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

• KSBB Journal
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• 제13권3호
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• pp.223-230
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• 1998

Experiments for lignin peroxidase production have been conducted by aerobic fermentation of Phanerochaete chrysosporium under low shear rate and enriched oxygen environment. The result of flask cultures of white rot fungus indicated that high oxygen concentration and low shear force were essential for enhancement of lignin peroxidase production. Pentachlorophenol was readily degraded by lignin peroxidase produced in nutrient limited flask cultures. Polyurethane foam was fond to be an effective immobilization matrix of P. chrysosporium.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 추계학술발표회
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• pp.454-457
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• 2003

A new approach for groundwater treatment combines a permeable Fe(0) barrier to breakdown higher chlorinated solvents like PCE and TCE with a downgradient aerobic biological treatment system to biotransform less chlorinated solvents, such as DCE and vinyl chloride (VC). The expected bacterial performance downgradient of an Fe(0) barrier was evaluated through laboratory batch experiments with a toluene-degrading mixed culture that cometabolically transforms cis-1,2-DCE and VC. The amount of cis-1,2-DCE (initially at 2,000 ppb) and VC (initially at 2,000 ppb) transformed was controlled by the initial toluene (20,000 ppb) concentration. VC was removed much more effectively than Cis-1,2-DCE, and a higher toluene concentration in comparison to the co-substrate concentrations was needed for complete co-substrate removal. Overall, the coupling of an Fe(0) barrier and subsequent biodegradation appears feasible for remediation of complex mixtures of chlorinated solvents and petroleum hydrocarbons in groundwater

• Journal of Microbiology and Biotechnology
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• 제21권3호
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• pp.252-255
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• 2011

Both Escherichia coli (E. coli) and Salmonella enterica serovar Typhimurium (S. Typhimurium) have a tdc operon that encodes enzymes involved in a metabolic pathway for the degradation of L-serine and L-threonine. However, S. Typhimurium does not have the tdcR gene, which is a positive regulator in E. coli. In the present study, transcriptional analysis revealed that tdcA expression in E. coli is higher under anaerobic than aerobic growth conditions, but the opposite is true in S. Typhimurium. Interestingly, a tdcR mutant strain of E. coli showed a similar expression pattern to that observed in S. Typhimurium and was also induced by anaerobic shock. These results suggest that the induction of tdcA expression by anaerobic conditions is observable when tdcA expression is low owing to the absence of TdcR.

• Journal of Microbiology and Biotechnology
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• 제10권5호
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• pp.724-727
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• 2000

A Phenanthrene-degrading bacterium, Strain 1-21 was isolated from oil-contaminated soil. This strain was a Gram-negative, aerobic, and rod-shaped bacterium, and exhibited a 99% sequence similarity of 16S rDNA to that of Sphingomonas subarctica. The major cellular fatty acid was a summed feature 7(18:1 w7c, 18:1 w9t, 18:1 s12t), which is a characteristic of the Sphingomonas species. When 200 and 1,000 ppm of phenanthrene was added as the sole carbon source, Strain 1-21 degraded 98% and 67% after 10 days of incubation, respectively. Futhermore, this strain was also able to utilized naphthalene and fluorene as sole carbon and energy sources.

• 한국미생물·생명공학회지
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• 제25권1호
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• pp.89-95
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• 1997

The current processer of the textile wastewater treatment are mostly consisted of a combination of a physico-chemical and a biological treatment. The overall efficiency of these processes is, however, assessed to be fairly low. It is even worse during the summer season when temperature of the wastewater rises above 40$\circ $C. Therefore, a feasible process of the textile wastewater treatment which can work efficiently at higher temperatures was investigated in this work. We used a bench scale reactor consisted of one 4 liter anaerobic and one 8 liter aerobic tank, and the thermophilic symbiotic PVA degraders, Pasteruella hemolytica KMG1 and Pseudomonas sp. KMG6 that had been isolated in our laboratory. In the preliminary flask experiments, we observed that the thermophilic symbiotic PVA degraders could not grow in the wastewater substrate. Then, we isolated the mutant strains by acclimating the KMG1and KMG6 strains to the wastewater medium. The mutant symbionts (KMG1-1 and KMG6-1) were isolated through 6 times successive transfers into the fresh wastewater medium after 5 days culture for each. The mutant strains obtained grew well in the mixed medium composed of 75% wastewater and 25% synthetic medium, and supplemented with 0.5% PVA as a sole carbon source. During the culture for 14 days at pH 7.0 and 40$\CIRC $C, the bacteria assimilated about 89% of the added PVA. The symbionts degraded equally well all the PVA substrates of different molecular weight (nd=500~30000). In contrast to the flask experiments, in the reactor system the mutant strains showed very low levels of the PVA and COD removal rates. However, the new reactor system with an additional aerobic tank attained 82% removal rate of COD, 94% of PVA degradation and 71% of color index under the conditions of 5% inoculm on the tank 2, incubation temperature of 40$\circ $C, dissolved oxygen level of 2~3 mg/l and retention time of 30 hours. This result ensures that the process described above could be an efficient and feasible treatment for the PVA contained textile wastewater at higher temperatures.

