• Journal of The Korean Society of Agricultural Engineers
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• v.58 no.4
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• pp.85-95
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• 2016

PBT (Plate Bearing Test) is a commonly used compaction estimation used to provide basal support for embankments. This study presents the results from experimental evaluations PBT, LWDT (Light Drop Weight Tester) test and Geogauge test with embankment materials which consist in sandy soil, crushed stone and rock. The results of this study indicate that the regression analyze results (r) from test results between Young's modulus and $k_{30}$, $E_v$ are 0.385 and 0.111~0.496, estimated very lack of correlation. The Geogauge is frequency vibration from machine to underground. Geogauge can not measure to accuracy test results when it is used on ground of the rock or crushed stone. The regression analyze results (r) from $E_v$ and Dynamic modulus are 0.502~0.847, different estimated by calculate method, as it were, when calculate $E_v$, least square method are appeared more accuracy than gradient of secant.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.625-628
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• 2001

To isolate novel strains that hydrolyzed the rac-ketoprofen ethyl ester to ketoprofen in the stereospecific manner, we screened broad ecological niches and soil samples in which the activity was expected to be found. From thousands of strains, we isolated a Pseudomonas sp. S34 producing a (S)-stereospecific esterase, and a thermostable esterase with (R)-form selectivity was also 。 btained from Bacillus stearothermophilus JYl44. To further analyse the gene structure and to induce a high level expression, two genes from each strain were cloned and sequenced. BLAST search results with the esterase gene from 534 revealed that both of gene (80-84 %) and amino acid sequences (89- 95 %) were highly conserved in the related esterases from Pseudomonas strains (fluorescens and aeruginosa). The thermostable esterase from JY144, however, revealed a relative low homology (45-52 %) to other esterase and/or lipase from related strains. Obviously, a complete conversion with pure enantiomer (R - or S) were readily achieved by recombinant clones expressing either (R)- or (S)- stereospecific esterase.

• Microbiology and Biotechnology Letters
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• v.24 no.3
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• pp.357-363
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• 1996

For the production of D-lactic acid from DL-2-chloropropionic acid, about 80 strains of bacteria capable of assimilating DL-2-chloropropionic acid as a sole carbon and energy source were isolated from the soil. JH-007 strain that showed the higest productivity of D-lactic acid and didn't produce L-lactic acid from DL-2-chloropropionic acid was selected from them and identified as Pseudomonas sp. The optimal conditions for the production of D-lactic acid from DL-2-chloropropionic acid were examined. The resting cells of JH-007 cultured in LB medium containing 3 g/l of DL-2-chloropropionic acid were used as an enzyme source. The reaction mixtures for the maximal production of D-lactic acid were consist of 10 g/l of resting cells and 3 g/l of DL-2-chloropropionic acid in 125 mM sodium carbonate buffer. The optimal pH for the reaction was 10.0 and the optimal temperature was 30$\circ$C. When 1 g/l of DL-2-chloropropionic acid was added intermittently to the reaction mixture under the above condition, 5.72 g/l of D-lactic acid was produced after incubation of 5 hrs. This amount of D-lactic acid corresponded to a 98.4% yields and the optical purity was 99.8%.

• Microbiology and Biotechnology Letters
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• v.24 no.3
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• pp.274-281
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• 1996

A bacterium producing Cyclodextrin Glucanotransferase (CGTase) and Cyclodextrinase (CDase) was isolated from soil, and named as Bacillus stearothermophilus KJ16. The growth of the isolated strain occurred in two steps, and syntheses of CGTase and CDase were dependedt on the growth cycle of the cell. CGTase was constitutively synthesized during the 1st growing phase, while CDase was synthesized inducibly during the 2nd growing phase. When the midium pH was controlled at 7.0 the maximum enzyme activities of CGTase and CDase were increased by 12-fold (1300 mU/ml) and 2-fold (225 mU/ml), respectively, compared with the pH-uncontrolled batch culture. The CGTase of the isolate converted soluble starch to CDs with the ratio of $\alpha$-CD:$\beta$-CD:$\gamma$-CD=42:46:12 at $55^{\circ}C$.The optimal pH and temperature of CGTase were 6.0 and $60^{\circ}C$, respectively and the optimal pH and temperature of CDase were 6.0 and $55^{\circ}C$. The molecular weights of the purified CGTase and CDase were estimated to be 65, 000 and 68, 000 dalton, respectively. Among several substrates, $\gamma$-CD was most rapidly hydrolyzed by the purified CDase.

