Degradation of straight-chain aliphatic and high-molecular-weight polycyclic aromatic hydrocarbons by a strain of Mycobacterium austroafricanum

Abstract

Aims: Our goal was to characterize a newly isolated strain of Mycobacterium austroafricanum, obtained from manufactured gas plant (MGP) site soil and designated GTI-23, with respect to its ability to degrade polycyclic aromatic hydrocarbons (PAHs). Methods and Results: GTI-23 is capable of growth on phenanthrene, fluoranthene, or pyrene as a sole source of carbon and energy; it also extensively mineralizes the latter two in liquid culture and is capable of extensive degradation of fluorene and benzo[a]pyrene, although this does not lead in either of these cases to mineralization. Supplementation of benzo [a]pyrene-containing cultures with phenanthrene had no significant effect on benzo[a]pyrene degradation; however, this process was substantially inhibited by the addition of pyrene. Extensive and rapid mineralization of pyrene by GTI-23 was also observed in pyrene-amended soil. Conclusions: Strain GTI-23 shows considerable ability to mineralize a range of polycyclic aromatic hydrocarbons, both in liquid and soil environments. In this regard, GTI-23 differs markedly from the type strain of Myco. austroafricanum (ATCC 33464); the latter isolate displayed no (or very limited) mineralization of any tested PAH (phenanthrene, fluoranthene or pyrene). When grown in liquid culture, GTI-23 was also found to be capable of growing on and mineralizing two aliphatic hydrocarbons (dodecane and hexadecane). Significance and Impact of the Study: These findings indicate that this isolate of Myco. austroafricanum may be useful for bioremediation of soils contaminated with complex mixtures of aromatic and aliphatic hydrocarbons.

Insight into the Modulation of Dissolved Organic Matter on Microbial Remediation of PAH-Contaminated Soils

“…And, the ratios of abundances of different PAH-degrading genes to bacterial 16S rRNA gene in some DOM-treated soils were significantly higher than that in the control on some incubation time. It indicated that addition of DOMs was an important driving force to stimulate the growth of bacteria especially those responsible for the [35][36][37][38]. The profiling analysis of microbial communities can contribute to identify the members of potential PAH-degrading microbial consortia and understand the patterns of microbial responses to external stimuli in polluted soils [14,39].…”

Biodegradation of phenanthrene by Pseudomonas sp. BZ-3, isolated from crude oil contaminated soil

“…Phenanthrene (PHE), a tricyclic aromatic hydrocarbon with three-fused rings in an angular fashion, is commonly used as a model compound for PAH biodegradation studies (Roy et al, 2012;Gao et al, 2013). Halophilic or halotolerant PHE-degrading bacteria have the capability of using PHE as a source of carbon and energy (Bogan et al, 2003). A variety of halophilic microorganisms have been isolated from marine or saline water and sediment for the degradation of PHE (Li and Bai, 2005).…”

Characterization of diesel degrading bacterial species from contaminated tropical ecosystem

“…This is possible because the microorganisms have catabolic gene pool that is necessary for synthesizing the enzymes that can mediate the critical steps in diesel oil degradation. Several, bacterial genera have exhibited great abilities in utilizing the hydrocarbon substrates (Bogan et al 2003;Chikere et al 2009). These bacterial species are wide spread in pristine and oil polluted environments (Hamamura et al 2006;Cappello et al 2007;Van Beilen and Funhoff 2007).…”