Sulfoxaflor biodegradation: environmental fate, degrading microorganisms, and mechanisms of nitrile...

Sulfoxaflor (SXF), a novel sulfoximine insecticide, has been widely used as a substitute for traditional neonicotinoids (NEOs) to control piercing-sucking pests in agriculture. However, its environmental persistence, high mobility in water and soil, and potential toxicity to non-target organisms (e.g., honeybees, aquatic invertebrates) as well as the toxic risks of its long-lasting metabolites (e.g., X11719474) have raised significant ecological concerns. Biodegradation, as an environmentally friendly and efficient remediation strategy, plays a crucial role in regulating the environmental fate of SXF, and has become a research hotspot in recent years. This review systematically summarizes the environmental behaviors of SXF, including its migration, transformation, and residue characteristics in water bodies, soils, and agricultural products. It focuses on collating the reported SXF-degrading microorganisms (mainly bacteria such as Ensifer, Pseudomonas, Aminobacter, and cyanobacteria like Synechocystis salina) and their degradation efficiencies under different environmental conditions. Moreover, the review elaborates on the core role of nitrile hydratase (NHase) in SXF biodegradation, including the types, structural characteristics, and catalytic mechanisms of SXF-degrading NHases, as well as the key factors (environmental factors, structural residues, chemical modulators) influencing NHase catalytic activity. Additionally, biotechnological optimization strategies for enhancing SXF biodegradation efficiency, such as heterologous expression and immobilization of NHase, are discussed in detail. Finally, the current research gaps and future research directions are prospected, aiming to provide comprehensive theoretical support for the scientific application and environmental risk control of SXF, and offer references for the biodegradation research of novel NEOs and similar insecticides.