• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 춘계학술발표대회
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• pp.554-557
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• 2000

Strain JV3 was isolated from commercial Swiss cheese products and identified as a bacteriocin producer, which has bactericidal activity against Leuconostoc mesenteroides KCCM 11324. Strain JW3 was identified tentatively as Lactococcus lactis by the API test. The activity of lacticin JW3, named tentatively as the bacteriocin produced by Lactococcus lactis JW3, was detected during the mid-log growth phase, and reached a maximum during the early stationary phase, and decreased after the late stationary phase. Its antimicrobial activity on sensitive indicator cells was completely disappeared by protease IV. The inhibitory activities of lacticin JW3 were detected during treatments of up to $121\'^{circ}C$ for 15 min. Lacticin JW3 was very stable over a pH range of 2.0 to 9.0 The apparent molecular mass of lacticin JW3 was estimated to be in the region of 3-3.5kDa, which was determined by the direct detection of bactericidal activity after SDS-PAGE.

• 한국미생물·생명공학회지
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• 제29권2호
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• pp.96-103
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• 2001

Phaffia rhodozyma is the most promising microbial source of astaxanthin production, though wild-type strains are needed to increase the astaxanthin content for commercial production. To increase astaxanthin content for commercial production, a mutant strain of P. rhodozyma was selected and culture conditions of the mutant selected were optimized. P. rhodozyma was treated with mutagenic agent such as NTG, acriflavine, and UV in serial order and carotenoids hyper-producing mutant strain was selected based on the capabilities of cell growth on the agar plate containing chemical inhibitors and carotenoids production. Among the mutants tested, a mutant WS-2 was finally selected. Mutant WS-2 produced 1.26mg carotenoids/g-dry cell weight and this value was about- 4-folds higher than that of wild-type. The optimum culture conditions were $24^{\circ}C$ of temperature, 1.5vvm of aeration and 300rpm of agitation. In the optimized condition, cell and carotenoids concentrations were 7.62g/l and 14.9mg/l, respectively.

• Journal of Microbiology and Biotechnology
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• 제32권6호
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• pp.783-791
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• 2022

Gamma-aminobutyric acid (GABA) improves various physiological illnesses, including diabetes, hypertension, depression, memory lapse, and insomnia in humans. Therefore, interest in the commercial production of GABA is steadily increasing. Lactic acid bacteria (LAB) have widely been reported as a GABA producer and are safe for human consumption. In this study, GABA-producing LAB were preliminarily identified and quantified via GABase assay. The acid and bile tolerance of the L. plantarum FBT215 strain were evaluated. The one-factor-at-a-time (OFAT) strategy was applied to determine the optimal conditions for GABA production using HPLC. Response surface methodology (RSM) with Box-Behnken design was used to predict the optimum GABA production. The strain FBT215 was shown to be acid and bile tolerant. The optimization of GABA production via the OFAT strategy resulted in an average GABA concentration of 1688.65 ± 14.29 ㎍/ml, while it was 1812.16 ± 23.16 ㎍/ml when RSM was applied. In conclusion, this study provides the optimum culture conditions for GABA production by the strain FBT215 and indicates that L. plantarum FBT215 is potentially promising for commercial functional probiotics with health claims.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 추계학술대회 논문집
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• pp.292-296
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• 2008

A new method of evaluating critical damage values of commercial materials is presented in this paper. The method is based on the previous study of the methodology [1] of acquisition of true stress-strain curves or flow stress curves over large strain from the tensile test in which the flow stress is described by the Hollomon law-like form, that is, by the strain dependent strength coefficient and the strain hardening exponent. The strain hardening exponent is calculated from the true strain at the necking point to meet the Considere condition. The strength coefficient is assumed to be constant before necking and represented by a piecewise linear function of strain after necking. With the predicted flow stress, a tensile test is simulated by a rigid-plastic finite element method with higher accuracy of less than 0.5% error between experiments and predictions. The instant when the fracture begins and thus the critical damage is obtained is determined by observing the stress variation at the necked region. It is assumed that the fracture due to damage begins when the pattern of stress around the necked region changes radically. The method is applied to evaluate the critical damage of a low carbon steel.

• 한국기계가공학회지
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• 제17권2호
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• pp.130-136
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• 2018

This study develops a seat with electric motor technology for a one-ton grade commercial vehicle. While applying electric motor technology, the FMVSS 210 seat frame strength test is also conducted to examine the product's weak parts. The seat frame strength test used the FMVSS 210 test standard and the ANSYS program was used to simulate the test and identify weak parts in the deformation and strain values. The test results showed that the cushion frame and slide rail connection bracket were fractured at loads of about 10,000 N. Similarly, the maximum stress and strain values in the bracket were obtained in the simulation results. On this basis, it was evaluated that the connection part bracket was a considerably weak part in the case of the first model, and changing the shape of the bracket and reinforcing the strength were required. In addition, the seat belt anchorage test results and simulation results were compared to assure their validity. In the comparison results, the error for each is about 5-10%. Therefore, the simulation performed in this study is considered to have produced reasonably accurate results.

