• Journal of Mushroom
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• v.12 no.3
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• pp.163-170
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• 2014

The potential ability of Button mushroom compost (BMC) to solubilize heavy metals was estimated with metal contaminated soils collected from abandoned mines of Boryeong area in South Korea. The bacterial strains in BMC were isolated for investigating the mobilization of metals in soil or plant by the strains and identified according to 16S rRNA gene sequence analysis. When metal solubilization potential of BMC was assessed in a batch experiment, the BMC was found to be capable of solubilizing metals in the presence of metals (Co, Pb and Zn) and the results showed that inoculation of BMC could increase the concentrations of water soluble Co, Pb and Cd by 35, 25 and 45% respectively, than those of non-inoculated soils. BMC-assisted growth promotion and metal uptake in sunflower (Helianthus annuus) was also evaluated in a pot experiment. In comparison with non-inoculated seedlings, the inoculation led to increase the growth of H. annuus by 27, 25 and 28% respectively in Co, Pb and Zn contaminated soils. Moreover, enhanced accumulation of Co, Pb and Zn in the shoot and root systems was observed in inoculated plants, where metal translocation from root to the above-ground tissues was also found to be enhanced by the BMC. The apparent results suggested that the BMC could effectively be employed in enhancing phytoextraction of Co, Pb and Zn from contaminated soils.

• Journal of Microbiology and Biotechnology
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• v.14 no.6
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• pp.1142-1149
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• 2004

Streptococcus mutans has the capacity of inducing dental caries. Thus, to develop a novel way of preventing dental caries, a cell wall hydrolase-producing strain was isolated and its characteristics were investigated. Among 200 alkalophilic strains isolated from soil, 8 strains exhibited lytic activities against Streptococcus mutans. However, strain YU5215 with the highest cell wall hydrolase activity was selected for further study. Strain YU5215 was identified as a novel strain of Bacillus based on analyzing its 16S rDNA sequence and Bergey's Manual of Systematic Bacteriology, and thus designated as Bacillus mutanolyticus YU5215. The optimal conditions for the production of the cell wall hydrolase from Bacillus mutanolyticus YU5215 consisted of glucose ($0.8\%$), yeast extract ($1.2\%$), polypeptone ($0.5\%$), $K_{2}HPO_{4}\;(0.1\%$), $MgSO_{4}{\cdot}7H_{2}O$ ($0.02\%$), and $Na_{2}CO_{3}\;(1.0\%$) at pH 10.0. Bacillus mutanolyticus YU5215 was cultured at 30^{circ}C for 72 h to produce the cell wall hydrolase, which was then purified by acetone precipitation and CM-agarose column chromatography. The molecular weight of the lytic enzyme was determined as 22,700 Da by SDS-PAGE. When the cell wall peptidoglycan of Streptococcus mutans was digested with the lytic enzyme, no increase in the reducing sugars was observed, while the free amino acids increased, indicating that the lytic enzyme had an endopeptidase-like property. The amino terminus of the cell wall peptidoglycan digested by the lytic enzyme was determined as a glutamic acid, while the lytic site of the lytic enzyme in the Streptococcus mutans peptidoglycan was identified as the peptide linkage of L-Ala and D-Glu.

• Journal of Microbiology and Biotechnology
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• v.8 no.6
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• pp.606-612
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• 1998

A microbial flocculant-producing gram-positive bacterium, strain TE11, was isolated from soil samples, and was identified as Bacillus subtilis by using the Midi system, the Biolog system, 16S rDNA sequence analysis, and some physiological and morphological characteristics. The maximum flocculant capsular biopolymer of TE11 strain (BCP, 4.9mg/ml) was obtained when it was grown in GA broth medium containing 3% glutamic acid, 2% glycerol, 0.5% citric acid, 0.5% $NH_4$Cl, 0.05% $MgSO_4.7H_2O,\; 0.05%\;K_2HPO_4\;,\; and\; 0.004%\; FeC1_3. 6H_2O,\; pH 7.2,\; at\; 30^{\circ}C$ for 70 h with shaking. When glycerol was used as an additional carbon source in the GA medium, TE11 produced only flocculant BCP without any by-product. The flocculant (BCP) was found to aggregate suspended kaolin and activated charcoal powder without cations, and its flocculating activity was significantly enhanced by the addition of bivalent cations such as $Ca^{2＋}.Zn^{2},\; and\; Mn^{2＋}$. The flocculation activity by addition of $Ca^{2+}$ was high in an acidic pH 4.0. In the case of $Zn^{2＋}$, high flocculating activity remained without significant loss in the broad range of pH 4.0 to 9.0.

