12-30: Biosurfactant production optimization using response surface

Biosurfactants or microbial surfactants are surface-active biomolecules produced by a variety of microorganisms. These molecules are capable of reducing surface and interfacial tensions in both aqueous solutions and hydrocarbon mixtures, which make them potential candidates for deemulsification processes and for oil recovery. The microorganism considered in this work was isolated in previous studies and identified as Serratia sp. Initially three media were tested for the biosurfactant production and the medium 1 presented best results. A factorial design optimization strategy  was used in order to enhance the tensio-active emulsifying agent produced by Serratia sp. having as variables medium 1 components as fermentation substrate. The best conditions for biosurfactant production in shake flasks were determined through an optimization process using an Experimental Design. A fractional factorial design was used to evaluate the fermentation factors such as initial peptone and glycerol amounts, initial pH and fermentation temperature. Then, a full factorial design was done and the optimum conditions for biosurfactant production were between 0.17 and 0.4% for peptone, between 2.0 and approximately 3.14% for glycerol, at 35 ⁰C and pH 7.0. Moreover, some biosurfactant properties were studied, such as, emulsifying capacity and stability at different pH values and temperatures.