Structural and physico-chemical characterization of a dirhamnolipid biosurfactant purified from Pseudomonas aeruginosa : application of crude biosurfactant in enhanced oil recovery

摘要: The present study describes the structural characterization and biotechnological application of a dirhamnolipid biosurfactant produced by Pseudomonas aeruginosa strain NBTU-01 isolated from petroleum oil-contaminated soil sample. Characterization partially purified LC-MS/MS analysis indicated predominant production (78%) dirhamnolipids Rha-Rha-C10-C10 Rha-Rha-C12-C10 with minor monorhamnolipids (22%). NMR major P. identified it as its deduced structure was L-rhamnosyl-L-rhamnosyl-β-hydroxydecanoyl-β-hydroxydecanoate. intracellular proteins key enzymes other associated regulation biosynthesis rhamnolipids. Critical micelle concentration determined at 72 ​± 2.25 mg l−1 reduced surface tension water 72.2 to 29.5 mN m−1. crude rhamnolipid effectively emulsified petroleum-oil, diesel, kerosene coconut oil, removed 70 ± 3.5% oil saturated sand pack column. Heating 100 °C for 5 h did not affect recovery Moreover, showed stability pH values between 6.0 10.0. crystallization melting temperature found be 99 134 °C, respectively, suggesting can withstand thermal denaturation is suitable in high wells tertiary recovery.