• Journal of Microbiology and Biotechnology
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• v.8 no.6
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• pp.639-644
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• 1998

Extracellular serine proteases were isolated from a soil bacterium, alkalophilic coryneform bacterium TU-19, which have been grown in a liquid medium optimized at 3$0^{\circ}C$ and pH 10.0. Three different sizes, 120 kDa (protease I), 80 kDa (protease II), and 45 kDa (protease III), of serine pro teases were purified using Sephadex G-150 and QAE-Sephadex chromatography (Kang et al. 1995. Agric. Chem Biotech. 38: 534-540). SDS-PAGE showed that the 120 kDa protease was degraded into the 80 kDa protease in 20 mM Tris-HCI (pH 8.0) buffer solution. This degradation was enhanced in the presence of 0.5 M NaCl and 5 mM EDTA, but was inhibited in the presence of 5 mM $CaCl_2$. These results indicated that the $Ca^{2＋}$ ion seems to stabilize the 120 kDa protease like other proteases derived from Bacillus species. The $NH_2$-terminal amino acid sequences of the 10 residues of both proteases were completely identical: Met-Asn-Thr-Gln-Asn-Ser-Phe-Leu-Ile-Lys. In contrast to this, the 80 kDa protease has 1.5 times higher specific activity than the 120 kDa protease does (Kang et al. 1995. Agric. Chern. Biotech. 38: 534-540). Therefore the C-terminal of the 120 kDa protease seems to be autolyzed to the 80 kDa protease but this autolysis did not decrease the protease activity. Optimum pH and temperature of both 80 kDa and 120 kDa proteases were pH 10.5 and $45^{\circ}C$, respectively, and pH and thermal stability were almost identical. Several divalent ions except the $Fe^{2＋}$ ion showed similar effects on activities of both proteases, which are similarly resistant to three different detergents.

• Journal of Microbiology and Biotechnology
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• v.16 no.3
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• pp.408-413
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• 2006

A strain, P821, with phospholipase D activity was isolated from soil and identified as a Streptomyces species. The phospholipase D enzyme was purified from a culture broth of the isolated strain using ammonium sulfate precipitation and DEAE-Sepharose, phenyl-Sepharose, and Superose 12 HR column chromatographies. The purified enzyme exhibited an optimum temperature and pH of $55^{\circ}C$ and 6.0, respectively, in the hydrolysis of phosphatidylcholine and remained stable up to $60^{\circ}C$ within a pH range of 3.5-8.0. The enzyme also catalyzed a transphosphatidylation reaction to produce phosphatidylserine with phosphatidylcholine and serine substrates. The optimum conditions for the transphosphatidylation were $30^{\circ}C$ and pH 5.0, indicating quite different optimum conditions for the hydrolysis and transphosphatidylation reactions. The gene encoding the enzyme was cloned by Southern hybridization and colony hybridization using a DNA probe designed from the conserved regions of other known phospholipase D enzymes. The resulting amino acid sequence was most similar to that of the PLD enzyme from Streptomyces halstedii (89.5%). Therefore, the enzyme was confirmed to be a phospholipase D with potential use in the production of phosphatidylserine.

• Journal of Microbiology and Biotechnology
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• v.20 no.6
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• pp.1001-1005
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• 2010

The chitinase-producing strain TKU008 was isolated from soil in Taiwan, and it was identified as a new species of Pseudomonas. The culture condition suitable for production of chitinase was found to be shaking at $30^{\circ}C$ for 4 days in 100 ml of medium containing 1% shrimp and crab shell powder, 0.1% $K_2HPO_4$, and 0.05% $MgSO_4{\cdot}7H_2O$ (pH 7). The TKU008 chitinase was suppressed by the simultaneously existing protease, which also showed the maximum activity at the fourth day of incubation. The molecular mass of the chitinase was estimated to be 40 kDa by SDS-PAGE. The optimum pH, optimum temperature, pH stability, and thermal stability of the chitinase were pH 7, $50^{\circ}C$, pH 6-7, and <$50^{\circ}C$, respectively. The chitinase was completely inhibited by $Mn^{2+}$ and $Cu^{2+}$. The results of peptide mass mapping showed that 11 tryptic peptides of the chitinase were identical to the chitinase CW from Bacillus cereus (GenBank Accession No. gi 45827175) with a 32% sequence coverage.

