• Journal of Microbiology
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• v.40 no.1
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• pp.20-25
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• 2002

An extracellular PHB depolymerase was purified from P. simplicissimum LAR13 cultural medium by Sepharose CL-6B chromatography. When the fungus was grown in a basal salt medium with poly(3-hydroxybutyrate) (PHB) as the sole carbon source, PHB depolymerase production reached maximum at its stationary phase. The mycelial growth rate was higher at 37$^{\circ}C$ than at 30$^{\circ}C$ and even higher than at 25$^{\circ}C$, However, the enzyme production was lower at 37$^{\circ}C$ than 30$^{\circ}C$ or 25$^{\circ}C$. The isolated enzyme is composed of a single polypeptide chain with a molecular mass of about 36 kDa as determined by SDS-PAGE. The optimum conditions for the enzyme activity are pH 5.0 and 45$^{\circ}C$. The enzyme was stable for 30 min at a temperature lower than 50$^{\circ}C$, and stable at pH higher than 2.0 but it was unstable at pH 1.0.1 mM Fe$\^$2+/ reduced the enzyme activity by 56% and the enzyme was inhibited almost completely by 4 mM Fe$\^$2+/ . The enzyme was partially inhibited by phenylmethylsulfonyl fluoride and was very sensitive to diazo-DL-norleucine methyl esters dithiothreitol and mercuric ion. However, N-p - tosyl - L - Iysinechloromethyl ketone, p -hydroxymercuricbenzoate and N- acetylimidazole had no influence upon its activity.

• Microbiology and Biotechnology Letters
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• v.27 no.1
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• pp.15-22
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• 1999

Various lactic acid bacteria were isolated from Korean Kimchi in order to study their antimutagenic substances. Ames test using Salmonella typhimurium TA98 and TA100 showed the strain KLAB21 to have the highest antimutagenic activity among the 230 isolated strains against MNNG (N-methyl-N'-nitro-N-nitrosoguanidine), NPD (4-nitro-O-phenylenediamine), NQO (4-nitrosoquinoline-1-oxide) and AFB1 (aflatoxin B1). The strain was identified as Lactobacillus plantarum based on its morphological, cultural and physiological characteristics. Antimutagenic activity of L. plantarum KLAB21 was found in culture supernatant suggesting the bacterium secrete antimutagenic substance in the media. No mutagenic activity was found in the culture supernatant. The isolated strain L. plantarum KLAB21 showed much higher antimutagenic activity than L. plantarum IAM1261 which is being used industrially for fermented milk production. The antimutagenic activity of L.plantarum KLAB21 was reconfirmed by the spore-rec assay using spores of Bacillus subtilis H17($Rec^+$) and M45($Rec^-$).

• Journal of Environmental Science International
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• v.6 no.5
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• pp.473-480
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• 1997

Microorganisms producing bioemulslfiler were isolated from the sea water In Pusan coastal area. The isolated strain which had the highest emulsification activity and stability was identified as the genus Achetobacter from the results of morphological. cultural and biochemical tests and named Achetobacter sp. EL-C6 for convenience. The compositions of optimum medium for emulsification of crude oil by Acinetobacter sp. EL-C6 were crude oil 2.0%, NH4NO3 0.2%, $K_2HPO_4$ 0.01%, $MgSO_4$.$7H_2O$ 1.o%, $CaCl_2$.$2H_2O$ 0.1% and NaCl 3.0% at initial pH 7.5 and 3$0^{\circ}C$, respectively. The cultivation for emulsification of crude ell was carried out in 500m1 shaking flask containing 100m1 of the optimum medium at 3$0^{\circ}C$. The highest emulsification was observed after 5 days. The utilization on the various hydrocarbon of the Achetobacter sp. EL-C6 showed that utilization of n-alkane compounds were better than that of aromatic compounds. Among the petroleum compounds, crude ell was best utilized by the Achetobacter sp. EL-C6.

• Journal of Microbiology and Biotechnology
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• v.5 no.2
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• pp.80-86
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• 1995

The bacterial strain WC-17 able to produce chitinase was isolated from soil using an enrichment technique. The isolated strain was identified as Acinetobacter sp. judging by their morphological and physiological characterisitics. The optimal culture conditions for the production of chitinase of Acinetobacter sp. WC -17 are 1.5% colloidal chitin and 1 % tryptone at $30^{\circ}C$ with pH 6.5. Since the enzyme was rapidly produced in a culture supplied with chitin, glucose, or N-acetylglucosamine but not with other polymers and monosaccharide, the enzyme was considered to be an inducible enzyme. Notably N- acetylglucosamine and glucose were found to be effective inducers at low concentrations but repressors at excessive concentrations. The cultural supernatant of Acinetobacter sp. WC-17 inhibited the growth of phytopathogenic fungi such as P.oryzae, R.solani, and F.solani. Among the phytopathogenic fungi tested, P.oryzae was the most sensitive. The conventional agar plate (PDA containing 1 % colloidal chitin) method also produced the same result.