• 한국버섯학회지
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• 제4권3호
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• pp.106-110
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• 2006

우수한 약리기능성을 보이는 검은비늘버섯의 병재배에 적합한 새로운 품종 진황을 교잡육종법으로 육성하였다. 진황은 포플라톱밥을 이용한 병제배와 폐면을 이용한 상자재배가 모두 가능하여 재배농가에서 생산이 용이하나, 약용 또는 기능성버섯으로서의 인지도가 낮으므로 소비 확대를 위한 약리효과의 홍보가 필요하다. 진황 검은비늘버섯의 주요특성은 다음과 같다. 가. 균사배양 최적용도는 $25^{\circ}C$ 자실체발생 및 생육온도는 $15 {\sim}18^{\circ}C$이다. 나. 자실체의 색깔은 황갈색이며 갓표면에 흰색~갈색의 인피가 덮혀 있으며 점성이 있다. 다. 병당 유효개채수가 평균 26개로 많고 대도 굵어 품질이 양호하다.

• 한국버섯학회지
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• 제12권2호
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• pp.82-87
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• 2014

Commonly known as the button mushroom, Agaricus bisporus is one of the most widely cultivated mushroom species of edible fungi. In the breeding of new button mushroom, Seolwon was developed by crossing two homokaryons. Because of the predominantly pseudohomothallic life cycle, only a small percentage of homokaryotic meiospores are produced, which do not fruit. Homokaryotic cultures derived from these types of single spores produce a vegetative mycelium that contain a variable number of genetically identical nuclei per cell. After crossing two homokaryons, hybrids were cultivated on a small scale and on a commercial scale at a farm. The spawn was made by a commercial spawn producer and the spawned compost by a commercial compost producer. Mycelial growth of Seolwon on CDA was better at $25^{\circ}C$ when it was compared with that of Seolgang. The mature cap shape of new strain Seolwon is oblate spheroid and the immature cap shape is round to oblate spheroid. The cap diameter was 39.7 mm on average. In comparison with white strain Seolgang, the strain had a yield that was 11% higher. It produced fruiting bodies which had a higher weight on average per fruiting body and were 9.7% firmer with a good shelf life. Days of fruiting body were 1-2 days later than those of Seolgang. The physical characteristics such as springiness, chewiness, adhesiveness, gumminess were better than that of Seolgang.

• Journal of Microbiology and Biotechnology
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• 제27권9호
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• pp.1701-1710
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• 2017

Classical swine fever virus (CSFV) is the etiologic agent of classical swine fever, a highly contagious disease that causes significant economic losses to the swine industry. The lapinized C-strain, a widely used vaccine strain against CSFV, has low growth efficiency in cell culture, which limits the productivity in the vaccine industry. In this study, a recombinant virus derived from C-strain was constructed and subjected to continuous passaging in PK-15 cells with the goal of acquiring a high progeny virus yield. A cell-adapted virus variant, RecCpp80, had nearly 1,000-fold higher titer than its parent C-strain but lost the ability to induce fever in rabbits. Sequence analysis of cell-adapted RecC variants indicated that at least six nucleotide changes were fixed in RecCpp80. Further adaption of RecCpp80 variant in swine testicle cells led to a higher virus yield without additional mutations. Introduction of each of these residues into the wild-type RecC backbone showed that one mutation, M979R (T3310G), located in the C-terminal region of E2 might be closely related to the cell-adapted phenotype. Rabbit inoculation revealed that $RecCpp40_{+10}$ failed to induce fever in rabbits, whereas $RecCpp80_{+10}$ caused a fever response similar to the commercial C-strain vaccine. In conclusion, the C-strain can be adapted to cell culture by introducing specific mutations in its E2 protein. The mutations in RecCpp80 that led to the loss of fever response in rabbits require further investigation. Continuous passaging of the C-strain-based recombinant viruses in PK-15 cells could enhance its in vitro adaption. The non-synonymous mutations at 3310 and 3531 might play major roles in the enhanced capacity of general virus reproduction. Such findings may help design a modified C-strain for improved productivity of commercial vaccines at reduced production cost.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.1078-1080
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• 2002

The pressure variation of interstitial fluid is one of the most important factors in bone physiology. In order to understand the role of interstitial fluid and the biomechanical interactions between fluid and solid constituents within bone, poroelastic theory was applied. The purpose of this study is to describe the behavior of calf vertebral trabecular bone composed of the porous solid trabeculae and the viscous bone marrow by using a commercial finite element analysis program based on the poroelasticity. In this study, the model was numerically tested for 5 different strain rates, i. e., 0.001, 0.01, 0.1, 1.0, and 10 per second. The material properties of the calf vertebral trabecular bone were utilized from the previous experimental study. Two asymptotic poroelastic response, the drained and undrained deformation, were predicted. From the predicted results for the simulated five strain rate, it was found that the pore pressure generation has a linearly increasing behavior when the strain rate is the highest at 10 per second, other wise it showed a nonlinear the strain rate Increased. Based on the results of the present study, it was suggested that the calf vertebral trabecular bone could be modeled as a porous material and its strain rate dependent material behavior could be predicted.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 춘계학술발표대회
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• pp.558-561
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• 2000

Strain JW3 was isolated from commercial Swiss cheese products and identified as a bacteriocin producer. Lactococcus lactis JW3 showed a broad spectrum of activity against most of the non-pathogenic and pathogenic microorganisms tested by the modified deferred method. Lacticin JW3 also showed a relatively broad spectrum of activity against non-pathogenic and pathogenic microorganisms as assessed using the spot-on-lawn method. It demonstrated a typical bactericidal mode of inhibition against Leuconostoc mesenteroides KCCM 11324.