• 한국미생물·생명공학회지
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• 제23권2호
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• pp.170-177
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• 1995

To search and develop the compounds exhibiting antifungal activities against the mycelial phase of Candida albicans, approximately 2,900 microorganisms isolated from soil were examined for antifungal activity. Among them, a strain with preferential activity against the mycelial phase of Candida albicans was isolated and identified as Streptomyces sp. A393. Isolation and purification of compounds A393 showing antifungal activity against the mycelial phase of C. albicans were performed using XAD-7 column chromatography, silica gel chromatography, preparative thin- layer silica gel chromatography, and HPLC. The molecular weights of compounds isolated from Streptomyces sp. A393 were determined as 774, 790, 804 and 820. These compounds appeared to have a structure of macrolide antibiotics, oligomycin A, B, C and E. Especially, oligomycin E, which is formerly reported to have no antifungal activity, showed antifungal activity against the mycelial phase of Candida albicans.

• 한국미생물·생명공학회지
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• 제24권5호
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• pp.534-539
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• 1996

Total 276 soil actinomycete strains were isolated from 46 soil samples collected at domestic natural caves; the Kosu, Chundong, and Nodong caves at Chungbook province, the Kossi cave at Kangwon province, the Sungruye cave at Kyungbook province, the Hyupjae, Ssangyong, and Manjang caves at Cheju province. All of these isolates were identified to the genus level based on morphological and physiological characteristics. As the result, 52.5% of those isolates were Streptomyces, 16.3% were Micromonospora, 22.8% were Nocardioform group, 1.1% were Actinomadura, 0.3% were Nocardiopsis, 0.3% were Streptosporangium, 0.3% were Nocardioides, 1.4% were Kineosporia, 4.7% were the others. Streptomycete strains were the most abundant, but were relatively less comparing to general distribution pattern. Nocardioform and Micromonospora strains were quite abundant, and other rare actinomycete groups were somewhat abundant comparing to general distribution pattern previously reported. Especially Nocardioform strains were highly abundant at almost of the natural caves.

• 한국미생물·생명공학회지
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• 제28권5호
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• pp.285-290
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• 2000

The effects of dissolved oxy-gen(DO) concentration and DO control modes on cell growth in a 4L computer-controlled bioreactor system were investigated using Phellinus linteus WI-001, a producer of protein-polysaccharides having potent anticancer activi-ties. When DO was controlled at about 20%, maximum cell concentration and specific growth rate of the strain were observed to increase 36% and 64%, respectively, as compared to the experiment performed without DO control. By adopting cascade automatic control of DO ar 20% in a mixed automatic control mode using computer-con-trolled program, 19.5g/L of maximum cell concentration was obtained. These results showed that the mixed auto-matic control mode was the effective method for enhancing cell growth of the shear sensitive Phellinus linteus.

• 한국미생물·생명공학회지
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• 제28권5호
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• pp.298-302
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• 2000

Fermentation parameters were estimated by use of a vent gas analyzer coupled to a computer data acquisition system in cultivation of Phellinus linteus WI-001, pro-ducer of polysaccharides known to have potent anticancer activities. Oxygen uptake rate(OUR), a critical indicator of the cells activities, was calculated by applying oxygen mass balance. In addition, by dividing the oxygen uptake rate hy the total oxygen consumed, on-line estimation of the cells specific growth rate was successfully done. It was also possible to estimate cell concentration directly bt use of oxygen-cell yield($Y_{x/o}$ ) which was obtained based on a correlation between cell growth and total oxygen consumed.

• 한국미생물·생명공학회지
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• 제21권5호
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• pp.414-420
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• 1993

Escherichia coli mrdAts and mrdBts mutants forming spherical cells at 42C, were employed to investigate the possible role of both inner and outer membrance structures in the determination of cell shape of gram-negative cells. Spherical cells, but not rod-shaped wild types, were specifically killed by anionic detergents, such as sarkosyl, sodium dodecylsulfate and sodium deoxycholate. From the spherical intact cells grown overnight at 42C, much more proteins were released by sakosyl.

