<abstract xmlns="http://www.w3.org/1999/xhtml"><p>Polycyclic aromatic hydrocarbon (PAHs) are common soil contaminants of concern due to their toxicity toward plants, animals and microorganisms. The use of indigenous or added microbes (bioaugmentation) is commonly used for bioremediation of PAHs. In this work, the biodegradation rates and changes in the bacterial community structure were evaluated. The enrichment culture was useful for unambiguously identifying members of the soil bacterial community associated with PAH degradation and yielded a low diversity community. No significant difference in the rate of PAH degradation was observed between the microcosm receiving only PAHs or PAHs and bioaugmentation. Moreover, identical matches to the bioaugmentation inoculum were only observed at the initial stages of PAH degradation on day 8. After 22 days of incubation, the substantial degradation of all PAHs had occurred in both microcosms and the PAH contaminated soil had statistically significant increases in Alphaproteobacteria. There were also increases in Betaproteobacteria. In contrast, the PAH contaminated and bioaugmented soil was not enriched in PAH degrading Proteobacteria genera and, instead, an increase from 1.6% to 8% of the population occurred in the phylum Bacteroidetes class Flavobacteria, with <italic>Flavobacterium</italic> being the only identified genus. In addition, the newly discovered genus <italic>Ohtaekwangia</italic> increased from 0% to 3.2% of the total clones. These results indicate that the same soil microbial community can give rise to different PAH degrading consortia that are equally effective in PAH degradation efficiency. Moreover, these results suggest that the lack of efficacy of bioaugmentation in soils can be attributed to a lack of persistence of the introduced microbes, yet nonetheless may alter the microbial community that arises in response to PAH contamination in unexpected ways.</p></abstract>

Polycyclic aromatic hydrocarbon (PAHs) are common soil contaminants of concern due to their toxicity toward plants, animals and microorganisms. The use of indigenous or added microbes (bioaugmentation) is commonly used for bioremediation of PAHs. In this work, the biodegradation rates and changes in the bacterial community structure were evaluated. The enrichment culture was useful for unambiguously identifying members of the soil bacterial community associated with PAH degradation and yielded a low diversity community. No significant difference in the rate of PAH degradation was observed between the microcosm receiving only PAHs or PAHs and bioaugmentation. Moreover, identical matches to the bioaugmentation inoculum were only observed at the initial stages of PAH degradation on day 8. After 22 days of incubation, the substantial degradation of all PAHs had occurred in both microcosms and the PAH contaminated soil had statistically significant increases in Alphaproteobacteria. There were also increases in Betaproteobacteria. In contrast, the PAH contaminated and bioaugmented soil was not enriched in PAH degrading Proteobacteria genera and, instead, an increase from 1.6% to 8% of the population occurred in the phylum Bacteroidetes class Flavobacteria, with Flavobacterium being the only identified genus. In addition, the newly discovered genus Ohtaekwangia increased from 0% to 3.2% of the total clones. These results indicate that the same soil microbial community can give rise to different PAH degrading consortia that are equally effective in PAH degradation efficiency. Moreover, these results suggest that the lack of efficacy of bioaugmentation in soils can be attributed to a lack of persistence of the introduced microbes, yet nonetheless may alter the microbial community that arises in response to PAH contamination in unexpected ways.

The Emergence of Different Functionally Equivalent PAH Degrading Microbial Communities from a Single Soil in Liquid PAH Enrichment Cultures and Soil Microcosms Receiving PAHs with and without Bioaugmentation

Polish Journal of Microbiology

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Polycyclic aromatic hydrocarbon (PAHs) are common soil contaminants of concern due to their toxicity toward plants, animals and microorganisms. The use of...

The Emergence of Different Functionally Equivalent PAH Degrading Microbial Communities from a Single Soil in Liquid PAH Enrichment Cultures and Soil Microcosms Receiving PAHs with and without Bioaugmentation

Article Category: original-paper

Published Online: Sep 04, 2018

Page range: 365 - 375

Received: Nov 27, 2018

Accepted: Jun 22, 2018

DOI: https://doi.org/10.21307/pjm-2018-046

Keywords
polycyclic aromatic hydrocarbon, PAH, soil microbial community, biodegradation, bioaugmentation

© 2018 Francine Amaral Piubeli et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

The Emergence of Different Functionally Equivalent PAH Degrading Microbial Communities from a Single Soil in Liquid PAH Enrichment Cultures and Soil Microcosms Receiving PAHs with and without Bioaugmentation

Article Category: original-paper

Published Online: Sep 04, 2018

Page range: 365 - 375

Received: Nov 27, 2018

Accepted: Jun 22, 2018

DOI: https://doi.org/10.21307/pjm-2018-046

Keywordspolycyclic aromatic hydrocarbon, PAH, soil microbial community, biodegradation, bioaugmentation

© 2018 Francine Amaral Piubeli et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Keywords
polycyclic aromatic hydrocarbon, PAH, soil microbial community, biodegradation, bioaugmentation