• Korean Journal of Microbiology
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• v.43 no.2
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• pp.142-146
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• 2007

Panax ginseng has been drawing world-wide attention since it was used for medicinal purposes and its effects was discovered in scientific manners. However, it is necessary to develope new ginseng products as functional foods to compete with western ginseng. Fermented ginseng could be an excellent solution, where useful probiotics are provided and ginsenosides are specifically transformed to functional forms. In this study, we investigated the growth and ginsenoside biotransformation by 21 Bacillus strains isolated from Chongkukjang and 12 lactic acid bacteria. 2.5% (w/v) and 1% (w/v) of ginseng were used in culture media containing only ginseng powder as a sole nutrient source, and their biotransformation abilities were tested after the growths were checked. All used Bacillus strains and lactic acid bacteria were able to grow well in ginseng powder media at higher levels than $10^{7}\;CFU/ml$. Most of Bacillus strains displayed ginsenoside transformation in a strain-specific manner. Therefore, the results of this study demonstrated that the strains tested in this study could be used as potential starters for the ginseng fermentation.

• Food Science of Animal Resources
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• v.33 no.3
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• pp.335-340
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• 2013

This study screened for radio-resistant strains lactic acid bacteria (LAB) by evaluating their capability to survive exposure to ionizing radiation. Ten strains of LAB - Lactobacillus bulgaricus, Lactobacillus paracasei, Lactobacillus casei, Lactobacillus acidophilus, Lactobacillus plantarum, Lactobacillus delbruekii, Lactococcus lactis, Streptococcus thermophilus, Bifidobacterium breve, and Pediocuccos pentosaceus - were selected and subcultuted twice. The LAB was then further cultured for 3 d at $37^{\circ}C$ to reach 7-10 Log colony-forming units (CFU)/mL prior to irradiation and immediately exposed to gamma rays or electron beams with absorbed doses of 0, 1, 2, 3, 4, 5, 6, 8, and 10 kGy. Gamma irradiation gradually decreased the number of the tested viable LAB, and the effect was irradiation dose dependent. A similar effect was found in electron beam-irradiated LAB. Radiation sensitivity of LAB was calculated as $D_{10}$ values, which ranged from 0.26 kGy to 0.9 kGy and 0.5 kGy to 1.44 kGy with exposure to gamma and electron beam irradiation, respectively, in all tested LAB. L. acidophilus was the most resistant to gamma and electron beam irradiation, with $D_{10}$ values of 0.9 kGy and 1.44 kGy, respectively. These results suggest that L. acidophilus might be suitable for the preparation of probiotics as direct-fed microbes for astronauts in extreme space environments.

• The Korean Journal of Mycology
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• v.24 no.1 s.76
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• pp.17-24
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• 1996

For screening of biological activities of culture broth of some wood rotting basidiomycetes, antimicrobial activity, plant growth regulating activity, antitumor activity, and various enzyme activities were checked. Coriolus versicolor 5129 and C. pubescens 5131 strains showed inhibition activity against gram-positive bacteria and Lenzites betulina 8029 strain showed the activity against gram-negative bacteria. L. betulina 8085 inhibited the growth of both bacteria and plant pathogenic fungi. All of tested basidiomycetes inhibited the germination and growth of radish and cabbage at concentration of 0.8ml/ml. Especially, Fomitopsis pinicolor 8059 and Fomitella fraxinea 8084 showed strong inhibition activity. In contrast, Bjerkandera adusta 8054 stimulated the growth of cabbage and radish at concentration of 0.4 and 0.2ml/ml. All polysaccharides from tested basidiomycetes showed anti-tumor activity against sarcoma 180 and the stronger antitumor activity was observed in L. betulina 8029 and unidentified 8058 strain. All tested basidiomycetes had also an ability to degrade cellulose and lignin.

• Journal of Microbiology and Biotechnology
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• v.15 no.2
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• pp.269-273
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• 2005

Five dibenzylbutyrolactones were isolated from a methanol extract of Arctii fructus (Arctium lappa L.) by bioassay-guided isolation, using the interleukin-l $\beta$ converting enzyme (caspase-l, ICE) production inhibitory assay in vitro. These compounds were spectroscopically identified as lappaol E (1), lappaol A (2), matairesinol (3), arctigenin (4), and arctiin (5). Among the compounds tested, arctigenin (4) showed the strongest inhibitory activity for ICE production in IL-$\beta$-induced proliferation of D 1 OS cells. Western blot analysis demonstrated that the arctigenin suppressed the expression of ICE protein in a dose-dependent manner. To estimate the biotransformation of Arctii fructus in vivo by human intestinal bacteria, we carried out an anaerobic incubation of the Arctii fructus extract with a human fecal suspension. From the HPLC analysis of metabolites, Arctiin (IC$_{50}$=74.2$\mu$g/ml), a major component of Arctii fructus, was transformed to aglycone, arctigenin (IC$_{50}$=12.5$\mu$g/ml), by human intestinal bacteria. The ICE production inhibitory activity of Arctii fructus would be much stronger in vivo than in vitro due to the biotransformation by human intestinal bacteria.

• Journal of Convergence for Information Technology
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• v.10 no.4
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• pp.104-114
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• 2020

We investigated the best antibiotics using blending oils after screening 11 kinds of essential oil known as antibiotics from plants. The minimum inhibitory concentration (MIC) and the minimum killing concentration (MBC) were found to be essential for essential oils B and E to inhibit target bacteria. All gram-positive bacteria containing S. aureus used in this experiment were shown highly antibiotic activity. And only A. baumanii in gram-positive bacteria and C. albicans in fungi were shown highly antibiotic activity. The essential oils used in our experiments showed better antibiotic activity compared to major studies using natural antibiotics with excellent antibiotic activity and essential oils from natural medicine. It is not known what mechanism of antimicrobial activity the essential oil used in the test has, but it is interpreted as a synthetic inhibitory mechanism of cell wall compared with other previous studies. From these results, it is expected that some substances or functional products with antibiotic activity will be developed.

