An Immobilized Streptomyces Bioformulation as an Effective Strategy for Atrazine Bioremediation in Soil

Intensive atrazine use in agriculture poses persistent risks to soil ecosystems and environmental health, highlighting the need for robust and scalable remediation technologies. In this study, we developed an innovative formulation based on Streptomyces sp. M7 immobilized on solid carriers to enhance functional performance and stability in soil environments. The microorganism was successfully immobilized on different supports, achieving efficiencies ranging from 39.4% to 97.2%. Among them, vermiculite emerged as a suitable carrier, promoting superior structural colonization, metabolic activity, and biofilm formation. Notably, the resulting bioformulation retained 75% cell viability after 28 days of storage at room temperature while preserving its functional activity, demonstrating its suitability for extended shelf-life and potential field application. Its performance was further evaluated in atrazine-contaminated soil microcosms (25 mg kg^- 1), where bioaugmentation with the immobilized system enhanced herbicide dissipation (51.5%) compared to non-inoculated controls. Importantly, no adverse effects were observed on native microbial density or soil enzymatic activity, indicating environmental compatibility. Overall, these results demonstrate that vermiculite-immobilized Streptomyces sp. M7 constitutes a robust, stable, and environmentally friendly strategy for atrazine bioremediation in soil systems.