Soil contamination by heavy metals, particularly lead (Pb), poses significant environtmental and health risks. This study examines the potential of biosurfactants produced by Bacillus licheniformis F16 functioning as bioremediation agent. The research optimizes biosurfactant performance condition of concentration, pH, and washing duration, while evaluating its efficacy across varying Pb contamination levels. The results reveal that a biosurfactant concentration of 1100.26 ppm, pH 9, and a 24-h washing duration achieved the highest Pb removal efficiency (72.21%) in soils contaminated with 300 ppm Pb. Further testing across three Pb contamination levels (100, 500, and 2000 ppm) under optimal biosurfactant conditions revealed the highest removal efficiency at 100 ppm (52.50%). Additionally, biosurfactant-treated soils exhibited enhanced microbial abundance, with an increase of 1–2 log cell numbers compared to synthetic surfactant treatments. Sequential extraction analysis demonstrated a significant reduction in reducible (62.91%) and residual (45.57%) Pb fractions, indicating effective metal mobilization. These findings highlight the ecological and functional advantages of biosurfactants in soil remediation, presenting a sustainable alternative to synthetic surfactants for mitigating heavy metal pollution. Further optimization is required to improve performance under higher contamination levels, along with future studies evaluating broader ecological impacts, including effects on plant growth and soil microbial diversity, as well as more detailed molecular characterization of the biosurfactant.Graphical Abstract
Purwasena et al. (Thu,) studied this question.