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Appl. Environ. Microbiol., Jan 1996, 13-19, Vol 62, No. 1
J Schneider, R Grosser, K Jayasimhulu, W Xue and D Warshawsky
The degradation of three polycyclic aromatic hydrocarbons (PAH), pyrene
(PYR), benz[a]anthracene (BAA), and benzo[a]pyrene (BaP), by Mycobacterium
sp. strain RJGII-135 was studied. The bacterium was isolated from an
abandoned coal gasification site soil by analog enrichment techniques and
found to mineralize [14C]PYR. Further degradation studies with PYR showed
three metabolites formed by Mycobacterium sp. strain RJGII-135, including
4,5-phenanthrene- dicarboxylic acid not previously isolated,
4-phenanthrene-carboxylic acid, and 4,5-pyrene-dihydrodiol. At least two
dihydrodiols, 5,6-BAA- dihydrodiol and 10,11-BAA-dihydrodiol, were
confirmed by high- resolution mass spectral and fluorescence analyses as
products of the biodegradation of BAA by Mycobacterium sp. strain
RJGII-135. Additionally, a cleavage product of BAA was also isolated. Mass
spectra and fluorescence data support two different routes for the
degradation of BaP by Mycobacterium sp. strain RJGII-135. The
7,8-BaP-dihydrodiol and three cleavage products of BaP, including
4,5-chrysene-dicarboxylic acid and a dihydro-pyrene-carboxylic acid
metabolite, have been isolated and identified as degradation products
formed by Mycobacterium sp. strain RJGII-135. These latter results
represent the first example of the isolation of BaP ring fission products
formed by a bacterial isolate. We propose that while this bacterium appears
to attack only one site of the PYR molecule, it is capable of degrading
different sites of the BAA and BaP molecules, and although the sites of
attack may be different, the ability of this bacterium to degrade these PAH
is well supported. The proposed pathways for biodegradation of these
compounds by this Mycobacterium sp. strain RJGII-135 support the
dioxygenase enzymatic processes reported previously for other bacteria.
Microorganisms like Mycobacterium sp. strain RJGII-135 will be invaluable
in attaining the goal of remediation of sites containing mixtures of these
PAH.
Copyright © 1996, American Society for Microbiology
Degradation of pyrene, benz[a]anthracene, and benzo[a]pyrene by Mycobacterium sp. strain RJGII-135, isolated from a former coal gasification site
Department of Environmental Health, University of Cincinnati, Ohio 45267-0056, USA.
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