[Isolation and identification of a novel phosphate-dissolving strain P21]

Phosphate-dissolving microorganisms can be applied for better use of insoluble phosphorus as fertilizer., A phosphate-dissolving strain P21 was isolated from soil samples in China. The isolate was identified as Erwinia herbicola var. ananas, based on its 16Sr DNA sequence and physiological characteristics. Its activity was measured in solid media as well as liquid media using different phosphate sources including tricalium phosphate, hydroxyapatite, ferric phosphate, aluminium phosphate, zinc phosphate, and rock phosphates. E. herbicola could strongly dissolve 1206.20 mg tricalium phosphate and 529.67 mg hydroxyapatite in per liter liquid media. The strain showed high phosphate-dissolving ability for rock phosphates from Jinning and Kunyang in Yunnan province, Yaan in Sichuan province and Jinping in Jiangsu province with the capacity of 6.64 mg, 78.46 mg, 67.07 mg and 65.24 mg soluble phosphate respectively per liter medium, whereas the phosphate-dissolving ability to the rest of the eight rock phosphates was weak. According to the experiments, the phosphate-dissolving ability of E. herbicola was specific to different rock phosphates, and phosphate-dissolving ability of E. herbicola was not directly related to pH reduction of liquid media.