Microbial-mediated degradation of benzyl paraben: isolation, characterization, and mechanistic insights

Paraben contamination has emerged as a significant environmental concern, prompting interest in microbial remediation as a sustainable and eco-friendly solution. This study investigates the biodegradation of benzylparaben (BeP) using three bacterial isolates: Serratia surfactantfaciens, Serratia nematodiphila, and Paenibacillus lautus. Biochemical profiling and 16 S rRNA gene sequencing confirmed their identities, showing 99% sequence similarity with known strains. All isolates tolerated high BeP concentrations (up to 800 mg/L) and exhibited notable degradation kinetics. High-performance liquid chromatography (HPLC) revealed a progressive decline in BeP levels, with S. surfactantfaciens achieving 99% degradation and S. nematodiphila reaching complete degradation within 120 h. P. lautus demonstrated superior efficiency, fully (~ 99%) degrading BeP in just 96 h. Fourier-transform infrared spectroscopy (FTIR) and high-resolution mass spectrometry (HRMS) confirmed structural transformation of BeP and the formation of intermediate metabolites. FTIR spectra lacked characteristic ester and carbonyl peaks in treated samples, indicating compound breakdown. Kinetic modelling revealed a fractional-order degradation pathway (n = 1.5 for Isolate_1; n = 0.5 for Isolates_2 and Isolate_3), suggesting a multi-step enzymatic mechanism. Statistical analysis validated the significant reduction of BeP levels by all isolates compared to controls. These findings underscore the potential of these bacterial strains for effective biodegradation of paraben-contaminated environments and support their application in sustainable wastewater treatment strategies.