The evaluation of free and encapsulated Aspergillus awamori for phosphate solubilization in fermentation and soil-plant system

Aspergillus awamori S19, a phosphate solubilizing filamentous fungi, was immobilized in Ca-alginate and agar. The immobilized microbial cells were applied in a repeated-batch fermentation process in order to test their effect on solubilization of Udaipur rock phosphate (URP) and tricalcium phosphate (TCP). Agar entrapped cells produced 106 mg l−1 whereas Ca-alginate entrapped cells produced 93 mg l−1 soluble P that was significantly higher than freely suspended cells with URP. In the presence of TCP, immobilized cells showed significantly better phosphate solubilization than free cells, viz. 340 and 345 mg l−1 in agar and Ca-alginate entrapment, respectively versus merely 291 mg l−1 with free cells. Further the immobilized cells were introduced into the soil supplemented with TCP and URP to analyze their effect on plant growth and P uptake of mung bean plants. The result showed significantly higher plant growth in the presence of fungal inoculates.