ARPHA Conference Abstracts : Conference Abstract
Conference Abstract
Biodegradation of Benzene Under Microaerobic Conditions: a Groundwater Microcosm Experiment Combined with a Multiomics Approach and DNA Stable Isotope Probing
expand article infoAndras Tancsics, Anna Bedics, André Soares§, Balázs Kriszt|
‡ Department of Molecular Ecology, Institute of Aquaculture and Environmental Safety, Hungarian University of Agriculture and Life Sciences, Gödöllő, Hungary
§ Environmental Metagenomics, Research Center One Health Ruhr of the University Alliance Ruhr, Faculty of Chemistry, University of Duisburg-Essen, Essen, Germany
| Department of Environmental Safety, Institute of Aquaculture and Environmental Safety, Hungarian University of Agriculture and Life Sciences, Gödöllő, Hungary
Open Access


Monoaromatic hydrocarbons such as benzene, toluene, ethylbenzene, and xylene (BTEX) are the most common contaminants of the groundwater and can easily contaminate drinking water sources due to their relatively high water solubility. Among these compounds, benzene is known to have carcinogenic properties and is considered to be persistent under anoxic conditions. Although deep knowledge was acquired both on the aerobic and anaerobic degradation of benzene in the past three decades, the diversity of those bacteria which are able to degrade it under microaerobic conditions, is still unknown. To come over this limitation aerobic and microaerobic benzene-degrading microcosms were established using groundwater sediment of a BTEX-contaminated site and the evolved bacterial communities were investigated through a polyphasic approach including multiomics analysis and DNA stable isotope probing. The obtained results shed light on the fact that the aerobic and microaerobic benzene-degrading bacterial communities were distinctly different. In the aerobic microcosms members of the genus Pseudomonas overwhelmingly dominated the bacterial communities by showing even 40-50% abundance. In contrast, under microaerobic conditions members of the genera Azovibrio and Malikia dominated the communities, while the abundance of Pseudomonas drastically decreased compared to that of was observable in the aerobic microcosms. Results obtained by the analysis of microcosms spiked with 13C6-benzene confirmed these observations. In heavy DNA fractions obtained from the aerobic microcosms the enrichment of Pseudomonas and Rhizobiaceae-related 16S rRNA gene fragments was observable. At the same time, labelled DNA from the microaerobic microcosms contained mostly Azovibrio and Malikia-related sequences, while the abundance of Pseudomonas 16S rRNA gene sequences was below 2%. Besides, by using metagenomic dataset of a previous microaerobic experiment we managed to reconstruct an Azovibrio genome, in which a complete meta-cleavage pathway for the aerobic degradation of aromatic hydrocarbons was identified. Overall, it can be concluded that under microaerobic conditions members of Comamonadaceae and Rhodocyclaceae can be the key benzene degraders in contaminated subsurface environments.


Azovibrio, Malikia, aromatic hydrocarbons, microaerobic conditions

Presenting author

Dr. András Táncsics

Presented at

poster presentation

session topic: Impacts from Anthropogenic Activities

Funding program

András Táncsics was supported through the “OTKA” Young Researcher Excellence Programme of the National Research, Development and Innovation Office of Hungary.

Grant title

Microbial biodegradation of aromatic hydrocarbons in subsurface environments: elucidating the genetic background of microaerobic degradation by stable isotope and „omics” approaches (grant No. FK 134439)

Hosting institution

Hungarian University of Agriculture and Life Sciences

Conflicts of interest

The authors have declared that no competing interests exist.
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