• Journal of Microbiology and Biotechnology
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• v.15 no.6
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• pp.1207-1213
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• 2005

In a search for bacteria capable of degrading styrene better than previously isolated strains, bacterium IS-3 was isolated from activated sludge and found to be most closely related to Pseudomonas sp. Styrene degradation by this strain was tested in liquid cultures and polyurethane-packed biofilters. In liquid cultures, the rate of styrene degradation by this bacterium increased from 24.93 to $76.53\;{\mu}mol\;g^{-1}\;DCW\;H^{-1}$ for an initial mass range from 8.7 to $34.8{\mu}mol$. The maximum styrene elimination capacity was 580-635 $g/m^{3}\cdot$h at a space velocity (SV) of 50-200/h. The critical elimination capacities guaranteeing $95\%$ removal of the input styrene were determined to be 635, 170, and 38 $g/m^{3}\cdot$h, respectively, at SVs of 50, 100, and 200/h. Kinetic analysis revealed that the maximum styrene elimination velocity ($V_{m}$) for this biofilter was 1,000 g/m$\cdot$h, and the saturation constant ($K_{m}$) was 454 ppmv. Together, these results suggest that a polyurethane biofilter containing Pseudomonas sp. IS-3 could have potential practical applications for the effective removal of styrene gas.

• Microbiology and Biotechnology Letters
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• v.28 no.1
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• pp.33-38
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• 2000

In order to produce ascorbic acid-2-phosphate from ascorbic acid, bacteria capable of transforming ascorbic acid to ascorbic acid-2-phosphate were isolated from soils and the stock cultures in our laboratory. Among them, a newly isolated bacterium LSH-3 having the best ability of producing ascorbic acid-2-phosphate was selected and partially identified as Pseudomonas sp. The optimum conditions for the production of ascorbic acid-2-phosphate from ascorbic acid and using its resting cells as the source os enzyme were investigated. The results were summarized as follows: The optimum cultivation time and the cell weight for the production of ascorbic acid-2-phosphate was 14 hours and 100g/I(wet weight), respectively. And 0.1%(v/v) Trition X-100 was the most effective surfactant. The optimum concentrations of ascorbic acid and pyrophosphate were 400mM and 500mM, respectively, which led to produce 14.54g/I of ascorbic acid-2-phosphate. The most effective buffer was 50mM sodium acetate. The optimum pH and temperature were 4.5 and $40^{\circ}C$, respectively. Under the above conditions, 17.71 g/I of ascorbic acid-2-phosphate was produced from ascorbic acid after 32 hour-incubation, which corresponded to 17.5% of conversion rate based on ascorbic acid.

• Microbiology and Biotechnology Letters
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• v.23 no.6
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• pp.652-658
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• 1995

We attempted simultaneous expression of genes coding for endoglucanase and $\beta $-glucosidase from Pseudomonas sp. by using a synthetic two-cistron svstem in Escherichia coli and Saccharomyces cerevisiae. Two-cistron system, 5'--tac promoter-endoglucanase gene--$\beta $-glucosidase gene-- 3', 5'-tac promoter--$\beta $-glucosidase gene--endoglucanase gene--3' and 5'-tac promoter--endoglucanase gene--SD sequence--$\beta $-glucosidase gene--3, were constructed, and expressed in E. coli and S. cerevisiae. The E. coli and S. cerevisiae contained two-cistron system produced simultaneously endoglucanase and $\beta $-glucosidase. The recombinant genes contained the bacterial signal peptide sequence produced low level of endoglucanase and $\beta $-glucosidase in S. cerevisiae transformants: Approximately above 44% of two enzymes was localized in the intracellular fraction. The production of endoglucanase and $\beta $-glucosidase in veast was not repressed in the presence of glucose or cellobiose. The veast strain contained recombinant DNA with two genes hydrolyzed carboxvmethyl cellulose, and these endoglucanase and $\beta $-glucosidase degraded CMC synergistically to glucose, cellobiose and oligosaccharide. This result suggests the possibility of the direct bioconversion of cellulose to ethanol by the recombinant yeast.

