• Journal of Microbiology and Biotechnology
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• v.28 no.9
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• pp.1527-1535
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• 2018

Bacterial strain BAS23 was isolated from rice field soil and identified as Bacillus amyloliquefaciens. Based on dual culture method results, the bacterium BAS23 exhibited potent in vitro inhibitory activity on mycelial growth against a broad range of dirty panicle fungal pathogens of rice (Curvularia lunata, Fusarium semitectum and Helminthosporium oryzae). Cell-free culture of BAS23 displayed a significant effect on germ tube elongation and mycelial growth. The highest dry weight reduction (%) values of C. lunata, H. oryzae and F. semitectum were 92.7%, 75.7%, and 68.9%, respectively. Analysis of electrospray ionization-mass spectrometry (ESI-MS) and $^1H$ nuclear magnetic resonance (NMR) spectroscopy revealed that the lipopeptides were iturin A with a C14 side chain (C14 iturinic acid), and a C15 side chain (C15 iturinic acid), which were produced by BAS23 when it was cultured in nutrient broth (NB) for 72 h at $30^{\circ}C$. BAS23, the efficient antagonistic bacterium, also possessed in vitro multiple traits for plant growth promotion and improved rice seedling growth. The results indicated that BAS23 represents a useful option either for biocontrol or as a plant growth-promoting agent.

• Applied Biological Chemistry
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• v.31 no.1
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• pp.100-105
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• 1988

A biofertilizer, having been deordorized and showing promotive effect on plant growth, was manufactured from the rice straw and hen feces by use of Thermoactinomycetes vulgaris. This strain grew vigorously on rice straw mixed with unsterilized hen feces at $50^{\circ}C,\;pH\;8.0{\sim}8.5$ and moisture content of 60% and got rid hen feces of malodour during treatment. The growth of plant(Brassica raga var. previdis) was experimented on humic volcanic ash soil, using pot in thermostatically controlled greenhouse. The biofertilizer was applied as N-fertilizer and air-dried lien feces or ammonium sulfate were used for comparison with the biofertilizer. The effect on. plant growth was evaluated on the basis of the amount of nitrogen as fertilizer, under a loading of 0.1g N/pot, all samples showed a promotion effect of plant growth. But ammonium sulfate and air-dried hen feces inhibited plant growth at the nitrogen content over 0.2 and 0.4g N/pot, respectively, whereas the biofertilizer showed a good promotion effect on plant growth without growth inhibition even at nitrogen content of 0.8g N/pot.

• Journal of Korean Tunnelling and Underground Space Association
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• v.16 no.1
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• pp.25-50
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• 2014

In order to identify a load transfer mechanism of ground anchors, the behavior of multi load transfer ground anchor systems was investigated and compared with those of compression type anchors and tension type anchors. Large scale model tests were performed and stress-strain relationships were obtained. The load transfer mechanism of ground anchors was also investigated in the field tests. Finally, numerical analyses to predict the load-displacement relationships of anchors were conducted. It is concluded that the load transfer characteristics of MLT anchors are mechanically much more superior in the pull-out resistance effect than those of existing compression and tension type anchors. From the results of research work, we could suggest that the max pull-out capacity of anchor capacity to each the soil condition. Also, the MLT anchors can be used to achieve both structural enhancement and economic construction in earth retaining or supporting structures.

• Microbiology and Biotechnology Letters
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• v.10 no.3
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• pp.185-190
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• 1982

A strain of Streptomyces sp. (YS-40) which was able to produce penicillinase, was isolated from soil and the enzymatic characteristics of this enzyme were investigated. The crude enzyme was obtained with the fractionation by 80 % cold acetone. The optimal temperature and pH of this enzyme was 45$^{\circ}C$ and 5.0 respectively. The stable pH range of the enzyme was between pH 5.5 and 8.0 at 37$^{\circ}C$. By heat treatment at 6$0^{\circ}C$ and 8$0^{\circ}C$ for 10 min, the remained relative activities were about 50%, 30% respectively. The activity of the enzyme was inhibited by Cu$^{＋＋}$, $_Mn^{＋＋}$, Zn$^{＋＋}$ but Co$^{＋＋}$, Li$^{＋＋}$, $Ca^{＋＋}$, $Mg^{＋＋}$ $Ba^{＋＋}$ did not affect. Among 11 chemical reagents, ethylenedi aminetetra-acetic acid disodium salt (EDTA-2Na), sodium dodecyl sulfate (SDS) and sodium fluoride inhibited the enzyme activity.

