Assessment on the effect of erythromycin on the microbiome of a bioslurry pilot plant for contaminated sediment bioprocessing

Bioslurry is a microbial-based technology that uses a bioreactor to treat sediments. The role of microbial metabolic capabilities is crucial for the removal performance of this technology and those factors that can affect microbial community. Particularly, antibiotics are among the environmental emergent contaminants. In this work, the effect of erythromycin was evaluated on the removal efficiencies of total petroleum hydrocarbons (TPHs), present in real sediments. On the basis of preliminary microcosm tests, an optimal erythromycin concentration (0.5 μg mL−1) was applied to a bioslurry pilot plant, using as control condition a parallel reactor without erythromycin addition. During experimentation the removal efficiency increased in both reactors, especially in the antibiotic-containing reactor where performance removal reached 81.5 %. A metataxonomic approach, based on a Next Generation Sequencing analysis of amplicons obtained from 16S rRNA encoding gene and ITS regions, showed that the presence of erythromycin affects the dynamic changes of both eukaryotic and prokaryotic communities in the reactor, selecting bacteria capable of degrading aromatic compounds, performing dehalogenation and methane oxidation as inferred by bioinformatic analysis.