• The Journal of Engineering Geology
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• v.20 no.1
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• pp.1-12
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• 2010

The objective of this study was to examine the hydrogeochemical and microbiological characteristics for stable maintenance of coastal LPG storage cavern. Cavern seepage water and groundwater in the vicinity of the LPG storage cavern were sampled and analyzed (February, May, August and October 2007). Groundwater samples of propane cavern showed high pHs of 8.1~12.4 due to dissolution of cement grouting materials that had been applied during the well and cavern construction. The EC values showed distinctive seasonal variation. The negative ORP indicated reduced condition. The seepage and surrounding groundwater are classified as Na-Cl type, which represents seawater effects. All of aerobic bacteria, anaerobic bacteria, slime forming bacteria and sulfate reducing bacteria were less than 500 CFU/mL, which indicated that there was no abrupt increase of bacteria in the cavern. Therefore there exist no hydrochemical symptoms to indicate unstable conditions of the cavern operation. However, regular and continuous monitoring is essentially required.

• Journal of Ecology and Environment
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• v.29 no.4
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• pp.399-404
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• 2006

This study was carried out to investigate the population densities, R/S ratios, and identification of heterotrophic bacteria on the rhizosphere soil of halophyte Suaeda japonica found on the western and southern mudflats of Korea. The population densities of aerobic and anaerobic heterotrophic bacteria on the rhizosphere soil of Suaeda japonica were in the range of $1.3\;{\pm}\;0.3\;{\times}\;10^6\;{\sim}\;6.3\;{\pm}\;3.3\;{\times}\;10^7\;and\;2.8\;{\pm}\;1.3\;{\times}\;10^4\;{\sim}\;1.8\;{\pm}\;0.7\;{\times}\;10^7\;cfu\;g^{-1}\;d.\;wt.$, respectively. In case of physiologically specific bacteria, population densities of amylolytic bacteria on the rhizosphere soil of Suaeda japonica were in the range of $4.4\;{\pm}\;0.6\;{\times}\;10^6\;{\sim}\;2.5\;{\pm}\;1.2\;{\times}\;10^7\;cfu\;g^{-1}\;d.\;wt.$, those of cellulolytic bacteria were from $8.5\;{\pm}\;6.0\;{\times}\;10^4\;{\sim}\;2.3\;{\pm}\;1.6\;{\times}\;10^6\;cfu\;g^{-1}\;d.\;wt.$, and those of proteolytic bacteria were from $3.8\;{\pm}\;1.8\;{\times}\;10^5\;{\sim}\;4.2\;{\pm}\;2.9\;{\times}\;10^6\;cfu\;g^{-1}\;d.\;wt.$, respectively. The R/S ratios were ranged from 2.33 to 2.39. Among eleven isolates from the roots of halophyte Suaeda japonica of Goheung bay by using 16S rDNA analysis, five clones were closely related to ${\gamma}-Proteobacteria$ group and six clones were closely related to ${\alpha}-Proteobacteria$ group. Among four isolates from Suncheon bay, two strains were related to ${\gamma}-Proteobacteria$ group and another two were related to Actinobacteria and Bacilli group, respectively.

• Research in Plant Disease
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• v.10 no.4
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• pp.285-289
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• 2004

The bloody watermelon exhibiting dark red and fermentation off-flavor results in a great economic loss. As an effort to clarify the cause of the bloody watermelon, relationship between the fermentational off-flavor and the presence of endophytic bacteria was studied. The number of endophytes was 2.2-37.0 ${\times}10^3$ cfu/g fw (fresh weight) in normal watermelons, compared to 1.26-1.75 ${\times}10^6$ cfu/g fw in bloody ones. Seventeen bacteria among 56 isolates from bloody watermelons could induce bloody watermelons. The bacteria responsible for bloody watermelons were mainly Gram negative: aerobic Pseudomonas spp and some anaerobic bacteria. The results in this study strongly suggested that the bloody watermelons were produced by abnormal fermentation and growth of endophytic Gram negative bacteria.

