• Microbiology and Biotechnology Letters
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• v.51 no.4
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• pp.484-499
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• 2023

Plant growth-promoting (PGP) bacteria can be used as bioresources to enhance phytoremediation through their PGP traits and pollutant removal capacity. In this study, 49 rhizobacteria were primarily isolated from the rhizosphere of tall fescue grown in diesel- and heavy metal-contaminated soil. Their biosurfactant production, phosphate (P) solubilization, and siderophore production were qualitatively and quantitatively evaluated to identify superior PGP bacteria. The optimal conditions for the growth of PGP bacteria and the stability of their PGP traits were a temperature of 35℃, a pH of 7, and 2 days of cultivation time. Four superior PGP bacteria (Pseudomonas sp. NL3, Bacillus sp. NL6, Bacillus sp. LBY14, and Priestia sp. TSY6) were finally selected. Pseudomonas sp. NL3 exhibited superior biosurfactant production and P solubilization. Bacillus sp. NL6 showed the highest P solubilization and superior production of biosurfactants and siderophores. Bacillus sp. LBY14 offered the best siderophore production and impressive P solubilization. Priestia sp. TSY6 had superior capacity for all three PGP traits. Through their secretion of beneficial PGP metabolites, the four bacteria isolated in this study have the potential for use in the phytoremediation of contaminated soil.

• Proceedings of the Microbiological Society of Korea Conference
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• 1997.04a
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• pp.57.1-57.1
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• 1997

• Proceedings of the Microbiological Society of Korea Conference
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• 2005.05a
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• pp.194.4-194
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• 2005

• Proceedings of the Microbiological Society of Korea Conference
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• 2005.05a
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• pp.195.1-195
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• 2005

• Proceedings of the Microbiological Society of Korea Conference
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• 1991.04a
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• pp.67-81
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• 1991

• Journal of Microbiology
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• v.38 no.4
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• pp.275-280
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• 2000

Pseudomonas sp. S-47 is capable of catabolizing 4-chlorobenzoate (4CBA) as rarbon and energy sources under aerobic conditions via the mesa-cleavage pathway. 4CBA-dioxygenase and 4CBA-dihydrodiol dehydrogenase (4CBA-DD) catalyzed the degradation af 4CBA to produce 4-chlorocatechol in the pathway. In this study, the xylL gene encoding 4CBA-DD was cloned from the chromosomal DNA of Pseudomonas sp. S-47 and its nucleotide sequence was analyzed. The xylL gene was found to be composed of 777 nucleotide pairs and to encode a polypeptide of 28 kDa with 258 amino acid residues. The deduced amino acid sequence of the dehydrogenase (XylL) from strain S-47 exhibited 98% and 60% homologies with these of the corresponding enzymes, Pseudomonas putida mt-2 (XyIL) and Acinetobacter calcoaceticus (BenD), respectively. However, the amino arid sequences show 30% or less homology with those of Pseudomonas putida (BnzE), Pseudomonas putida Fl (TodD), Pseudomonas pseudoalcaligenes KF707 (BphB), and Pseudomonas sp. C18 (NahB). Therefore, the 4CBA-dihydrodiol dehdrogenase of strain S-47 belongs to the group I dehydrogenase involved in the degradation of mono-aryls with a carboxyl group.

• Korean Journal of Microbiology
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• v.40 no.2
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• pp.121-126
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• 2004

Comamonas sp. strain DJ-12 is a 4-chlobiphenyl(4CB)-degrading bacterium that was reidentified from Pseudomonas sp. DJ-12. The genomic DNA was isolated from the strain DJ-12 and amplified by PCR with primers for cloning pcbABCD genes responsible for degradation of 4CB. The amino acid sequences deduced from the nucleotide sequences of pcbA1, pcbA2, pcbA3, pcbA4, pcbB, pcbC2, and pcbD2 genes showed 91, 87, 99, 87, 97, 90 and 87％ homologies with those of Pseudomonas sp. KKS102, respectively. The pcbC1D1 genes that are involved in the degradation of (4-chloro)1,2-dihydroxybiphenyl produced from 4CB by pcbAB gene products were previously reported in the recombinant plasmid pCU1 from Pseudomonas sp. DJ-12. However, the pcbC2D2 genes in the plasmid pCT4 and pCT5 cloned from Comamonas sp. DJ-12 in this study showed 51 and 62％ homologies with those of pcbC1D1 in their nucleotide sequences. The pcbC1D1 and pcbC2D2 genes were found by Southern hybridization to be located at different loci on the chromosome of DJ-12 strain. These results indicate that Comamonas sp. strain DJ-12 has two different sets of pcbCD genes responsible for deg-radation of (4-chloro)1,2-dihydroxybiphenyl.

