Stress Induced Phosphate Solubilization by Aspergillus awamori bxq33110 Isolated from Waste Mushroom Bed of Agaricus bisporus

Abstract

A fungal strain, capable of solubilizing insoluble phosphate under diverse temperature, pH and salt conditions was isolated from Waste Mushroom bed of Agaricus bisporus in South Korea. Based on 18S rRNA analysis, the strain was identified as Aspergillus awamori bxq33110. The strain showed maximum phosphate solubilization in AYG medium (525 µg mL-1) followed by NBRIP medium (515 µg mL-1). The strain solubilized Ca3(PO4)2 to a greater extent and rock phosphate and FePO4 to a certain extent. However AlPO4 solubilizing ability of the strain was found to be very low. Glucose at the rate of 2% (561µg mL-1) was found be the best carbon source for Aspergillus awamori bxq33110 to solubilize maximum amount of phosphate. However, no significant difference (P ≤ 0.05) in phosphorus solubilization was found between 1% and 2% glucose concentrations. (NH4)2SO4 was the best nitrogen source for Aspergillus awamori bxq33110 followed by NH4Cl and NH4NO3. At pH 7, temperature 30℃ and 5% salt concentration (674 µg mL-1) were found to be the optimal conditions for insoluble phosphate solubilization. However, strain Aspergillus awamori bxq33110 was shown to have the ability to solublize phosphate under different stress conditions at 30-40℃ temperature, pH 7-10 and 0-10% salt concentrations indicating it’s potential to be used as bio-inoculants in different environmental conditions.