Analyzing microbial communities and their biodegradation of multiple pharmaceuticals in membrane bioreactors

Abstract

Pharmaceuticals are of concern to our planet and health as they can accumulate in the environment. The impact of these biologically active compounds on ecosystems is hard to predict, and information on their biodegradation is necessary to establish sound risk assessment. Microbial communities are promising candidates for the biodegradation of pharmaceuticals such as ibuprofen, but little is known yet about their degradation capacity of multiple micropollutants at higher concentrations (100 mg/L). In this work, microbial communities were cultivated in lab-scale membrane bioreactors (MBRs) exposed to increasing concentrations of a mixture of six micropollutants (ibuprofen, diclofenac, enalapril, caffeine, atenolol, paracetamol). Key players of biodegradation were identified using a combinatorial approach of 16S rRNA sequencing and analytics. Microbial community structure changed with increasing pharmaceutical intake (from 1 to 100 mg/L) and reached a steady-state during incubation for 7 weeks on 100 mg/L. HPLC analysis revealed a fluctuating but significant degradation (30–100%) of five pollutants (caffeine, paracetamol, ibuprofen, atenolol, enalapril) by an established and stable microbial community mainly composed of Achromobacter, Cupriavidus, Pseudomonas and Leucobacter. By using the microbial community from MBR1 as inoculum for further batch culture experiments on single micropollutants (400 mg/L substrate, respectively), different active microbial consortia were obtained for each single micropollutant. Microbial genera potentially responsible for degradation of the respective micropollutant were identified, i.e. Pseudomonas sp. and Sphingobacterium sp. for ibuprofen, caffeine and paracetamol, Sphingomonas sp. for atenolol and Klebsiella sp. for enalapril. Our study demonstrates the feasibility of cultivating stable microbial communities capable of degrading simultaneously a mixture of highly concentrated pharmaceuticals in lab-scale MBRs and the identification of microbial genera potentially responsible for the degradation of specific pollutants. Key points • Multiple pharmaceuticals were removed by stable microbial communities. • Microbial key players of five main pharmaceuticals were identified.

Phenotypic and metabolic adaptations of Rhodococcus cerastii strain IEGM 1243 to separate and combined effects of diclofenac and ibuprofen

“…We opted for this high concentration of NSAIDs due to the potential application of Rhodococcus -based biocatalysts in local post-treatment technologies during drug manufacturing, where influents contain elevated pharmaceutical levels. Moreover, previous research on biodegradation and the diverse effects of pharmaceuticals on bacteria supports the use of higher dosages ( Alobaidi et al, 2021 ; Żur et al, 2021 ; Mohamed et al, 2023 ; Suleiman et al, 2023 ). D-glucose was employed as an additional carbon and energy source at a concentration of 0.5 g/L.…”

“…The experiments were conducted in 250 mL Erlenmeyer flasks containing 100 mL of "RS" (Rhodococcus Surfactant) mineral salt medium. The composition of the medium (Alobaidi et al, 2021;Żur et al, 2021;Mohamed et al, 2023;Suleiman et al, 2023). D-glucose was employed as an additional carbon and energy source at a concentration of 0.5 g/L.…”

Investigation of biologically active zeolite: Role of colonization in the removal of 14C-labelled sulfamethoxazole in wastewater

“…This library was then sequenced with a 16S™ NGS Library Prep Kit (V4) (ZymoResearch Corp., USA) using an Illumina MiSeq (Illumina, USA). Bacterial community analyses sequencing and data analyses were carried out as described elsewhere [31]. Barcode primers and DNA quantification data are available in the supplementary information.…”