Degradation of bromacil by a Pseudomonas sp.

A gram-negative rod, identified as a Pseudomonas sp., was isolated from soil by using bromacil as the sole source of carbon and energy. During growth on bromacil or 5-bromouracil, almost stoichiometric amounts of bromide were released. The bacterium was shown to harbor two plasmids approximately 60 and 100 kilobases in size. They appeared to be associated with the ability to utilize bromacil as a sole source of carbon and also with resistance to ampicillin. This microorganism also showed the potential to decontaminate soil samples fortified with bromacil under laboratory conditions.     

Degradation of 2-chloroallylalcohol by a Pseudomonas sp.

Three Pseudomonas strains capable of utilizing 2-chloroallylalcohol (2-chloropropenol) as the sole carbon source for growth were isolated from soil. The fastest growth was observed with strain JD2, with a generation time of 3.6 h. Degradation of 2-chloroallylalcohol was accompanied by complete dehalogenation. Chloroallylalcohols that did not support growth were dechlorinated by resting cells; the dechlorination level was highest if an alpha-chlorine substituent was present. Crude extracts of strain JD2 contained inducible alcohol dehydrogenase activity that oxidized mono- and dichloroallylalcohols but not trichloroallylalcohol. The enzyme used phenazine methosulfate as an artificial electron acceptor. Further oxidation yielded 2-chloroacrylic acid. The organism also produced hydrolytic dehalogenases converting 2-chloroacetic acid and 2-chloropropionic acid.     

Degradation of 3-phenylbutyric acid by Pseudomonas sp.

Pseudomonas sp. isolated by selective culture with 3-phenylbutyrate (3-PB) as the sole carbon source metabolized the compound through two different pathways by initial oxidation of the benzene ring and by initial oxidation of the side chain. During early exponential growth, a catechol substance identified as 3-(2,3-dihydroxyphenyl)butyrate (2,3-DHPB) and its meta-cleavage product 2-hydroxy-7-methyl-6-oxononadioic-2,4-dienoic acid were produced. These products disappeared during late exponential growth, and considerable amounts of 2,3-DHPB reacted to form brownish polymeric substances. The catechol intermediate 2,3-DHPB could not be isolated, but cell-free extracts were able only to oxidize 3-(2,3-dihydroxyphenyl)propionate of all dihydroxy aromatic acids tested. Moreover, a reaction product caused by dehydration of 2,3-DHPB on silica gel was isolated and identified by spectral analysis as (--)-8-hydroxy-4-methyl-3,4-dihydrocoumarin. 3-Phenylpropionate and a hydroxycinnamate were found in supernatants of cultures grown on 3-PB; phenylacetate and benzoate were found in supernatants of cultures grown on 3-phenylpropionate; and phenylacetate was found in cultures grown on cinnamate. Cells grown on 3-PB rapidly oxidized 3-phenylpropionate, cinnamate, catechol, and 3-(2,3-dihydroxyphenyl)propionate, whereas 2-phenylpropionate, 2,3-dihydroxycinnamate, benzoate, phenylacetate, and salicylate were oxidized at much slower rates. Phenylsuccinate was not utilized for growth nor was it oxidized by washed cell suspensions grown on 3-PB. However, dual axenic cultures of Pseudomonas acidovorans and Klebsiella pneumoniae, which could not grow on phenylsuccinate alone, could grow syntrophically and produced the same metabolites found during catabolism of 3-PB by Pseudomonas sp. Washed cell suspensions of dual axenic cultures also immediately oxidized phenylsuccinate, 3-phenylpropionate, cinnamate, phenylacetate, and benzoate.     

Degradation of 1,4-dichlorobenzene by a Pseudomonas sp.

