Identification of Bacteria Utilizing Biphenyl, Benzoate, and Naphthalene in Long-Term Contaminated Soil. IMG CAS CR

Bacteria were identified associated with biodegradation of selected aromatic contaminants or their analogues - biphenyl, benzoate, and naphthalene - in a PCB and PAH-contaminated soil. In order to avoid biases of culture-based approaches, stable isotope probing was applied in combination with sequence analysis of 16S rRNA gene pyrotags amplified from 13C-DNA. Accuracy and efficiency of amplification and sequencing strategy as well as determination of appropriate parameters for sample sequences processing were based on mock community analysis. Biotransformation of all studied aromatics was predominantly mediated by specific populations of * Proteobacteria*. Sequences clustering with the genus *Rhodanobacter* were not only associated with the metabolism of naphthalene and benzoate, which was described earlier, but newly also with biphenyl. Additionally, * Rhodanobacter* spp. were the major populations to derive carbon from biphenyl. Besides *Rhodanobacter*, populations of *Burkholderia*, *Pandoraea*, and *Dyella* were detected to derive carbon from all three substances. Pseudomonads were identified to largely dominate carbon acquisition from 13C-labeled naphthalene and benzoate. Results of this study contribute to our understanding of biodegradation processes and carbon flow in contaminated soil. Obtained data can be beneficial for more effective designing of engineered bioremediation strategies based, for instance, on intrinsic microflora biostimulation.