Rutere Njeru, C*; Posselt, M; Horn, M: Microbial degradation of Ibuprofen in the hyporheic zone of a lowland stream
Poster, VAAM Annual Meeting 2017, Würzburg, Germany: 2017-03-05 - 2017-03-08

Ibuprofen is a non-steroidal anti-inflammatory pain reliever and among pharmaceutical residues detected in aquatic environments. Widespread use of the drug coupled with incomplete removal during wastewater treatment results in its persistence in effluents and receiving waters. Potential total removal by microbial activity in the hyporheic zone (HZ) of rivers downstream of wastewater treatment plant discharge sites has been hypothesised. Microbial communities associated with ibuprofen degradation are essentially unknown. To address this hypothesis, two sets of oxic HZ sediment microcosms spiked exclusively with ibuprofen (5, 40, 200 and 400 μM), or ibuprofen (5, 40, 200 and 400 μM), and 1 mM acetate were set up under laboratory conditions. Ibuprofen degradation in non-sterile sediments relative to autoclaved sediments indicated removal by microbial degradation. Ibuprofen was completely consumed in the absence and presence of supplemental acetate after approximately 11 and 16 days, respectively. Refeeding of ibuprofen and acetate in the respective setups after the initial depletion resulted in complete degradation within 24 hours in all treatments. Metabolites of ibuprofen included 1-, 2-, 3-Hydroxy- and Carboxyibuprofen. Quantitative real-time PCR revealed no pronounced differences in copy numbers of 16S rRNA gene or transcripts between non-spiked controls and treatments. Time -resolved triplicate amplicon Illumina MiSeq sequencing targeting the 16S rRNA genes and transcripts revealed increased relative abundances of operational taxonomic units affiliating with Proteobacteria, Acidobacteria, Actinobacteria and Firmicutes in treatments with rather than without ibuprofen. Alpha-, Beta- and Deltaproteobacteria were most active as indicated by RNA -based analyses. The collective results indicated that (i) HZ sediments are capable of ibuprofen removal and (ii) more diverse microbes than previously thought including the genera Fodinicola, Hyphobacterium, and members of Acidobacteria subdivision 6 are associated with such an ecosystem service.

last modified 2017-03-15