Enhanced biosurfactant production by immobilized Acinetobacter haemolyticus isolated from industrial waste; process...

Industrial wastewater from food processing and petroleum industries represents a major sources of persistent organic pollutants, thereby underscoring the urgent demand for sustainable remediation approaches. Acinetobacter haemolyticus was identified as a biosurfactant producer through functional screening and 16S rRNA gene sequencing. Biosurfactant production was confirmed using emulsification activity, oil displacement, and drop-collapse tests. To enhance production efficiency; bacterial cells were immobilized onto Aquaporous gel carriers and assessed across multiple consecutive batch cycles. The immobilized cells exhibited sustained high viability (6.3-6.8 log CFU g^-1) and produced biosurfactant concentrations ranging from 1.80 to 1.15 g/L over successive cycles, thereby demonstrating operational stability. Structural elucidation via FTIR and NMR revealed glycolipid-like amphiphilic architecture. A Plackett-Burman experimental design was employed for process optimization, identifying inoculum size, engine oil, and glucose as significant determinants of biosurfactant production. Subsequent optimization integrating both Plackett-Burman and Box-Behnken designs yielded a strong correlation between predicted and observed values, thereby validating the predictive reliability of the model. In contrast to earlier studies relying on single-batch cultures, the present investigation demonstrate that cell-entrapped A. haemolyticus sustains production capacity across multiple successive cycles, functioning as a recoverable system with stable short-term performance.