• 한국미생물·생명공학회지
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• 제22권5호
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• pp.561-563
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• 1994

For the more effective isolation of soil actinomycetes, we have developed HHV (Hair hydrolysate-vitamin) agar medium, containing hair as the sole source of carbon and nitrogen. The HHV agar medium was superior to other media such as colloidal chintin agar, glycerol-arginine agar and starch-casein-nitrate agar, and HV (humic acid-vitamin) agar. The maximum effect of this medium has been shown in hair dry weight 0.4 g/l medium. Of each soil sample, the greatestest number of actinomycetes was isolated from the potato annual planted soil among the tested samp- les. The genus of actinomycetes isolated from the potato annual planted soil sample was identified such 5 group as Stretomyces, Micromonospora, Microbispora, Nocardia and Saccharopolyspora.

• 한국미생물·생명공학회지
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• 제22권6호
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• pp.571-576
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• 1994

One strain of cellulose-producing Acetobacter was isolated from the traditionally fermen- ted grape vinegar in Korea. The isolated strain, designated as KI strain was identified as the Acetobacter xylinum with respect to physiological and biochemical characteristics. KI produced acetic acid from ethanol, and then decomposed acetate to CO$_{2}$ and H$_{2}$O. When the isolated strain was cultivated statically in broth culture, a thick cellulose pellicle was formed. KI was tolerance of 8% ethanol and 30% glucose, and the isolate was positive in ketogenesis from glycerol, $\gamma$-pyrone from glucose and fructose, and 2-ketogluconic acid from glucose. KI strain possessed straight-chain C$_{18:1}$, C$_{16:0}$, and C$_{14:0}$ fatty acid, and contained ubiquinone Q$_{9}$ and Q$_{10}$ as isoprenoid quinone. DNA base composition of KI strain was 57.6% G+C.

• 한국미생물·생명공학회지
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• 제27권2호
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• pp.102-106
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• 1999

To investigate the effect of wormwood extract on intestinal Microorganisms of human, we examined the changes of the intestinal microflora of 6 volunteers for 13 days. Numbers of total anaerobes in feces of 6 volunteers showed 1010cfu/g before and after intake of wormwood extract. In case of beneficial Microorganisms, wormwood extract did not have an effect on the growth of bifidobacteria and Lactobacillus spp. On the other hand, the growth of C. perfringens and E. coli, the harmful Microorganisms of human intestines, was inhibited by the wormwood extract.

• 한국미생물·생명공학회지
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• 제22권6호
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• pp.565-570
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• 1994

The pullulan production and morphological change of Aureobasidium pullulans ATCC 9348 were investigated both in batch fermentation and in continuous fermentation. The best carbon source for pullulan production was sucrose among seven different carbon sources. The pullulan production of A. pullulans was increased with increasing the carbon to nitrogen ratio of the medium using sucrose as a carbon source. In batch fermentation, production of pullullan occurred following exhaustion of the nitrogen source from the medium. The continuous fermentation showed that the pullulan production was closely parallelled with cell growth and was most effective at a dilution rate of 0.06~0.07 hr$^{-1}$-. The ratio of yeast-like cells(blastospores) of A. pullulans increased with the increase of growth rate, and reached 100% over the growth rate of 0.07 hr$^{-1}$. The growth rate, within a certain range, affected not only on the cell morphology, but on the specific pullulan productivity of A. pullulans.

• 한국미생물·생명공학회지
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• 제22권2호
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• pp.222-225
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• 1994

Three kinds of pretreatment methods were used for selectivel isolation of soil actinomy cetes. One hundred and six strains were isolated on Bennet's agar and 114 strains were on humic acid-vitamin agar from 5 domestic soil samples. All of these isolates were identified to the genus level based on morphological and physiological characheristics. Among three methods, dry heat was most effective to isolate many different strains including rare actinomycetes. On genus, Bennet's agar was effective for selective isolation of Nocardia but bumic acid-vitamin agar for another rare actinomycetes.