Isolation and Characterization of Phosphate Solubilizing Fungus in Vitro

Abstract

Series of laboratory (in vitro) examinations were carried out to recognize the most potent fungi isolates and optimum culture conditions helps in solubilizing sparing phosphate in soil. Therefore, the present study aimed to isolate and screening of phosphate solubilizing fungi (PSF), study the contribution of PSF on solubilization of tri-calcium phosphate through excretion of acid and alkaline phosphatase and determine the optimal conditions for phosphate solubilization. From 12 fungal isolates, only four were chosen depending on their capacity to convert tri-calcium-P into soluble one. In this regard, Aspergillus niger, Aspergillus flavus, Aspergillus ficuum and Fusarium oxysporum were efficient in producing halo zone around the colonies on petri dish. Aspergillus niger was the most efficient phosphate solubilizer on Pikovskaya's agar plates (PVK) achieving solubilization index (PSI) 2.4, followed by Aspergillus flavus with a SI= 2.3. The perfect activities of selected fungal isolates were detected with incubation periods 7 days and temperature 30°C for maximum phosphate solubilization, acid and alkaline phosphatase activities, pH 7.0 for maximum phosphate solubilization, pH 6.0 for maximum acid phosphatase activity while pH 8.0 was suitable for maximum alkaline phosphatase activity for both A. niger and A.flavus. olyptical Characteristics Of Cake Fortified By Irradiated Broccoli (Brassica Oleracea L.Var Italica) Powder (15) ABSTRACT l and Organolyptical Characteristics Of Cake Fortified By oli (Brassica Oleracea L.Var Italica) Powder aadani, R.M.A. 1 ; Mervat, M. Anwar 2 and Hamed Aly 2 018 018 The present study aims to improve the antioxidant and antimicrobial properties of cake and produce low calorie cake through substitution of wheat flour (WF) by irradiated broccoli (Brassica oleracea L.var italica) powder. In this study broccoli heads powder and broccoli leaves powder were gamma irradiated at dose levels of 0, 3, 5 and 7 kGy. Results showed that ethanolic (70%) extract of irradiated broccoli heads powder (IBHP) and irradiated broccoli leaves powder (IBLP) at a dose level of 5 kGy had higher total phenolic compounds (TPC) and antioxidant activity (AOA) compared to control and other doses. Thus, IBHP and IBLP at dose level of 5 kGy were selected for fortification of cake. IBHP was used to substitute (0, 1.5, 3, and 4.5 %) of WF in making cake, as well, replacement of WF (0, 1, 2 and 3%) by IBLP. The results showed that the cake processed from IBHP and IBLP had pronounced improvement (%) in its chemical composition (protein, lipids, ash and fiber content) while, the energy value and carbohydrate content decreased with increasing the replacement level. Also, the results showed that the TPC content, AOA, volume and specific volume were increased by increasing substitution level of IBHP and IBLP compared to control samples. On the other hand, total intensity, L*and a* values of the crust and crumb were decreased, whereas Chroma and b* values were increased for crumb and decreased for crust for all cake treatments by the addition of IBHP and IBLP compared to control sample. For microbiological properties, the results Physico-Chemical and Organolyptical Character