A Pseudomonas species able to degrade p-dichlorobenzene as the sole source of carbon and energy was isolated by selective enrichment from activated sludge. The organism also grew well on chlorobenzene and benzene. Washed cells released chloride in stoichiometric amounts from o-, m-, and p-dichlorobenzene, 2,5-dichlorophenol, 4-chlorophenol, 3-chlorocatechol, 4-chlorocatechol, and 3,6-dichlorocatechol. Initial steps in the pathway for p-dichlorobenzene degradation were determined by isolation of metabolites, simultaneous adaptation studies, and assay of enzymes in cell extracts. Results indicate that p-dichlorobenzene was initially converted by a dioxygenase to 3,6-dichloro-cis-1,2-dihydroxycyclohexa-3,5-diene, which was converted to 3,6-dichlorocatechol by an NAD+-dependent dehydrogenase. Ring cleavage of 3,6-dichlorocatechol was by a 1,2-oxygenase to form 2,5-dichloro-cis, cis-muconate. Enzymes for degradation of haloaromatic compounds were induced in cells grown on chlorobenzene or p-dichlorobenzene, but not in cells grown on benzene, succinate, or yeast extract. Enzymes of the ortho pathway induced in cells grown on benzene did not attack chlorobenzenes or chlorocatechols.     

Degradation of 1,2-dichlorobenzene by a Pseudomonas sp.

A Pseudomonas sp. that was capable of growth on 1,2-dichlorobenzene (o-DCB) or chlorobenzene as a sole source of carbon and energy was isolated by selective enrichment from activated sludge. The initial steps involved in the degradation of o-DCB were investigated by isolation of metabolites, respirometry, and assay of enzymes in cell extracts. Extracts of o-DCB-grown cells converted radiolabeled o-DCB to 3,4-dichloro-cis-1,2-dihydroxycyclohexa-3,5-diene (o-DCB dihydrodiol). 3,4-Dichlorocatechol and o-DCB dihydrodiol accumulated in culture fluids of cells exposed to o-DCB. The results suggest that o-DCB is initially converted by a dioxygenase to a dihydrodiol, which is converted to 3,4-dichlorocatechol by an NAD+-dependent dehydrogenase. Ring cleavage of 3,4-dichlorocatechol is by a catechol 1,2-oxygenase to form 2,3-dichloro-cis,cis-muconate. Preliminary results indicate that chloride is eliminated during subsequent lactonization of the 2,3-dichloro-cis,cis-muconate, followed by hydrolysis to form 5-chloromaleylacetic acid.     

Degradation of bromacil by a Pseudomonas sp

A gram-negative rod, identified as a Pseudomonas sp., was isolated from soil by using bromacil as the sole source of carbon and energy. During growth on bromacil or 5-bromouracil, almost stoichiometric amounts of bromide were released. The bacterium was shown to harbor two plasmids approximately 60 and 100 kilobases in size. They appeared to be associated with the ability to utilize bromacil as a sole source of carbon and also with resistance to ampicillin. This microorganism also showed the potential to decontaminate soil samples fortified with bromacil under laboratory conditions.     

Degradation of carbazole and its derivatives by a Pseudomonas sp.

Carbazole, carbazoles with monomethyl or dimethyls substituted on different positions (C₁-carbazoles or C₂-carbazoles), and benzocarbazoles, as toxic and mutagenic components of petroleum and creosote contamination, were biodegradable by an isolated bacterial strain Pseudomonas sp. XLDN4-9. C₁-carbazoles were degraded in preference to carbazole and C₂-carbazoles. The biodegradation of C₁-carbazoles or C₂-carbazoles was influenced by the positions of methyl substitutions. Among C₁-carbazole isomers, 1-methyl carbazole was the most susceptible. C₂-carbazole isomers with substitutions on the same benzo-nucleus were more susceptible at a concentration of less than 3.4 μg g⁻¹ petroleum, especially when harboring one substitution on position 1. In particular, 1,5-dimethyl carbazole was the most recalcitrant dimethyl isomer.     

