Abstract:
Bacterial strains isolated from green house soils were incubated in vitro for seven days to assess their
phosphate solubilizing capacity, solubilization index, organic acid production and acid and alkaline
phosphatase activity. All the tested isolates solubilized inorganic phosphates in varying degrees in
NBRIP liquid culture medium. Acidification by means of producing organic acids may be the key
mechanism attributed to increased phosphate solubilization as revealed by the strong negative
correlation (r = - 0.923 ± 0.1, P ≤ 0.05) observed between the amount of phosphorus released and pH in
the culture medium. Moreover, acid and alkaline phosphatase released by the isolates may also have
certain contribution to phosphate solubilization. Gluconic acid was the most common acid produced by
isolated organisms followed by citric and oxalic acid. Out of the isolates, strains PSB–1(Pantoea
agglomerans), PSB–5 (Burkholderia anthina) and PSB–8 (Enterobacter ludwigii) solubilized significantly
higher amount of inorganic phosphate within a day, exhibiting their higher potential to be used as soil
inoculants to enhance soil fertility and plant growth.
