K. Petrikov, Ya. Delegan, A. Surin, O. Ponamoreva, I. Puntus, A. Filonov, A. Boronin
G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, Pushchino 142290, Russia.
We studied formation and structural features of biosurfactants produced by five oil-degrading Pseudomonasand Rhodococcus strains. These bacteria were found to be capable of intense formation of extracellular glycolipid biosurfactants when grown on mineral salts medium with 2% hexadecane. Under these conditions, the surface tension of the cultures decreased from 77 mN/m to 31–34 mN/m. The strain Rhodococcus sp. S26 forming up to 780 mg glycolipids/l of culture medium proved the most efficient biosurfactant producer. Extracellular glycolipids were purified from the crude extracts by column chromatography. Their structural features were determined by thin layer chromatography and electrospray ionization mass spectrometry. Strains Pseudomonas putida BS3701 and Pseudomonas fluorescens 142NF synthesized a number of glycolipids identified as rhamnolipid B and its homologues. Glycolipids produced by Rhodococcus sp. X5 and Rhodococcus sp. S26 were assigned to trehalose tetraesters.