Investigation of the activity of Acinetobacter calcoaceticus biodemulsifier to break stable water in oil emulsions

Abstract

Biodemulsifier production by Acinetobacter calcoaceticus and its capability to break the stable water in oil emulsions were investigated. The chemical structure of the isolated biodemulsifiers from cultivation on various nitrogen sources were preliminarily analyzed by Fourier-transform infrared spectroscopy (FT-IR). The cultivation conditions such as temperature, pH and carbon to nitrogen source concentration (C/N) ratio were optimized for maximum demulsification activity through response surface methodology. It was disclosed that the composition of the isolated biodemulsifiers was depended on the utilized nitrogen source in the medium and altered from a cyclic lipopeptide (on soybean) to a lipopolysaccharide (on ammonium salts). The obtained optimum conditions for the biodemulsifier produced on ammonium nitrate (as the nitrogen source) were 35°C for temperature, 10 for C/N ratio and 5 for pH. Results indicated that the produced extracellular biodemulsifier can reduce the surface tension to 38.6mN/m and break 95% of a surfactant stabilized emulsion at the optimum conditions. © 2018 Elsevier Ltd.