• Journal of the Korean Society of Visualization
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• v.17 no.1
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• pp.69-77
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• 2019

This paper introduces microfluidic manipulation of microorganism by opto-electrokinetic technique, named rapid electrokinetic patterning (REP). REP is a hybrid method that utilizes the simultaneous application of a uniform electric field and a focused laser to manipulate various kinds and types of colloidal particles. Using the technique in preliminary experiments, we have successfully aggregated, translated, and trapped not only spherical polystyrene, latex, and magnetic particles but also ellipsoidal glass particles. Extending the manipulation target to cells, we attempted to manipulate saccharomyces cerevisiae (S. cerevisiae), the most commonly used microorganism for food fermentation and biomass production. As a result, S. cerevisiae were assembled and dynamically trapped by REP at arbitrary location on an electrode surface. It firmly establishes the usefulness of REP technique for development of a high-performance on-chip bioassay system.

• Journal of Korean Society on Water Environment
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• v.21 no.2
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• pp.118-124
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• 2005

The oxygen solubilized device(O.S.D) and standardized microorganism culture system is more efficient than physical and chemical purification techniques in closed water. This study was to determine how the O.S.D and standardized culture system is efficient in purification capacity in closed water based on the lab scale and pilot plant. In the batch test, inducing the quantitative results from pilot plant operation condition, removal efficiency of COD and TN were about 48.3% and 35% respectively, while SS and chlorophyll-a were 94.9% and 68.7%. The pilot plant results showed that suspended solid(SS) and chlorophyll-a removal efficiency were 60% and 59% respectively, due to coagulation characteristics by standardized culture. Total nitrogen(TN) and total phosphorus(TP)showed good effect for the purification of target pond water quality from field data. Additionally, released velocity was determined in control condition of $5.31mgPO{_4}^{3-}{\cdot}m^{-2}{\cdot}day^{-1}$ and $2486.8mgCOD{\cdot}m^{-2}{\cdot}day^{-1}$. Otherwise, phosphate and COD reflux in the aeration and microorganism condition was showed $-9.95mgPO{_4}^{3-}{\cdot}m^{-2}{\cdot}day^{-1}$ and $-397.88mgCOD{\cdot}m^{-2}{\cdot}day^{-1}$. This technology is the most effective not only removal of SS and chlorophyll-a but also control of phosphate and COD release which is very important phenomena in evaluating water quality in closed water like a reservoir and pond.

• Journal of The Korean Society of Agricultural Engineers
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• v.57 no.1
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• pp.111-118
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• 2015

This research aims to utilize lapilli from the Mt. Baekdusan as environmently-friendly construction material. First of all, the neutralizing method for fabricating lapilli-cement-mixed bioblock was examined. And then, by use of the neuralized bioblock with microorganism for water purification, the growth inhibition effect against the pathogenic coliform bacillus was evaluated. The result regarding growth inhibition effect on pathogenic coliform bacillus indicates that the pretreatment condition, which is a concurrent procession with aqueous solution of 10% di-ammonium Phosphate after water curing, led to pH degraded below 10 which was the target value. Therefore it was concluded that the method was effective on bio-block neutralization. The microorganisms purifying water and di-ammonium phosphate were detected through the examination for microorganism existence on the bioblock, therefore it was concluded that the bioblock composed of lapilli and cement is able to be utilized in various structures as an environment friendly construction material.

• Bulletin of the Korean Chemical Society
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• v.30 no.12
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• pp.2993-2998
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• 2009

An enzyme-linked immunosorbent assay (ELISA)-on-a-chip (EOC) biosensor combined with cell concentration technology based on immuno-magnetic separation (IMS) was investigated for use as a potential tool for early screening of Listeria monocytogenes (L. monocytogenes) in food products. The target analyte is a well-known pathogenic foodborne microorganism and outbreaks of the food poisoning typically occur due to contamination of normal food products. Thus, the aim of this study was to develop a rapid and reliable sensor that could be utilized on a daily basis to test food products for the presence of this pathogenic microorganism. The sensor was optimized to provide a high detection capability (e.g., 5.9 ${\times}\;10^3$ cells/mL) and, to eventually minimize cultivation time. The cell density was condensed using IMS prior to analysis. Since the concentration rate of IMS was greater than 100-fold, this combination resulted in a detection limit of 54 cells/mL. The EOC-IMS coupled analytical system was then applied to a real sample test of fish intestines. The system was able to detect L. monocytogenes at a concentration of 2.4 CFU/g after pre-enrichment for 6 h from the onset of cell cultivation. This may allow us to monitor the target analyte at a concentration less than 1 CFU/g within a 9 h-cultivation provided a doubling time of 40 min is typically maintained. Based on this estimation, the EOC-IMS system can screen and detect the presence of this microorganism in food products almost within working hours.

• The Korean Journal of Food And Nutrition
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• v.16 no.3
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• pp.180-186
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• 2003

In order to prediction of lethal effects on target microorganisms, this study was developed the program in the basis of Excel that was systemized with Visual Basic. This program was automatically calculated the lethal effects (L and Fo value) by using thermal characteristics (D and z value), kinetic model and mathematic model. For the selection of target microorganisms, we are selected two microorganisms because of spoilage increasing by acid production and decreasing quality of food, and heat resistance microorganisms. The target microorganisms were Bacillus cereus (D$_{121.1}$=0.0065 min, z=7.8$^{\circ}C$) and Bacillus subtilis (D$_{121.1}$=0.5 min, z =12$^{\circ}C$). The program was developed for the target microorganisms, and that was very useful for various microorganisms that direct introducing known D and z value.

