Characterization of Pantoea Sp. Strain MK1D, and Erwinia Sp. Strain MK2Y as Tricalcium Phosphate Dissolving Bacteria Isolated from Calcareous Soil

Abstract

This study aimed to isolate and characterize bacterial strains capable of solubilizing tricalcium phosphate (TCP) as the most commonly and insoluble phosphate in soils. Normal and molecular approaches were used to isolate and characterize phosphate dissolving bacteria (PDB) adapted to arid and semi-arid climate conditions. In this study, two strains were successfully isolated and taxonomically classified as Pantoea sp. strain MK1D, and Erwinia sp. strain MK2Y based on sequences of their 16S rRNA gene and were given GenBank accession numbers KU358676 and KU358677, respectively. This was confirmed by the formation of large halo zones on both Pikovskaya (PVK) and National Botanical Research Institute's Phosphate (NBRIP) culture media. The significant bacterial growth on liquid media was associated with the reduction of pH from 7.0 to 2.0 which lead to 83% solubilization of added TCP of 0.75 g/L. This study confirmed that both PVK and NBRIP media were reliable and comparable for the isolation of PDB and measuring their efficiency. Further studies are needed to confirm the effectiveness of these strains under pot and field conditions and their potential for commercial biofertilizers production.