Abstract
The over-usage of paracetamol (PCT) has increased its concentration in aquatic environments,
indicating the inefficiency of wastewater treatment plants (WWTPs) in PCT removal.
Its accumulation, along with its metabolites, poses risks to aquatic ecosystems and organisms
relying on these water sources. This study hypothesized that bacteria isolated from
gold mine tailings possess the ability to biodegrade PCT effectively. Six bacterial species,
Bacillus clausii, Bacillus niacini, Bacillus thuringiensis, Bacillus licheniformis, Staphylococcus capitis,
and Rhizobium flavum, were isolated and identified via 16S rRNA sequencing. Their PCT
degradation capabilities (100 – 500 mg/L) were assessed using High-performance liquid
chromatography (HPLC), while metabolites were identified using liquid chromatography
quadrupole time-of-flight mass spectrometry (LC-QTOF-MS). B. clausii achieved >95% degradation
at 100 mg/L but exhibited reduced efficiency (<45%) at higher concentrations,
while B. niacini, B. thuringiensis, and B. licheniformis achieved >75% degradation for 200 –
500 mg/L PCT. Kinetic analysis revealed predominantly zero-order kinetics, while B. clausii
followed first and second-order kinetics for 200 and 500 mg/L PCT, respectively. FTIR analysis
indicated PCT degradation by Bacillus strains, with no changes observed in abiotic controls.
The biodegradation pathway led to the formation of value-added metabolites, including 2-
(2,6-diisopropylphenyl)-5-hydroxyisoindole-1,3-dione, Oleoyl-L-carnitine, tetrahydropalmatine,
minocycline, tentoxin, 4-nitrophenol, and pyrocatechol, which exhibit potential pharmaceutical
and cosmetic applications. The recovery, characterization, and pharmacological properties
of these compounds are significant for understanding their potential and application.
This study demonstrated the degradation potential of extremophilic bacteria PCT and introduced
a novel pathway for converting pharmaceutical pollutants into valuable bioactive
compounds, promoting environmental sustainability and resource recovery.