• Microbiology and Biotechnology Letters
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• v.1 no.1
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• pp.37-42
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• 1973

C-74 belonging to the genus of Aspergillus species was selected from two hundred and seventy microorganisms stored at the lab, of microbiology. 1. Sample Inulase was precipitated mainly at pH 8 to 5 by isoelectric point fraction method. 2. The optimum pH of Inulase activity of the enzyme from C-74 strain was about 3.0 3. The optimum temperature of Inulase activity of the enzyme from C-74 strain was about $55^{\circ}C$ 4. The Inulase from C-74 strain was stable at $50^{\circ}C$ for 10mins. 5. The range of the pH stability of the Inulase from C-74 strain was about 2.5-4.5 6. Effect of metal ions on the Inulase activity of the enzyme from C-74 strain was activated by Mg$\^$++/, Sb$\^$+++/ and inhibited by Ag$\^$++/, Hg$\^$++/.

• Journal of Microbiology and Biotechnology
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• v.34 no.9
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• pp.1819-1825
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• 2024

An aerobic, Gram-stain-negative, catalase-positive, rod-shaped, and motile bacteria, designated as a strain WR6^T was isolated from soil in Republic of Korea. Strain WR6^T grew at temperatures of 10-37℃, at pH of 5.0-9.0, and at NaCl concentrations of 0-3.0% (w/v). Phylogenetic and 16S rRNA gene nucleotide sequence analysis confirmed that strain WR6^T affiliated to the genus Mesorhizobium, with the nearest relative being Mesorhizobium waimense ICMP 19557^T (98.5%). The genome of strain WR6^T was 5,035,462 bp with DNA G+C content of 62.6%. In strain WR6^T, Q-10 was sole ubiquinone; summed feature 8 (C_18:1ω7c and/or C_18:1ω6c) and C_19:0 cyclo ω8c were predominant fatty acids; and diphosphatidylglycerol, phosphatidylglycerol, phosphatidylmethylethanolamine, phosphatidylcholine, and phosphatidylethanolamine were major polar lipids. Based on these polyphasic taxonomic data, strain WR6^T represents a novel species in the genus Mesorhizobium. Accordingly, we propose the name Mesorhizobium koreense sp. nov., with the type strain WR6^T (=KCTC 92695^T =NBRC 116021^T).

• Microbiology and Biotechnology Letters
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• v.22 no.6
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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.

• Microbiology and Biotechnology Letters
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• v.45 no.2
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• pp.168-177
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• 2017

Strain A28-5, which can degrade xylan and agar in solid medium, was isolated from a coastal seawater sample collected from Jeju Island, South Korea. This strain was found to be a gram-negative, $Na^+$-requiring bacterial strain with a polar flagellum for motility. Additionally, the strain was tolerant to antibiotics such as ampicillin and thiostrepton. The G+C content of the genome was 43.96% and menaquinone-7 was found to be the predominant quinone. Major fatty acids constituting the cell wall of the strain were $C_{16:1}$ ${\omega}7c/iso-C_{15:0}$ 2-OH (23.32%), $C_{16:0}$ (21.83%), and $C_{18:1}$ ${\omega}7c$ (17.98%). The 16S rRNA gene sequence of the strain showed the highest similarity (98.94%) to that of Catenovulum agarivorans YM01, which was demonstrated by constructing a neighbor-joining phylogenetic tree. A28-5 was identified as a novel species of the genus Catenovulum via DNA-DNA hybridization with Catenovulum agarivorans YM01, and thus was named as Catenovulum jejuensis A28-5. The formation of tetramers and hexamers of xylooligosaccharides and (neo)agarooligosaccharides, respectively, were confirmed by thin-layer chromatography analysis using an enzyme reaction solution containing xylan or agarose with two crude enzymes prepared from the liquid culture of the strain.

• Transactions of Materials Processing
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• v.10 no.1
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• pp.35-41
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• 2001

The high temperature deformation behavior of SCM 440 can be characterized by the hot torsion test in the temperature ranges of $900^{\circ}C$~$1100^{\circ}C$ and strain rate ranges of 0.05/sec~5/sec. The aim of this paper is to establish the quantitative equation of the volume fraction of dynamic recrystallization (DRX) as a function of processing variables, such as strain rate ($\varepsilon$), temperature (T), and strain ('$\varepsilon$). During hot deformation, the evolution of microstructure could be analyzed from work hardening rate ($\theta$). For the exact prediction of dynamic softening mechanism the critical strain ($\varepsilon_c$), the strain for maximum softening rate ($\varepsilon^*$ and Avrami' exponent (m') were quantitatively expressed by dimensionless parameter, Z/A, respectively. The transformation-effective strain-temperature curve for DRX could be composed. It was found that the calculated results were agreed with the experimental data for the steel at any deformation conditions.

