Bacillus subtilisCB 8 A by HPLC (Fig.4.2). Six organic acids produced byBacillus
subtilisCB 8 A are oxalic acid, gluconic acid, formic acid, 2-ketogluconic acid, citric
acid, and fumaric acid. Out of these, major organic acids were gluconic acid
(1.43%) and citric acid (0.67%) (Fig.4.2 ). The reason of P solubilization by
organic acid production may be: decrease in the pH; complex formation with metal
ions of insoluble P (calcium phosphate, iron phosphate) andfinally, P release; by
competing with P for sites on the soil.
Fig. 4.2 HPLC chromatograms of authentic organic acids (a) and culture supernatant ofBacillus
subtilisCB 8 A grown for 3 days in PVK broth (b). Adopted from Mehta et al. (2013a).OAOxalic
acid;GAgluconic acid;FAformic acid;ICAisocitric acid;LAlactic acid;2-KGA2-ketogluconic
acid;SAsuccinic acid;MAmaleic acid;CAcitric acid; andFumAfumaric acid
70 A. Walia et al.