• Restorative Dentistry and Endodontics
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• v.11 no.1
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• pp.97-103
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• 1985

The purpose of this study was to compare Black-pigmented Bacteroides isolated from necrotic pulp with the presence or absence of eight symptoms associated with pulpal necrosis and to identify the proportion of each Black-pigmented Bacteroides species. The canal contents of fourteen traumatically and cariously necrotized teeth were sampled with a special technique and cultured aerobically and anaerobically for growth in blood agar plate and for Black-pigmented Bacteroides on selective blood agar plate. Each Black-pigmented Bacteroides species were identified by Gram's stain, hemolysis reaction, colony color and morphology and biochemical tests. The results were as follows; 1. 60.9 percent of the bacteria isolated were anaerobic and 39.1 percent were aerobic. 2. Four Black-pigmented Bacteroides species were isolated; B. loescheii (74.1%), B. denticola (11.1%), B. intermedius (7.4%) and B. gingivalis (7.4%). 3. Black-pigmented Bacteroides was found to be significantly related to sinus tract formation and exudate.

• Journal of Microbiology and Biotechnology
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• v.22 no.10
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• pp.1311-1323
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• 2012

In the present work, current knowledge on the potential fate, microbial degradation, and toxicity of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) was thoroughly reviewed, focusing on the toxicological assessment of a variety of potential RDX degradation pathways in bacteria and fungi. The present review on microbial degradation pathways and toxicities of degradation intermediates suggests that, among aerobic RDX degradation pathways, the one via denitration may be preferred in a toxicological perspective, and that among anaerobic pathways, those forming 4-nitro-2,4-diazabutanal (NDAB) via ring cleavage of 1-nitroso-3,5-dinitro-1,3,5-triazinane (MNX) may be toxicologically advantageous owing to its potential mineralization under partial or complete anoxic conditions. These findings provide important information on RDX-degrading microbial pathways, toxicologically most suitable to be stimulated in contaminated fields.

• Microbiology and Biotechnology Letters
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• v.25 no.1
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• pp.89-95
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• 1997

The current processer of the textile wastewater treatment are mostly consisted of a combination of a physico-chemical and a biological treatment. The overall efficiency of these processes is, however, assessed to be fairly low. It is even worse during the summer season when temperature of the wastewater rises above 40$\circ $C. Therefore, a feasible process of the textile wastewater treatment which can work efficiently at higher temperatures was investigated in this work. We used a bench scale reactor consisted of one 4 liter anaerobic and one 8 liter aerobic tank, and the thermophilic symbiotic PVA degraders, Pasteruella hemolytica KMG1 and Pseudomonas sp. KMG6 that had been isolated in our laboratory. In the preliminary flask experiments, we observed that the thermophilic symbiotic PVA degraders could not grow in the wastewater substrate. Then, we isolated the mutant strains by acclimating the KMG1and KMG6 strains to the wastewater medium. The mutant symbionts (KMG1-1 and KMG6-1) were isolated through 6 times successive transfers into the fresh wastewater medium after 5 days culture for each. The mutant strains obtained grew well in the mixed medium composed of 75% wastewater and 25% synthetic medium, and supplemented with 0.5% PVA as a sole carbon source. During the culture for 14 days at pH 7.0 and 40$\CIRC $C, the bacteria assimilated about 89% of the added PVA. The symbionts degraded equally well all the PVA substrates of different molecular weight (nd=500~30000). In contrast to the flask experiments, in the reactor system the mutant strains showed very low levels of the PVA and COD removal rates. However, the new reactor system with an additional aerobic tank attained 82% removal rate of COD, 94% of PVA degradation and 71% of color index under the conditions of 5% inoculm on the tank 2, incubation temperature of 40$\circ $C, dissolved oxygen level of 2~3 mg/l and retention time of 30 hours. This result ensures that the process described above could be an efficient and feasible treatment for the PVA contained textile wastewater at higher temperatures.

