDS showed that the community of ground-dwelling arthropods were separated by vegetation types. Species numbers of arthropods were different among different plant communities. Our results indicate that vegetation structure and composition can influence both abundance of diversity of terrestrial fauna.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.830-835
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• 2011

Total soil microbial activities have great impact to soil management for organic farming. This study was evaluated in the soil microbial community by fatty acid methyl ester (FAME) in a controlled horticultural field for strawberry organic farm. Experimental plots were prepared with a high level of soil electrical conductivity (EC) and a optimum level of soil EC. Soil microbial biomasses and communities of total bacteria, Gram-negative bacteria, Gram-positive bacteria, actinomycetes, fungi, and arbuscular mycorrhizal fungi in the high level of soil EC were significantly larger than those in the optimum level of soil EC. Lower ratios of cy17:0 to 16:$1{\omega}7c$ and cy19:0 to 18:$1{\omega}7c$ were found in the optimum level of soil EC than those in the high level of soil EC, indicating that microbial stress decreased.

• Korean Journal of Microbiology
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• v.46 no.1
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• pp.33-37
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• 2010

Rhizobacterial strain isolated from barren soil, Bacillus subtilis RFO41 exhibits a high level of phosphate solubilizing activity and produces some phytohormones. Its promoting effect on the growth of Xanthium italicum Moore, a wild plant growing at lakeside barren land and thus a good candidate plant for revegetation of barren lakeside was evaluated in the in situ test for 19 weeks at Lake Paro, Kangwon-do. Strain RFO41 could enhance the dry weight of X. italicum by 67.7%. It also increased the shoot length of X. italicum plant by 21.1% compared to that of uninoculated control. Both growth enhancements had statistical significance. However, the inoculation did not show any effect on the root growth, which might be due to the breakage of tiny root. Denaturing gradient gel electrophoresis analysis showed that the inoculated bacteria were maintained in the soils, and the indigenous bacterial community did not exhibit any significant change. This plant growth promoting capability may be utilized as an environment-friendly and low cost revegetation method, especially for the sensitive areas such as barren lakeside lands.

• Korean Journal of Microbiology
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• v.33 no.2
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• pp.125-130
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• 1997

Microbial reduction of hexava1ent(VI) to trivalent(lII) chromium is regarded as one of the mechanisms that confers resistance to bacteria. In order to verify this hypothesis, we compared Cr(VI) resistance with Cr(VI) reduction among 20 phenotypically distinct environmental isolates from Cr-contaminated and uncontaminated soils. With glucose as an electron donor, Cr(VI) reduction by washed cell suspensions ranged from 0.014 to 0.305 mM Cr(VI) reduced $h^1$. Cr(VI) resistance of the isolates were measured by growth inhibitions on a liquid medium containing 2 mM Cr(VI) based on their decrease of $A_{630}1$ as compared to the controls without Cr(VI). The isolates had a broad range of resistance from no inhibition to 93.4% inhibition of their growth. Upon correlation analysis, there was no significant relationship between those two phenomena. At a population level, a comparison of % resistant viable counts among the Cr-contaminated and uncontaminated soils showed 19.1 % and 0.4% of their total viable counts, respectively. The difference of % resistance between two site,. strongly suggested that the Cr(VI) present in the soils influences natural selection for resistant phenotypes. However, it is unlikely that the Cr(VI) resistance is dependent solely on the reduction as judged by the correlation analysis.

• Korean Journal of Microbiology
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• v.49 no.2
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• pp.184-190
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• 2013

Cave environment provides special ecosystems for evolution of lives distant from surface environments. We investigated bacterial and archaeal communities of wall biofilm obtained from of a volcanic cave (Daesubee) in Jeju, Republic of Korea. Bacterial and archaeal 16S rRNA genes were PCR-amplified and sequenced using pyrosequencing technologies. Unique prokaryotic communities with low diversities were observed. The main bacterial sequences (ca. 83% of total reads) were affiliated with Pseudonocardia mongoliensis of phylum Actinobacteria and clustered with clones obtained from various caves. Reflection of light on the wall surface of cave might be caused by formation of beads of water caused by hydrophobic filaments of actinobacterial colonies. Main archaeal sequences (ca. 65.7% of total reads) were related with those of I.1a-Associated group of phylum Thaumarchaeota. The sequences were related with that of Candidatus Nitrosotalea devanaterra which was known to oxidize ammonia under acidic condition (ca. pH 5.0). Nutrients leached through volcanic soils contribute formation of unique microbial communities of wall biofilm of cave Daesubee.