• Journal of Microbiology and Biotechnology
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• v.20 no.6
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• pp.995-1000
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• 2010

A novel deoC gene was identified from Paenibacillus sp. EA001 isolated from soil. The gene had an open reading frame (ORF) of 663 base pairs encoding a protein of 220 amino acids with a molecular mass of 24.5 kDa. The amino acid sequence was 79% identical to that of deoxyribose 5-phosphate aldolase (DERA) from Geobacillus sp. Y412MC10. The deoC gene encoding DERA was cloned into an expression vector and the protein was expressed in Escherichia coli. The recombinant DERA was purified using Ni-NTA affinity chromatography and then characterized. The optimum temperature and pH of the enzyme were $50^{\circ}C$ and 6.0, respectively. The specific activity for the substrate deoxyribose 5-phosphate (DR5P) was $62\;{\mu}mol/min/mg$. The $K_m$ value for DR5P was determined to be 145 mM with the $k_{cat}$ value of $3.2{\times}10^2/s$ from Lineweaver-Burk plots. The EA001 DERA showed stability toward a high concentration of acetaldehyde (100 mM).

• Microbiology and Biotechnology Letters
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• v.46 no.1
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• pp.40-44
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• 2018

An isolate capable of inhibiting the growth of gram-positive bacteria was obtained from the soil of Mushim stream, Cheongju. The isolate was identified as Pseudomonas otitidis PS by 16S rRNA gene sequence analysis. P. otitidis PS produced antibiotics as a secondary metabolite when cultured in 1% soybean meal with 0.5% glucose. The maximum yield was about 0.1%. The antibiotic substance of P. otitidis PS extracted using ethyl acetate displayed a minimum inhibitory concentration of $2{\mu}g/ml$ for Staphylococcus aureus KCTC 1261. The antibiotic substance produced an orange halo on chrome azurol S agar due to siderophore activity. Growth inhibition was decreased when the iron was depleted. Since the antibiotic activity was lost upon the addition of the reducing agent ascorbic acid or during anaerobic culture, it was considered that antibiotic of P. otitidis PS strain exerts its bactericidal effect by the generation of reactive oxygen species.

• Journal of the Korea Organic Resources Recycling Association
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• v.14 no.3
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• pp.148-156
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• 2006

Potential hydrocarbon degrading bacteria were screened from the site artificially polluted with 20,000 ppm of diesel. Among the isolates, two strains, SJD2 and SJD4, showed higher activities to degrade diesel on the Bushnell-Hass broth medium containing 2% of diesel. 16S rDNA sequence analysis revealed that SJD2 and SJD4 were Bacillus fusifomis and B. cereus, respectively. Both strains were found to grow in a wide range of temperature between $20^{\circ}C-55^{\circ}C$, with the best at $30^{\circ}C-37^{\circ}C$. This is the first report, as far as we know, that B. fusifomis is capable of degrading diesel. We hope that a new isolate, B. fusifomis, will efficiently conduct bioremediation at the contaminated sites with petroleum hydrocarbons.

• Journal of Microbiology and Biotechnology
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• v.12 no.3
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• pp.437-443
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• 2002

A number of soil and wastewater samples were collected from the vicinity of an effluent treatment plant for the chemical industry. Several microorganisms were screened fur their ability to decolorize the triphenylmethane group of dyes. As a result, a novel crystal violet dye-degrading strain LK-24 was isolated. Taxonomic identification including 16S rDNA sequencing and phylogenetic analysis indicated that the isolate had a $99.5\%$ homology in its 16S rDNA base sequence with Stenotrophomonas maltophilia. The triphenylmethane dye, crystal violet, was degraded extensively by growing cells of Stenotrophomonas maltophilia LK-24 in agitated liquid cultures, although their growth was strongly inhibited in the initial stage of incubation. This group of dyes is toxic, depending on the concentration used. The dye was significantly degraded at a relatively lower concentration, below $100{\mu}g\;ml^-1$, yet the growth of the cells was totally suppressed at a dye concentration of $250{\mu}g\;ml^-1$. The degradation products of crystal violet were identified as 4,4'-bis(dimethylamino)-benzophenone and ${\rho}$-dimethylaminophenol by Gas chromatography-Mass spectrometry. The 4,4'-bis(dimethylamino)-benzophenone was easily obtained in a reasonable yield, as it was not metabolized further by S. maltophilia LK-24; however, the ${\rho}$-dimethylaminophenol was not easily identifiable, as it was further metabolized.