• Journal of Microbiology
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• v.41 no.4
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• pp.349-352
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• 2003

Recent studies have shown that some of the PCB (polychlorinated biphenyl)-degraders are able to effectively degrade PCB in the presence of monoterpenes, which act as inducers for the degradation pathway. Rhodococcus sp. T104, an effective PCB degrader, has been shown to induce the degradation pathway by utilizing limonenes, cymenes, carvones, and pinenes as sole carbon sources which can be found in the natural environment. Moreover, the strain T104 proved to possess three separate oxidation pathways of limonene, biphenyl, and phenol. Of these three, the limonene can also induce the biphenyl degradation pathway. In this work, we report the presence of three distinct genes for aromatic oxygenase, which are putatively involved in the degradation of aromatic substrates including biphenyl, limonene, and phenol, through PCR amplification and denaturing gradient gel electrophoresis (DGGE). The genes were differentially expressed and well induced by limonene, cymene, and plant extract A compared to biphenyl and/or glucose. This indicates that substrate specificity must be taken into account when biodegradation of the target compounds are facilitated by the plant natural substrates.

• Journal of Microbiology
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• v.40 no.1
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• pp.86-89
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• 2002

Rhodococcus sp. strain T104, which is able to grow on either biphenyl or limonene, was found to utilize phenol as sole carbon and energy sources. Furthermore, T104 was positively identified to possess three separate pathways for the degradation of limonene, phenol, and biphenyl. The fact that biphenyl and limonene induced almost the same amount of catechol 1,2-dioxygenase activity indicates that limonene can induce both upper and lower pathways for biphenyl degradation by T104.

• Journal of Environmental Science International
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• v.19 no.11
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• pp.1391-1396
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• 2010

Three biphenyl-degrading microorganisms were isolated from polluted soil samples in Sasang-gu, Busan. Among them, isolate DS-94 showing the strong degrading activity was selected. The morphological, physiological, and biochemical characteristics of DS-94 were investigated by API 20NE and other tests. This bacterium was identified as the genus Pseudomonas by 16S rDNA sequencing and designated as Pseudomonas sp. DS-94. The optimum temperature and pH for the growth of Pseudomonas sp. DS-94 were $25^{\circ}C$ and pH 7.0, respectively. This isolate could utilize biphenyl as sole source of carbon and energy. Biphenyl-degrading efficiency of this isolate was measured by HPLC analysis. As a result of biological biphenyl-degradation at high biphenyl concentration (500 mg/L), biphenyl-removal efficiency by this isolate was 73.5% for 7 days.

• Journal of Microbiology
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• v.42 no.2
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• pp.160-162
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• 2004

Rhodococcus sp. strain T104 is able to utilize both limonene and biphenyl as growth substrates. Fur-thermore, T104 possesses separate pathways for the degradation of limonene and biphenyl. Previously, we found that a gene(s) involved in limonene degradation was also related to indigo-producing ability. To further corroborate this observation, we have cloned and sequenced a 8,842-bp genomic DNA region with four open reading frames, including one for indole oxygenase, which converts indole to indigo (a blue pigment). The reverse transcription PCR data demonstrated that the identified indole oxygenase gene is specifically induced by limonene, thereby implicating this gene in the degradation of limonene by T104.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.04a
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• pp.28-30
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• 2005

Because of high population diversity in soil microbial communities, it is difficult to accurately assess the capability of biodegradation of toxicant by microbes in soil and sediment. Identifying biodegradative microorganisms is an important step in designing and analyzing soil bioremediation. To remove non-important noise information, it is necessary to selectively enrich genomes of biodegradative microorganisms fromnon-biodegradative populations. For this purpose, a stable isotope probing (SIP) technique was applied in selectively harvesting the genomes of biphenyl-utilizing bacteria from soil microbial communities. Since many biphenyl-using microorganisms are responsible for aerobic PCB degradation In soil and sediments, biphenyl-utilizing bacteria were chosen as the target organisms. In soil microcosms, 13C-biphenyl was added as a selective carbon source for biphenyl users, According to $13C-CO_2$ analysis by GC-MS, 13C-biphenyl mineralization was detected after a 7-day of incubation. The heavy portion of DNA(13C-DNA) was separated from the light portion of DNA (12C-DNA) using equilibrium density gradient ultracentrifuge. Bacterial community structure in the 13C-DNAsample was analyzed by t-RFLP (terminal restriction fragment length polymorphism) method. The t-RFLP result demonstates that the use of SIP efficiently and selectively enriched the genomes of biphenyl degrading bacteria from non-degradative microbes. Furthermore, the bacterial diversity of biphenyl degrading populations was small enough for environmental genomes tools (metagenomics and DNA microarrays) to be used to detect functional (biphenyl degradation) genes from soil microbial communities, which may provide a significant progress in assessing microbial capability of PCB bioremediation in soil and groundwater.

• Journal of Microbiology
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• v.35 no.2
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• pp.141-148
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• 1997

Alcaligenes xylosoxydans strain SMN3 capable of utilizing biphenyl grew not only on phenol, and benzoate, but also on salicylate. Catabolisms of biphenyl and salicylate appear to be interrelated since benzoate is a common metabolic intermediate of these compounds. Enzyme levels in the excatechol 2. 3-dioxygenas which is meta-cleavage enzyme of catechol, but did not induce catechol 1, 2-dioxygenase. All the oxidative enzymes of biphenyl and 2, 3,-dihydroxybiphenyl (23DHBP) were induced when the cells were grown on biphenyl and salicylate, respectively. Biphenyl and salicylate could be a good inducer in the oxidation of biphenyl and 2, 3-dihydroxybiphenyl. The two enzymes for the degradation of biphenyl and salicylate were induced after growth on either biphenyl or salicylate, suggesting the presence of a common regulatory element. However, benzoate could not induce the enzymes responsible for the oxidation of these compounds. Biphenyl and salicylate were good inducers for indigo formation due to the activity of biphenyl dioxygenase. These results suggested that indole oxidation is a property of bacterial dioxygenase that form cis-dihydrodiols from aromatic hydrocarbon including biphenyl.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.489-492
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• 2000

