• The Korean Journal of Pesticide Science
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• v.15 no.1
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• pp.55-60
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• 2011

To work out quality control methods of environmental-friendly organic materials (EFOMs), the reason and basis for EFOM-selection and farmer's favorite formulation type of EFOMs, etc were investigated on farmers who had been practicing environmental-friendly agriculture. EFOMs used were soil amendments, control agents of plant diseases and insect pests, plant growth promotion formulations, in turns. In EFOMs application time, 22.7% of farmers sprayed EFOMs without delay after they were bought, in other hand, 77.3% of farmers used EFOMs which had been bought and stored for some period. Microbial density on seventeen environmental-friendly microbial formulates (EFMFs) including microbial pesticides, a microbial fertilizer, and environmental-friendly organic materials was investigated at different storing temperature and shelf life. When the microbial density of EFMFs was investigated without delay after they were bought, all used microbial pesticides and a microbial fertilizer was confirmed to be optimal for the certified density but two of environmental-friendly organic materials was confirmed not to be optimal. When microbial density of 17 EFMFs were investigated after storing them for six months at $4^{\circ}C$, only one of 9 microbial pesticides was confirmed not to be optimal, the other hand four of seven environmental-friendly organic materials not to be optimal, which each of their microbial density was less than the certified density. Population dynamics of microbial agents was much more influenced in fluctuated temperature (room temperature) than in static temperature condition ($5^{\circ}C$ and $25^{\circ}C$). Shelf life of microbial agents according to microbial formulation type were high in granule type, liquid wettable type and liquid type in turns.

• Particle and aerosol research
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• v.19 no.3
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• pp.77-87
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• 2023

We present the development of a wetcyclone sampler designed for the sampling of airborne bacteria. The wetcyclone design involves a combination of two traditional cyclone shapes and computational fluid dynamics (CFD) analysis to validate its effectiveness in terms of pressure drop and collection efficiency. The wetcyclone exhibits a collection efficiency of over 90% for bacteria, specifically targeting Staphylococcus aureus. Additionally, the wetcyclone enables continuous bioaerosol sampling using a liquid medium (deionized water), demonstrating a concentration ratio exceeding >105 and a stable microbial recovery rate of 81.9%. The application of real-time quantitative polymerase chain reaction (qPCR) and the colony counting method ensures precise measurement of the concentration ratio and microbial recovery rate.

• Journal of Microbiology and Biotechnology
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• v.19 no.9
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• pp.1028-1033
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• 2009

In this study, the dynamics of living cells (LC) and dead cells (DC) in a laboratory-scale biofilm membrane bioreactor for waste gas treatment was examined. Toluene was used as a model pollutant. The bacterial cells were enumerated as fluoromicroscopic counts during a 140 operating day period using BacLight nucleic acid staining in combination with epifluorescence and confocal laser scanning microscopy (CSLM). Overall, five different phases could be distinguished during the biofilm development: (A) cell attachment, (B) pollutant limitation, (C) biofilm establishment and colonization, (D) colonized biofilm, and (E) biofilm erosion. The bioreactor was operated under different conditions by applying different pollutant concentrations. An optimum toluene removal of 89% was observed at a loading rate of 14.4 kg $m^{-3}d^{-1}$. A direct correlation between the biodegradation rate of the reactor and the dynamics of biofilm development could be demonstrated. This study shows the first description of biofilm development during gaseous toluene degradation in MBR.

• Bulletin of the Korean Chemical Society
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• v.26 no.8
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• pp.1203-1208
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• 2005

A computational study based on molecular dynamics (MD) simulations was performed in order to explain the difference in aqueous solubilities of two flavonoid/$\beta$-cyclodextrin ($\beta$-CD) complexes, hesperetin/$\beta$-CD and naringenin/$\beta$-CD. The aqueous solubility of each flavonoid/$\beta$-CD complex could be characterized by complexwater interaction not by flavonoid-CD interaction. The radial distribution of water around each inclusion complex elucidated the difference of an experimentally observed solubility of each flavonoid/$\beta$-CD complex. The analyzed results suggested that a bulky hydrophobic moiety (-$OCH_3$) of B-ring of hesperetin nearby primary rim of $\beta$-CD was responsible for lower aqueous solubility of the hesperetin/$\beta$-CD complex.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2000.05a
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• pp.137-140
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• 2000

The purpose of this study is to see the effect of SVE (Soil Vapor Extraction) and Bioventing (biostimulation) hydrocarbon contaminated areas. The removal rate of VOC for three weeks were 17.43 kg on 3.6 ㎥/hr at steady-state. In the application of Bioventing, every flow rate were tested, and it was found that 4.0 ㎥/hr were adequate for best control of the system. At this stage, the addition of microbial agent accelerated the biodegradation of the hydrocarbon.

• Environmental Engineering Research
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• v.12 no.5
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• pp.231-237
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• 2007

The microbial eco-physiology has been the vital key of microbial ecological research. Unfortunately, available methods for direct identity of microorganisms and for the investigation of their activity in complicated community dynamics are limited. In this study, metagenomics was considered as a promising functional genomics tool for improving our understanding of microbial eco-physiology. Its potential applications and challenges were also reviewed. Because of tremendous diversity in microbial populations in environment, sequence analysis for whole metagenomic libraries from environmental samples seems to be unrealistic to most of environmental engineering researchers. When a target function is of interest, however, sequence analysis for whole metagenomic libraries would not be necessary. For this case, nucleic acids of active populations of interest can be selectively gained using another cutting-edge functional genomic tool, SIP (stable isotope probing) technique. If functional genomes isolated by SIP can be transferred into metagenomic library, sequence analysis for such selected functional genomes would be feasible because the reduced size of clone library may become adequate for sequencing analysis. Herein, integration of metagenomics with SIP was suggested as a novel functional genomics approach to study microbial eco-physiology in environment.

