Biodegradation of high-strength methylparaben and trichlorocarbanilide by a defined bacterial consortium: kinetic evaluation and HPTLC monitoring

Abstract

Conventional wastewater treatment plants often struggle to manage episodic “shock loads” of emerging contaminants, particularly persistent preservatives such as methylparaben (MeP) and antimicrobial compounds such as trichlorocarbanilide (TCC). While most biodegradation studies focus on trace environmental concentrations, industrial effluents may contain substantially higher contaminant loads that challenge biological treatment systems. This study evaluates the biodegradation kinetics of MeP and TCC at elevated concentrations (100 mg L⁻ 1 ) using a defined bacterial consortium consisting of Alcaligenes sp. and Rhodococcus sp. PK06. Degradation performance was assessed in both nutrient broth and a synthetic wastewater matrix designed to simulate high-strength wastewater conditions. In addition, a high-performance thin-layer chromatography method was developed as a cost-effective analytical tool for monitoring contaminant degradation. Kinetic analysis indicated that the biodegradation process followed pseudo-first-order behavior (R 2 > 0.9). The consortium demonstrated strong resilience under high contaminant loads, achieving a TCC degradation rate constant of 0.045 h⁻ 1 (t½ = 15.4 h) and nearly complete removal within 120 h. Methylparaben degradation proceeded more gradually but reached 82.85% removal over the same period with a rate constant of 0.015 h⁻ 1 . These results demonstrate the capacity of defined bacterial consortia to degrade high-strength emerging contaminants and highlight the potential of combining microbial biodegradation with accessible analytical monitoring approaches for improved management of pharmaceutical and personal care pollutants in wastewater systems.

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