author(s)
Kumbhar SC, Karade VM, Lohate SR and Kashti PD

abstract
Phosphorus is a critical macronutrient for plant growth, yet much of it in soil exists in insoluble forms, rendering it unavailable to plants. Phosphate-solubilizing bacteria (PSB) are recognized as a sustainable alternative to chemical fertilizers, capable of mobilizing fixed soil phosphorus through acid production, enzymatic activity, and other biochemical processes. This study systematically collected 42 agricultural soil samples from Satara and Sangli districts of Western Maharashtra, representing diverse soil types and cropping patterns. Forty-two PSB isolates were screened qualitatively using Pikovskaya’s agar and quantitatively in Pikovskaya’s broth. Ten high-performing isolates were characterized for cultural, morphological, and biochemical traits, pH reduction, titrable acidity, and phosphatase enzyme activity. Among these, isolates Tas-1, Pal-1, and Pal-2 exhibited superior phosphate solubilization efficiency, with Tas-1 showing the highest solubilization index (4.08), phosphate solubilization efficiency (308.06%), and soluble phosphorus (180.5 mg/L). These isolates also demonstrated robust acid production (pH reduction to 3.7-3.9; titrable acidity up to 1.7%) and high phosphatase activity, highlighting their potential for biofertilizer development. The findings are consistent with earlier reports on Bacillus and Pseudomonas spp., and reinforce the promise of PSB for sustainable phosphorus management in agriculture.