Surface-Engineered Organo-Montmorillonites as Tunable Urease Inhibitors: Interfacial Hydrophobic Anchoring and...

Rapid urea hydrolysis in soil triggers substantial ammonia volatilization; it severely limits nitrogen use efficiency and increases greenhouse gas emissions. In this work, we describe a series of surface-engineered organo-montmorillonites that could achieve >80% suppression of urease activity through the hydrophobic interaction with urease. Kinetic analysis revealed a trend indicative of a chain-length-dependent transition from competitive-like inhibition to non-competitive-like inhibition driven by entropy-favored hydrophobic anchoring. Multi-technique characterizations combined with molecular dynamics simulations showed that long-chain surfactants induce partial unfolding of the urease secondary structure while rigidifying the flap domain of the active site. The optimal organo-montmorillonite exhibited 16-fold stronger binding (-1850 kJ/mol) than the native montmorillonite; it delayed urea conversion, increased wheat yield, and enhanced nitrogen uptake in field trials, matching the commercial urease inhibitor N-(n-butyl)thiophosphoric triamide. Metagenomic profiling confirmed that the organo-montmorillonite preserved microbial diversity while selectively enriching plant-beneficial taxa, such as Mesorhizobium. With the bridging of clay surface chemistry with enzyme structural mechanics, this study establishes a sustainable paradigm for regulating the conformational change of enzymes and managing nitrogen in agroecosystems.