Rhamnolipid-Like Glycolipid Biosurfactant from <i>Achromobacter xylosoxidans</i> BP(1)5: Single-Factor Optimization, Characterization, and Oil Removal Application

<i>Achromobacter</i> is commonly associated with the production of glycolipid biosurfactants, which are sought after for diverse applications in biomedical and environmental fields. Given the increasing demand for biosurfactants, this study focuses on optimizing culture conditions, characterizing the biosurfactant product, and examining its potential application for enhanced motor oil removal from contaminated sand. The study was conducted using minimal salt medium (MSM), and the one-factor-at-a-time approach was used to vary incubation time, carbon source, nitrogen source, and carbon-nitrogen ratio (C/N). The biosurfactant was acquired through chloroform: methanol: acetone extraction and subsequently characterized using TLC, FTIR, GC-MS, and LC-MS. Biosurfactants at various concentrations were used to examine motor oil removal ability at 24 h of incubation. The best conditions for biosurfactant production involve glucose as the carbon source and yeast extract as the nitrogen source at a C/N ratio of 6/1, pH 7, temperature 30°C, and 72 h of incubation. The biosurfactant product was identified as a rhamnolipid-like glycolipid with a carbon chain ranging from C₈ to C₁₆. To the best of our knowledge, this is the first report describing a C₁₆-dominant rhamnolipid-like glycolipid from <i>A. xylosoxidans</i> BP (1)5. At critical micelle concentration (CMC), the biosurfactant showed potential for removing motor oil from contaminated sand, achieving a removal rate of 91.80%. This study provides a basis for designing large-scale fermentation processes for biosurfactant production and highlights its potential application.