Opportunistic bacteria dominate the soil microbiome response to phenanthrene in a microcosm-based study
Bioremediation offers a sustainable approach for removal of polycyclic aromatic hydrocarbons (PAHs) from the environment; however, information regarding the microbial communities involved remains limited. In this study, microbial community dynamics and the abundance of the key gene (PAH-RHDα) enc...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English English English |
| Published: |
Frontiers
2018
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| Subjects: | |
| Online Access: | http://irep.iium.edu.my/67881/ http://irep.iium.edu.my/67881/ http://irep.iium.edu.my/67881/ http://irep.iium.edu.my/67881/1/Mardiana_2018.pdf http://irep.iium.edu.my/67881/7/67881_Opportunistic%20bacteria%20dominate%20the%20soil%20microbiome_SCOPUS.pdf http://irep.iium.edu.my/67881/13/67881%20Opportunistic%20Bacteria%20Dominate%20the%20Soil%20Microbiome%20WOS.pdf |
| Summary: | Bioremediation offers a sustainable approach for removal of polycyclic aromatic
hydrocarbons (PAHs) from the environment; however, information regarding the microbial
communities involved remains limited. In this study, microbial community dynamics and
the abundance of the key gene (PAH-RHDα) encoding a ring hydroxylating dioxygenase
involved in PAH degradation were examined during degradation of phenanthrene in
a podzolic soil from the site of a former timber treatment facility. The 10,000-fold
greater abundance of this gene associated with Gram-positive bacteria found in
phenanthrene-amended soil compared to unamended soil indicated the likely role
of Gram-positive bacteria in PAH degradation. In contrast, the abundance of the
Gram-negative PAHs-RHDα gene was very low throughout the experiment. While
phenanthrene induced increases in the abundance of a small number of OTUs from
the Actinomycetales and Sphingomonadale, most of the remainder of the community
remained stable. A single unclassified OTU from the Micrococcaceae family increased
∼20-fold in relative abundance, reaching 32% of the total sequences in amended
microcosms on day 7 of the experiment. The relative abundance of this same OTU
increased 4.5-fold in unamended soils, and a similar pattern was observed for the
second most abundant PAH-responsive OTU, classified into the Sphingomonas genus.
Furthermore, the relative abundance of both of these OTUs decreased substantially
between days 7 and 17 in the phenanthrene-amended and control microcosms. This
suggests that their opportunistic phenotype, in addition to likely PAH-degrading ability,
was determinant in the vigorous growth of dominant PAH-responsive OTUs following
phenanthrene amendment. This study provides new information on the temporal
response of soil microbial communities to the presence and degradation of a significant
environmental pollutant, and as such has the potential to inform the design of PAH
bioremediation protocols. |
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