%0 Journal Article
%T Isolation and Identification of Pyrene Mineralizing Mycobacterium spp. from Contaminated and Uncontaminated Sources
%A Christopher W. M. Lease
%A Richard H. Bentham
%A Sharyn E. Gaskin
%A Albert L. Juhasz
%J Applied and Environmental Soil Science
%D 2011
%I Hindawi Publishing Corporation
%R 10.1155/2011/409643
%X Mycobacterium isolates obtained from PAH-contaminated and uncontaminated matrices were evaluated for their ability to degrade three-, four- and five-ring PAHs. PAH enrichment studies were prepared using pyrene and inocula obtained from manufacturing gas plant (MGP) soil, uncontaminated agricultural soil, and faeces from Macropus fuliginosus (Western Grey Kangaroo). Three pyrene-degrading microorganisms isolated from the corresponding enrichment cultures had broad substrate ranges, however, isolates could be differentiated based on surfactant, phenol, hydrocarbon and PAH utilisation. 16S rRNA analysis identified all three isolates as Mycobacterium sp. The Mycobacterium spp. could rapidly degrade phenanthrene and pyrene, however, no strain had the capacity to utilise fluorene or benzo[a]pyrene. When pyrene mineralisation experiments were performed, 70¨C79% of added 14C was evolved as 14CO2 after 10 days. The present study demonstrates that PAH degrading microorganisms may be isolated from a diverse range of environmental matrices. The present study demonstrates that prior exposure to PAHs was not a prerequisite for PAH catabolic activity for two of these Mycobacterium isolates. 1. Introduction Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental pollutants that have been widely distributed as a result of anthropogenic activities including the combustion of fossil fuels and organic matter, coal liquefaction and gasification processes, oil seepage, and accidental spillage of hydrocarbons [1, 2]. Due to their acute toxicity and/or mutagenic, teratogenic, or carcinogenic properties [3¨C5], there is toxicological concern about the presence of PAHs in the environment. As a result, the need to develop inexpensive and practical remediation technologies for PAH-contaminated soil is evident. Over the past 20 years, bioremediation has been promoted as a potential economic strategy for the remediation of PAH-contaminated soil. A wealth of information has accumulated in the scientific literature on bacterial PAH degradation including rate and extent of degradation, metabolic pathways, molecular mechanisms of PAH degradation, and application of these organisms to bioremediation strategies. A number of papers have reviewed the catabolic diversity of bacterial, fungal, and algal degradation of PAHs [6¨C8], whilst the review of Juhasz and Naidu [2] focussed on the microbial degradation of benzo[a]pyrene. It is apparent from these reviews and earlier suggestions by Kastner et al. [9], that nocardioform bacteria, in particular Mycobacteria, may play a crucial
%U http://www.hindawi.com/journals/aess/2011/409643/