Optimization of process inputs for the synthesis of waste Rice bran oil isolated Pseudomonas aeruginosa MTCC 424 Biosurfactant using response surface methodology for oil recovery applications

Abstract In this current study, the process variables i.e., the concentration of RBO (2–4%), pH (4–10), and incubation time (4–11 days) for the preparation of Rhamnolipid biosurfactant based on Pseudomonas aeruginosa MTCC 424 and Rice bran oil (RBO) were analyzed using response surface methodology- central composite design (RSM-CCD). At 5 0.02% of RBO, 7.3 pH, and 9.5 days of incubation time, maximum biosurfactant production was achieved. The process parameter was strongly affected by RBO, followed by the marginal effect of time and pH of incubation. The optimized biosurfactant was further analyzed using various techniques viz. surface tension measurement, Fourier transform infrared spectroscopy (FTIR), emulsifying ability test and oil displacement technique. As compared to synthetic chemical surfactant, the lower critical micelle concentration (CMC) (28.5 mN/m), impressive oil-free zone displacement (17.26 ± 0.18 cm2) and benchmark emulsifying ability demonstrated the perfect use of the biosurfactant for oil recovery applications.