Isolation and Characterization of the Wastewater Micropollutant Phenacetin-Degrading Bacterium Rhodococcus sp. Strain PNT-23

Phenacetin, an antipyretic and analgesic drug, poses a serious health risk to both humans and aquatic organisms, which is of concern since this micropollutant is frequently detected in various aquatic environments. However, rare pure bacterial cultures have been reported to degrade phenacetin. Therefore, in this study, the novel phenacetin-degrading strain PNT-23 was isolated from municipal wastewater and identified as a Rhodococcus sp. based on its morphology and 16S rRNA gene sequencing. The isolated strain could completely degrade 100 mg/L phenacetin at an inoculum concentration of OD600 1.5 within 80 h, utilizing the micropollutant as its sole carbon source for growth. Strain PNT-23 exhibited optimal growth in LB medium at 37 degrees C and a pH of 7.0 with 1% NaCl, while the optimal degradation conditions in minimal medium were 30 degrees C and a pH of 7.0 with 1% NaCl. Two key intermediates were identified during phenacetin biodegradation by the strain PNT-23: N-acetyl-4-aminophenol and 4-aminophenol. This study provides novel insights into the biodegradation of phenacetin using a pure bacterium culture, expands the known substrate spectra of Rhodococcus strains and presents a potential new candidate for the microbial removal of phenacetin in a diverse range of environments.

Automated summary

In this study, a novel phenacetin-degrading strain PNT-23 was isolated from municipal wastewater and identified as a Rhodococcus sp. The isolated strain could completely degrade 100 mg/L phenacetin within 80 h, utilizing it as its sole carbon source for growth. Two key intermediates, N-acetyl-4-aminophenol and 4-aminophenol, were identified during the phenacetin biodegradation by strain PNT-23. This study provides new insights into phenacetin biodegradation and presents a potential candidate for its microbial removal in various environments.