• Journal of Microbiology and Biotechnology
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• 제20권10호
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• pp.1440-1445
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• 2010

Rhodococcus sp. JDC-11, capable of utilizing di-n-butyl phthalate (DBP) as the sole source of carbon and energy, was isolated from sewage sludge and confirmed mainly based on 16S rRNA gene sequence analysis. The optimum pH, temperature, and agitation rate for DBP degradation by Rhodococcus sp. JDC-11 were 8.0, $30^{\circ}C$, and 175 rpm, respectively. In addition, low concentrations of glucose were found to inhibit the degradation of DBP, whereas high concentrations of glucose increased its degradation. Meanwhile, a substrate utilization test showed that JDC-11 was also able to utilize other phthalates. The major metabolites of DBP degradation were identified as monobutyl phthalate and phthalic acid by gas chromatography-mass spectrometry, allowing speculation on the tentative metabolic pathway of DBP degradation by Rhodococcus sp. JDC-11. Using a set of new degenerate primers, a partial sequence of the 3,4-phthalate dioxygenase gene was obtained from JDC-11. Moreover, a sequence analysis revealed that the phthalate dioxygenase gene of JDC-11 was highly homologous to the large subunit of the phthalate dioxygenase from Rhodococcus coprophilus strain G9.

• Journal of Microbiology
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• 제40권1호
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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 Microbiology
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• 제43권1호
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• pp.49-53
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• 2005

Putative genes for a two-component signal transduction system (akbS and akbT) were detected near the alkylbenzene-degrading operon of Rhodococcus sp. DK17. Sequence analysis indicates that AkbS possesses potential ATP-binding and histidine autophosphorylation sites in the N- and C-terminal regions, respectively, and that AkbT has a typical response regulator domain. Mutant analysis combined with RT-PCR experiments further shows that AkbS is required to induce the expression of o-xylene dioxygenase in DK17.

• Journal of Microbiology
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• 제42권2호
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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.

• Journal of Microbiology and Biotechnology
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• 제15권6호
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• pp.1189-1196
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• 2005

The cyclohexanol dehydrogenase (ChnA), produced by Rhodococcus sp. TK6, which is capable of growth on cyclohexanol as the sole carbon source, has been previously purified and characterized. However, the current study cloned the complete gene (chnA) for ChnA and its flanking regions using a combination of a polymerase chain reaction (PCR) based on the N-terminal amino acid sequence of the purified ChnA and plaque hybridization from a phage library of Rhodococcus sp. TK6. A sequence analysis of the 5,965-bp DNA fragment revealed five potential open reading frames (ORFs) designated as partial pte (phosphotriesterase), acs (acyl-CoA synthetase), scd (short chain dehydrogenase), stp (sugar transporter), and chnA (cyclohexanol dehydrogenase), respectively. The deduced amino acid sequence of the chnA gene exhibited a similarity of up to $53\%$ with members of the short-chain dehydrogenase/reductase (SDR) family. The chnA gene was expressed using the pET21 a(+) system in Escherichia coli. The activity of the expressed ChnA was then confirmed (13.6 U/mg of protein) and its properties investigated.

• 한국미생물·생명공학회지
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• 제37권3호
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• pp.243-247
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• 2009

The usage of ethanol (EtOH)-blended gasoline (gasohol), has been increasing in recent years. EtOH has influence on the distribution and biodegradation of aromatic compounds such as BTEX (benzene (B), toluene (T), ethylbenzene (B), and xylene (X)) that are gasoline compositions. In this study, the effect of EtOH on the aerobic biodegradation of B, T and E was investigated using a BTEX and EtOH-degrading bacterium, Rhodococcus sp. EH831. The degradation rates of B in the conditions of 1:1, 1:4, and 1:0.25 mixtures with EtOH (B:EtOH, mol:mol) were ranged from $3.82{\pm}0.20$ to $5.00{\pm}0.37{\mu}mol{\cdot}g-dry$ cell wight $(DCW)^{-1}{\cdot}h^{-1}$. The degradation rate of T was the fastest in the 1:0.25 mixture ($6.63{\pm}0.06{\mu}mol{\cdot}g-DCW^{-1}{\cdot}h^{-1}$), and it was the lowest in the 1:4 mixture ($4.41{\pm}0.04{\mu}mol{\cdot}DCW^{-1}{\cdot}h^{-1}$). The degradation rates of E were increased with increasing the addition amount of EtOH: The degradation rate of E was the highest in the 1:4 mixture ($1.60{\pm}0.03{\mu}mol{\cdot}g-DCW^{-1}{\cdot}h^{-1}$), and the rates were $1.42{\pm}0.06$, $1.30{\pm}0.01$, and $1.01{\pm}0.30{\mu}mol{\cdot}g-DCW^{-1}{\cdot}h^{-1}$ in the 1:1, 1:0.25, 1.0 mixtures, respectively. In conclusion, the biodegradation of B, T, E by Rhodococcus sp. EH831 was not significantly inhibited by the co-existence of EtOH.

