Cross-induction of pyrene and phenanthrene in a<i>Mycobacterium</i>sp. isolated from polycyclic aromatic hydrocarbon contaminated river sediments

Molina, Marirosa; Araujo, Rochelle; Hodson, Robert E.

doi:10.1139/w99-018

Cited by 45 publications

(30 citation statements)

References 29 publications

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“…2). Likewise, Molina et al observed that when Mycobacterium strains were exposed to phenanthrene, de novo protein synthesis was not required for rapid mineralization of pyrene (31). In addition, a majority of the pyrene-specific proteins found in strain 6PY1 were similar in sequence to enzymes responsible for phenanthrene degradation in Nocardioides strain KP7 (Table 2).…”

Section: Discussionmentioning

confidence: 97%

Identification of Pyrene-Induced Proteins in Mycobacterium sp. Strain 6PY1: Evidence for Two Ring-Hydroxylating Dioxygenases

Krivobok

Kuony²,

Meyer³

et al. 2003

J Bacteriol

190

151

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In this study, the enzymes involved in polycyclic aromatic hydrocarbon (PAH) degradation were investigated in the pyrene-degrading Mycobacterium sp. strain 6PY1. [14 C]pyrene mineralization experiments showed that bacteria grown with either pyrene or phenanthrene produced high levels of pyrene-catabolic activity but that acetate-grown cells had no activity. As a means of identifying specific catabolic enzymes, protein extracts from bacteria grown on pyrene or on other carbon sources were analyzed by two-dimensional gel electrophoresis. Pyrene-induced proteins were tentatively identified by peptide sequence analysis. Half of them resembled enzymes known to be involved in phenanthrene degradation, with closest similarity to the corresponding enzymes from Nocardioides sp. strain KP7. The genes encoding the terminal components of two distinct ring-hydroxylating dioxygenases were cloned. Sequence analysis revealed that the two enzymes, designated Pdo1 and Pdo2, belong to a subfamily of dioxygenases found exclusively in gram-positive bacteria. When overproduced in Escherichia coli, Pdo1 and Pdo2 showed distinctive selectivities towards PAH substrates, with the former enzyme catalyzing the dihydroxylation of both pyrene and phenanthrene and the latter preferentially oxidizing phenanthrene. The catalytic activity of the Pdo2 enzyme was dramatically enhanced when electron carrier proteins of the phenanthrene dioxygenase from strain KP7 were coexpressed in recombinant cells. The Pdo2 enzyme was purified as a brown protein consisting of two types of subunits with M r s of about 52,000 and 20,000. Immunoblot analysis of cell extracts from strain 6PY1 revealed that Pdo1 was present in cells grown on benzoate, phenanthrene, or pyrene and absent in acetate-grown cells. In contrast, Pdo2 could be detected only in PAH-grown cells. These results indicated that the two enzymes were differentially regulated depending on the carbon source used for growth.Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous contaminants in soils and sediments and are of environmental concern because of their mutagenic and/or carcinogenic effects. While low-molecular-weight PAHs (composed of two or three rings) are readily degraded by bacteria, PAHs consisting of four rings or more are recalcitrant to biodegradation and persist in the environment (6, 41). The biodegradation of lowmolecular-weight PAHs, especially naphthalene, has been extensively studied with pseudomonads, leading to a good understanding of the bacterial catabolic pathway (42). On the other hand, relatively little information is available on the metabolism of high-molecular-weight PAHs (20). A number of bacterial isolates capable of pyrene mineralization have been described. Most of them are actinomycetes and belong to the genus Mycobacterium (2, 7, 37), Rhodococcus (4, 40), or Gordonia (21). A few pyrene-degrading strains have been identified as gram-negative species, including Stenotrophomonas maltophilia, Pseudomonas fluorescens (3), Sphingomonas paucimobilis (22), and Burkholder...

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Section: Discussionmentioning

confidence: 97%

Identification of Pyrene-Induced Proteins in Mycobacterium sp. Strain 6PY1: Evidence for Two Ring-Hydroxylating Dioxygenases

Krivobok

Kuony²,

Meyer³

et al. 2003

J Bacteriol

190

151

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“…The low water solubility and high sorbtion capacity of PAHs are often found to greatly influence biodegradation, but other factors, including production of toxic or dead-end metabolites, metabolite repression, the presence of preferred substrates, and the lack of cometabolic or inducer substrates, must be considered when PAH persistence is evident (433,295). Understanding how these factors affect the transformation of and determining any given PAH is difficult; understanding the processes in natural environments when mixtures of PAHs and their myriad metabolites are present is more difficult, especially as the majority of work has focused on a narrow selection of species.…”

