• Korean Journal of Microbiology
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• v.51 no.1
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• pp.48-60
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• 2015

612 strains isolated from Korean traditional fermented food in Sunchang and their investigated biochemical characterization and ability of biogenic amines non-producing. We selected the SCJ4 having various activity by measurement of extracellular enzyme, antioxidant and antimicrobial activities. Selected strain SCJ4 by 16S rRNA sequencing and biochemical characterization was named Bacillus subtilis SCJ4. And then, we investigated cell growth of SCJ4, and optimized of culture medium constituents using response surface methodology as statistically method. Response surface methodology used Plackett-Burman experimental design for screening of medium constituent. Tryptone, peptone and $MgSO_4$ as medium constituent improving cell growth selected. In order to find out optimal concentration on each constituent, we carried out central composite design. Consequently, optimized concentrations of tryptone, peptone and $MgSO_4$ were predicted to be 15.35 g/L, 12.235 g/L, and 3.5 g/L respectively. Through the model verification, we confirmed about 1.28-fold improvement of the dried cell weight from 0.8767 g/L to 1.1222 g/L when compared to basal medium.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.40 no.3
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• pp.307-311
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• 2014

2,3,5-Triphenyltetrazolium chloride (TTC) is used as a redox indicator in culture media. It is colorless in the oxidized form and is reduced to formazan, an insoluble pigment, by dehydrogenases in actively growing microbial cells. The aim of this study was to assess by microbial test of the pathogenic microorganisms using TTC reduction. The pathogenic microorganisms were reduced in medium by dehydrogenase to produce insoluble red formazan. We observed that the optimization method of TTC allowed more than 12 h incubation in 0.04% concentration. Also, the growth of microorganisms with media was increased formazan production. We confirmed that microorganisms were quickly observed to grow colonies cultured red color without affecting the growth of microorganisms. It is suggested that the microbial test using TTC can provide better and quicker test method in cosmetics development.

• Journal of Ginseng Research
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• v.40 no.4
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• pp.315-324
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• 2016

Background: Biocontrol agents are regarded as promising and environmental friendly approaches as agrochemicals for phytodiseases that cause serious environmental and health problems. Trichoderma species have been widely used in suppression of soil-borne pathogens. In this study, an endophytic fungus, Trichoderma gamsii YIM PH30019, from healthy Panax notoginseng root was investigated for its biocontrol potential. Methods: In vitro detached healthy roots, and pot and field experiments were used to investigate the pathogenicity and biocontrol efficacy of T. gamsii YIM PH30019 to the host plant. The antagonistic mechanisms against test phytopathogens were analyzed using dual culture, scanning electron microscopy, and volatile organic compounds (VOCs). Tolerance to chemical fertilizers was also tested in a series of concentrations. Results: The results indicated that T. gamsii YIM PH30019 was nonpathogenic to the host, presented appreciable biocontrol efficacy, and could tolerate chemical fertilizer concentrations of up to 20%. T. gamsii YIM PH30019 displayed antagonistic activities against the pathogenic fungi of P. notoginseng via production of VOCs. On the basis of gas chromatography-mass spectrometry, VOCs were identified as dimethyl disulfide, dibenzofuran, methanethiol, ketones, etc., which are effective ingredients for antagonistic activity. T. gamsii YIM PH30019 was able to improve the seedlings' emergence and protect P. notoginseng plants from soil-borne disease in the continuous cropping field tests. Conclusion: The results suggest that the endophytic fungus T. gamsii YIM PH30019 may have a good potential as a biological control agent against notoginseng phytodiseases and can provide a clue to further illuminate the interactions between Trichoderma and phytopathogens.

• Korean Journal of Food Science and Technology
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• v.28 no.6
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• pp.1089-1094
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• 1996

The in vivo effect of tyrosinase inhibitors in the melanogenesis of gold fish (jet black color) was evaluated by measuring surface color and observing melanin pigment. The fish was firstly cultivated in 0.9% NaCl solution for 1 week to induce melanogenesis, and then, it was transferred to each treatment group containing tyrosinase inhibitor. The fish was grouped into control. food additive group (addition of 5 mM glutathione, 5 mM cysteine, and 1 mM benzoic acid), microbial inhibitor group (addition of culture broth of Aspergillus oryzae in shiitake and glucose medium), and plant extract group (addition of the mixed extracts of green tea, beet, red chicory, and nameko). After 6 days, the fish was anesthetized by electric shock, and color of pectoral region, lateral region, and dorsal fin was measured. Hunter's L and b values of treated group were generally higher than those of control group, indicating that the tyrosinase inhibitors could inhibit the melanogenesis of the fish. Effect of plant extract was apparent, though relatively weak, not because it did not work in vivo, but because a sufficient amount of extract could not be added to fish globes. If a large amount of extract was added, fish gradually died due to a microbial contamination. Microscopic observation of melanin in lateral scale and dorsal fin showed that in the treated groups with tyrosinase inhibitors, the number of melanophore per unit area and the size of one melanophore decreased.

