ISOLATION OF PHOSPHOROUS SOLUBILIZING BACTERIA AND FUNGI FROM RHIZOSPHERE AND ITS EFFICIENCY ON ROCK PHOSPHATE SOLUBILIZATION

Abstract

Laboratory experiment was conducted to isolate and select the most efficient bacterial and fungal isolates in rock phosphate solubilization in culture medium. Results showed that bacterial isolates exhibited a different efficiencies in their ability to solubilize rock phosphate. Bacillus subtilis and Pseudomonas fluorescence were the greatest efficient among other bacterial isolates tested (14 isolates) in their acids production and decreasing medium pH value which droped to 5.35 and 5.2 and increasing in available phosphorous to 50 and 56 mg P. L-1 after 24 days incubation respectively. The correlation coefficient (R2) between incubation time and pH value were 0.65 and 0.59 while the correlation between pH value and available phosphorous were high reached 0.98 in both bacterias. Results also showed that fungal isolates which related to the genera Alternaria and Aspergillus were the greatest efficient among other fungal isolates tested (14 isolates) in their acid production and decreasing pH value , which droped to 4.7 and 3.35 with increasing in available phosphorous to 77.7 and 118.3 mg P. L-1 after 24 days incubation respectively. The correlation coefficient between incubation time and pH value were 0.33 and 0.6 while the correlation between pH value and available phosphorous were 0.65 and 0.45 respectively .