• Journal of Microbiology and Biotechnology
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• v.12 no.3
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• pp.417-422
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• 2002

Gene fusions were constructed by the transcriptional fusion of the dnaK promoter of pseudomonas sp. DJ-12 or E. coli to the lux or luc marker gene. The dnaKp-DJ::luxCDABE bioluminescent fusion in the biosensor using the Pseudomonas sp. DJ-12 dnaK promoter exhibited about 5-fold more extensive response to ethanol than that of dnaKp-EC::luxCDABE. The bioluminescent response of the dnaK-DJ::luc fusion to ethanol was much weaker than those of the other fusions. The biosensor harboring the dnaKp-DJ::luCDABE fusion was examined for its bioluminescence production based on exposure to aromatic compounds, such as biphenyl, 4-chlorobiphenyl (4CB), 4-hydroxybenzoate (4HBA), and catechol. In particular, the bioluminescence produced by the dnaKp-DJ::luxCDABE fusion was most sensitive to 1 mM biphenyl and 4CB when exposed for 80 min, and the responses were also very strong to other aromatics. Therefore, the biosensor bearing the dnaKp-DJ::luxCDABE fusion would appear to be the most useful for the detection of aromatics and other pollutants.

• Journal of Microbiology and Biotechnology
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• v.5 no.1
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• pp.14-17
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• 1995

Endoglucanase gene of Pseudomonas sp. LBC505 was previously cloned in pUC19 to yield plasmid pLCl. The Pseudomonas sp. LBC505 endoglucanase gene was subcloned in a temperature-regulated Es-cherichia coli expression vector, pAS1, containing the leftward promoter $P_L$ of bacteriophage lambda. The level of gene expression was controlled by the thermal inactivation of the heat-sensitive lambda cI857 repressor. Best yield of endoglucanase was obtained by lowering the incubation temperature to $37^{\circ}C$ after induction at $42^{\circ}C$ for 1h. Under these conditions enzyme production continued for about 5h at a gradually decreasing rate. Ecoli harboring recombinant plasmid pASC10 expressed 4.3 times as much CMCase activity as E.coli containing pLCl. To enhance the expression level of endogl, ucanase gene, we have also changed the presumptive Shine-Dalgamo sequence (AGAGGT) of the gene to consensus sequence (AGGAGGT) by site-directed mutagenesis. The genes mutated were subcloned in pASl resulting in the formation of recombinant plasmid pASS50. E.coli harboring the plasmid pASS50 expressed 6.2-fold higher levels of CMCase activity than that of E.coli harboring pLC1.

• Journal of Microbiology and Biotechnology
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• v.9 no.1
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• pp.56-61
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• 1999

Pseudomonas sp. SW1 grew and produced biosurfactants on 3% hexadecane as the energy and carbon source. As a result of biosurfactant synthesis, the surface tension of the medium was reduced from 72 dyne/cm to 30 dyne/cm. The properties of biosurfactants that were purified from Pseudomonas sp. SW1 were investigated. The purification procedure included acid precipitation from culture supernatant, silica gel G60 column chromatography, and Sephadex G-150 gel filtration. The biosurfactants were separated into two different types, viz., types I and II. Biosurfactant type Isignificantly reduced the surface tension of water from 72 to 27 dyne/cm at concentration levels above 30 mg/l. The surface tension of water was reduced to a minimum of approximately 30 dyne/cm by biosurfactant type II at concentration levels over 80 mg/l. The biosurfactants were effective in a wide range of pHs, at NaCl concentrations of up to 4%, at $CaCl_2$ concentration up to 100 mM, and at temperatures up to $200^{\circ}C$ for 8 h.