The eventual goal of this study is to elucidate roles of plant terpenoids (e.g., cymene, limonene and others) as natural substrates in the cometabolic biodegradation of PCBs and to develop an effective PCB bioremediation technology. The aim of this study was to examine how plant terpenoids, as natural substrates or inducers would affect the biodegradation of PCB congeners. Various PCB degraders that could grow on biphenyl and several terpenoids were tested for their PCB degradation capabilities. The PCB congener degradation activities were first monitored through resting cell assay technique that could detect degradation products of the substrate. The congener removal was also confirmed by concommitant GC analysis. The PCB degraders, Pseudononas sp. P166 and Caynebacterium sp. T104 were found to grow on both biphenyl and terpenoids ((S)-(-) limonene, p-cymene and ${\alpha}-terpinene$) whereas Arthrobacter B1B could not grow on the terpenoids as a sole carbon source. The strain B1B grown on biphenyl showed a good degradation activity for 4,4'-dichlorobiphenyl (DCBp) while strains P166 and T104 gave about 25% of B1B activity. Induction of degradation by cymene, limonene and terpine was hardly detected by the resting cell assay technique. This appeared to be due to relatively lower induction effect of these terpenoids compared with biphenyl. However, a subsequent GC analysis showed that the congener could be removed up to 30% by the resting cells of T104 grown on the terpenoids. This indicates that terpenoids, widely distributed in nature, could be utilized as both growth and/or inducer substrate for PCB biodegradation.

• Microbiology and Biotechnology Letters
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• v.34 no.2
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• pp.174-179
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• 2006

Bacterium capable of using biphenyl as a sole source of carbon and energy were isolated from soil, and based on the results of 16S rDNA sequence, strain BK10 identified as a Sphingobium yanoiktiyae. The optimum cultural conditions were as follows; $NH_4NO_3$ 1g, $K_2HPO_4$ 1g, $MgSO_4{\cdot}7H_2O$ 0.5g, $CaCO_3$ 0.2 g per 1 liter of distilled water. The Sphingobium yanoikuyae BK10 strain was completely utilized biphenyl in mineral salt media containing biphenyl at concentration 500 $\mu$g/ml of biphenyl as a sole carbon and energy source within 48 hours. Optimumal pH and temperature for biphenyl degradation and cell growth of strains were 6.0$\sim$8.0 and 20$\sim$50$^{\circ}C$, respectively. Especially, at 30$^{\circ}C$, cell-growth were higher than other temperature. Cell grown on biphenyl has been shown to have a higher removal rate for biphenyl than grown on sucrose. This study shows that Sphingobium yanoikuyae BK10 strain had a high biodegradation capability of biphenyl and can be simulate a candidate compounds the bioremediation of PCBs (Polychlorinated biphenyl) contaminant soil and water.

• Journal of Microbiology and Biotechnology
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• v.26 no.11
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• pp.1943-1950
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• 2016

Polycyclic aromatic hydrocarbons (PAHs) are commonly present xenobiotics in natural and contaminated soils. We studied three (phenanthrene, naphthalene, and biphenyl) xenobiotics, catabolism, and associated proteins in Sphingobium chungbukense DJ77 by two-dimensional gel electrophoresis (2-DE) analysis. Comparative analysis of the growth-dependent 2-DE results revealed that the intensity of 10 protein spots changed identically upon exposure to the three xenobiotics. Among the upregulated proteins, five protein spots, which were putative dehydrogenase, dioxygenase, and hydrolase and involved in the catabolic pathway of xenobiotic degradation, were induced. Identification of these major multifunctional proteins allowed us to map the multiple catabolic pathway for phenanthrene, naphthalene, and biphenyl degradation. A part of the initial diverse catabolism was converged into the catechol degradation branch. Detection of intermediates from 2,3-dihydroxy-biphenyl degradation to pyruvate and acetyl-CoA production by LC/MS analysis showed that ring-cleavage products of PAHs entered the tricarboxylic acid cycle, and were mineralized in S. chungbukense DJ77. These results suggest that S. chungbukense DJ77 completely degrades a broad range of PAHs via a multiple catabolic pathway.

• Archives of Pharmacal Research
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• v.24 no.2
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• pp.159-163
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• 2001

The accelerated stability of dimethoxy biphenyl monocarboxylate.HCl (DDB-S) was investigated in 6 mg/mL water solution in the pH ranging 2-10 and the temperature of $45-85^{\circ}C$. The observed rate of degradation followed first-order kinetics. The energy of activation for DDB-S degradation was calculated to be 14.1 and 16.5 $Kcal/mole$ at pH 5 and in distilled watery respectively. The degradation rate constant ($K_{25^{\circ}C}$) obtained by trending line analysis of Arrhenius plots for DDB-S was $5.3{\times}10^{-6}h^{-1}$. The times to degrade 10% ($t_{10}$) and 50% $t_{500}$) at $K_{25^{\circ}C}$ were 829 and 5,416 days, respectively. DDB-S exhibited the fastest degradation at pH 10 and the slowest rate at pH 5. In addition, at $K_{65^{\circ}C}$, degradation rate constants of DDB-S were 0.066, 0.059, 5.460, 32.171, and $1.4{\times}10^{-6}h^{-1}$ at pH 2, 5, 8, 10 and in distilled water, respectively. These observations indicated that the rate-pH profile of DDB-S showed general acid-base catalysis reaction in the range of pH 2-10.