• Journal of Life Science
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• v.32 no.9
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• pp.721-728
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• 2022

This study investigated the diversity of intestinal microbial communities isolated from the intestine of topshell (Turbo cornutus) from the coast of Jeju Island (Beobhwan, Seogwipo city). Pure cultivation using the standard marine agar (MA) medium showed the most significant number of clusters. Aerobic and anaerobic culture allowed isolation of strains of 1.8×10⁵ CFU·g^-1 and 0.4×10 CFU·g^-1 on average, respectively. The microbial population in the topshell intestine was classified into 4 phyla, 12 families, 26 genera, and 67 species. The microbes in the topshell intestine were detected by homology with 93~100% with standard strains. The microbes in the topshell intestine consisted of Proteobacteria 39%, Firmicutes 34%, Actinobacteria 21%, and Bacteroidets 6%. The identified families were Alteromonadaceae (1), Shewanellaceae (4), Vibrionaceae (12), Phyllobacteriaeceae (1), Rhodobacteraceae (8), Bacillaceae (21), Paenibacillaceae (2), Cellulomonadaceae (1), Mycobacteriaceae (6), Nocardiaceae (4), Streptomycetaceae (3) and Flavobacteriaceae (4). Bacillus sp. and Vibrio sp. accounted for the greatest portion of the separated strains. Among the isolated microorganisms, some strains had probiotic functions.

• Korean Journal of Food Science and Technology
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• v.29 no.2
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• pp.343-347
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• 1997

Effect of culture conditions on the fermentation of wheat flour solution by mixed lactic acid bacteria of Lactobacillus brevis, L. fermentum and L. plantarum was investigated. The optimum temperature for the fermentation of wheat flour solution was $35^{\circ}C$ because pH decreased the lowest value and TTA (total titrable acidity) increased the highest value at this temperature. In aerobic condition, fermentor was purged with air at 1.0 vvm and was purged with nitrogen gas at 1.0 vvm in anaerobic condition. The decrease of pH and the increase of TTA in aerobic condition were higher than those in anaerobic condition. In aerobic condition, the optimum condition of oxygen supply was found to be oxygen transfer rate coefficient of $60\;hr^{-1}$ which corresponded to agitation speed of 250 rpm in a 5 L fermentor. Repeated fed-batch cultures were performed using pH-stat in order to increase the productivity of fermented wheat flour. With increasing the repeated fraction of culture volume, mean cycle time increased but maximum operation time decreased. However, the volume of produced broth per culture volume per time and total volume of produced broth per culture volume were maximum at the repeated fraction of culture volume of 20%. In a repeated fed-batch fermentation of wheat flour solution using mixed lactic acid bacteria, the culture condition was optimum at temerature of $35^{\circ}C$, aeration rate of 1.0 vvm, oxygen transfer rate coefficient of $60\;hr^{-1}$, and repeated fraction of culture volume of 20%.

• KSBB Journal
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• v.14 no.3
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• pp.284-290
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• 1999

Glucose fed-batch culture was studied to improve cellulose productivity by Acetobacter xylinum BRC5. When initial glucose concentrations in batch cultures were less than 20 g/L, yield coefficients of cellulose (Yp/s) remained a constant value of 0.21 g cellulose/g glucose. But a low yield coefficient, Yp/s=0.13 was obtained from an initial glucose concentration of 40 g/L. Since initial high glucose concentrations in batch culture resulted in low yields of cellulose, constant fed-batch cultures were carried out. The optimal feed rate for fed-batch culture was 2.22 g glucose/L.h. In constant fed-batch culture without DO control, 10 g/L of cellulose was obtained from 40 g/L of glucose with this feed rate, which was approximately two fold higher than that of the batch culture with the same initial glucose concentration. In DO stat plus fed-batch culture, the highest cellulose productivity could be obtained when dissolved oxygen level was controlled at 10% of air saturation, and cellulose productivity increased about 1.5 times compared with that of the culture without DO control.