• Journal of Microbiology and Biotechnology
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• v.15 no.6
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• pp.1221-1228
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• 2005

Carbon electrode was applied to a wastewater treatment system as biofilm media. The spatial distribution of heterotrophic bacteria in aerobic wastewater biofilm grown on carbon electrode was investigated by scanning electron microscopy, atomic force microscopy, and biomass measurement. Five volts of electric oxidation and reduction potential were charged to the carbon anode and cathode of the bioelectrochemical system, respectively, but were not charged to electrodes of a conventional system. To correlate the biofilm architecture of bacterial populations with their activity, the bacterial treatment efficiency of organic carbons was measured in the bioelectrochemical system and compared with that in the conventional system. In the SEM image, the biofilm on the anodic medium of the bioelectrochemical system looked intact and active; however, that on the carbon medium of the conventional system appeared to be shrinking or damaging. In the AFM image, the thickness of biofilm formed on the carbon medium was about two times of those on the anodic medium. The bacterial treatment efficiency of organic carbons in the bioelectrochemical system was about 1.5 times higher than that in the conventional system. Some denitrifying bacteria can metabolically oxidize $H_{2}$, coupled to reduction of $NO_{3}^{-}\;to\;N_{2}$. $H_{2}$ was produced from the cathode in the bioelectrochemical system by electrolysis of water but was not so in the conventional system. The denitrification efficiency was less than $22\%$ in the conventional system and more than $77\%$ in the bioelectrochemical system. From these results, we found that the electrochemical coupling reactions between aerobic and anaerobic reactors may be a useful tool for improvement of wastewater treatment and denitrification efficiency, without special manipulations such as bacterial growth condition control, C/N ratio (the ratio of carbon to nitrogen) control, MLSS returning, or biofilm refreshing.

• Microbiology and Biotechnology Letters
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• v.24 no.2
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• pp.247-253
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• 1996

Changes in microorganisms, enzyme activities and major components of two types of Doenjang prepared with spring Meju and autumn Meju and Kochujang were investigated during 4 months of fermentation. The viable cell counts of aerobic bacteria in Doenjang and Kochujang were increased up to 60 days of fermentation, but viable cell counts of anaerobic bacteria did not show remarkable changes during fermentation. Viable cell count of yeast showed a rapid increase up to 15 days of fermentation in Doenjang and 60 days in Kochujang. It was found that $\alpha$-amylase activity of autumn Meju Doenjang and glucoamylase activity of Kochujang were higher than the other. Acidic and neutral protease showed the highest activity during 15-30 days of fermentation. The pH of Doenjang was increased up to pH 7.0 until 60 days of fermentation, but pH of Kochujang gradually decreased during fermentation. Moisture content of spring Meju Doenjang and Kochujang decreased to 40% during ferme- ntation and reducing sugar content of Kochujang increased up to 15 days of fermentation, but decreased after that.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.5
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• pp.888-893
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• 2001

Soy sauce has a long history used as a food ingredient. However, hydrolyzed vegetable protein, mono-sodium glutamate, starch syrup, and fructose are added to soy sauce during fermentation for the taste and flavor of product. But consumers have been reluctant to the taste of these artificial additives. In this experiment, anchovy sauce was used to prepare soy sauce to enhance the quality and brine was used as a control. To evaluate the quality of soy sauce added with anchovy, total nitrogen (TN) and soluble nitrogen contents, total soild contents, total sugar reducing sugar. lactic acid content and protease activity were monitored during fer-mentation. Total microbial numbers and lactic acid bacteria were not significantly changed among the cases. Aerobic and anaerobic microorganisms. and lactic acid bacteria were not significantly changed among the cases we studied, For the total sensory test, it was also estimated that the cases using anchovy sauce were superior to the control. From the results mentioned above, we could obtain shorter fermenation period as well as the quality improvement in the case of using anchovy sauce instead of salty water in the fermented soy sauce production.

• Journal of Hydrogen and New Energy
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• v.15 no.2
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• pp.166-174
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• 2004

Purple non-sulfur bacteria, Rhodobacter sphaeroides KD131 grew to reach the maximum cell concentration in 45 hrs of incubation in the synthetic media containing (NH4)2SO4, L-aspartic acid and succinic acid as the carbon and nitrogen sources, respectively, at 30oC under 8 klux irradiance using halogen lamp. The strain produced hydrogen from the middle of the logarithmic growth phase and continued until the cell growth leveled out. The strain grew and produced hydrogen under the irradiance of 3-30 klux, but cell growth was inhibited over 100 klux. In addition, anaerobic/light culture condition was better than the aerobic/dark on the hydrogen production. Among various photo-bioreactors examined, the flat-vertical reactor manufactured using clear acrylic plastic material showed the best hydrogen production rate at the given culture condition.