Pseudomonads Rule Degradation of Polyaromatic Hydrocarbons in Aerated Sediment

Given that the degradation of aromatic pollutants in anaerobic environments such as sediment is generally very slow, aeration could be an efficient bioremediation option. Using stable isotope probing (SIP) coupled with pyrosequencing analysis of 16S rRNA genes, we identified naphthalene-utilizing po...

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Main Authors:	Wald, Jiri, Hroudova, Miluse, Jansa, Jan, Vrchotova, Blanka, Macek, Tomas, Uhlik, Ondrej
Format:	Online
Language:	English
Published:	Frontiers Media S.A. 2015
Online Access:	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4652016/

id	pubmed-4652016
recordtype	oai_dc
spelling	pubmed-46520162015-12-03 Pseudomonads Rule Degradation of Polyaromatic Hydrocarbons in Aerated Sediment Wald, Jiri Hroudova, Miluse Jansa, Jan Vrchotova, Blanka Macek, Tomas Uhlik, Ondrej Microbiology Given that the degradation of aromatic pollutants in anaerobic environments such as sediment is generally very slow, aeration could be an efficient bioremediation option. Using stable isotope probing (SIP) coupled with pyrosequencing analysis of 16S rRNA genes, we identified naphthalene-utilizing populations in aerated polyaromatic hydrocarbon (PAH)-polluted sediment. The results showed that naphthalene was metabolized at both 10 and 20°C following oxygen delivery, with increased degradation at 20°C as compared to 10°C—a temperature more similar to that found in situ. Naphthalene-derived 13C was primarily assimilated by pseudomonads. Additionally, Stenotrophomonas, Acidovorax, Comamonas, and other minor taxa were determined to incorporate 13C throughout the measured time course. The majority of SIP-detected bacteria were also isolated in pure cultures, which facilitated more reliable identification of naphthalene-utilizing populations as well as proper differentiation between primary consumers and cross-feeders. The pseudomonads acquiring the majority of carbon were identified as Pseudomonas veronii and Pseudomonas gessardii. Stenotrophomonads and Acidovorax defluvii, however, were identified as cross-feeders unable to directly utilize naphthalene as a growth substrate. PAH degradation assays with the isolated bacteria revealed that all pseudomonads as well as Comamonas testosteroni degraded acenaphthene, fluorene, and phenanthrene in addition to naphthalene. Furthermore, P. veronii and C. testosteroni were capable of transforming anthracene, fluoranthene, and pyrene. Screening of isolates for naphthalene dioxygenase genes using a set of in-house designed primers for Gram-negative bacteria revealed the presence of such genes in pseudomonads and C. testosteroni. Overall, our results indicated an apparent dominance of pseudomonads in the sequestration of carbon from naphthalene and potential degradation of other PAHs upon aeration of the sediment at both 20 and 10°C. Frontiers Media S.A. 2015-11-19 /pmc/articles/PMC4652016/ /pubmed/26635740 http://dx.doi.org/10.3389/fmicb.2015.01268 Text en Copyright © 2015 Wald, Hroudova, Jansa, Vrchotova, Macek and Uhlik. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
repository_type	Open Access Journal
institution_category	Foreign Institution
institution	US National Center for Biotechnology Information
building	NCBI PubMed
collection	Online Access
language	English
format	Online
author	Wald, Jiri Hroudova, Miluse Jansa, Jan Vrchotova, Blanka Macek, Tomas Uhlik, Ondrej
spellingShingle	Wald, Jiri Hroudova, Miluse Jansa, Jan Vrchotova, Blanka Macek, Tomas Uhlik, Ondrej Pseudomonads Rule Degradation of Polyaromatic Hydrocarbons in Aerated Sediment
author_facet	Wald, Jiri Hroudova, Miluse Jansa, Jan Vrchotova, Blanka Macek, Tomas Uhlik, Ondrej
author_sort	Wald, Jiri
title	Pseudomonads Rule Degradation of Polyaromatic Hydrocarbons in Aerated Sediment
title_short	Pseudomonads Rule Degradation of Polyaromatic Hydrocarbons in Aerated Sediment
title_full	Pseudomonads Rule Degradation of Polyaromatic Hydrocarbons in Aerated Sediment
title_fullStr	Pseudomonads Rule Degradation of Polyaromatic Hydrocarbons in Aerated Sediment
title_full_unstemmed	Pseudomonads Rule Degradation of Polyaromatic Hydrocarbons in Aerated Sediment
title_sort	pseudomonads rule degradation of polyaromatic hydrocarbons in aerated sediment
description	Given that the degradation of aromatic pollutants in anaerobic environments such as sediment is generally very slow, aeration could be an efficient bioremediation option. Using stable isotope probing (SIP) coupled with pyrosequencing analysis of 16S rRNA genes, we identified naphthalene-utilizing populations in aerated polyaromatic hydrocarbon (PAH)-polluted sediment. The results showed that naphthalene was metabolized at both 10 and 20°C following oxygen delivery, with increased degradation at 20°C as compared to 10°C—a temperature more similar to that found in situ. Naphthalene-derived 13C was primarily assimilated by pseudomonads. Additionally, Stenotrophomonas, Acidovorax, Comamonas, and other minor taxa were determined to incorporate 13C throughout the measured time course. The majority of SIP-detected bacteria were also isolated in pure cultures, which facilitated more reliable identification of naphthalene-utilizing populations as well as proper differentiation between primary consumers and cross-feeders. The pseudomonads acquiring the majority of carbon were identified as Pseudomonas veronii and Pseudomonas gessardii. Stenotrophomonads and Acidovorax defluvii, however, were identified as cross-feeders unable to directly utilize naphthalene as a growth substrate. PAH degradation assays with the isolated bacteria revealed that all pseudomonads as well as Comamonas testosteroni degraded acenaphthene, fluorene, and phenanthrene in addition to naphthalene. Furthermore, P. veronii and C. testosteroni were capable of transforming anthracene, fluoranthene, and pyrene. Screening of isolates for naphthalene dioxygenase genes using a set of in-house designed primers for Gram-negative bacteria revealed the presence of such genes in pseudomonads and C. testosteroni. Overall, our results indicated an apparent dominance of pseudomonads in the sequestration of carbon from naphthalene and potential degradation of other PAHs upon aeration of the sediment at both 20 and 10°C.
publisher	Frontiers Media S.A.
publishDate	2015
url	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4652016/
_version_	1613503558073712640

Pseudomonads Rule Degradation of Polyaromatic Hydrocarbons in Aerated Sediment

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