• Journal of Applied Biological Chemistry
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• v.43 no.1
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• pp.44-48
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• 2000

Burkholderia cepacia strain G4 (pHG-2) containing toluene 2-monooxygenase and toluene dioxygenase, was able to grow on toluene and accumulate cis-3-methyl-3,5-cyclohexadien-1,2-diol (cis-toluene dihydrodiol) in the liquid culture. The cis-toluene dihydrodiol produced was identical to the authentic compound, as judged through mass spectrometry and nuclear magnetic resonance analysis. Our results indicate that pHG-2 provides an economical means to produce chemically-important chiral synthons while growing on toluene.

• KSBB Journal
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• v.15 no.5
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• pp.474-481
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• 2000

The effects of growth substrates such as toluene and phenol on cometabolic biodegradation of trichloroethylene (TCE) by Burkholderia cepacia G4 were investigated. The dual effects of primary substrate on TCE biodegradation, stimulatory effects of toluene and phenol at low concentrations (0.5∼2 ppm & 0.1∼0.5 ppm, respectively) and a competitive inhibition at high concentration, were observed in batch experiments. These stimulatory effects of toluene and phenol were found to be due to the increments in the amount of reducing power like NADH which could be generated during the assimilation of toluene and phenol as the carbon and energy source. The efficiency of TCE biodegradation in trickling biofilm reactor (TBR) could be also enhanced up to the TCE removal efficiency of 58.1% by the supply of appropriate amounts of phenol (0.94∼4.7 ppm).

• Microbiology and Biotechnology Letters
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• v.31 no.4
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• pp.421-428
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• 2003

To develop the functional-compost containing antifungal substance by using antagonistic microorganisms, Spinacia oleracea L and Rhizoctonia solani Kuhn O-28 were used as a model plant and phytopathogen, respectively. Total 80 strains were isolated from the compost of various waste foods mixture processed for a year. Among them, No.15-2 strain was selected due to its highest antifungal activity against R. solani Kuhn O-28 and was identified phyno- and phylogenotypically as Burkholderia cepacia genomovar V. which is rare probability in pathogen, by 16S rDNA sequencing and specific primer pair PCR method. B. cepacia No.15-2 preferentially dominated during the compost and its cell numbers were maintained almost $${\times}$10^{13}$ cuf/g for 15 days. The morbidity caused by R. solani Kuhn O-28 in S. oleracea L cultivation was reduced to 40% by addition of B. cepacia No.15-2. In conclusion, the antifungal compost using B. cepacia No.15-2 could be applied to biocontrol of various crops blights caused by fungal pathogen.

• KSBB Journal
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• v.13 no.5
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• pp.561-568
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• 1998

Two cometabolic trichloroethylene (TC) degraders, Pseudomonas putida F1 and Burkholderia (Pseudomonas) cepacia G4, were found to catabolize phenol, benzene, toluene, and ethylbenzene as carbon and energy sources. Resting cells of P. putida F1 and B. cepacia G4 grown in the presence of toluene and phenol, respectively, were able to degrade not only benzene, toluene and ethylenzene but also TCE and p-xylene. However, these two strains grown in the absence of toluene or phenol did not degrade TCE and p-xylene. Therefore, it was tentatively concluded that cometabolic degradation of TC and p-xylene was mediated by toluene dioxygenase (P. putida F1) or toluene-2-monooxygenase (B. cepacia G4). Maximal degradation rates of BTEX and TCE by toluene- and phenol-induced resting cells of P. putida F1 and B. cepacia G4 were appeared to be 4-530 nmol/(min$.$mg cell protein) when a single compound was solely served as a target substrate. In case of double substrates, the benzene degradation rate by P. putida F1 in the presence of toluene was decreased up to one seventh of that for the single substrate. TCE degradation rate was also linearly decreased as toluene concentration increased. On the other hand, toluene degradation rate was enhanced by benzene and TCE. For B. cepacia G4, degradation rates of TCE and toluene increased 4 times in the presence of 50 ${\mu}$M phenol. From these results, it was concluded that a degradation rate of a compound in the presence of another cosubstrate(s) could not be predicted by simply generalizing antagonistic or synergistic interactions between substrates.

• KSBB Journal
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• v.16 no.5
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• pp.511-515
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• 2001

In this paper, we development and operated a two-stage continuous stirred tank reactor (CSTR)/trickling biofilter(TBF)system for the long-term continuous treatment of trichloroethylene (TCE) using Burkholderia cepacia G4. In this reactor system. CDTR with cell recycle from TBF was coupled to the TBF for the reactivation of the cells deactivated during TCE degradation. The critical elimination capacity was determined to be 25.3 mg TCE/L day and the reactor has been stably operated for more than 1 months, which clearly represented that CSTR/TBF system can be used for long-term treatment of TCE.

