Isolation of phosphate solubilizing bacteria from the rhizosphere of local aromatic rice in Bada Valley Central Sulawesi, Indonesia

Abstract

Phosphate Solubilizing Bacteria (PSB) can be used to increase the efficiency and availability of P in the soil as it can help the process of releasing the bound of P elements so that they become available to the plants. This study aims to isolate and determine the morphological characteristics of the PSB colonies in the rhizosphere of the local aromatic rice plant, analyze the phosphate solubility of each isolate. A total of eleven rhizospheres bacterial were successfully isolated from the local aromatic rice rhizosphere. The morphological characteristics, including the size, edge, shape, elevation, and color of the colony, were obtained vary. The bacteria found were gram-positive and gram-negative, which are 81.81% and 18.18%, respectively. The result of the catalase reaction test showed 72.72% positive and 27.27% negative catalase. Furthermore, eight bacterial isolates formed a clear zone with an area of 0.84–2.66 cm. The Phosphate solubility was 116.67–133.00, and the Phosphate dissolving index was 2.17–2.33 at acidic pH between 4.27–5.67. The concentration of dissolved phosphate was 5.152 mg L−1 – 9.382 mg L−1. The results showed that the PSB has a potential being an alternative way to be developed as a biological fertilizer agent in supporting sustainable agriculture.