• Journal of Microbiology and Biotechnology
• /
• 제8권6호
• /
• pp.692-695
• /
• 1998

Pseudomonas sp. DJ-12 was able to degrade 4-chlorobenzoate by hydrolytic dechlorination to produce 4-hydroxybenzoate and chloride ion. The fcbABC genes responsible for the hydrolytic dechlorination were cloned from the chromosomal DNA of the organism. The genes were found to be organized in the order fcbB-fcbA-fcbC, but there was an intergenic space between the fcbA and fcbC genes.

• Biotechnology and Bioprocess Engineering:BBE
• /
• 제5권6호
• /
• pp.449-455
• /
• 2000

Pseudomonas sp. strain DJ-12 is a bacterial isolate capable of degrading 4-chlorobiphenyl (4CBP) as a carbon and energy source. The catabolic degradation of 4CBP by the strain DJ-12 was studied along with the genetic organization of the genes responsible for the crucial steps of the catabolic degradation. The catabolic pathway was characterized as being conducted by consecutive reactions of the meta-cleavage of 4CBP, hydrolytic dechlorination of 4-chlorobenzoate (4CBA), hydroxylation of 4-hydroxybenzoate, and meta-cleavage of protocatechuate. The pcbC gene responsible for the meta-cleavage of 4CBP only showed a 30 to 40% homology in its deduced amino acid sequence compared to those of the corresponding genes from other strains. The amino acid sequence of 4CBA-CoA dechlorinase showed an 86% homology with that of Pseudomonas sp. CBS3, yet only a 50% homology with that of Arthrobacter spp. However, the fcb genes for the hydrolytic dechlorination of 4CBA in Pseudomonas sp. DJ-12 showed an uniquely different organization from those of CBS3 and other reported strains. Accordingly, these results indicate that strain DJ-12 can degrade 4CBA completely via meta-cleavage and hydrolytic dechlorination using enzymes that are uniquely different in their amino acid sequences from those of other bacterial strains with the same degradation activities.

• Journal of Microbiology
• /
• 제41권4호
• /
• pp.277-283
• /
• 2003

Haloaliphatic hydrocarbons have been widely used as solvents and ingredients of pesticides and herbicides. However, when these compounds contaminate the environment, they can be very hazardous to animals and humans because of their potential toxicity and carcinogenicity. Therefore, lots of studies have been made for microbial degradation of those pollutant chemicals. In this study, 11 bacterial strains capable of degrading 1,2-dichloroethane (1,2-DCA), 2-chloropropionic acid (2-CPA), 2,3-dichloropropionic acid (2,3-DCPA), and 2-monochloroacetic acid (2-MCA) by hydrolytic dechlorination under aerobic conditions were isolated from wastewaters and rice paddy soil samples. Their morphological and biochemical characteristics and their degradation capabilities of haloaliphatic hydrocarbons were examined. On the basis of the 16S rDNA sequences, 8 different kinds of microbial species, including Pseudomonas plecoglossicida, Xanthobacter flavus, Ralstonia eutropha, were identified. All of the isolated strains can degrade MCA. In particular, strains UE-2 and UE-15 degraded 1,2-DCA, and strain CA-11 degraded 2,3-DCPA, which are hardly degraded by other strains.

• Journal of Microbiology
• /
• 제35권4호
• /
• pp.290-294
• /
• 1997

4-Chlorobiphenyl-degrading Pseudomonas sp. DJ-12 was able to degrade 4-chlorobenzoate(4CBA), 4-iodobenzoate, and 4-bromobenzoate completely under aerobic conditions. During. the degradation of 4CBA by Pseudomonas sp. DJ-12, chloride ions were released by dechlorination and 4-hydroxybenzoate was produced as an intermediate metabolite. The NotI-KNA fragments of pKC157 containing dechlorination genes hybridized with the gene encoding 4CBA:CoA dehalogenase of Pseudomonas sp. CBS3 which is responsible for the hydrolytic dechlorination of 4CBA. These results imply that Pseudomonas sp. DJ-12 degrades 4CBA to 40hydroxybenzoate via dechlorination as the initial step of its degradativ pathway. The genes responsible for dechlorination of 4CBA were found to be blcated on the chromosomal DNA of Pseudomonas sp. DJ-12.

• 한국미생물학회:학술대회논문집
• /
• 한국미생물학회 2000년도 International Meeting 2000
• /
• pp.66-72
• /
• 2000

• 한국동물학회:학술대회논문집
• /
• 한국동물학회 1998년도 한국생물과학협회 학술발표대회
• /
• pp.325.1-325
• /
• 1998

No Abstract, See Full Text

• Journal of Microbiology
• /
• 제41권2호
• /
• pp.89-94
• /
• 2003

Bacterial strain No. P08 isolated from wastewater at the Cheongju industrial complex was found to be capable of degrading 4-chlorobenzoate under aerobic condition. P08 was identified as Comamonas sp. from its cellular fatty acid composition and 16S rDNA sequence. The fcb genes, responsible for the hydrolytic dechlorination of 4-chlorobenzoate, were cloned from the plasmid pJJl of Comamonas sp. P08. The fcb gene cluster of comamonas sp. PO8 was organized in the order fcbB-fcbA-fcbTl-fcbT2-fcbT3-fcbC. This organization of the fcb genes was very similar to that of the fcb genes carried on the chromosomal DNA of pseudomonas sp. DJ-12. However, it differed from the fcbA-fcbB -fcbC ordering of Arthrobacter sp. SU. The nucleotide sequences of the fcbABC genes of strain P08 showed 98% and 53% identities to those of Pseudomonas sp. DJ-12 and Arthrobacter sp. SU, respectively. This suggests that the fcb genes might have been derived from Pseudomonas sp. DJ-12 to form plasmid pJSl in Comamonas sp. P08, or that the fcb genes in strain DJ-12 were transposed from Comamonas sp. P08 plasmid.