• KSBB Journal
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• 제13권2호
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• pp.195-202
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• 1998

Rhodococcus sp. 3T6-5Mj 균주의 배양액으로부터 0.2${\mu}m$ membrane filter을 통과시키고, 아세톤 침전, DEAE-Sephadex A-50 column chromatography의 약음이온 교환수지,cholesterol affinity column chromatography를 통과시켜서 콜레스테롤 산화 효소를 25.6units/mg의 비활성도, 15%의 회수율,88배로 정제할 수 있었다. 본 균주가 생산하는 콜레스테롤산화효소의 분자량은 SDS-PAGE로 측정한 결과 약,52,000 daltons 정도로 추정되었다. 그리고 이 효소의 Km값은 콜레스테롤을 기질로 측정하였을 때 $3.2{\times}10^{-4}M$ 이었다. 본 효소의 최적온도는 $50^{\circ}C$최적 pH는 7.0으로 나타났으며, 열에 대한 안정성은 30~$45^{\circ}C$,pH에 대한 안정성은 6.5~11.0으로 나타났다. 본 효소는 cholesterol, campesterol, stigmasterol, hecogenin, $\beta$m-sistosterol의 기질에 특이성을 나타내었다. 본 효소의 아미노산 440개의 잔기로 이루어져 있으며,그 아미노산 조성은 aspararine/aspartate > glutamine/glutamate > proline > alaline > histidine 의 순으로 나타났다. 본 효소는 효소적 혈중 콜레스테롤의 측정방법에 필수적인 콜레스테롤 산화 효소의 이용 가능성을 보여 주었다.용 가능성을 보여 주었다.

• KSBB Journal
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• 제16권1호
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• pp.61-65
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• 2001

BTX를 배출하는 지역에서 얻어진 슬러지를 적절한 배지에 3개월 간 적응시킨 결과, benzene과 toluene을 빠르게 분해하는 MY컨소시엄와 p-, m-, o-xylene을 빠르게 분해하는 MA컨소시엄을 획득하였다. 균주의 동정결과 MA 및 MA컨소시엄의 주된 균주는 Rhodococcus ruber DSM 43338T과 Rhodococcus sp.로 밝혀졌다. BTX 단일성분의 분해속도 측정결과 benzene > toluene > o-xylene > p-xylene > m-xylene의 순으로 분해가 일어났다. MY 및 MY컨소시엄으 동시배양을 이용한 2-5종의 복합 BTX의 분해실험결과 대부분의 경우 108시간내에 완전히 분해되었으며, 각 혼합물의 조성에 따라 촉진 및 방해작용을 나타내었다. 분 연구에서 획득한 2종의 미생물컨소시엄은 BTX의 생물학적 처리에 매우 유용하게 사용될 수 있을 것으로 사료된다.

• 한국미생물·생명공학회지
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• 제27권2호
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• pp.124-128
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• 1999

TK6 was able to produce NAD+ dependent cyclohexanol dehydrogenase(CDH). The production of CDH was increased rapidly at the logarithmic phase and maintained constantly after that. In order to investigate the inductive production of CDH by various substrates, the bacteria were grown in the media containing alicyclic hydrocarbons and various alcohols as a sole crabon souce. CDH was induced most actively by cyclohexanol. Cyclohexanone and cyclohexane-1,2-diol also induced remarkable amount of CDH but it was induced weakly by 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 2-propanol, and 2-methyl-1-propanol. The dehydrogenase of the bacteria grown in the media containing cyclohexanol were weakly active for various alcohols, but the dehydrogenase activity for cyclohexane-1,2-diol was twice as much as that for cyclohexanol. Activity staining on PAGE of the cell free extract of Rhodococcus sp. TK6 grown in the media containing cyclohexanol reveals at least sever isozyme bands of CDH and we nominated the four major activity bands as CDH I, II, III, and IV. CDH I was strongly induced by cyclohexanol, cyclohexane-1,2-diok, but its activity was specific to cyclohexane-1,2-diol and 1-pentanol. CDH IV was strongly induced by cyclohexanol and cyclohexane-1,2-diol, and its activity was very specific to cyclohexane-1,2-diol.

• Journal of Microbiology and Biotechnology
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• 제16권4호
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• pp.511-518
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• 2006

A gene cluster for cyclohexanone oxidation was cloned from Rhodococcus sp. TK6, which is capable of growth on cyclohexanone as the sole carbon source. The 9,185-bp DNA sequence analysis revealed seven potential open reading frames (ORFs), designated as ssd-chnR-chnD-chnC-chnB-chnE-partial pcd. The chnBCDE genes encode enzymes for the four-step conversion of cyclohexanone to adipic acid, catalyzed by cyclohexanone monooxygenase (ChnB), $\varepsilon-caprolactone$ hydrolase (ChnC), 6-hydroxyhexanoate dehydrogenase (ChnD), and 6-oxohexanoate dehydrogenase (ChnE). Furthermore, the presence of a regulatory element in the downstream region of the chnD gene supports the notion that chnR is a putative regulatory gene. Among them, the activity of ChnB was confirmed and characterized, following their expression and purification in Escherichia coli harboring the modified chnB gene (chnB gene with 6 successive codons for His at the 3' terminus).