Harnessing landfill-derived Bacillus subtilis (LLS-04) for bio-electrodegradation of di-butyl phthalate: Comprehensive toxicity assessment across multiple biological models

Abstract

Di-butyl phthalate (DBP), a pervasive environmental contaminant, poses significant ecological and health risks due to its persistence and toxicity. This study investigates the potential of a landfill-derived Bacillus subtilis strain (LLS-04) in bio-electrodegradation of DBP, alongside a comprehensive toxicity assessment across multiple biological models. Bio-electrodegradation efficiency was compared to biodegradation and electrodegradation, revealing that bio-electrodegradation achieved a remarkable 98.57 % reduction in DBP concentration significantly outperforming the other methods. This enhanced degradation was attributed to improved microbial activity and enzyme production, as indicated by higher protein content and increased esterase and dehydrogenase activities in the bio-electrodegradation system. The optimized conditions facilitated efficient degradation, with HPLC-MS/MS analysis confirming the breakdown of DBP into non-toxic end products via a proposed metabolic pathway. A comprehensive toxicity assessment, including in-silico analysis, in-vitro cytotoxicity and brine shrimp lethality assays, demonstrated a significant reduction in toxicity of BES treated effluent compared to DBP untreated effluent. Furthermore, in-vivo toxicity studies using animal model supported these findings, demonstrating reduced toxicity in the BES treated effluent compared to the DBP untreated effluent. Overall, these findings highlight the potential application of bio-electrodegradation in bioremediation strategies for phthalate pollution, offering an effective solution for reducing both DBP concentration and its environmental toxicity.