• Environmental Engineering Research
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• v.24 no.2
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• pp.181-190
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• 2019

Constructed wetlands are improvised man-made systems, designed for adopting the principle of natural wetlands for purifying wastewater - the elixir of life. They are used widely as a cost-effective and energy-efficient solution for treating greywater generated from different tertiary treatment sources. It provides an elaborate platform for research activities in an attempt to recycle earth's natural resources. Among the several organic impurities removal mechanisms existing in constructed wetland systems, the earth's active microbial population plays a vital role. This review deals with the recent advancements in constructed wetland systems from a microbiological perspective to (effect/ devise/ formulate) chemical and physical treatment for water impurities. It focuses on microbial diversity studies in constructed wetlands, influence of wetland media on microbial diversity and wetland performance, role of specific microbes in water reuse, removal of trace elements, some heavy metals and antibiotics in constructed wetlands. The impurities removal processes in constructed wetlands is achieved by combined interactive systems such as selected plant species, nature of substrate used for microbial diversity and several biogeochemical effected reaction cycles in wetland systems. Therefore, the correlation studies that have been conducted by earlier researchers in microbial diversity in wetlands are addressed herewith.

• Journal of Soil and Groundwater Environment
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• v.17 no.6
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• pp.23-32
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• 2012

This study was conducted to monitor microbial species dynamics within the aquifer due to long term operation of geothermal heat pump system. The species were identified by molecular biological methods of 16S rDNA. Groundwater sample was collected from both open (S region) and closed geothermal recovery system (J region) along with the control. J measured and control as well as S measured found Ralstonia pickettii as dominant species at year 2010. In contrast, Rhodoferax ferrireducens was dominantly observed for the control of S. In 2011, Sediminibacterium sp. was universely identified as the dominant species regardless of the monitoring places and type of sample, i.e., measured or control. The difference in the dynamics between the measured and the control was not critically observed, but annual variation was more strikingly found. It reveals that possible environmental changes (e.g. ORP and DO) due to the operation of geothermal heat recovery system in aquifer could be more exceedingly preceded to differentiate annual variation of microbial species rather than positional differences.

• Journal of Microbiology and Biotechnology
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• v.20 no.1
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• pp.21-29
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• 2010

The phenolic compounds are a major contaminant class often found in industrial wastewaters and the biological treatment is an alternative tool commonly employed for their removal. In this sense, monitoring microbial community dynamics is crucial for a successful wastewater treatment. This work aimed to monitor the structure and activity of the bacterial community during the operation of a laboratory-scale continuous submerged membrane bioreactor (SMBR), using PCR and RT-PCR followed by denaturing gradient gel electrophoresis (DGGE) and 16S rRNA libraries. Multivariate analyses carried out using DGGE profiles showed significant changes in the total and metabolically active dominant community members during the 4-week treatment period, explained mainly by phenol and ammonium input. Gene libraries were assembled using 16S rDNA and 16S rRNA PCR products from the fourth week of treatment. Sequencing and phylogenetic analyses of clones from the 16S rDNA library revealed a high diversity of taxa for the total bacterial community, with predominance of Thauera genus (ca. 50%). On the other hand, a lower diversity was found for metabolically active bacteria, which were mostly represented by members of Betaproteobacteria (Thauera and Comamonas), suggesting that these groups have a relevant role in the phenol degradation during the final phase of the SMBR operation.

• Journal of the korean society of oceanography
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• v.37 no.1
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• pp.35-44
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• 2002

To assess the relative contribution of bacterial and phytoplankton biomasses to particulate organic matter (POM) in the water column, microbial abundance and biomass were from two transects in the western channel of the Korea Strait in 1996. Bacterial abundance had a mean value of $5.9{\times}10^5$ cells/ml and chlorophyll-a averaged 0.14 ${\mu}g/l$. Bacterial abundance in the Korea Strait showed a positive relationship with chlorophyll-a concentration, while the distribution of POM did not covary with chlorophyll-a. Particulate organic carbon (POC) and nitrogen (PON) concentrations were greater in August than in October. Bacterial carbon (POC) and nitrogen (PON) concentrations were greater in August than in October. Bacterial carbon and nitrogen biomasses were 7.29 ${\mu}gC/l$ and 1.24 ${\mu}gN/l$, respectively, during the study periods. Bacterial biomass was larger in October than in August due to the autumn phytoplankton bloom. Phytoplankton biomass based on chlorophyll-a was 7.67 ${\mu}gC/l$ for carbon and 1.10${\mu}gN/l$l for nitrogen. The ratio of bacterial carbon (BC) to phytoplankton carbon (Cp) averaged 0.95 in the Korea Strait in 1996. Bacteria may play a more significant role in the dynamics of POM than phytoplankton do in August, with BC/Cp ratio of 1.26. The ratio of BC to Cp increased with a decrease in chlorophyll-a concentration. Averaged over all the samples in both cruises, the contribution of microbial biomass to POC and PON was about 43% and 51%, respectively. Bacterial assemblage constituted a significant fraction of POC (21%) and PON (27%). Phytoplankton accounted for 22% of POC and 24% of PON. Microbial biomass played a more important role in the dynamics of POC and PON in October than in August due to a significant increase in microbial biomass in the southern transect (transect-B) in October by the autumn phytoplankton bloom. This study showed that marine microbes may constitute a significant part in the reservoir of POM in the Korea Strait.