Phosphate-Solubilizing Microbiota of Compost Elicited with Different Silicon Oxide Nanostructures to Increase Their Mineralization and Solubilization Properties

The overreliance on non-renewable phosphate fertilizers necessitates sustainable alternatives for phosphorus recycling in agriculture. This study aimed to characterize and enhance the metabolic activity of phosphate-solubilizing microorganisms isolated from compost by eliciting them with two distinct mesoporous silica nanoparticles: standard SBA-15-S and short-pore SBA-15-C. Bacterial strains with broad-spectrum P solubilization and mineralization capacities were isolated from the mesophilic phases of tomato greenhouse and cow manure composts. These isolates received treatment with nanoparticle concentrations of 0.1, 10, and 100 ppm. The results demonstrated that nanoparticle elicitation significantly altered microbial growth, solubilization halos on tricalcium phosphate, and the specific activity of acid, neutral, and alkaline phosphatases in a strain- and nanoparticle-dependent manner. Notably, SBA-15-C at 100 ppm consistently enhanced multiple P-recycling properties across several strains, including <i>Proteus</i> and <i>Myroides</i> species. Principal component analysis revealed distinct behavioral clusters between composting phases and isolation methods. The findings indicate that tailored silicon oxide nanostructures can serve as eustressors to modulate and enhance the P-solubilizing and mineralizing functions of compost-derived microbiota, offering a promising nanobiostimulation strategy for developing enhanced biofertilizers.