Background: The global phosphorus crisis is an evolving concern as the world's phosphorus sources are running out and demand for agricultural production is rising. Phosphorus shortages undermine food security and demand long-term management practices to assure phosphorus availability. Methods: Aspergillus strains were first screened on PVK media to get phosphorus solubilizing species and then the best strain was used to produce acid phosphatases. Finally, the effect of various assay conditions was analyzed to characterize extracellular acid phosphatases. Results: Out of four isolated strains, only A. niger, A. oryzae, and A. flavus were able to solubilize phosphate on PVK, of which A. niger stood out with a maximum solubility index of 2.38. The optimal pH and temperature for enzyme activity were recorded as 4.5 and 30°C. Furthermore, the substrate concentration of 100 mM with a 40-minute incubation period was found as a standard condition to achieve maximum specific activity i.e. 12 U/mg and a 17% higher free phosphorus level. After optimization, a 43.8% increment in the activity of extracellular acid phosphatases was observed. Conclusion: The study concludes that A. niger was the prominent performer, with improved phosphate solubilization and enzyme activity, as well as higher phosphorus release, demonstrating its potential for
enhancing phosphorus availability not only in agricultural and environmental fields but in setups with lower phosphate availability too.