Section: Aerobic Pah Metabolismmentioning

confidence: 99%

“…For example, Molina et al (433) observed that, for both a mixed culture and Mycobacterium sp. strain M1, crossacclimation occurred between phenanthrene and pyrene metabolism in that pyrene-grown cells did not require new protein synthesis to degrade phenanthrene.…”

Section: Aerobic Pah Metabolismmentioning

confidence: 99%

Recent Advances in Petroleum Microbiology

Hamme¹,

Singh

Ward

2003

Microbiol Mol Biol Rev

1,195

640

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Recent advances in molecular biology have extended our understanding of the metabolic processes related to microbial transformation of petroleum hydrocarbons. The physiological responses of microorganisms to the presence of hydrocarbons, including cell surface alterations and adaptive mechanisms for uptake and efflux of these substrates, have been characterized. New molecular techniques have enhanced our ability to investigate the dynamics of microbial communities in petroleum-impacted ecosystems. By establishing conditions which maximize rates and extents of microbial growth, hydrocarbon access, and transformation, highly accelerated and bioreactor-based petroleum waste degradation processes have been implemented. Biofilters capable of removing and biodegrading volatile petroleum contaminants in air streams with short substrate-microbe contact times (<60 s) are being used effectively. Microbes are being injected into partially spent petroleum reservoirs to enhance oil recovery. However, these microbial processes have not exhibited consistent and effective performance, primarily because of our inability to control conditions in the subsurface environment. Microbes may be exploited to break stable oilfield emulsions to produce pipeline quality oil. There is interest in replacing physical oil desulfurization processes with biodesulfurization methods through promotion of selective sulfur removal without degradation of associated carbon moieties. However, since microbes require an environment containing some water, a two-phase oil-water system must be established to optimize contact between the microbes and the hydrocarbon, and such an emulsion is not easily created with viscous crude oil. This challenge may be circumvented by application of the technology to more refined gasoline and diesel substrates, where aqueous-hydrocarbon emulsions are more easily generated. Molecular approaches are being used to broaden the substrate specificity and increase the rates and extents of desulfurization. Bacterial processes are being commercialized for removal of H2S and sulfoxides from petrochemical waste streams. Microbes also have potential for use in removal of nitrogen from crude oil leading to reduced nitric oxide emissions provided that technical problems similar to those experienced in biodesulfurization can be solved. Enzymes are being exploited to produce added-value products from petroleum substrates, and bacterial biosensors are being used to analyze petroleum-contaminated environments

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“…As noted earlier, only very limited success has so far been achieved in the application of bioremediation technologies to PAH contaminated sites [110][111][112] and this is partly due to the lack of induction of the catabolic enzymes [113,114]. External addition of the inducers is generally neither a cost-effective nor an ecofriendly alternative.…”

Section: Expression Of the Degradative Genesmentioning

confidence: 99%

“…One of the problems in extrapolating laboratory bioremediation experiments to the fi eld has been the poor survival of the degrading strains in the fi eld environment [113][114]. The inoculated strains are affected by the predation of protists and competition with indigenous microorganisms for nutrients or electron acceptors.…”

Section: Survival Of the Degrading Strainmentioning

confidence: 99%

Bacterial metabolism of polycyclic aromatic hydrocarbons: strategies for bioremediation

et al. 2008

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Polycyclic aromatic hydrocarbons (PAHs) are compounds of intense public concern due to their persistence in the environment and potentially deleterious effects on human, environmental and ecological health. The clean up of such contaminants using invasive technologies has proven to be expensive and more importantly often damaging to the natural resource properties of the soil, sediment or aquifer. Bioremediation, which exploits the metabolic potential of microbes for the clean-up of recalcitrant xenobiotic compounds, has come up as a promising alternative. Several approaches such as improvement in PAH solubilization and entry into the cell, pathway and enzyme engineering and control of enzyme expression etc. are in development but far from complete. Successful application of the microorganisms for the bioremediation of PAH-contaminated sites therefore requires a deeper understanding of the physiology, biochemistry and molecular genetics of potential catabolic pathways. In this review, we briefl y summarize important strategies adopted for PAH bioremediation and discuss the potential for their improvement.

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Cross-induction of pyrene and phenanthrene in aMycobacteriumsp. isolated from polycyclic aromatic hydrocarbon contaminated river sediments

Cited by 45 publications

References 29 publications

Identification of Pyrene-Induced Proteins in Mycobacterium sp. Strain 6PY1: Evidence for Two Ring-Hydroxylating Dioxygenases

Identification of Pyrene-Induced Proteins in Mycobacterium sp. Strain 6PY1: Evidence for Two Ring-Hydroxylating Dioxygenases

Recent Advances in Petroleum Microbiology

Bacterial metabolism of polycyclic aromatic hydrocarbons: strategies for bioremediation

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