• Korean Journal of Food Science and Technology
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• v.20 no.1
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• pp.23-27
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• 1988

In order to investigate the combined effect of potassium sorbate and sodium benzoate and the synergistic effect of sodium chloride on bacterial cell growth inhibition, Bacillus subtilis was cultured with or without shaking in tryptone-glucose-yeast extract broth containing 0.1% potassium sorbate and/or 0.03% sodium benzoat, which are equivalent to half of the maximum permissible levels, respectively. The combined treatment of the two preservatives did not show any synergistic effect of tne growth inhibition of B. subtilis. Addition of 2% sodium chloride, however, showed remarkable synergistic effect on the growth inhibition of the bacterium by potassium sorbate.

• The Korean Journal of Food And Nutrition
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• v.12 no.6
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• pp.559-563
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• 1999

Essential oil of Artemisia lavandulaefolia the chrysanthemum family plant used in the chinese medicine was extracted and antibacterial and antifungal activity with many kinds of the pathogenic bacterium and fungi was experimented by it. Ataphylococcus epidermidis and Streptococcus aureus gram positive bacterium at the concentration of 200ppm and Streptococcus mutans at the concentration of 1,000ppm showed the growth injibition effect of the cell. These showed statistically significant difference(p<0.05) Zymomonas mobilis Entrecoccus faecalis gram negative bacterium at the concentration of 200ppm and Pseudomonas putida at the concentration of 400ppm showedd the growth inhibition effect of the cell)p<0.05) V. Parahaemolyticus at the concentration of 800ppm and Pseudomonas aeruginosa at the concentration of 1,000ppm showed the growth inhibition effect of the cell(p<0.05) Candida albicans and Cryptococcus neoformans yeast-type fungi showed the gorwth inhibition effect of the cell at the concentration of 200ppm(p<0.05) Altenaria mali Aspergillus nidulans and Fusarium oxysporum filamentous fungi took the growth inhibition effect of the cell at the concentration of 600ppm, 400ppm, and 100ppm. respectively.

• Biotechnology and Bioprocess Engineering:BBE
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• v.3 no.2
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• pp.115-118
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• 1998

Utilization of yeast extract and formation of byproduct metabolite were investigated for hyperthermophilic archaeon Sulfolobus solfataricus (DSH 1617). In both batch and fed-batch cultivations of S. solfataricus, maximal cell density, {{{{ { NH}`_{4 } ^{ +} }}} ion production and pH change were highly dependent on the ratio of yeast extract to glucose in the medium. Variation of {{{{ { NH}`_{4 } ^{ +} }}}} ion level was identified as a major cause of pH change during cultivation, and acidification of culture broth was attributed to consumption of {{{{ { NH}`_{4 } ^{ +} }}}} ions rather than formation of acid byproducts. It was also observed that increase of {{{{ { NH}`_{4 } ^{ +} }}}} ion concentrations in the medium resulted in greater degree of growth inhibition.

• Food Science and Biotechnology
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• v.15 no.3
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• pp.469-473
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• 2006

Film-forming yeasts generate an undesirable yeasty flavor in fermented vegetables such as kimchi in the presence of oxygen. Antimicrobial materials including garlic oil (GO), heated garlic (HG), and allyl alcohol (AA) were investigated for use as alternative natural food preservatives to inhibit the growth of film-forming yeasts in fermented vegetables. Using the fermentation of cucumber pickles as a model system, GO, HG, and AA were effective in preventing film formation at concentrations of 0.006, 3.0, and 0.02%, respectively. The effectiveness of HG in preventing the growth of a film yeast, Hansenula anomala, was not influenced by pH, while that of potassium sorbate, a typical anti-yeast food preservative, was highly dependent on pH. All tested materials were effective when added at the beginning of fermentation due to their negligible inhibitory activity toward lactic acid bacteria.

• Korean Journal of Microbiology
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• v.51 no.4
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• pp.448-452
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• 2015

The bacterial strain that was isolated from chinese cabbage rhizosphere, showed inhibition of yeast growth. This strain was identified as Pseudomonas fluorescens BB2 by API 20NE test and 16S rRNA gene sequence analysis. P. fluorescens BB2 strain produced antibiotics against yeast as a secondary metabolite effectively when the culture was carried out in YM medium with 3% glucose at $20^{\circ}C$. The protein antibiotic of BB2 strain which was concentrated by ammonium sulfate precipitation and n-butanol extraction inhibited the growth of yeast with the minimal inhibitory concentration of $10{\mu}g/ml$ against Candida albicans KCTC 7965, and the growth of yeast was completely inhibited at $80{\mu}g/ml$. The hydrophilic fraction of n-butanol extraction inhibited the growth of Bacillus cereus ATCC 21366, showed orange halo on chrome azurol S plate, which means the fraction contained iron chelating siderophore. The results of crystal violet uptake through the cell membrane showed that membrane permeability was increased about 9% than control, when the concentration of hydrophobic antibiotic against yeast C. albicans was $60{\mu}g/ml$. As a result, the antibiotic produced by P. fluorescens BB2 against yeast Candida is considered antimicrobial peptide, and this is the first report in the genus Pseudomonas.

