Abstract
The pervasive administration of antiretroviral drugs (ARVs) for the management of HIV/AIDS has led to their continuous entry into aquatic ecosystems via excretion and the suboptimal removal efficacy of conventional wastewater treatment plants (WWTPs). Efavirenz (EFV), a non-nucleoside reverse transcriptase inhibitor (NNRTI), is prominently detected and recalcitrant in the environment, exhibiting removal efficiencies below 50% in conventional WWTPs due to its hydrophobic nature, halogenation, and structural recalcitrance. This study reports the isolation of a novel Acinetobacter bereziniae strain (designated EFV-D1) from mine waste, which exhibited significant potential in the bioremoval of EFV. The isolate was cultured in a mineral salt medium with 50 mg/L EFV as the sole carbon source and identified through 16S rRNA gene sequencing, revealing 99.8% similarity to the A. bereziniae species. Batch removal experiments demonstrated that strain EFV-D1 achieved over 50% EFV removal within 24 hours under optimized conditions (pH 7.0, 35°C, agitation at 100rpm). Kinetic modelling followed pseudo–first-order kinetics, yielding a rate constant of 0.044 h-1 and an estimated half-life of 15.6 h, confirming efficient substrate utilization. Growth assays further demonstrate that A. bereziniae EFV-D1 could tolerate and metabolize EFV concentrations reaching its minimum inhibitory concentration (MIC), indicating resilience and adaptability to pharmaceutical-contaminated wastewater. This investigation establishes A. bereziniae EFV-D1 as a potent biocatalyst for the removal of EFV from wastewater, presenting a proof-of-concept of a scalable and cost-effective bioremediation strategy for emerging contaminants of concern. By integrating microbial bioremoval with existing treatment processes, A. bereziniae EFV-D1 offers a cost-efficient, environmentally benign, and scalable solution to mitigate the environmental persistence of EFV and analogous pharmaceutical pollutants in wastewater systems.
