A new bacterial-derived biosurfactant for biotechnological applications in the oil industry: production, optimization, biosurfactant functional and physicochemical characterization

Aiming at the potential application of lipopeptide biosurfactant (BioS) in bioremediation, we studied its production by a novel, isolated strain of Bacillus sp. MI27. Using the experimental design methodology, a sucrose-based medium composed of 2% sucrose, 0.27% Na2HPO4, 0.2% ammonium sulfate, 0.02% NaCl, 0.02% CaCl2, 0.02% MgSO4, 0.001% MnSO4, 0.06% KH2PO4, 0.005% FeSO4 and 0.005% ZnSO4 was optimized. With this composition, strain MI27 produces 1.4 g/L with maximum surface tension (ST) reduction of 23 mN/m and a dispersion diameter of around 10 cm. Emulsifying and foaming activities have been also confirmed. The critical micelle concentration (CMC) value of about 120 mg/L with a maximal decrease of ST of 23 mN/m with a maximum dispersion and an emulsification index (EI) of about 12 cm and 45% at 1,000 mg/L. Moreover, the foaming capacity is about 80% at 1,000 mg/L stable over 1 h of incubation. Additionally, we studied the effect of different values of pH, temperature and salinities on MI27 BioS activity and stability. Obtained results showed interesting surface activities at extreme physicochemical conditions, especially at acidic and alkaline pH values, high and low temperatures and higher salinities. All these characteristics enable the possible application of BioS in water treatment biotechnology under diverse environmental conditions.