• Microbiology and Biotechnology Letters
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• v.25 no.2
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• pp.183-188
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• 1997

Antimicrobial activity of various extracts of Xanthium strumarium L. was tested against 25 strains of bacteria, yeast and fungus. The crude ethylacetate extract exhibited strong growth inhibition to the tested strains with the exception of partial Gram-negative bacteria. The property of antimicrobial compound was very stable under heat treatment at $120^{\circ}C$, but it was unstable in acid (pH 3.0) and alkali (pH 10.0) treatment. The antimicrobial compounds were purified by boiling water extraction, ethylacetate extraction, charcoal column chromatography, silica gel column chro- matography and reverse phase HPLC. The purified compound A and B were detected in a single peak (each above 98% purity) through the HPLC analysis. The compound A and B showed a strong growth inhibition against Gram-negative and positive bacteria in the agar diffusion method. When tested by the FDA method using the esterase, compound A mainly inhibited the growth of bacteria and compound B showed the growth inhibition of both bacteria and yeasts.

• Archives of Pharmacal Research
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• v.22 no.2
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• pp.143-150
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• 1999

melatonin (MLT), N-acetyl-5-methoxytryptamine, is mainly secreted by the pineal gland. The ultraviolet (UV), infrared (IR) and 1H-NMR spectra of irradiated and non-irradiated MLT were measured, and phototoxicity tests of MLT, anthracence (positive control) and sodium lauryl sulfate (SLS, negative control) were performed. The methods employed include both in vitro test such as MTS assay using the human fibroblast cell and yeast growth inhibition assay using Candida albicans and in vivo method using the skin of guinea pig. UV absorption spectra and 1H-NMR spectra of MLT were changed by UVA (365 nm, 15 J/$\textrm{cm}^2$), but IR spectra of MLT were not changed. The fifty percent inhibitory concentration (IC50) ratio (UV-/UV+) of MLT was 10. The inhibition zone of irradiated-paper disks treated with MLT was not observed. According to the results of histophathological examination, no pathologic lesion was observed in the non-irradiated group, but slight degeneration of keratinocytes in the epidermis, homorrhage and vasodilation in dermis were observed in the irradiated group. These results indicated that the molecular structure of MLT is altered by UVA to unidentified photoproducts and a moderate phototoxicity of MLT is predicted.

• Journal of the FoodService Safety
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• v.4 no.1
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• pp.21-28
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• 2023

Saccharomyces cerevisiae and Zygosaccharomyces rouxii are known to produce alcohol in gochujang. To reduce alcohol production, garlic and chives were applied to gochujang solution to find their inhibitory effect on S. cerevisiae and Z. rouxii. The 70% ethanol extract of garlic and chives showed significant inhibition activity against S. cerevisiae and Z. rouxii, showing growth inhibition zone of 14.00±0.00~25.33±0.58 mm by disc diffusion method. In addition, the addition of 70% ethanol extract of garlic and chives in 10% gochujang solution spiked with S. cerevisiae and Z. rouxii reduced the numbers of total aerobic bacteria (below 7 Log CFU/g) and yeast (below 4 Log CFU/g), alcohol content (below 0.30%), respectively. In conclusion, the addition of garlic ethanol (70%) extract or chives ethanol (70%) extract to gochujang inhibited the growth of S. cerevisiae and Z. rouxii, resulting in reduced alcohol content in gochujang. For further study, it is necessary to conduct food application experiments by using real gochujang paste.

• Applied Chemistry for Engineering
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• v.29 no.4
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• pp.419-424
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• 2018

In this work, effect of the culture medium composition on the fermentation process of Clostridium ljungdahlii, which is acetogenic bacteria to product ethanol from synthesis gas, was examined to improve the microbial growth and ethanol production. Components of the culture medium such as yeast extract, fructose, $NH_4Cl$, and $K_2HPO_4$ were selected as influence factors for the cell growth and ethanol production. As the concentration of yeast extract increased, both of the cell growth and ethanol production increased. And the ethanol productivity was the highest at an yeast extract of 0.05 g/L, which is lower than that of base medium. As the concentration of fructose increased, the cell growth increased, but the ethanol production decreased when the concentration of fructose was higher than that of base medium (5 g/L). In an experiment with the yeast extract of 5 g/L, produced ethanol concentration was the highest (0.297 g/L) when fructose concentration was 5 g/L, however, the specific ethanol productivity was higher (0.281 g/g DCW) when the fructose was not added due to very low cell mass. The cell growth and ethanol production were not significantly influenced by $NH_4Cl$ concentration, however the growth inhibition was observed at a 30 g/L of $NH_4Cl$. When the concentration of $K_2HPO_4$ increased, both of the cell growth and ethanol production increased. In experiments with $NH_4Cl$ and $K_2HPO_4$, specific ethanol productivities were higher when the low concentration of yeast extract was used.

• Natural Product Sciences
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• v.9 no.4
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• pp.299-303
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• 2003

For the screening of inhibitors of sterol biosynthesis from natural products, a simple and rapid assay method was developed using recombinant yeast carrying human lanosterol synthase, main target of this assay method. Sterol biosynthesis inhibition activity was monitored only by the inhibition of growth of the recombinant yeast. By changing the substrate, this assay method can figure out which step is inhibited in the sterol biosynthesis by the test material. With this assay method total 102 plant samples were screened for their inhibitory activity of sterol biosynthesis. Among plant water extracts screened, 11 plant samples showed inhibitory activity on sterol biosynthesis in ergosterol (-) medium. For selection of the specific inhibitory materials, 11 plant samples were reassayed in ergosterol (+) medium. After all 5 plant samples, Abutilon avicennae Gaertn. (stem), Alnus japonica Steud. (stem), Amaranthus mangostanus L. (aerial part), Philadelphus schrenckii Pupr. (leaf) and Pimpinelia brachycarpa Nakai (aerial part), showed specific inhibitory activity.