• Microbiology and Biotechnology Letters
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• v.10 no.3
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• pp.177-184
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• 1982

Studies were carried out to investigate the optimal culture conditions for the production of penicillinase using a strain of Streptomyces sp. isolated from soil, YS-40. Among the carbon and nitrogen sources, glucose and L-asparagine increased the peniciilinase production. The addition of M $n^{＋＋}$, $Ca^{＋＋}$ and L $i^{＋}$ increased the enzyme production, but depressed by F $e^{＋＋＋}$, F $e^{＋＋}$, $Mg^{＋＋}$, Z $n^{＋＋}$, A $g^{＋＋}$, $Ba^{＋＋}$ and S $n^{＋＋}$. L-Leucine slightly increased the enzyme production but L-histidine, L-methionine depressed. Among the vitamins riboflavine, i-inositol, hesperidine, niacin-amide, biotin, folic acid, DL-$\alpha$-lipoic acid increased the enzyme formation. The addition of cephradine, cephalexin, ampicillin, cloxacillin more increased the enzyme formation than that of other$\beta$-lactam antibiotics and antibiotics. Optimal pH and temperature on the enzyme formation was pH 7.0 and 28$^{\circ}C$ respectively Amount of the enzyme production reached at maximum with incubation for 3 days on the optimal condition.

• Microbiology and Biotechnology Letters
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• v.9 no.4
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• pp.207-212
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• 1981

A strain of Penicillium sp. which produces considerable amount of $\beta$-galactosidase was selected from extracellular $\beta$-galactosidase-producing fungi isolated from soil. The enzyme was found to be very stable in neutral pH range. Maximum enzymatic activity was reached after 72 hr of incubation in a wheat bran medium at 3$0^{\circ}C$. Productivity of the enzyme appeared not to be affected by the addition of carbon sources to the medium but the activity of the enzyme was increased from 14% to 85% by the addition of various nitrogen sources. The enzyme extracted from the wheat-bran culture of the Penicillium sp. was purified to 5050-fold by ammonium sulfate fractionation, SP-Sephadex C-50 chromatography, Ultrogel AcA 44 filtration and hydroxyapatite chromatography. The purified $\beta$-galactosidase was homogeneous on ultracentrifugation and disc electrophoresis.

• Microbiology and Biotechnology Letters
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• v.22 no.2
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• pp.175-181
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• 1994

A bacterial strain producing highly viscous polysaccharide(A29 POL) was isolated from soil and identified sa Bacillus sp. A29. The cultural conditions of the Bacillus sp. A29 for the polysaccharide prouction were dextrin 12%, soytone 0.2%, SnCl$_{2}$ $\cdot $2H$_{2}$O 0.02%, Na$_{2}$HPO$_{4}$ $\CDOT $12H$_{2}$O 0.36%, L-alanine 0.01%, initial pH6.8, and 30$\circ $C at pH 3 FOR 4 days. Final viscosity of the culture broth was 65, 000 cp and then the amount of produced polysaccharide was 8.3 g/l. A29 POL was composed of glucose and xylose. A29 POL showed high viscosity at low concentration(0.1%) and in the presence of the salts such as NaCl or CaCl$_{2}$. A29 POL showed high viscosity acid condition and at alkali condition and high pseudoplasticity in the presence of a NaCl or CaCl$_{2}$. It was shown that the viscosity at high temperature(80$\circ $C) was decreased but it was recovered at low temperature (20$\circ $C. A29 POL was able to from film and gel in the presence of MgSO$_{4}$ $\CDOT $7H$_{2}$O, Na$_{2}$CO$_{3}$ \CDOT $H$_{2}$O, MnSO$_{4}$ $\CDOT $ 7H$_{2}$O. A29 POL had anionic charge.