• Microbiology and Biotechnology Letters
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• v.16 no.5
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• pp.379-383
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• 1988

To evaluate the treatability of activated sludge induced by benzene with microorganisms, isolation and characterization of benzene-degrading microorganisms were carried out. Six bacterial isolates from the activated sludge were identified ; Pseudomonas fluorescens, Enterobacter agglomerans, Enterobacter cloacae, Klebsiella oxytoca, Citrobacter freundii and Klebsiella pneumoniae. P. fluorescens degraded 55% of benzene contained in the medium as a sole carbon source, E. cloacae 24%, E. agglomerans 41%, and K. oxytoca 32%. Optimal temperature, pH and benzene concentration for growth of P. fluorescens appeared to be 31$^{\circ}C$, pH 7.0, and 300mg benzene per liter. When the P. fluorescens was dominant in the activated sludge induced by benzene, the indicator protozoa was Aspidisca sp. When concentration of benzene was about 387mg per liter, the growths of Aspidisca sp. and Litonotus sp. were high. Protozoa, Litonotus sp. and Vorticella sp. did not grow over 1600mg of benzene per liter.

• Korean Journal of Soil Science and Fertilizer
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• v.31 no.2
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• pp.204-210
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• 1998

The experiment was conducted to obtain the basic data required to characterize and improve rhizosphere environment of salt-accumulated greenhouse(SAG) soils by comparing the soil properties and the microbial flora of such soils to those of unprotected arable upland(UAU) soils. Soils were sampled from greenhouses and unprotected upland fields around the country. Microbial propulation, biomass C content and soil chemical properties were of interest. Population density of fluorescent Pseudomonas was high in UAU soils, while those of pathogenic Fusarium sp. and fluorescent Pseudomonas were low in SAG soils. With increasing soil organic matter(OM) content, the population densities of Bacillus sp., fluorescent Pseudomonas sp., Enterobacteriaceae, and microbial biomass C content increased. As soil electrical conductivity(EC) increased higher than $5.1dS\;m^{-1}$, the ratios of bacteria to fungi(B/F) and actinomycetes to fungi(A/F) and the population density of fluorescent Pseudomonas decreased remarkably. The soil pH was positively related to the population density of aerobic bacteria, while it was negatively related to that of fungi. The soil OM content was significantly correlated to the population densities of actinomycetes($r=0.226^*$). Bacillus sp.($r=0.334^{**}$), Enterobacteriaceae($r=0.276^*$), and the microbial biomass C content($R=0.439^{**}$). The population density of actinomycetes was also significantly correlated with soil exchangeable Ca($r=0.334^{**}$) and Mg($r=0.352^{**}$).

• Microbiology and Biotechnology Letters
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• v.38 no.1
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• pp.77-83
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• 2010

The fructus of Crataegus pinnatifida Bunge (CBF) has been used as medicinal and food source in worldwide. In this study, antimicrobial activity of the methanol extract and its sequential organic solvent fractions of CBF against different pathogenic bacteria and fungi, including multidrug resistant Pseudomonas aeruginosa and Candida sp., were investigated. The methanol extract of CBF was active against various gram-positive and gram-negative bacteria, and the ethylacetate and butanol fractions of CBF showed strong antibacterial activity against Listeria monocytogenes, Staphylococcus epidermidis, Staphylococcus aureus, Bacillus subtilis, Salmonella typhimurium, Proteus vulgaris, Escherichia coli and various multidrug resistant Pseudomonas aeruginosa with minimal inhibitory concentration of 1.0~7.5 mg/mL. Also the fractions showed anti-Candida activity against C. albicans, C. kruseis and C. geochares. The methanol extract of CBF and its solvent fractions, except n-hexane fraction, did not show any hemolytic activity against human red blood cell up to $500\;{\mu}g/mL$, respectively. The hemolysis in n-hexane fraction at $500\;{\mu}g/mL$ was less than 9.9%. Our results suggest that the CBF could be developed as a potent antibacterial agent, especially for multidrug resistant Pseudomonas aeruginosa.