Degradation of 2,4-dihydroxybenzoate by Pseudomonas sp. BN9

Abstract The aerobic degradation of 2,4-dihydroxybenzoate by Pseudomonas sp. BN9 was studied. Intact cells of Pseudomonas sp. BN9 grown with 2,4-dihydroxybenzoate oxidized 2,4-dihydroxybenzoate but not salicylate. Cell-free extracts of Pseudomonas sp. BN9 converted 2,4-dihydroxybenzoate after the addition of NAD(P)H. A partially purified protein fraction converted 2,4-dihydroxybenzoate with NADH to 1,2,4-trihydroxybenzene. 1,2,4-Trihydroxybenzene was converted by a 1,2-dioxygenase to maleylpyruvate, which was reduced by a NADH-dependent enzyme to 3-oxoadipate. 2,4-Dihydroxybenzoate 1-monooxygenase, 1,2,4-trihydroxybenzene 1,2-dioxygenase and maleylpyruvate reductase were induced in Pseudomonas sp. BN9 after growth with 2,4-dihydroxybenzoate.     

Degradation of o-toluate by Pseudomonas sp. strain WR401

Abstract A Pseudomonas sp. strain WR401 was isolated for growth on 3-, 4-, and 5-methylsalicylate. The organism was capable of growth on o -toluate. The data on enzyme activities in cell-free extracts, DHB dehydrogenase and catechol 2,3-dioxygenase, as well as the cooxidation of the substrate analog 2-chlorobenzoate yielding 3-chlorocatechol indicated a pathway for o -toluate degradation through 6-methyldihydrodihydroxybenzoate, 3-methylcatechol and further through the meta -pathway. In contrast to other toluate dioxygenating enzymes found in m - and p -toluate degrading organisms, strain WR401 was able to dioxygenate a wider range of chlorobenzoates including 2-chlorobenzoate.     

Anaerobic Degradation of Endosulfans by a Mixed Culture of Pseudomonas sp. and Staphylococcus sp.

Applied Biochemistry and Microbiology - Three endosulfan-degrading bacterial strains, Pseudomonas sp. KT1, Pseudomonas sp. KT2 and Staphylococcus sp. DKT, were isolated and investigated for their...     

三株Pseudomonas sp.的吡啶降解多样性分析

目的:为了探讨3株Pseudomonas sp.对吡啶降解存在多样性.方法:基于16S rRNA和ISR序列分析,对3株分离菌株进行初步鉴定,进而通过Touch -Down PCR,对3株细菌降解吡啶的多样性进行分析.结果:3株细菌XJUHX -1、XJUHX - 12和XJUHX - 16初步鉴定为Pseudomonas,3株实验菌株的部分降解基因的扩增条带有差异.结论:同属的3株 Pseudomonas在吡啶降解上存在多样性.     

Degradation of 1,2-dichlorobenzene by a Pseudomonas sp

A Pseudomonas sp. that was capable of growth on 1,2-dichlorobenzene (o-DCB) or chlorobenzene as a sole source of carbon and energy was isolated by selective enrichment from activated sludge. The initial steps involved in the degradation of o-DCB were investigated by isolation of metabolites, respirometry, and assay of enzymes in cell extracts. Extracts of o-DCB-grown cells converted radiolabeled o-DCB to 3,4-dichloro-cis-1,2-dihydroxycyclohexa-3,5-diene (o-DCB dihydrodiol). 3,4-Dichlorocatechol and o-DCB dihydrodiol accumulated in culture fluids of cells exposed to o-DCB. The results suggest that o-DCB is initially converted by a dioxygenase to a dihydrodiol, which is converted to 3,4-dichlorocatechol by an NAD+-dependent dehydrogenase. Ring cleavage of 3,4-dichlorocatechol is by a catechol 1,2-oxygenase to form 2,3-dichloro-cis,cis-muconate. Preliminary results indicate that chloride is eliminated during subsequent lactonization of the 2,3-dichloro-cis,cis-muconate, followed by hydrolysis to form 5-chloromaleylacetic acid.     

