Effects of bisphenol A on nitrogen removal in sulfur autotrophic denitrification-Anammox microbial consortia: Resilience, biotransformation, and toxicity

This study investigated the impact of bisphenol A (BPA) on nitrogen removal in sulfur autotrophic denitrification-Anammox (SAD/A) microbial consortia. Batch tests revealed a concentration-driven biphasic response: 1 μg/L–50 mg/L BPA stimulated denitrification, increasing nitrate removal efficiency by 9.82–29.17 % and total nitrogen removal efficiency by 4.05–6.24 % by providing organics. 50 mg/L BPA inhibited Anammox, reducing ammonia removal efficiency by 19.71 % and causing nitrite accumulation (12.06 ± 4.38 mg/L). Microbial analysis confirmed BPA promoted Proteobacteria-dominated denitrifiers but suppressed Planctomycetota (Anammox bacteria hosts). Two anaerobic BPA biodegradation pathways were identified, with hydroxylation and oxidative cleavage as primary routes. Although the SAD/A microbial consortia effectively detoxified BPA through sequential transformation, one intermediate (4-hydroxybenzaldehyde) exhibited elevated chronic toxicity. The SAD/A microbial consortia achieve dual goals for nitrogen removal and BPA mitigation. These findings provide effective strategies for treating endocrine-disrupting compounds polluted nitrogen-containing wastewaters.