Screening of the drought tolerant phosphate solubilizing bacteria in dissolving P-inorganic

Abstract

The drought tolerant phosphate solubilizing bacteria is needed to dissolve inorganic phosphate (P) which is usually low in the availability at dry land. This study is aimed to obtain a combination of drought tolerant phosphate solubilizing bacteria which has high potential in dissolving P-inorganic. An experimental study which has 4 treatments of bacterial combinations has been conducted in a laboratory. The first treatment was the combination between Pseudomonas azotoformans (A) and Acinetobacter baumannii (B). The second treatment was the combination of A and Bacillus paramycoides (C). The third treatment was B and C, then the fourth treatment was A, B, and C. The potential of the bacterial combination in dissolving P-inorganic was measured qualitatively using phosphate solubilizing index (PSI) on pikovskaya solid medium. While, the potential of the bacterial combination in dissolving P-inorganic was measured quantitatively by measuring dissolved P using the ascorbic acid method in pikovskaya liquid medium containing 0.5% Ca3(PO4)2. The results showed that the combination of those three bacteria (A B and C) has the best potential to dissolve P-inorganic compared to other combinations. In addition, the three bacteria combination also resulted in the highest dissolved P with 0.29% potential dissolution of the total Ca3(PO4)2 contained in the pikovskaya liquid medium, followed by combination of B and C (0.19%), and A and C (0.18%), respectively. Thus, before the combination of these three bacteria is applied in soil, it is needed further experiment of the potential of the bacteria in dissolving soil P-inorganic.