Degradation of 1,4-dichlorobenzene by a Pseudomonas sp

A Pseudomonas species able to degrade p-dichlorobenzene as the sole source of carbon and energy was isolated by selective enrichment from activated sludge. The organism also grew well on chlorobenzene and benzene. Washed cells released chloride in stoichiometric amounts from o-, m-, and p-dichlorobenzene, 2,5-dichlorophenol, 4-chlorophenol, 3-chlorocatechol, 4-chlorocatechol, and 3,6-dichlorocatechol. Initial steps in the pathway for p-dichlorobenzene degradation were determined by isolation of metabolites, simultaneous adaptation studies, and assay of enzymes in cell extracts. Results indicate that p-dichlorobenzene was initially converted by a dioxygenase to 3,6-dichloro-cis-1,2-dihydroxycyclohexa-3,5-diene, which was converted to 3,6-dichlorocatechol by an NAD+-dependent dehydrogenase. Ring cleavage of 3,6-dichlorocatechol was by a 1,2-oxygenase to form 2,5-dichloro-cis, cis-muconate. Enzymes for degradation of haloaromatic compounds were induced in cells grown on chlorobenzene or p-dichlorobenzene, but not in cells grown on benzene, succinate, or yeast extract. Enzymes of the ortho pathway induced in cells grown on benzene did not attack chlorobenzenes or chlorocatechols.     

一株假单胞菌HZ-1降解石油烃的初步研究

从石油废水活性污泥中分离到一株可以较好降解石油烃的假单胞菌（Pseudomonas sp）HZ-1,采用生物膜法对该菌株在30℃条件下降解某炼油厂废水中的烃类物质进行了研究.研究结果表明不同营养盐NH4NO3、NaH2PO4、NH4Cl对菌株HZ-1处理石油废水的作用不同,终浓度为1000mg/L的NH4NO3对菌株HZ-1处理石油废水效果最佳.并在30℃和pH 8.0的条件下,初步研究了该菌株降解萘的情况,在萘浓度低于78 mg/L的情况下,120 rpm好氧振荡培养144h,这株菌对萘的降解率在86%以上.     

假单胞菌S-2降解甲胺磷性能的研究

从甲胺磷生产车间分离到一株假单胞菌编号为S-2。S-2可利用甲胺磷为唯一氮源,但不能利用甲胺磷为唯一磷源。该文对S-2体内具有的降解甲胺磷的酶类进行了研究,初步断定：S-2可代谢产生酸性磷酸酶,主要在胞外降解甲胺磷。S-2在甲胺磷诱导的情况下,这些降解酶类可大量聚积。用诱导过的菌液降解甲胺磷比未经诱导的快了2d左右。     

Degradation of alkylphenol ethoxylates by Pseudomonas sp. strain TR01.

An alkylphenol ethoxylate-degrading bacterium was isolated from activated sludge of a municipal sewage treatment plant by enrichment culture. This organism was found to belong to the genus Pseudomonas; since no corresponding species was identified, we designated it as Pseudomonas sp. strain TR01. This strain had an optimal temperature and pH of 30 degrees C and 7, respectively, for both growth and the degradation of Triton N-101 (a nonylphenol ethoxylate in which the average number of ethylene oxide [EO] units is 9.5). The strain was unable to mineralize Triton N-101 but was able to degrade its EO chain exclusively. The resulting dominant intermediate was identified by normal-phase high-performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry as a nonylphenol ethoxylate with 2 mol of EO units. A carboxylated metabolite, [(nonylphenoxy)ethoxy]acetic acid, was detected by gas chromatography-mass spectrometry. This bacterium also metabolized alcohol ethoxylates with various numbers of EO units but not polyethylene glycols whatever their degree of polymerization. By oxygen consumption assay, the alkyl group or arene corresponding to the hydrophobic part of alcohol ethoxylates or alkylphenol ethoxylates was shown to contribute to the induction of the metabolic system of the EO chain of Triton N-101, instead of the EO chain itself, which corresponds to its hydrophilic part. Thus, the isolated pseudomonad bacterium has unique substrate assimilability: it metabolizes the EO chain only when the chain linked to bulky hydrophobic groups.     

