Intensification of biosurfactant synthesis by Acinetobacter calcoaceticus IMV B-7241 on a hexadecane-glycerol mixture

Abstract

The possibility of enhanced biosurfactant (BS) synthesis by the cultivation of Acinetobacter calcoaceticus IMV B-7241 on a mixture of energetically nonequivalent substrates (hexadecane and glycerol) was shown. Based on theoretical calculations of the energy requirements for biomass production and the synthesis of surface-active trehalose monomycolate from the energy-deficient substrate (glycerol), the concentration of the energy-excessive substrate (hexadecane), which increased the efficiency of the substrate carbon conversion to BS, was determined. The synthesis of extracellular BS on a mixture of hexadecane and glycerol in a molar ratio of 1: 7 at C/N ratio of 30 increased 2.6–3.5-fold compared to that on single-substrate media. Increased BS synthesis by Acinetobacter calcoaceticus IMV B-7241 grown on a hexadecane-glycerol mixture was accompanied by a 1.3–2.4-fold increase in activities of the enzymes involved in their biosynthesis, as well as by simultaneous functioning of two anaplerotic pathways (the glyoxylate cycle and the phosphoenolpyruvate carboxylase reaction).