Accelerated ibuprofen removal in soils via bioaugmentation: Insights into the involved microbiomes

Ibuprofen (IBP), a widely used pharmaceutical compound, is increasingly detected in soils, raising concerns regarding its persistence and potential impacts on microbial communities and crop health. This study evaluated the adsorption, desorption, and biodegradation of IBP in three soils (ALC, CON, ETS) with contrasting agricultural uses, physicochemical and microbiological characteristics, and monitored shifts in microbial communities during bioremediation. Sorption was weak and strongly influenced by soil organic matter. Desorption was substantial in ALC and CON soils (38-50%) but nearly negligible in ETS (<6.5%). Biodegradation assays confirmed microbial activity as the primary dissipation pathway. Abiotic controls exhibited limited removal (14-23.5%), whereas endogenous microbiota facilitated faster dissipation in ALC and CON (DT₅₀ = 3.3 days) and slower in ETS (12.2 days), associated with its low desorption rate. Bioaugmentation with the IBP-degrading C7 consortium markedly accelerated dissipation across all soils (DT₅₀ = 0.3-0.6 days), demonstrating its strong potential for IBP remediation. DNA metabarcoding (16S, ITS2) revealed significant alterations in bacterial and fungal communities during biodegradation. Microbial richness declined after IBP contamination but recovered upon IBP dissipation in ALC and ETS soils, whereas CON exhibited limited recovery. The dominant bacterial phyla in original soils included Proteobacteria, Firmicutes, Actinobacteria, and Chloroflexi; fungal communities were primarily composed of Ascomycota and Basidiomycota. In bioaugmented soils, genera such as Pseudomonas, Labrys, and Sphingomonas increased, particularly in CON. These findings underscore the effectiveness of targeted bioaugmentation for accelerating IBP dissipation in soils and provide insights into microbial resilience and community dynamics during IBP contamination and recovery.