• Journal of Microbiology
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• v.34 no.4
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• pp.349-354
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• 1996

Pseudomonas sp. P20 is a natural isolate which is capable of degrading biphenyl and 4-chlorobiphenyl. From a clone of pCK1022 harboring pcbCD genes of Pseudomonas sp P20, a pcbD gene encoding 2-hydroxy-6-oxo-6-phenylhexa-2, 4-dienoic acid (HOPDA) hydrolase was subcloned in Escherichia coli XL-1-Blue by using pBluescript SK(+) vector. The 2.8-kb HindII fragment harboring the pcbD gene cloned in pCK 1024 had a single site for each of XhoI, SalI, BstXI, and XbaI restriction enzymes. Escherichia coli CK1024 had a single site for each of XhoI, SalI, BstXI, and XbaI restriction enzymes. Escherichia coli CK1024 carrying pCK0124 degraded HOPDA to benzoate and 2-hydroxypenta-2, 4-dienoate by HOPDA hydrolase encoded by pcbD gene as effectively as E coli CK 1022 HARBORING pcbCD genes.

• Biotechnology and Bioprocess Engineering:BBE
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• v.6 no.1
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• pp.56-60
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• 2001

The pcbC gene encoding (4-chloro-)2,3-dihydroxybiphenyl dioxygenase was cloned from the genomic DNA of Pseudomonas sp. P20 using pKT230 to construct pKK1. A recombinant strain, E. coli KK1, was selected by transforming the pKK1 into E. coli XL1-Blue. Another recombinant strain, Pseudomonas sp. DJP-120, was obtained by transferring the pKK1 of E. coli KK1 into Pseudomonas sp. DJ-12 by conjugation. Both recombinant strains showed a 23.7 to 26.5 fold increase in the degradation activity to 2,3-dihydroxybiphenyl compared with that of the natural isolate, Pseudomonas sp. DJ-12. The DJP-120 strain showed 24.5, 3.5, and 4.8 fold higher degradation activities to 4-chlorobiphenyl, catechol, and 3-methylcatechol than DJ-12 strain, respectively. The pKK1 plasmid of both strains and their ability to degrade 2,3-dihydroxybiphenyl were stable even after about 1,200 generations.

• Journal of Microbiology and Biotechnology
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• v.5 no.1
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• pp.18-21
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• 1995

Endoglucanase gene of Pseudomonas sp. LBC505 was previously cloned in pUCl9 to yield plasmid pLC1. overproduction of endoglucanase was attempted by following ways. First, the endoglucanase gene of Pseudomonas sp. LBC505 cloned in pUCl9(pLC1) was tandemly inserted, step by step, into a expression vector pKK223-3 in a directly repeated form to enhance productivity of endoglucanase. Escherichia coli containing pKCC30 among the resulting plasm ids showed the higher yield of the endoglucanase. Ecoli harboring pKCC30 which had three inserted endoglucanase genes expressed about 12.3 times as much CMCase activity as Ecoli harboring pLCl. Second, the endoglucanase gene was subcloned into Bacillus subtilis expression vector pgnt41 for both overproduction and extracellular secretion of the endoglucanase. A resulting plasmid pgntc15 in Bacillus subtilis expressed 4.3-fold higher levels of CMCase activity than that of E.coli harboring pLCl and the endoglucanase produced was entirely secreted into the culture medium.

• Korean Journal of Microbiology
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• v.55 no.1
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• pp.83-85
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• 2019

Pseudomonas sp. PAMC 29040 was isolated from a maritime tundra soil in Antarctica for its ability to degrade lignin and subsequently confirmed to be able to depolymerize heterogeneous humic substance (HS), a main component of soil organic matter. The draft genome sequences of PAMC 29040 were analyzed to discover the putative genes for depolymerization of polymeric HS (e.g., dye-decolorizing peroxidase) and catabolic degradation of HS-derived small aromatics (e.g., vanillate O-demethylase). The information on degradative genes will be used to finally propose the HS degradation pathway(s) of soil bacteria inhabiting cold environments.