Bacillus safensis producing a structurally characterized bacillibactin-like siderophore enhances hydroponic phytostabilization of lead in Epipremnum aureum

Microbial siderophores have emerged as promising agents for heavy-metal phytoremediation, yet direct evidence linking structurally characterized purified siderophores with hydroponic lead (Pb) phytostabilization remains limited. This study investigated the novel role of purified bacillibactin from the endophytic bacterium Bacillus safensis BH1 in enhancing Pb phytostabilization in Epipremnum aureum under hydroponic conditions. Endophytic bacteria isolated from roadside Bougainvillea leaves were screened for siderophore production, and the most efficient isolate (BH1) was identified by 16S rRNA sequencing. The purified siderophore was characterized using chemical assays,1H NMR, and high-resolution mass spectrometry. Hydroponic phytostabilization was evaluated through plant morphology, chlorophyll content, and Pb accumulation determined by atomic absorption spectroscopy. Data are presented as mean ± SD (n = 3), and differences between untreated and BH1-treated plants were analyzed using Welch’s t-test (p < 0.05). Bacillus safensis BH1, producing a structurally characterized bacillibactin-like siderophore (1H NMR and HRMS), significantly enhanced Pb phytostabilization by improving plant vigor, increasing chlorophyll content, and reducing Pb bioavailability under hydroponic conditions. Since fresh BH1 fermentation broth was used, the observed effects reflect the combined contribution of bacterial colonization and bacillibactin-like siderophore production, supporting an eco-friendly, sustainable remediation and bio-assisted strategy for phytostabilization of Pb-contaminated environments.