Acetylacetone alleviates tetracycline stress in Chlorella vulgaris: Detoxification mechanisms and adaptive response

Microalgae-based system represents a promising and eco-friendly solution for mitigating antibiotic pollution. However, their efficacy is often compromised by antibiotics stress. Here, we demonstrate that acetylacetone (AA), a natural small molecule with potential to regulate microalgal growth and metabolism, significantly alleviates tetracycline (TC) toxicity in Chlorella vulgaris , enhancing TC removal in aquaculture wastewater from 1 mg L -1 to 0.01 mg L -1 . The AA-treated effluent showed no significant developmental toxicity to wheat and negligible antibiotic resistance gene propagation. Proteomic and metabolomic analyses revealed that AA restores cellular homeostasis in microalgae by counteracting TC-induced oxidative stress and metabolic dysregulation, thereby sustaining removal performance under stressful conditions. This stress-regulation mechanism enables robust microalgae-based antibiotic degradation while preserving aquatic ecological safety, providing a sustainable strategy for antibiotic-containing wastewater treatment.