To evaluate antimicrobial activities of chongkukjang slime fermented by different strains, growth characteristics were compared using various standard microorganisms with addition of chongkukjang slime. Chongkukgang slime was prepared by fermenting cooked soybean after inoculating with Bacillus circulars K-1, Bacillus spp N-1 and Bacillus subtilis CH-1, respectively. Significant antimicrobial activity was observed by chongkukjang slime on gram positive bacteria (Staphylococcus aureus, Bacillus cereus, Bacillus subtilis, Micrococcus luteus), gram negative bacteria(Escherichia coli O157:H7, Salmonella Typhimurium, Pseudomonas fluorescens), and yeast (Pichia membranaefaciens, Saccharomyces cerevisiae, Candida albicans). In case of B. cereus growth inhibition of 80% was achieved by the addition of chongkukjang slime; on the contrary, to Escherichia coli O157:H7 only 20% inhibition was observed. Slime from Bacillus subtilis CH-1, in parkicular, inhibition of 40% toward bacteria and yeast, whereas slime from Bacillus circulars K-1, Bacillus spp N-1 showed only 20% inhibition.

The ethanol extract from the root bark of Morus alba showed the strongest antimicrobial activity on the growth of almost all the tested microorganisms which were food-borne pathogens and food-related microorganisms. In order to isolate and purify of antimicrobial substance extracted from the root bark of Morus albs, the antimicrobial substance from the ethanol extract which exhibited a strong antimicrobial activity was purified by solvent fractionation, silica gel column chromatography, TLC and HPLC. Among the fractions fractionated by 4 kinds of solvents from the ethanol extract, the antimicrobial activity of ethyl acetate fraction had the strongest antimicrobial activity against B. subtilis. Unknown compounds were isolated from the ethyl acetate fraction by silica gel column chromatography, TLC and HPLC and the compounds showed strong absorbance at 207, 217 and 285 nm, therefore, it was supposed to be a kinds of aromatic compound.

To develop environment-friendly agricultural products with anti-microbial activity against Sclerotinia sclerotiorum as a pathogen of sclerotium disease, Aristolochia tagala Champ. was extracted by methanol and its extract was fractionated into several solvent fractions. The chloroform fraction, which showed the highest antimicrobial activity, was separated by column chromatography and obtained forty three subfractions. The forty three fractions were searched the anti-fungal activities by bioassay. The most active No. 26 subfraction was analyzed by GC-MS. Each mass spectra, corresponding to each peak of chromatogram, was compared to MS database of Wiley library. As a result, 2,4-di-tetra-butyl-phenol, 2-mono-palmitin, 1-mono-stearin were profiled as maine compounds in No. 26 subfraction. Bioassay using commercial 1-mono-stearin to test for the anti-microbial activity conformed the antimicrobial active compound. In conclusion, 1-mono-stearin identified from Aristolochia tagala Champ. was antimicrobial chemical against Sclerotinia sclerotiorum.

To develop environment-friendly agricultural products with anti-microbial activity against Sclerotinia sclerotiorum as a pathogen of sclerotium disease, Usnea longissima was extracted by methanol and its extract was fractionated into several solvent fractions. The chloroform fraction, which showed the highest antimicrobial activity, was separated by silica gel-column chromatography and obtained into nine group subfractions. The nine group fractions were searched the antifungal activities by bioassay. The most active No. 3 subfraction was analyzed by GC-MS. Each mass spectra, corresponding to each peak of chromatogram, was compared to database of Wiley library. As a result, Usnic acid was identified as main compounds. In conclusion, Usnic acid isolated from Usnea longissima was antimicrobial chemical against Sclerotinia sclerotiorum as a pathogen of sclerotium disease.

황금의 천연항균제 개발을 위하여 황금의 일반성분 및 미량물질들을 분석하였으며 항균활성물질의 검색을 위하여 LC-MS를 이용하였고 검색되어진 성분들에 대해서는 항균력 비교시험을 하였으며 항균활성물질들에 대해서는 HPLC를 이용하여 그 양을 정량하였다. 황금의 일반성분으로는 수분 , 탄수화물 , 조회분 , 조단백질 및 조지방 이었고 미량성분에 있어서는 칼륨 12,050mg/kg과 마그네슘4,296 mg/kg의 함량이 현저하게 높았다. LC-MS

The antimicrobial effect of each fraction after fractionation of an ethanol extract of leaf mustard was examined in terms of nucleic acid, chloroform, ethylacetate, and butanol. The ethylacetate fraction, which showed the strongest level of antimicrobial effect among the different ethanol extract fractions of leaf mustard, was isolated and purified using silica gel column chromatography and HPLC, respectively, to obtain a single antimicrobial substance called KLM-1. The antimicrobial effect of this substance was 10 times higher than that of the ethylacetate fraction. A further study is on the way to confirm the structure of the antimicrobial substance KLM-1 through LC/Mass and NMR.

This study was performed to investigate the single and combined effect of concentrations of garlic juice according to the pH and temperature on the growth of Salmonella enteritidis in brain heart infusion broth, and to develope Response surface model for the effect of concentrations of garlic extract. The results of electric conductibility of Salmonella enteritidis growing in the range of incubation temperature (25～42℃), pH (5.5～9.0) and concentration of garlic juice (0～0.8%) showed that a badge with high temperature had low D.T.value and concentration of garlic extract were significantly correlated with D.T.value (p<0.01). Growth of Salmonella enteritidis in the condition of 37℃ and pH 7.0 presented the lowest D.T.value.

An antimicrobial substance-producing microorganism was isolated from soil samples. Based of the taxonomic characteristics of its morphological, cultural, physiological properties and 16s rRNA sequence alignment, this microorganism was identified as Pseudomonas aeruginosa, and we named Pseudomonas aeruginosa EL-KM. The optimal culture condition for production of antimicrobial substance was 1% mannitol, 0.4% yeast extract, 0.5% Nacl, 0.2% K₂SO₄, 100μM MgSO₄.7H2O, 10μM CaCl2.$2H_2O$, 1μM $FeSO_4$.7H2O, 1μM MnSO4.$4-5H_2O$, initial pH 7 and 200 rpm at 30℃. The purification of the antimicrbial substance was performed by silica gel column chromatographys, and fraction with TLC $R_f$ 0.77 value represented good antimicrobial activity. The crude antimicrbial substance was stable within a pH range of 3-10 and temperature range of 4°C-121°C autoclaving. This crude antibacterial substance acted as bacteriolytic agent against Vibrio cholerae non-Ol ATCC 25872, and also exhibited excellent properties, when the substance was demonstrated against many other gram-positive, gram-negative bacteria, yeast and fungi.

To investigate the effect of several bactericides and fungicides against fruit & vegetable decay grapefruit seed extract(GFSE) was tested in a dilution solution. GFSE was shown to be effective against decay and rind breakdown and to extend the shelf-life of fruits and vegetables during storage and tiansport. Antimicrobial efficiency of GFSE on a wide spectra of gram + & - bacteria, moulds and yeasts was demonstrated by the measurement of minimal inhibitory concentrations performed (Bacteria 10-500ppm, Fungi:250-1,000ppm, Yeasts:100-250ppm). GFSE was separated and extracted into water-soluble fraction, water-insoluble and non-dialyzed fraction to isolate the antimicrobial substances. The water-soluble fraction showed the most active antimicrobial effect. The antimicrobial substances were isolated by gas chromatography. As the result of the isolation using GC, Peak-D was found to be the antimicrobial compound in GFSE. The identification of the most antimicrobial substance was carried out by using GC-MS.