• Microbiology and Biotechnology Letters
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• v.25 no.1
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• pp.62-67
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• 1997

A potential biocontrol bacterium, YB-70 was isolated from a rhizosphere in suppressive soil and identified as a strain of Bacillus subtilis. In several biochemical and in vitro antibiosis tests on Fusarium solani with the culture filterates from B. subtilis YB-70, we found that antifungal mechanism of B. subtilis YB-70 was mediated by antibiotic substances produced from the bacterium. These antifungal substances were appeared to be hear-resistant, micromolecular, and ethy alcohol soluble. Antifungal agents produced by B. subtilis YB-70 showed strong inhibified against root-rotting fungi F. solani in in vivo pot test. An antifungal substance. YBS-1s, was purified from the culture broth of B. subtilis YB-70 by isoelectronic precipitation, silica gel column chromatography and Sephadex LH-20 column chromatography analysis by Fab-MASS, $^{1}$H-NMR, $^{13}$C-NMR, DEPT, and amino acid analyzer revealed that the YBS-1A was a peptide antibiotics of iturin class containing seven amino acids from five different groups, and the other(YBS-1B) was an analogue of iturin group composed of 11 amino acids with larher molecular weight of about 1, 500 dalton, which was lager than that of iturin A.

• Journal of Life Science
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• v.12 no.4
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• pp.392-398
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• 2002

38 strains were isolated in order to utilize lignin degrading ability from soil and compost. A organism having high lignin degrading ability of the isolated strains determined morphologcal and biochemical characteristics. Enrichment technique yielded a lignin degrading bacterium characterized as Pseudomonas sp. LC-2. This strain was able to degrade lignin which are the true representatives of native lignin and transform lignin to a lot of aromatic compounds as HPLC analysis of culture. By polyacrylamide gel analysis, it was determined that peroxidase consisted of three enzymes, with only one, the lignin peroxidase having high activity.

• Journal of the Korean GEO-environmental Society
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• v.2 no.3
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• pp.89-99
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• 2001

In this study, the numerical analysis of piezocone penetration and dissipation tests has been conducted using the Modified Cam-Clay model, which is generally used in soil mechanics. The Modified Cam-Clay model and related mathematical equations in finite element derivation have been formulated in the Updated Lagrangian reference frame to take the large displacement and finite strain nature of piezocone penetration into consideration. The cone tip resistance, the pore water pressure, and the dissipation curve obtained from the finite element analysis have been compared and investigated with the experimental results from piezocone penetration test performed in Yangsan site. The numerical results showed good agreement with the experimental results; however, the better numerical simulation of the continuous and deep penetration needs further research.

• BMB Reports
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• v.28 no.4
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• pp.348-352
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• 1995

A thermophilic Bacillus sp. strain KK-1 isolated from soil produced an extracellular xylanase. From the culture supernatant of Bacillus sp., the xylanase was purified to homogeneity by ammonium sulfate precipitation and DEAE-Sephadex A-50 chromatography. The molecular weight of the purified xylanase was estimated to be 45 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gel permeation chromatography. The apparent $K_m$ values for xylanase, using oat spelt xylan and birchwood xylan as substrates, were 7.1 mg/ml and 3.2 mg/ml, and $V_{max}$ values were $27.0\;{\mu}mol{\cdot}min^{-1}{\cdot}mg^{-1}$ and $29.0\;{\mu}mol{\cdot}min^{-1}{\cdot}mg^{-1}$, respectively. The xylanase hydrolyzed oat spelt xylan to mostly xylobiose, xylotriose, and xylose. The amino acid composition indicated that the xylanase contained high amounts of amino add residues of glutamic acid and glutamine (Glx) and aspartic acid and asparagine (Asx).

• Microbiology and Biotechnology Letters
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• v.21 no.1
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• pp.36-40
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• 1993

A bacterial strain, producing extracellular inulin fructotransferase which converts inulin into di-D-fructofuranose dianhydride (DFA) was isolated from soil and presumed as Enterobacter sp. The DFA isolated on Bio-gel P2 column was identified as DFA III by high performance liquid chromatography and $^13C-nmr$ spectroscopy. The enzyme production was induced by inulin and markedly enhanced by the addition of corn steep liquor and $NH_4H_2P0_4$ for nitrogen source. Under optimum condition, the enzyme activity in the culture broth reached at maximum, 0.22 unit/ml after cultivation for 72 hour.

• Korean Journal of Poultry Science
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• v.36 no.4
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• pp.343-350
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• 2009

This study was carried out to investigate the possibility to utilize feather meal by bacterial strains. A bacterial strain SE-103 producing keratinolytic enzyme was isolated from the soil of the poultry slaughterhouses. It was identified as Bacillus sp. by judging from its morphological and physiological characteristics. Subsequently the optimal culture conditions for the production of keratinolytic protease by Bacillus sp. SE-103 were investigated. The composition of optimal medium was 3.0% glucose, 0.4% urea, 0.2% $NaNO_3$, and 0.15% KCl. In addition, optimal initial pH and temperature were 6.0 and $35^{\circ}C$, respectively.