Rathi Devi P and Packialakshmi N

ABSTRACT

Soil is a mixture of organic nutrients, which provides nutrients for plant growth. Plants require N, P & K for their growth and vegetative propagation. Among vital nutrients, Phosphorus is less available to plants and microorganisms aid in phosphate solubilization. The present study is an ecofriendly method to induce phosphate solubilization in Rhizosphere soil. Totally 25 isolates were isolated from rhizosphere using Pikovskaya mediumand screened for phosphate solubilization using Tricalcium phosphate supplemented minimal medium.Of these, Aspergillus sp and Penicillium sp were found to produce remarkable solubilization index. Hence these two isolates were used for further assays. Enzyme assay was carried out to determine the enzyme activity using cell free extractsand the activity was analyzed by spectrophotometry.In addition, HPLC also performed to determine the end products of phosphate solubilization.The results of HPLC studies revealed that tricalcium phosphate was solubilized into organic acids like citric acid, gluconic acid and malic acid. The results of present study are an evidence for the production of organic acids by Aspergillus sp and phosphate solubilization which induce crop improvement as well as sustainable agriculture. Keywords : Fungi, Phosphate solubilization, Enzyme assay, HPLC, Organic acids.