• Journal of Environmental Health Sciences
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• v.34 no.1
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• pp.101-107
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• 2008

Bio-filtration utilizes microorganisms fixed to a porous medium to metabolize pollutants present in an air stream. The microorganisms grow in a bio-film on the surface of a medium or are suspended in the water phase surrounding the medium particles. Therefore, bio-filter support media play one of the most important key roles in bio-filtration of gas phase pollutants. To characterize and select the appropriate support media, gas adsorption capacity and microorganism immobilization were investigated in lab-scale experiments for the selected target support media which were compost I (compost from lab-scale process), compost II (compost from municipal facility), bark, wood chip, orchid stone and vermiculite. As odor materials, ammonia and trimethylamine were utilized. From the result of experiments, bark was superior to any other support media tested in adsorption capacity as much as 12.5 mg ammonia per 1 g bark. In trimethylamine adsorption, bark and wood chip showed a remarkable results of 21.1 and 14.1 mg/g respectively. On the other hand, microorganism fixation test determined by the count of nitrogen oxidizing microbes population, the compost II and wood chips showed the best results. Considering the characteristics of materials and the operating condition of the bio-filter, bark, wood chip, and compost II are applicable to the support media of bio-filter when they are appropriately blended on the basis of studying the media pH, packing porosity and moisture contents.

• Korean Journal of Pharmacognosy
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• v.42 no.4
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• pp.354-360
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• 2011

In order to screen new allogeneic mixed lymphocyte culture (allo-MLR) inhibitor which is expected to be immunomodulating drug lead, we have investigated allo-MLR inhibitory activity on the marine-derived symbiotic microorganisms (1,895 strains) from the marine algae. The potent inhibitory activities (over 45% inhibition of proliferation at 10 and 2 ${\mu}g/ml$) without cytotoxicity were observed in the extracts of 46 strains. While, the significant stimulating activities (over 100% proliferation at 10 and 2 ${\mu}g/ml$) without cytotoxicity were observed in the extracts of 5 strains. In the second assay using 46 bioactive strains, 14 strains exhibited again significant allo-MLR inhibitory activity. Finally, 11 strains among the 14 strains inhibited proliferation and IFN-${\gamma}$ production of CD4+ T cells during the stimulation with specific antigen in the third assay. On the basis of above results, the marine algae is nice source for isolation of immunomodulating microorganism, and the marine algae-associated microorganism is also nice target for development of the new immunomodulating drug lead.

• Fisheries and Aquatic Sciences
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• v.16 no.4
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• pp.273-277
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• 2013

Vibriosis caused by Vibrio anguillarum and edwardsiellosis caused by Edwardsiella tarda are septicemic diseases of many commercially important freshwater and marine fishes, and threaten the aquaculture industry in Korea. Early diagnosis and accurate identification of these two bacterial species could help to prevent these diseases and minimize the damage to cultured marine species. This study designed a duplex polymerase chain reaction (PCR) method for the simultaneous detection of two major fish pathogens: V. anguillarum and E. tarda. Each pair of oligonucleotide primers exclusively amplified the target groEL gene of the specific microorganism. Twenty-two Vibrio and ten non-Vibrio enteric species were used to check the specificity of the primers, which were found to be highly specific for the target species, even among closely related species. The detection limit was 400 pg for V. anguillarum and 4 ng for E. tarda when mixed purified DNA was used as the template. This assay showed high specificity and sensitivity in the simultaneous detection of V. anguillarum and E. tarda from artificially inoculated seawater and fish.

• Journal of Microbiology and Biotechnology
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• v.33 no.4
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• pp.419-429
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• 2023

Ultraviolet C (UV-C, 200-280 nm) light has germicidal properties that inactivate a wide range of pathogenic and spoilage microorganisms. UV-C has been extensively studied as an alternative to thermal decontamination of fruit juices. Recent studies suggest that the efficacy of UV-C irradiation in reducing microorganisms in fruit juices is greatly dependent on the characteristics of the target microorganisms, juice matrices, and parameters of the UV-C treatment procedure, such as equipment and processing. Based on evidence from recent studies, this review describes how the characteristics of target microorganisms (e.g., type of microorganism/strain, acid adaptation, physiological states, single/composite inoculum, spore, etc.) and fruit juice matrices (e.g., UV absorbance, UV transmittance, turbidity, soluble solid content, pH, color, etc.) affect the efficacy of UV-C. We also discuss the influences on UV-C treatment efficacy of parameters, including UV-C light source, reactor conditions (e.g., continuous/batch, size, thickness, volume, diameter, outer case, configuration/arrangement), pumping/flow system conditions (e.g., sample flow rate and pattern, sample residence time, number of cycles), homogenization conditions (e.g., continuous flow/recirculation, stirring, mixing), and cleaning capability of the reactor. The collective facts indicate the immense potential of UV-C irradiation in the fruit juice industry. Existing drawbacks need to be addressed in future studies before the technique is applicable at the industrial scale.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.13 no.2
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• pp.59-65
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• 2007

Packaged food products often undergo retort processing, a thermal processing in a pressurized vessel called a retort, to ensure their microbiological safety or shelf-stability under normal non-refrigerated conditions of storage and distribution. Retort processing is generally aimed to accomplish commercial sterility of packaged foods with acceptable nutritional and sensorial qualities. Fundamental principles on retort processing, such as thermal resistance kinetics of target microorganism, heat penetration theory, and methods for evaluating process sterility and food quality loss, were reviewed. Factors affecting process severity, heat transfer mechanism, and heat penetration efficiency were summarized. General features of retortable packaging formats including metal cans, glass jars, and plastic packages were also briefly reviewed.