• 한국동물학회:학술대회논문집
• /
• 한국동물학회 1999년도 한국생물과학협회 학술발표대회
• /
• pp.278.2-278
• /
• 1999

No Abstract, See Full Text

• 환경생물
• /
• 제17권2호
• /
• pp.129-138
• /
• 1999

난분해성 유기화합물의 일종인 염화 방향족화합물은 냉각제, 소화제, 페인트, 용매, 플라스틱류, 유압제, 제초제, 농약, 그리고 화학합성에 필요한 전구물질 등에 널리 사용된다. 이들은 친지질 특성을 가지므로 생물체의 세포막에 쉽게 흡착되며 먹이사슬에 의한 생물학적 농축과정을 통해 인간을 포함하는 각종 생물체에 축적된다. 그 결과 생물체의 세포막 구조가 변화되고 기능이 저해될 뿐더러 암과 돌연변이를 유발하고 $\ulcorner$환경호르몬$\lrcorner$으로서 생물체의 내분비계 기능을 교란하는 등 심각한 보건학적 그리고 환경생물학적 문제를 일으키고 있다. 염화 방향족화합물들은 벤젠고리 구조와 벤젠고리에 염소가 치환된 탄소-염소 결합을 공통적으로 가지고 있으며 벤젠고리에 치환된 염소의 수와 같은 수의 염소라도 붙어있는 위치에 따라 난분해 특징이 결정된다. 염화 방향족화합물들의 분해를 위해서는 미생물에 의한 벤젠 구조의 개환과정과 함께 벤젠 고리구조로부터 염소 치환기를 제거하는 탈염소화 과정이 반드시 일어나야만 한다. 호기적 환경에서 미생물에 의한 탈염소화는 분해 초기단계에서 dehalogenase라는 효소에 의해 촉매되는 oxygenolytic, reductive, 그리고 hydrolytic catalysis에 의해 일어나거나, 분해 대사과정 중에 저절로 염소치환기가 떨어져 나가는 경우도 있다. 탈염소화 과정을 거쳐 분해하는 미생물들을 이용한 염화 방향족 오염물질의 생물학적 분해방법은 이미 사용되고 있는 물리ㆍ화학적 방법보다 경제적이며 2차 오염의 부작용 없이 그 오염물질들을 매우 효과적으로 처리할 수 있다. 따라서 탈염소화 기작을 포함한 분해과정의 이해는 생물학적 분해의 기본적인 정보를 제공할 뿐더러 난분해성 환경 오염물질의 분해처리를 위하여 보다 집중적으로 연구해야 할 과제라고 할 것이다.

• Journal of Microbiology
• /
• 제42권3호
• /
• pp.188-193
• /
• 2004

Xanthobacter flavus strain UE15 was isolated in wastewater obtained from the Ulsan industrial complex, Korea. This strain functions as a 1,2-dichloroethane (1,2-DCA) degrader, via a mechanism of hydrolytic dechlorination, under aerobic conditions. The UE15 strain was also capable of dechlorinating other chloroaliphatics such as 2-chloroacetic acid and 2-chloropropionic acid. The dhlA gene encoding 1,2-DCA dechlorinase was cloned from the genomic DNA of the UE15 strain, and its nucleotide sequence was determined to consist of 933 base pairs. The deduced amino acid sequence of the DhlA dechlorinase exhibited 100％ homology with the corresponding enzyme from X. autotrophicus GJ10, but only 27 to 29％ homology with the corresponding enzymes from Rhodococcus rhodochrous, Pseudomonas pavonaceae, and Mycobacterium sp. strain GP1, which all dechlorinate haloalkane compounds. The UE15 strain has an ORF1 (1,356 bp) downstream from the dhlA gene. The OFR1 shows 99％ amino acid sequence homology with the transposase reported from X. autotrophicus GJ10. The transposase gene was not found in the vicinity of the dhlA in the GJ10 strain, but rather beside the dhlB gene coding for haloacid dechlorinase. The dhlA and dhlB genes were confirmed to be located at separate chromosomal loci in the Xanthobacter flavus UE15 strain as well as in X. autotrophicus GJ10. The dhlA and transposase the UE15 strain were found to be parenthesized by a pair of insertion sequences, 181247, which were also found on both sides of the transposase gene in the GJ10 strain. This unique structure of the dhlA gene organization in X. flavus strain UE15 suggested that the dechlorinase gene, dhlA, is transferred with the help of the transposase gene.