Biosurfactant synthesis by Rhodococcus erythropolis IMV Ac-5017, Acinetobacter calcoaceticus IMV B-7241 and Nocardia vaccinii IMV B-7405 on byproduct of biodiesel production

Abstract

The possibility of using technical glycerol (waste product of biodiesel production) as a substrate for the synthesis of the extracellular surfactants by Acinetobacter calcoaceticus IMV B-7241, Rhodococcus erythropolis IMV Ac-5017 and Nocardia vaccinii IMV In-7405 was investigated. When the components of glycerol fraction (potassium and sodium salts – 2.5%, methanol and ethanol – 0.3%) were introduced into the medium with purified glycerol (1%, v/v) an increase in conditional surfactant concentration by 11–68% was established when compared to a medium without these salts and alcohols. The maximum concentration of surfactants synthesized by R. erythropolis IMV Ac-5017 (1.6g/L), N. vaccinii IMV B-7405 (4.2g/L), and A. calcoaceticus IMV B-7241(5.6g/L) was reached in the medium with technical glycerol (4–6%, v/v). The possibility of intensifying surfactants synthesis by R. erythropolis IMV Ac-5017 and N. vaccinii IMV B-7405 can be established as a result of exogenous precursors (organic acids, sunflower oil, glucose, 0.05–0.1%) introduction into the medium with technical glycerol (2.2%, v/v). The increased amount of product was obtained when R. erythropolis IMV Ac-5017 and A. calcoaceticus IMV B-7241 were grown on a mixture of technical glycerol and n-hexadecane in a molar ratio of 1:8.