• Microbiology and Biotechnology Letters
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• v.39 no.3
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• pp.218-223
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• 2011

To obtain eicosapentaenoic acid (EPA)-producing bacteria, some 600 strains of bacteria were isolated from Antarctic sediment and marine organisms during the summer expedition of 1999-2000 and 7 EPA-producing bacteria were obtained through screening with TLC and GC. A strain designated as L93 showed the highest EPA production, which was gram-negative, rod-shaped bacterium. L93 strain was identified as Shewanella sp., from the sequence analysis of 16S rDNA. Optimal conditions temperature and pH for the growth and EPA production were about $4^{\circ}C$ and pH 7. In addition, its production was optimized by 50%(w/v) sea salt. We establish the optimal production system to produce about 320 mg per liter by using this optimal EPA production conditions. EPA-methyl ester was purified from cultured L93 strain to a purity of higher than 97% and typical purification yield is greater than 72% of the input amount via urea complexation and HPLC.

• Korean journal of food and cookery science
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• v.16 no.4
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• pp.372-377
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• 2000

Six kinds of herbs(applemint, geranium, lemonbalm, rosemary, sage and thyme) were extracted with water and 95% methanol, and the electron donating ability, antibacterial activity and nitrite scavenging effect were examined. The electron donating ability of herbs ranged from 60.7 to 92.2% and the highest value was observed in geranium, followed by sage and lemonbalm. Antibacterial activity of methanol extracts was much stronger than that of water extracts and gram positive bacteria were more sensitive than gram negative bacteria. Rosemary and geranium exhibited excellent antimicrobial activities against a wide range of bacteria. Nitrite scavenging activity, which was measured at various pH conditions(1.2, 3.0, 3.6, 4.2), was the highest in all herbs at pH 1.2 and the lowest at pH 4.2, suggesting that it is pH dependent. Methanol fraction also provided higher nitrite scavenging effect than the water fraction.

• Microbiology and Biotechnology Letters
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• v.40 no.3
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• pp.169-179
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• 2012

Microbiological calcium carbonate precipitation (MCCP) is being applied for the aesthetic restoration of cement buildings destroyed by biochemical processes and to block water penetration into the cement's inner structure. After determining the advantages of this technique, many related studies in the area of architecture concerning the application of microorganisms to improve construction material have been reported in both America and Europe. The techniques compatibility with cement material is especially interesting because of the needed screening of various calcium carbonate forming-bacteria and the required development of their application methods. The purpose of this review is to describe the mechanism of MCCP and related researches with eco-friendly construction materials. Mainly, we describe the methodological studies focused on biodeposition on the surface of building materials and the research trends concerning the addition of microorganisms to improve the durability of cement structures. Additionally, the concepts and technical aspects focused on the development of self-healing smart concrete, with the use of multi-functional bacteria, have been considered.

• Microbiology and Biotechnology Letters
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• v.48 no.2
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• pp.148-157
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• 2020

Eucalyptus oil is a rich source of bioactive compounds with a variety of biological activities and is widely used in traditional medicine. Eucalyptus citriodora is cultivated for the production of essential oils. However, the mode of antibacterial action of essential oils from E. citriodora is not well-known. This study aimed to determine the chemical components, microbial inhibitory effect, and mechanism of action of the essential oil from E. citriodora. The oil was extracted from E. citriodora leaves by hydro-distillation and the chemical components were analyzed using gas chromatography-mass spectrometry. The antibacterial activities of eucalyptus oil against gram-positive bacteria (Bacillus subtilis, Staphylococcus aureus, and Staphylococcus intermedius) and gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) were screened by disc diffusion method and quantitative analysis was conducted by the microdilution method. The mechanism of action of the extracted essential oil was observed using SEM and analyzed by SDS-PAGE. The major components of E. citriodora oil were citronellal (60.55 ± 0.07%), followed by dl-isopulegol (10.57 ± 0.02%) and citronellol (9.04 ± 0.03%). The antibacterial screening indicated that E. citriodora oil exhibited prominent activity against all tested strains. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against B. subtilis were 0.5% and 1.0%, respectively. The MIC and MBC concentrations against S. aureus, S. intermedius, E. coli, and P. aeruginosa were 1% and 2%, respectively. As observed by SEM, the antibacterial mechanism of E. citriodora oil involved cell wall damage; SDS-PAGE revealed decrease in protein bands compared to untreated bacteria. Thus, E. citriodora oil showed significant antimicrobial properties and caused cellular damage.

• The Korean Journal of Mycology
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• v.42 no.4
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• pp.333-340
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• 2014

The aim of this study was to isolate a potential multifunctional biocontrol agent from bacteria for control of multiple plant diseases as an alternative to fungicides. A total of 201 strains were isolated from soil undamaged by repeated cultivation in Sunchang and their ability to produce antibiotics, siderophores and extracellular enzymes such as protease, cellulase and amylase was investigated. Selected strain SCS3 produced cellulose, protease and amylase. This strain also produced siderophores and showed excellent antifungal activity against various phytopathogens. SCS3 was identified as Bacillus subtilis using 16S rRNA sequencing, and named Bacillus subtilis SCS3. Finally, physiological and biochemical characteristics of B. subtilis SCS3 were examined. From the results, B. subtilis SCS3 was found to be a useful multifunctional biocontrol agent against various phytopathogens.