• Journal of Microbiology and Biotechnology
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• v.11 no.5
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• pp.804-811
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• 2001

In many Gram-negative bacteria, autoinducers, such as N-acyl-L-homoserine lactone(acyl-HSL) and its derivative molecules, mediate the cell-density-dependnet expression of certain operons. The current study identified the autoinducers produced by Burkholderia cepacia G4, a trichloroethylene-degrading lagoon isolate, using TLC bioassays with Agrobacterium tumefaciens NT1(pDCI141E33) and Chromobacterium violaceum CVO26, and a GC-MS analysis. The ${R_f}\;and\;{R_t}$ values and mass spectra were compared with those of synthetic compounds. Based on the analyses, it was confirmed that G4 produces N-hexanoyl (C6)-, N-octanoyl (C8)-, N-decanoyl (C10)-, N-dodecanoyl (C12)-HSL, and an unknown active species. The integration of the GC peak areas exhibited a ratio of C8-HSL:C10-HSL:C12-HSL at 3:17:1 with C6-HSL and C10-HSL production at trace and micromolar levels, respectively, in the culture supernatants. Nutants partially defective in producing acyl-HSLs were also partially defective in the biosynthesis of an antibiotic substance. These results indicate that the autoinducer-dependent gene regulation in G4 is dissimilar to the clinical B. cepacia strains isolated from patients with cystic fibrosis.

• Archives of Pharmacal Research
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• v.27 no.5
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• pp.570-575
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• 2004

2-Hydroxymuconic semialdehyde (2-HMS) dehydrogenase catalyzes the conversion of 2-HMS to 4-oxalocrotonate, which is a step in the meta cleavage pathway of aromatic hydrocarbons in bacteria. A tomC gene that encodes 2-HMS dehydrogenase of Burkholderia cepacia G4, a soil bacterium that can grow on toluene, cresol, phenol, or benzene, was overexpressed into E. coli HB 101, and its gene product was characterized in this study. 2-HMS dehydrogenase from B. cepacia G4 has a high catalytic efficiency in terms of V$_{max}$K$_{max}$ towards 2-hydroxy-5-methyl-muconic semialdehyde followed by 2-HMS but has a very low efficiency for 5-chloro-2-hydroxymuconic semialdehyde. However, the enzyme did not utilize 2-hydroxy-6-oxo-hepta 2,4-dienoic acid and 2-hydroxy-6-oxo-6-phenylhexa-2,4-dienoic acid as substrates. The molecular weight of 2-HMS dehydrogenase from B. cepacia G4 was predicted to be 52 kDa containing 485 amino acid residues from the nucleotide sequence of the tomC gene, and it exhibited the highest identity of 78% with the amino acid sequence of 2-HMS dehydrogenase that is encoded in the aphC gene of Comamonas testosteroni TA441. 2-HMS dehydrogenase from B. cepacia G4 showed a significant phylogenetic relationship not only with other 2-HMS dehydrogenases, but also with different dehydrogenases from evolutionarily distant organisms.sms.

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.218.2-219
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• 2003

2-Hydroxymuconic semialdehyde dehydrogenase catalyzes the conversion of 2-hydroxymuconic semialdehyde (HMS) to an enol form of 4-oxalocrotonate which is a step in the catechol-meta cleavage pathway. A tomC gene encoding 2-HMS dehydrogenase of Burkholderia cepacia G4, a soil bacterium that can grow on toluene, cresol, phenol or tricholoro ethylene, is identified in between catechol 2,3-dioxygenase gene and HMS hydrolase gene, its sequence is analysed and the enzyme is characterised. (omitted)

• KSBB Journal
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• v.16 no.5
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• pp.466-473
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• 2001

A bacterium was isolated from soils in Suwon, Korea for the purpose of H$_2$S removal using a biofilter system. The isolate was gram-negative, rod-shaped, catalase-positive, motile, and the isolated bacterium showed a positve in utilizing energy sources including citrate, mannitol, sucrose, fructors, and trehalsoe. Based on its biochemical characteristics it was identified as Burkholderia(Pseudomonas) cepacia. The growth rate of the bacterium in thiosulfate medium with yeast extract was 0.15 hr$\^$-1/ and generation time was 4.6 hr. The cell productivity was 8.05 mg/L$.$h and the isolate grew logarithmically up to 12 hr. The maximum rate of sulfur oxidation was 0.18 g-S/L$.$h. The optimum pH and temperature for the growth of the bacterium were 7.0 and 30$\^{C}$, respectively. The pH range for the growth of B. cepacia was 5.0-8.0. The oxidation rate of thiosulfate was lowered by a substrate thiosulfate when the concentration was higher than 0.12 M. both growth rate and sulfur oxidation rate of Burkholderia(Pseudomonas) cepacia was enhanced about 1.5 times with the addition of 0.2% yeast extract. The removal of hydrogen sulfide was investigated by immobilized B. cepacia with Ca-alginate. The maximum rate removal for H$_2$S was 6.25 g$.$㎤ $.$h$\^$-1/ when 12 L/h of flow rate was supplied. From this study suggest the immobilized B. cepacia could have a potential for H$_2$S removal.

• KSBB Journal
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• v.15 no.4
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• pp.393-397
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• 2000

The cometaboic biodegradation conditionso f trichloroethylene(TCE) by Burkholderia cepacia G4 were optimized using response surface analysis. The experimental sets of phenol concentration temperature and pH were designed using central composite experimental design. The optimal conditions of phenol concentration temperature and pH were determined to be 0.91 ppm 21.5$^{\circ}C$ and 7.65 respectively by the Ridge analysis of the contour plot for TCE biodegradation rates. The TCE biodegradation rate could be enhanced up to 2.43 nmol.mg protein$.$min by response surface methodology.