Synergistic Remediation of Organic Arsenicals via an Integrated Plant–Microbe Remediation Platform: A Multiomics Interrogation of Degradation and Detoxification Mechanisms

The organic arsenic compounds diphenylarsonic acid (DPAA) and phenylarsonic acid (PAA) are pervasive and hazardous soil pollutants. To address this, we constructed a remediation system by first screening and combining two functional bacteria: Bacillus subtilis and Bacillus cereus. This synthetic consortium rapidly degraded DPAA and PAA within 24 h, primarily through the cleavage of arsenic–carbon bonds and aromatic rings, facilitated by specific enzymes (ArsI and ring-opening dioxygenase). Concurrently, we employed alfalfa, a plant capable of efficiently absorbing inorganic arsenic released during microbial degradation. This plant–microbe system, tested over 60 days in contaminated soil, successfully removed both organic pollutants and the derived inorganic arsenic. Multiomics analyses confirmed that the remediation process beneficially restructured the soil environment, stimulating microbial activity and key metabolic functions and reducing potential risks like antibiotic resistance genes. This integrated strategy, verified through multiomics to drive beneficial soil ecosystem restructuring, provides a novel and mechanistically informed approach for the sustainable cleanup of complex organoarsenical contamination.