• Microbiology and Biotechnology Letters
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• v.48 no.2
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• pp.205-214
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• 2020

Cyanobacteria are microorganisms which have important roles in the nitrogen cycle due to their ability to fix nitrogen in water and soil ecosystems. They also produce valuable materials that may be used in various industries. However, some species of cyanobacteria may limit the use of water resources by causing harmful algal blooms in water ecosystems. Many culture collection depositories provide cyanobacterial strains for research, but their systematic preservation is not well-developed in Korea. In this study, we developed a method for the cryopreservation of the cyanobacteria Trichormus variabilis (syn. Anabaena variabilis), using alginate microcapsules. Two approaches were used for the experiments and their outputs were compared. One of the methods involved the cryopreservation of cells using only a cryoprotectant and the other used the cryoprotectant within microcapsules. After cryopreservation for 35 days, cells preserved with both methods were successfully regenerated from the initial 1.0 × 10⁵ cells/ml to a final concentration of 6.7 × 10⁶ cells/ml and 1.1 × 10⁷ cells/ml. Irregular T. variabilis shapes were found after 14 days of regeneration. T. variabilis internal structures were observed by transmission electron microscopy (TEM), revealing that lipid droplets were reduced after cryopreservation. The expression of the mreB gene, known to be related to cell morphology, was downregulated (54.7%) after cryopreservation. Cryopreservation using cryoprotectant alone or with microcapsules is expected to be applicable to other filamentous cyanobacteria in the future.

• Asian Journal of Turfgrass Science
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• v.23 no.2
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• pp.219-228
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• 2009

The construction procedures and artificial turf maintenance program on golf course definitely influence on the distortion of its environment. Soil microbial communities in soil profile were affected directly by those practises on turf areas. In Jeju island, the environmental impact assessment has been required to apply the first quality class granular activated carbon(GAC), which has a high absorbent character to agricultural chemicals, on the soil profiles of golf green system to reduce the pesticide leaching to ground water. This research was carried out to analyze the changes of microbial communities and chemical properties on soil profiles where GAC had been applied at the construction stage at two golf courses in Jeju. The changes of soil microbial population and chemical properties associated with construction methods of soil profile and agrochemical management program were analyzed by monthly at the surface and sub-soil profiles during April through October, 2007. The total numbers of bacteria and fungi, soil moisture content, soil physio-chemical properties were measured on greens and fairways of the both golf courses with different GAC treatment on the green and fairway soil profiles. The results showed that GAC had positive effects on the water holding capacity, pH and EC, however, it did not improved the holding capacity of available nutrients ${NO_3}^-,{NH_4}^+$, and phosphorus by its sorption phenomenon. In microbial count test, the total numbers of bacteria and fungi showed a great variation during sampling dates. That may directly relate to the agrochemical application, however, the ratio of total bacterial number versus total fungus number showed a constant value on a sub-soil of 15~30cm depth. Thus, the construction method of GAC in soil profile, and application of fertilizer and pesticide, both impacted on the changes of microbial population. It's means that the construction method of soil profile and turf management using agro-materials might greatly affect on the turfgrass culture and the environment of golf course.

• Journal of Life Science
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• v.29 no.8
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• pp.861-870
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• 2019

This study was undertaken to establish optimum medium compositions for cost-effective mannitol production by Leuconostoc mesenteroides SRCM201425 isolated from kimchi. L. mesenteroides SRCM21425 from kimchi was selected for efficient mannitol production based on fructose analysis and identified by its 16S rRNA gene sequence, as well as by carbohydrate fermentation pattern analysis. To enhance mannitol production by L. mesenteroides SRCM201425, the effects of carbon, nitrogen, and mineral sources on mannitol production were first determined using Plackett-Burman design (PBD). The effects of 11 variables on mannitol production were investigated of which three variables, fructose, sucrose, and peptone, were selected. In the second step, each concentration of fructose, sucrose, and peptone was optimized using a central composite design (CCD) and response surface analysis. The predicted concentrations of fructose, sucrose, and peptone were 38.68 g/l, 30 g/l, and 39.67 g/l, respectively. The mathematical response model was reliable, with a coefficient of determination of $R^2=0.9185$. Mannitol production increased 20-fold as compared with the MRS medium, corresponding to a mannitol yield 97.46% when compared to MRS supplemented with 100 g/l of fructose in flask system. Furthermore, the production in the optimized medium was cost-effective. The findings of this study can be expected to be useful in biological production for catalytic hydrogenation causing byproduct and additional production costs.