Abstract
Abstract Mangrove ecosystems have diverse microbial communities that play an important role in soil biological processes and plant growth enhancement. This study aimed to isolate and characterize rhizosphere bacteria from the mangrove rhizosphere in Bagek Kembar, Sekotong, West Lombok, for their potential application as biofertilizer agents. Soil samples were collected from the rhizosphere of Rhizophora spp., and bacterial isolates were evaluated for their phosphate solubilization ability qualitatively using the Vikovskaya method for the phosphate solubility index test, and quantitatively using colorimetry (molybdenum blue spectrophotometry), and Indole-3-Acetic Acid (IAA) production using qualitative and quantitative tests using the Salkowski method. A total of 20 bacterial isolates were successfully obtained, showing considerable variation in their functional properties. Isolate A7 showed the highest phosphate solubilization index (1.75), indicating a strong capacity to convert insoluble phosphate into plant-available forms. In addition, the highest IAA production was found in isolates A8, MU9, and MU10, reaching concentrations of 57.03 ppm, 52.70 ppm, and 50.06 ppm, respectively. Overall, isolates A7, A8, MU9, and MU10 showed promising functional characteristics and are recommended as potential candidates for multi-strain biofertilizer consortia to increase nutrient availability and stimulate plant growth, supporting soil biological health and sustainable agricultural productivity.