Identification of a Novel Ibuprofen Biotransformation Pathway in Streptomyces sp. D218 and Detoxification as Indicated by the Green Algae Scenedesmus obliquus

Ibuprofen, a widely used nonsteroidal anti-inflammatory drug, contaminates agricultural products and potentially threatens human health due to its frequent detection and poor biodegradability. Microbial metabolism dominates the elimination of residual ibuprofen in the environment. In mineral salt medium at pH 6 with 5 mM glucose, Streptomyces sp. D218 transformed ibuprofen concentrations ranging from 0.05 to 0.40 mM in 24 h. The optimal temperature, pH, and initial OD600 nm for ibuprofen transformation by strain D218 were 25–37 °C, 5.0–6.0, and 1.0–1.5, respectively. Strain D218 could simultaneously transform ibuprofen into the intermediates 2-hydroxyibuprofen and ibuprofen amide (IBUA). The two intermediates were further metabolized to 2-hydroxyibuprofen amide (2HIBUA), thus relieving the growth inhibition of ibuprofen in Scenedesmus obliquus. This is the first complete pathway reported for the detoxification of ibuprofen transformation by a Gram-positive strain. These findings further our understanding of the microbial catabolism of the IBU.