Degradation of 2-Methylnaphthalene by Pseudomonas sp. Strain NGK1

Pseudomonas sp. strain NGK1, a soil bacterium isolated by naphthalene enrichment from biological waste effluent treatment, capable of utilizing 2-methylnaphthalene as sole source of carbon and energy. To deduce the pathway for biodegradation of 2-methylnaphthalene, metabolites were isolated from the spent medium and identified by thin-layer chromatography and high-performance liquid chromatography. The characterization of purified metabolites, oxygen uptake studies, and enzyme activities revealed that the strain degrades 2-methylnaphthalene through more than one pathway. The growth of the bacterium, utilization of 2-methylnaphthalene, and 4-methylsalicylate accumulation by Pseudomonas sp. strain NGK1 were studied at various incubation periods. Received: 20 March 2001 / Accepted: 25 April 2001     

Monooxygenase-Mediated 1,2-Dichloroethane Degradation by Pseudomonas sp. Strain DCA1

A bacterial strain, designated Pseudomonas sp. strain DCA1, was isolated from a 1,2-dichloroethane (DCA)-degrading biofilm. Strain DCA1 utilizes DCA as the sole carbon and energy source and does not require additional organic nutrients, such as vitamins, for optimal growth. The affinity of strain DCA1 for DCA is very high, with a K_m value below the detection limit of 0.5 μM. Instead of a hydrolytic dehalogenation, as in other DCA utilizers, the first step in DCA degradation in strain DCA1 is an oxidation reaction. Oxygen and NAD(P)H are required for this initial step. Propene was converted to 1,2-epoxypropane by DCA-grown cells and competitively inhibited DCA degradation. We concluded that a monooxygenase is responsible for the first step in DCA degradation in strain DCA1. Oxidation of DCA probably results in the formation of the unstable intermediate 1,2-dichloroethanol, which spontaneously releases chloride, yielding chloroacetaldehyde. The DCA degradation pathway in strain DCA1 proceeds from chloroacetaldehyde via chloroacetic acid and presumably glycolic acid, which is similar to degradation routes observed in other DCA-utilizing bacteria.     

Degradation of high concentrations of cresols by Pseudomonas sp. CP4

Pseudomonas sp. CP₄, a potent phenol-degrading laboratory isolate could mineralize all three isomers of cresol. This strain readily utilized up to 1.4, 1.1 and 2.2 g/l of o- m- and p-cresol, respectively as the sole sources of carbon and energy. These are the highest concentrations of cresols reported to be degraded by a bacterial strain. The rates of degradation of the three isomers were in the order: o- > p- > m-cresol. All the isomers of cresol were catabolized through a meta-cleavage pathway. Fairly high catechol 2,3-dioxygenase (C230) activity against catechol was observed in the cell-free extracts of the culture grown on these compounds and were in the order: m- > o- > p-cresol.     

Degradation of hydrocarbons and biosurfactant production by Pseudomonas sp. strain LP1

Pseudomonas sp. strain LP1, an organism isolated on the basis of its ability to grow on pyrene, was assayed for its degradative and biosurfactant production potentials when growing on crude, diesel and engine oils. The isolate exhibited specific growth rate and doubling time of 0.304 days⁻¹ and 2.28 days, respectively on crude oil (Escravos Light). The corresponding values on diesel were 0.233 days⁻¹ and 2.97 days, while on engine oil, were 0.122 days⁻¹ and 5.71 days. The organism did not show significant biosurfactant production towards crude oil and diesel, but readily produced biosurfactant on engine oil. The highest Emulsification index (E₂₄) value for the biosurfactant produced by LP1 on engine oil was 80.33 ± 1.20, on day 8 of incubation. Biosurfactant production was growth-associated. The surface-active compound which exhibited zero saline tolerance had its optimal activity at 50°C and pH 2.0.