• Microbiology and Biotechnology Letters
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• v.30 no.4
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• pp.332-338
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• 2002

A strain YB-4 producing the extracellular $\alpha$-galactosidase was isolated from soil, and has been identified as Streptomyces sp. on the basis of its cultural, morphological and physiological properties. The partially purified $\alpha$-galactosidase was most active on paranitrophenyl-$\alpha$-D-galactopyranoside at pH 6.0 and 6$0^{\circ}C$. The enzyme retained 90% of its maximum activity between pH 4.0 and pH 10.0 after pre-incubation for 1 h. The enzyme was able to hydrolyze oligomeric substrates such as melibiose, raffinose and stachyose to liberate galactose residue, indicating that the $\alpha$-galactosidase of Steptomyces sp. YB-4 hydrolyzed $\alpha$-1,6 linkage.

• Microbiology and Biotechnology Letters
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• v.19 no.4
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• pp.315-318
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• 1991

- A bacterial strain No. S-76 which produced pullulanase powerfully was isolated frorn soil. The isolated bacterium was 0.4~$0.6\times 0.8$~1.4 $\mu\textrm{m}$ in size, gram negative, rods, motile and was identified as Aerornonas caviae by Bergey's manual of determinative bacteriology with various characteristics investigated. The highest yield of pullulanase of the strain was obtained by using the following medium: 1% pullulan, soluble starch or corn starch as a carbon sources and 0.5% yeast extract, peptone as nitrogen sources with an initial pH of 9.0. The optimal cutture conditions for production of pullulanase were at $32^{\circ}C$ for 2 days.

• Korean Journal of Microbiology
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• v.39 no.2
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• pp.102-107
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• 2003

With the enrichment culture technique, bacterial strains which degrade diesel oil were isolated from soil contaminated with diesel oil. One of the isolates named GENECO 1 showed the highest activity for emulsification of diesel oil as well as the highest growth rate. This strain, GENECO 1, was identified as a Pseudomonas sp. based on its biochemical, physiological characteristics and 16S rDNA sequences. The optimal cultural conditions for cell growth and oil emulsifying activity of its culture were as follow; $30^{\circ}C$ for temperature, 7.0 for pH. Diesel oil degradation was analysed by the gas chromatography. More than 95% of 1% treated diesel oil were converted into a form no longer extractable by mixed organic solvents after 96 hours incubation.

• The Korean Journal of Food And Nutrition
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• v.13 no.6
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• pp.611-618
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• 2000

For the purpose of the isolation of microorganisms which have the capability of nitrification, we isolated the microorganisms in 6 samples collected from the stream of Kyonggi area. 60 strains were isolated. The selected strain were identified as a Aeromonas hydrophila based on the data obtained from the morphological, biochemical and cultural characteristics defined experiments. Among them Aeromonas hydrophila (AH-1), (AH-3) , (AH-4), (AH-6) showed the highest nitrification capability. All isolates were resistant to amoxillin, ampicillin, cephalothin and ticarcillin. Optimum culture conditions of isolates were 37$^{\circ}C$ and 1${\times}$10$\^$8/ cells/ml for 4 hours in the nitrate medium.

• Mycobiology
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• v.40 no.3
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• pp.189-194
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• 2012

Four Cladobotryum isolates were collected from four different commercially grown mushroom types infected with cobweb disease in Cheongdo-gun and Chilgok-gun of Gyeongbuk Province, Korea in 2010. The isolates were identified as C. mycophilum from Agaricus bisporus and Pleurotus eryngii, C. varium from Flammulina velutipes and Hypsizygus marmoreus. The cultural characteristics of the four isolates were investigated using potato dextrose agar (PDA) media under nine different temperatures ranging from $5{\sim}32^{\circ}C$. Rapid growth of the isolates to colony diameters of 47~82 mm was observed at conditions of $18{\sim}22^{\circ}C$. No growth was observed at $32^{\circ}C$. C. mycophilum produced a yellowish red pigment while C. varium produced a cream colored pigment after cultivation for 25 days on PDA. Phylogenetic analysis of the internal transcribed spacer region and partial 28S rDNA from the four isolates confirmed they were C. mycophilum and C. varium. Cross pathogenicity tests revealed that the two isolates of C. mycophilum were highly pathogenic toward three mushroom types, but not toward H. marmoreus. The two isolates of C. varium were less pathogenic than those of C. mycophilum, but were pathogenic toward all mushroom types evaluated.

• Journal of Microbiology and Biotechnology
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• v.19 no.1
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• pp.99-107
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• 2009

Strain PUPC1 produces an antifungal protease as well as plant growth promoting enzymes such as 1-aminocyclopropane-1-carboxylate (ACC) deaminase and phosphatase. Morphological, cultural, and physiological characteristics as well as 16S rRNA gene-sequence-based phylogenetic analysis confirmed the taxonomic affiliation of PUPC1 as Chryseobacterium aquaticum. The optimum growth of PUPC1 was observed at pH 6.0 and $30^{\circ}C$, and maximum protease production was observed in medium B amended with 1% tryptone, 0.5% sucrose, and 0.005% $MnCl_2$. The protease was purified by ammonium sulfate precipitation, Sephadex G-75 gel filtration chromatography, and electroelution from preparative SDS-PAGE. The protease had a molecular mass of 18.5 kDa. The optimum pH and temperature stability of the protease were pH 5.0-10.0 and temperature $40-70^{\circ}C$. Chryseobacterium aquaticum PUPC1 and its protease showed a broad-spectrum antifungal activity against phytopathogenic fungi. Strain PUPC1 also exhibited plant growth promoting traits. The objective of the present investigation was to isolate a strain for agricultural application for plant growth promotion and biocontrol of fungal diseases.