• Journal of Microbiology and Biotechnology
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• v.25 no.6
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• pp.893-902
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• 2015

Various Lactobacillus reuteri strains were screened for the ability to convert glycerol to 1,3-propanediol (1,3-PDO) in a glycerol-glucose co-fermentation. Only L. reuteri DSM 20016, a well-known probiotic, was able to efficiently carry out this bioconversion. Several process strategies were employed to improve this process. Co²⁺ addition to the fermentation medium, led to a high product titer (46 g/l) of 1,3-PDO and to improved biomass synthesis. L. reuteri DSM 20016 produced also ca. 3 µg/g of cell dry weight of vitamin B₁₂, conferring an economic value to the biomass produced in the process. Incidentally, we found that L. reuteri displays the highest resistance to Co²⁺ ions ever reported for a microorganism. Two waste materials (crude glycerol from biodiesel industry and spruce hydrolysate from paper industry) alone or in combination were used as feedstocks for the production of 1,3-PDO by L. reuteri DSM 20016. Crude glycerol was efficiently converted into 1,3-PDO although with a lower titer than pure glycerol (33.3 vs. 40.7 g/l). Compared with the fermentation carried out with pure substrates, the 1,3-PDO produced was significantly lower (40.7 vs. 24.2 g/l) using cellulosic hydrolysate and crude glycerol, but strong increases of the maximal biomass produced (2.9 vs 4.3 g/l CDW) and of the glucose consumption rate were found. The results of this study lay the foundation for further investigations to exploit the biotechnological potential of L. reuteri DSM 20016 to produce 1,3-PDO and vitamin B₁₂ using industry byproducts.

• Journal of the Korea Organic Resources Recycling Association
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• v.11 no.4
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• pp.49-56
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• 2003

The strain Ralstonia eutopha JMP134 (formerly Alcaligenes eutrophus JMP134) can degrade trichloroethylene(TCE) through a chromosomal phenol-dependent pathway. The phenol hydroxylase was previously found to be a single responsible enzyme for TEC degradation. Here, we demonstrate that a recombinant bacterium, R. eutopha AEK301, one of Tn5-induced mutants of JMP134 containing a recombinant plasmid pYK3011, degrades TCE in the absence of inducer, phenol and in the presence of various carbon sources. Complete removal of TCE ($50{\mu}M$) was observed in minimal medium containing only 0.05% ethanol as a carbon source within 24 hours. The bacterium removed $200{\mu}M$ of TCE to below detectable level within two days under non-selective pressure. When TCE concentration was increased up to $400{\mu}M$, the degradation had been continued until two days, then ceased with removal of 70% of detectable TCE.

• Microbiology and Biotechnology Letters
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• v.30 no.4
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• pp.352-358
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• 2002

An amylase that hydrolyzes starch into maltopentaose as a main product was found in the culture supernatant of a strain of Bacillus megaterium KSM B-404 isolated from local soil. The enzyme was purified 129-fold by ammonium sulfate precipitation, DEAE-Toyopearl and Superdex 75 HR 10/30 column using a FPLC system. The molecular weight of the amylase was determined as about 68 kDa by using SDS-PAGE. Optimum pH and temperature of amylase were found to be $50^{\circ}C$ and pH 6.0~7.0, respectively. The enzyme was stable up to $60^{\circ}C$ by addition of $Ca^{2+}$ and its pH stability was in the range of 6.0~10.0. The activity of enzyme was inhibited by $Cu^{2+}$ $Hg^{2+}$ , and $Fe^{3+}$ and maintained by $Ca^{2+}$ and $Mg^{2+}$ . EDTA and pCMB also showed inhibitory effect to the enzyme. TLC and HPLC analysis of the products of the enzyme reaction showed the presence of maltopentaose(52%), maltotriose (25%), maltose (11%), glucose, and maltotetraose in the starch hydrolysates.