Native Klebsiella and Serratia isolates exhibit potential as bioremediating agents of triclosan - an emerging pharmaceutical and personal care product (PPCPs) pollutant

Abstract

Pharmaceuticals and Personal Care Products (PPCPs) are now known as pseudo persistent pollutants, which over time can harm the aquatic ecosystem by being released in the environment. Of those, triclosan has been a particular focus due to its environmental persistence, bioaccumulation, toxic transformation products, and apparent toxicity to aquatic organisms at environmentally relevant levels. This study was designed to isolate and screen the microorganisms that could degrade triclosan from the water samples collected from Hindon River and evaluate their potential as triclosan bioremediation agents for the water contaminated with triclosan. Microbial isolates were isolated on selective media such as Nutrient Agar (NA), Mineral Salts Medium (MSM) with 50, 100 and 500 mg L⁻¹ of triclosan. The findings demonstrated a progressive decline in viable bacterial counts with increasing triclosan concentration, decreasing from 1.2 × 10³ CFU/mL in the control to 8 × 10 2 CFU/mL at 50 mg/L , 300 CFU/mL at 100 mg/L and 11 CFU/mL at 500 mg/L. These selected isolates were found to have clear zone on triclosan containing media and grew well on Mineral Salts Medium (MSM) supplemented with 500 mg/L triclosan and their 16S rRNA gene sequencing identified them as Klebsiella pneumoniae (HM101) and Serratia marcescens (HN101) which could degrade triclosan and used in future bioremediation applications.