Degradation of Phenanthrene and Anthracene by Cell Suspensions ofMycobacteriumsp. Strain PYR-1

Abstract

Cultures of Mycobacterium sp. strain PYR-1 were dosed with anthracene or phenanthrene and after 14 days of incubation had degraded 92 and 90% of the added anthracene and phenanthrene, respectively. The metabolites were extracted and identified by UV-visible light absorption, high-pressure liquid chromatography retention times, mass spectrometry, 1 H and 13 C nuclear magnetic resonance spectrometry, and comparison to authentic compounds and literature data. Neutral-pH ethyl acetate extracts from anthracene-incubated cells showed four metabolites, identified as cis-1,2-dihydroxy-1,2-dihydroanthracene, 6,7-benzocoumarin, 1-methoxy-2-hydroxyanthracene, and 9,10-anthraquinone. A novel anthracene ring fission product was isolated from acidified culture media and was identified as 3-(2-carboxyvinyl)naphthalene-2-carboxylic acid. 6,7-Benzocoumarin was also found in that extract. When Mycobacterium sp. strain PYR-1 was grown in the presence of phenanthrene, three neutral metabolites were identified as cis-and trans-9,10-dihydroxy-9,10-dihydrophenanthrene and cis-3,4-dihydroxy-3,4-dihydrophenanthrene. Phenanthrene ring fission products, isolated from acid extracts, were identified as 2,2-diphenic acid, 1-hydroxynaphthoic acid, and phthalic acid. The data point to the existence, next to already known routes for both gram-negative and gram-positive bacteria, of alternative pathways that might be due to the presence of different dioxygenases or to a relaxed specificity of the same dioxygenase for initial attack on polycyclic aromatic hydrocarbons.Anthracene and phenanthrene are tricyclic aromatic hydrocarbons that are found in high concentrations in polycyclic aromatic hydrocarbon (PAH)-contaminated sediments, surface soils, and waste sites. These hydrophobic contaminants are widely distributed in the environment, occurring as natural constituents of fossil fuels and their anthropogenic pyrolysis products (6,24,55). Unlike the higher-molecular-weight PAHs, phenanthrene and anthracene do not pose a risk to human health, since they exhibit no genotoxic or carcinogenic effects. However, they have been shown to be toxic to fish and algae (45,46). Anthracene and phenanthrene are considered prototypic PAHs and serve as signature compounds to detect PAH contamination, since their chemical structures are found in carcinogenic PAHs, such as benzo[a]pyrene and benz[a]anthracene. They have also been used as model PAHs to determine factors that affect the bioavailability, biodegradation potential, and rate of microbial degradation of PAHs in the environment (5,6,24,48).A variety of bacterial species have been isolated that have the ability to utilize anthracene or phenanthrene as the sole source of carbon and energy (6,33,48). The initial reactions in the degradation of anthracene and phenanthrene are catalyzed by multicomponent dioxygenases that incorporate both atoms of molecular oxygen into the PAH nucleus to produce cisdihydrodiols (1,22). Genes involved in PAH metabolism and its regulation have been described for Pseudomonas, Sphin...

Biodegradation of naphthalene and anthracene by chemo-tactically active rhizobacteria of populus deltoides

“…Among these, four isolates were found to utilize both anthracene and naphthalene as sole source of carbon. In fact, PAH degrading organisms and higher degradation rates have been detected in the bulk soil collected from planted treatments than in the bulk soil collected from unplanted treatments in rhizoremediation studies (18,29). These findings are promising indications that certain trees may positively affect the number of degrading microorganisms in a large volume of soil, beyond the immediate vicinity of the roots traditionally defined as the rhizosphere.…”

Co-variations of bacterial composition and catabolic genes related to PAH degradation in a produced water treatment system consisting of successive anoxic and aerobic units

“…Biochemical pathways for many lower-molecular-weight PAHs (LMW PAHs) and their biodegradation mechanisms have been clarified. Most LMW PAHs could be decomposed through direct biological degradation (Moody et al, 2001). The high-molecular-weight PAHs (HMW PAHs), on the other hand, used to be considered as being resistant to biodegradation.…”

Bacterial degradation of phthalate isomers and their esters

“…These plasticizing agents are not linked by covalent interactions to the parent chemical, imparting fl exibility to the product and are leached out easily by organic and polar solvents [2,38,40,45,97]. Besides synthetic origin, few of these compounds are metabolic intermediates in the degradation of polyaromatic hydrocarbons, for example, in several bacterial species o-phthalate was shown to be an intermediate in phenanthrene, pyrene, fl uorine and fl uoranthrene catabolism [37,42,48,56,68,79]. Bioaccumulation of these compounds in nature led to adaptation and evolution of new metabolic pathways for the degradation of these compounds.…”