Plant Phytoremediation and Biosurfactant-Producing Pseudomonas Sp. S3 Enhances Growth in Petrolium-Contaminated Soil

Petroleum hydrocarbon contamination severely affects soil fertility, microbial diversity, and crop productivity due to the toxic and phytotoxic effects of hydrocarbons. The present study evaluates the bioremediation and plant growth-promoting potential of a biosurfactant-producing r strain, Pseudomonas sp. S3, isolated from petroleum-contaminated soil. The strain exhibited strong biosurfactant activity, including a 42–43% emulsification index (E24), positive oil displacement and drop collapse tests, and significant surface tension reduction from 61.9 mN/m to 34.5 mN/m (Ambust, S., Das, A. J., & Kumar, R. (2021). Strain S3 demonstrated multiple plant growth-promoting (PGP) traits such as phosphate solubilization (94.46 µg/mL), siderophore production (64.41% SU), indole-3-acetic acid and (IAA) production (80.41 µg/mL). Pot experiments conducted in petroleum-contaminated soil (1%, 3%, and 5%) showed that treatments amended with S3 and crude biosurfactant significantly enhanced seed germination, root and shoot length, compared to untreated contaminated controls. Among all treatments, EX5 (1 kg soil + 1 L water + Pseudomonas sp S3 + 300 mL crude biosurfactant) showed the highest improvement (10–15%) in plant growth parameters. The findings confirm that biosurfactant-producing plant growth-promoting PGP) such as Pseudomonas sp. S3 effectively reduce petroleum-induced phytotoxicity, enhance hydrocarbon bioavailability and degradation, and restore soil fertility, providing a sustainable strategy for remediation of petroleum-contaminated agricultural soils.