• Korean Journal of Microbiology
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• v.42 no.2
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• pp.116-124
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• 2006

In this study was performed to analyze quantitatively the number of viable but non-culturable bacteria in the Pine and Quercus forest soil by improved direct viable count (DVC) and plate count (PC) methods. The number of living bacteria of Pine and Quercus forest soil by PC method were less then 1% of DVC method. This result showed that viable but non-culturable (VBNC) bacteria existed in the forest soil with high percentage. Diversity and structure of VBNC bacterial populations in forest soil were analyzed by direct extracting of DNA and 16S rDNA-ARDRA from Pine and Quercus forest soil. Each of them obtained 111 clones and 108 clones from Pine and Quercus forest soil. Thirty different RFLP types were detected from Pine forest soil and twenty-six different RFLP types were detected from Quercus forest soil by HeaIII. From ARDRA groups, dominant clones were selected for determining their phylogenetic characteristics based on 16S rDNA sequence. Based on the 16S rDNA sequences, dominant clones from ARDRA groups of Pine forest soil were classified into 7 major phylogenetic groups ${\alpha}$-proteobacteria (12 clones), ${\gamma}$-proteobacteria (3 clones), ${\delta}$-proteobacteria (1 clone), Flexibacter/Cytophaga (1 clone), Actinobacteria (4 clones), Acidobacteria (4 clones), Planctomycetes (5 clones). Also, dominant clones from ARDRA groups of Quercus forest soil were classified into 6 major phylogenetic groups : ${\alpha}$-proteobacte,ia (4clones), ${\gamma}$-proteobacteria (2 clones), Actinobacteria (10 clones), Acidobacteria (8 clones), Planctomycetes (1 clone), and Verrucomicobia (1 clone). Result of phylogeneric analysis of microbial community from Pine and Quercus forest soils were mostly confirmed at uncultured or unidentified bacteria, VBNC bacteria of over 99% existent in forest soil were confirmed variable composition of unknown micro-organism.

• Journal of Mushroom
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• v.22 no.1
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• pp.22-26
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• 2024

Tricholoma matsutake is a traditional favorite food in East Asia, cultivated in fairy rings called "shiro," which are found near Pinus densiflora. For effective artificial cultivation of Tri. matsutake, microorganisms from symbiotic fairy rings are co-cultivated. In this study, one bacterial isolate (Y22_B35) and two fungal isolates (Y22_F64 and Y22_F68) displayed growth-promoting effects on Tri. matsutake mycelium (158.47, 125.00, and 122.26% enhanced growth, respectively). For identification, 16S rRNA or ITS regions from the microorganisms¡¯ genomes were sequenced. Other sequences, including BenA, CaM, and RPB2 were sequenced in the fungal isolates. The bacterial isolate Y22_B35 was identified as Bacillus cereus. Y22_F64 and Y22_F68 were identified as Umbelopsis nana and Aspergillus parvulus, respectively. To identify the effects of the dominant microorganisms on Tri. Matsutake cultivation, metagenomic analyses were performed. Discovery of these Tri. matsutake mycelium growth-promoting microorganisms and metagenomics analyses are expected to contribute to our understanding of Tri. matsutake fruiting body growth and construction of biomimicry.

• Journal of Wetlands Research
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• v.11 no.1
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• pp.123-130
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• 2009

Hyporheic zone is an area where hydraulic exchanges occur between surface water and ground water. Such transient area is anticipated to facilitate diverse biogeochemical reactions by providing habitats for various microorganism. However, only a few data are available about microbial properties in hyporheic zone, which would be important in better understanding of biogeochemical reactions in whole streams. The study site is Naesung stream, located in the north Kyoung-Sang Province, of which sediment is sandy with little anthropogenic impacts. Soil samples were collected from a transect placed perpendicular to stream flow. The transect includes upland fringe area dominated by Phragmites japonica, bare soil, and soil adjacent to water. In addition, soil samples were also collected from downwelling and upwelling areas in hyporheic zone within the main channel. Soils were collected from 3 depth in each area, and water content, pH, and DOC were measured. Various microbial properties including extracellular enzyme activities ($\beta$-glucosidase, N-acetylglucosaminidase, phosphatase and arylsulfatase), and microbial community structure using T-RFLP were also determined. The results exhibited a positive correlation between water content and DOC, and between extracellular enzyme activities and DOC. Distinctive patterns were observed in soils adjacent to water and hyporheic zone compared with other soils. Overall results of study provided basic information about microbial properties of hyporheic zone, which appeared to be discernable from other locations in the stream corridor.

• Korean Journal of Microbiology
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• v.43 no.3
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• pp.210-216
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• 2007

The principal objective of this study was to analyze 16S rDNA-ARDRA of the humus forest soil via an improved manual method and an ISOIL kit on the basis of the UPGMA clustering of the 16S rDNA combined profile, 44 ARDRA clusters of 76 clones via the ISOIL kit method and 45 ARDRA clusters of 136 clones via the improved manual method. On the basis of the 16S rDNA sequences, 44 clones from the ARDRA clusters by the ISOIL kit were classified into 3 phyla : ${\alpha}-,\;{\beta}-,\;{\gamma}-,\;{\delta}-Proteobacteria$, Acidobacteria and Actinobacteria. Using the improved manual method, the specimens were classified into 6 phyla : the ${\alpha}-,\;{\beta}-,\;{\gamma}-,\;{\delta}-Proteobacteria$, Acidobacteria, Bacteroides, Verrucomicrobia, Planctomycetes and Gemmatomonadetes. As a result, the modified manual method indicated greater phylogenetic diversity than was detected by the ISOIL kit. Approximately 40 percent of the total clones were identified as ${\alpha}-Proteobacteria$ and 30 percent of the total clones were ${\gamma}-Proteobacteria$ and assigned to dominant phylogenetic groups using the ISOIL kit. Using the modified manual method, 41 percent of the total clones were identified as Acidobacteria and 28 percent of total clones were identified as ${\alpha}-proteobacteria$ and assigned to dominant phylogenetic groups.