• Microbiology and Biotechnology Letters
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• v.23 no.5
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• pp.559-564
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• 1995

Twenty microbial strains producing the acylase were isolated from soil by using Micrococcus luteus ATCC 9341 as an indicator strain, using either D-($\alpha $)-phenylglycine methylester and 7-aminocephalosporanic acid (7-ACA) or glutaric acid dimethylester and 7-ACA as substrates. Among the isolates, only one strain was turned out to be the 7-ACA producer from either cephalosporin C or glutaryl 7-ACA as the substrates by using the overlay of 7-ACA sensitive strain (SS5). 7-ACA produced from cephalosporin C by an isolate (APS20) was detected by high performance liquid chromatography. The isolated strain (APS20) was identified to Bacillus macerans on the basis of cellular fatty acid profile by gas chromatography. Bacillus macerans APS20 had no $\beta $-lacta-mase activity on cephalosporin C, and that is very important for the enzymatic production process of 7-ACA. However, this strain was resistant up to 100 $\mu $g/ml of cephalosporin C.

• KSBB Journal
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• v.17 no.3
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• pp.247-254
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• 2002

Two kinds of crude oil-degrading microorganisms from soil and one kind from sea were isolated and named strain Al32, strain F722 and strain OM1, respectively. These microorganism were identified Acinetobacter sp., Pseudomonas aeruginosa and Acinetobacter calcoaceticus, respectively. The optimum cultivation temperature of Acinetobacter sp. A132 and P. aeruginosa F722 was $35^{\circ}C$ and optimum growth pH was 8 and 9, respectively. The growth was the highest at 2.0% (w/v) substrate concentration when crude oil was only carbon source. The growth of A. calcoaceticus OM1 isolated from sea was the highest at 3.0% (w/v) of crude oil. In inspection of crude oil degradability, strain Al32 showed 5.49 g/L.day with Eleuthera (OMAN), 2.0% (w/v). P. aeruginosa F722 showed 1.19 g/L g/L.day with L-Zakum (AFRICA). In case of kerosene $nC_9\simnC_{20}$ and diesel $nC_9\simnC_{28}$, A. calcoaceticus OM1 was degraded 95% and 75%, respectively, for 7 days culture, and P. aeruginosa F722 was 80% after 10 days.

• Transactions of Materials Processing
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• v.20 no.3
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• pp.229-235
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• 2011

The formability of magnesium alloy sheets at room temperature is generally low because of the inherently limited number of slip systems, but higher at temperatures over $150^{\circ}C$. Therefore, prior to the practical application of these materials, the forming limits should be evaluated as a function of the temperature and strain rate. This can be achieved experimentally by performing a series of tests or analytically by deriving the corresponding modeling approaches. However, before the formability analysis can be conducted, a model of flow stress, which includes the effects of strain, strain rate and temperature, should be carefully identified. In this paper, such procedure is carried out for Mg alloy AZ31 and the concept of flow stress surface is proposed. Experimental flow stresses at four temperature levels ($150^{\circ}C$, $200^{\circ}C$, $250^{\circ}C$, $300^{\circ}C$) each with the pre-assigned strain rate levels of $0.01s^{-1}$, $0.1s^{-1}$ and $1.0s^{-1}$ are collected in order to establish the relationships between these variables. The temperature-compensated strain rate parameter which combines, in a single variable, the effects of temperature and strain rate, is introduced to capture these relationships in a compact manner. This study shows that the proposed concept of flow stress surface is practically relevant for the evaluation of temperature and strain dependent formability.

• The Plant Pathology Journal
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• v.25 no.1
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• pp.62-69
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• 2009

In this study, we characterized the bacterial strain KJ2C12 in relation with its biocontrol activity against Phytophthora capsici on pepper, and identified this strain using morphological, physiological, biochemical, fatty acid methyl ester, and 16S rRNA gene sequence analyses. Strain KJ2C12 significantly (P=0.05) reduced both final disease severity and areas under the disease progress curves of 5-week-old pepper plants inoculated with P. capsici compared to buffer-treated controls. As for the production of antibiotics, biofilms, biosurfactant, extracellular enzyme, HCN, and swarming activity, strain KJ2C12 produced an extracellular enzyme with protease activity, but no other productions or swarming activity. However, Escherichia coli produced weak biofilm only. Strain KJ2C12 could colonize pepper roots more effectively in a gnotobiotic system using sterile quartz sand compared to E. coli over 4 weeks after treatments. However, no bacterial populations were detected in 10 mM $MgSO_4$ buffer-treated controls. Strain KJ2C12 produced significantly higher microbial activity than the $MgSO_4$-treated control or E. coli over 4 weeks after treatments. Bacterial strain KJ2C12 was identified as Bacillus luciferensis based on morphological, physiological, and biochemical characteristics as well as FAME and 16S rRNA gene sequence analyses. In addition, these results suggested that B. luciferensis strain KJ2C12 could reduce Phytophthora blight of pepper by protecting infection courts through enhanced effective root colonization with protease production and an increase of soil microbial activity.

• Microbiology and Biotechnology Letters
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• v.3 no.3
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• pp.123-134
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• 1975

Out of 96 yeast strains isolated from various natural habitats, five strains were screened based on their ability to ferment agricultural biproducts such as rice-, barley-and wheat-bran, and sawdust. These were identified as Hansenula anomala var anomala, Candide utilis, C. pelliculosa, Debaryomyces hansenii, and Irpex lacteus. Using these yeasts the above mentioned agricultural biproducts were fermented in various combinations. The fermented product was fed to 180 male Starcroses for eight weeks and obtained a body weight increase of 15.1g a day, while the unfermented control feed increased 10.5g a day.