Cultivation and characterization of bacterial isolates capable of degrading pharmaceutical and personal care products for improved removal in activated sludge wastewater treatment

Pharmaceutical and personal care products (PPCPs) discharged with wastewater treatment plant (WWTP) effluents are an emerging surface water quality concern. Biological transformation has been identified as an important removal mechanism during wastewater treatment. The aim of this research was the identification of bacteria with characteristics for potential bioaugmentation to enhance PPCP removal. We report here the cultivation and characterization of bacteria capable of degrading PPCPs to ng/L concentrations. An isolation approach was developed using serial enrichment in mineral medium containing 1 mg/L of an individual PPCP as the sole organic carbon source available to heterotrophs until the original activated sludge inocula was diluted to similar to 10(-8) of its initial concentration, followed by colony growth on solid R2A agar. Eleven bacteria were isolated, eight that could remove triclosan, bisphenol A, ibuprofen, or 17 beta-estradiol to below 10 ng/L, one that could remove gemfibrozil to below 60 ng/L, and two that could remove triclosan or E2, but not to ng/L concentrations. Most bacterial isolates degraded contaminants during early growth when grown utilizing rich carbon sources and were only able to degrade the PPCPs on which they were isolated. Seven of the bacterial isolates were sphingomonads, including all the triclosan and bisphenol A degraders and the ibuprofen degrader. The study results indicate that the isolated bacteria may have a positive influence on removal in WWTPs if present at sufficient concentrations and may be useful for bioaugmentation.