• Applied Biological Chemistry
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• 제25권2호
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• pp.93-98
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• 1982

농약의 사용량이 급격히 증가함에 따른 농약의 자연 환경에 미치는 영향을 살펴보고 농약의 안전성 평가에 관한 연구방법을 정립하기 위하여 우리나라에서 많이 쓰이고 있는 수도용농약중 살균제인 후치왕(Fujione, Isoprothiolane)과 살충제인 오트란(Ortran, Acephate)의 토양에서의 잔류성과 수도작물에의 잔류성에 대해 포장실험 및 실험실적 방법으로 조사하였다. 벼, 볏짚, 현미 및 백미에서의 농약의 잔류 또는 농약의 처리된 횟수에 따라 다르게 나타났는데 후치왕의 경우 백미중 농약 함양은 $0.07{\sim}0.09ppm$ 이었고 오트란은 $0.01{\sim}0.53ppm$이었다. 또한 후치왕의 반감기는 실험실적인 방법으로 호기조건하에서 30일, 담수조건하에서 150일인데 반해 포장에서는 약 100일로 나타났다. 오트란의 경우는 호기, 담수조건하에서 각각 $3{\sim}4$일, $13{\sim}14$일이었다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제11권3호
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• pp.205-210
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• 2006

The widespread use and distribution of chloroethylene organic compounds is of serious concern owing to their carcinogenicity and toxicity to humans and wildlife. In an effort to develop active bacterial consortia that could be useful for bioremediation of chloroethylene-contaminated sites in Africa, 16 combinations of 5 dichloroethylene (DCE)-utilizing bacteria, isolated from South Africa and Nigeria, were assessed for their ability to degrade cis- and trans- DCEs as the sole carbon source. Three combinations of these isolates were able to remove up to 72% of the compounds within 7 days. Specific growth rate constants of the bacterial consortia ranged between 0.465 and $0.716\;d^{-1}$ while the degradation rate constants ranged between 0.184 and $0.205\;d^{-1}$ with $86.36{\sim}93.53\;and\;87.47{\sim}97.12%$ of the stoichiometric-expected chloride released during growth of the bacterial consortia in cis- and trans-DCE, respectively. Succession studies of the individual isolates present in the consortium revealed that the biodegradation process was initially dominated by Achromobacter xylosoxidans and subsequently by Acinetobacter sp. and Bacillus sp., respectively. The results of this study suggest that consortia of bacteria are more efficient than monocultures in the aerobic biodegradation of DCEs, degrading the compounds to levels that are up to 60% below the maximum allowable limits in drinking water.

• 미생물학회지
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• 제44권1호
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• pp.22-28
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• 2008

본 실험은 생분해가 어려운 절삭유를 단일 균주에 의해 생물학적 처리를 하는 데에 목적이 있다. 절삭유, 절삭폐유로부터 호기 균주 81개를 분리하여 이중 절삭유 분해능이 가장 높은 균주로, 48시간 내에 90.4%를 제거한(초기농도 699.1 mg/L) KS47을 선별하였다. KS47은 형태학적, 생리 화학적, 16S rDNA 염기서열, 그리고 지방산 분석을 통해 Pseudomonas aeruginosa로 동정되었다. P. aeruginosa KS47은 절삭유를 탄소원으로 사용하여 성장 할 수 있었으며, 절삭유 분해시, 최적 분해 조건은 1.5 g/L(wet weight), pH 7.0, $30^{\circ}C$이었다. 최적 조건 하에서 절삭유의 제거능을 본 결과, 1,060 mg/L의 절삭유를 12시간 내에 83.7% 제거함을 확인하였다.

• 미생물학회지
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• 제20권2호
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• pp.53-66
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• 1982

1. When Chong Ju and Chung Ju soils possessing different physicochemical properties were treated with 500 ppm of TOK and incubated in flooded anaerobic condition for 2, 4, and 6 months, respectively, they produced 4-Chloro-4'-amino diphenyl ether, 2,4-Dichloro-4'-amino diphenyl ether(amin-TOK), N-[4'-(4-Chlorophenoxy)] phenyl acetamide, and N-[4'-(4-Chlorophenoxy)] phenyl formamide as the metabolities. This result indicates that TOK undergose the reduction of its $NO_2\;to\;NH_2$ group, dechlorination, acetylation, and formylation under this condition. The cleavage of ether linkage does not occur. In addition, TOK degrades more readily in Chung Ju soil which is characterized by pH 6.43 and higher contents of $Ca^{++}$ and C.E.C. than in Chong Ju soil which is lower in pH, $Ca^{++}$, and C.E.C. 2. In the aerobic incubation of TOK of 25ppm in Chung Ju soil suspension for 21 days, the ratio of the resulting metabolites, TOK : amino-TOK : 4-Chloro-4'-amino diphenyl ether was 100 : 130 : 76. Meanwhile, in the 42 day incubation, the ratio was 100 : 19 : 5, which indicates that TOK in aerobic condition dose not necessrily degrade as a function of the incubation period. 3. The citrate buffer extract of Chung Ju soil has the capability of degrading TOK, which was verified to be due to the action of the microorganisms involved. 4. Twelye strains of soil bacteria were isolated from the TOK-treated soils. In the incubation of TOK in pure cultures of the respective isolates, the strain T-1-1 isolated from Chong Ju soil had almost no degradability whereas the strain T-2-3 was the most potent. The degradation of TOK by the isolates constituted mostly the reduction of the nitro group to amino group. 5. In a test for the degradability of TOK by some selected microorganisms, Pseudomonas species were more potent than fungi. Yet, Isolate B which had been isolated from Chung Ju soil suspension was the most potent.