APPLICATION OF EXTRACTION METHOD FOR ISOLATION OF BIOGENIC SURFACE-ACTIVE RHAMNOLIPIDS
Authors:   Department of Physical Chemistry of Fossil Fuels of the Institute of Physical-Organic Chemistry and Coal Chemistry named after L. M. Lytvynenko of the National Academy of Sciences of Ukraine, KARPENKO Іlоna , MIDYANA Galyna ,   Department of Physical Chemistry of Fossil Fuels of the Institute of Physical-Organic Chemistry and Coal Chemistry named after L. M. Lytvynenko of the National Academy of Sciences of Ukraine, KARPENKO Olena ,   Department of Physical Chemistry of Fossil Fuels of the Institute of Physical-Organic Chemistry and Coal Chemistry named after L. M. Lytvynenko of the National Academy of Sciences of Ukraine, SEMENIUK Igor ,   Department of Physical Chemistry of Fossil Fuels of the Institute of Physical-Organic Chemistry and Coal Chemistry named after L. M. Lytvynenko of the National Academy of Sciences of Ukraine, MIDYANYY Stepan ,   Stepan Gzhytskyy National University of Veterinary Medicine and Biotechnologies, PAL’CHIKOVA Olena ,   Institute of Geology and Geochemistry of Fossil Fuels of the National Academy of Sciences of Ukraine
Published: October 2020

The priority task of modern biotechnology is development of the rational technologies for the microbial synthesis of practically important products. Among these products, a significant place belongs to surfactants (biosurfactants), which are widely used in many sectors of the economy. The most problematic stage of the biosurfactants production is isolation from the post fermentative cultural liquid of bacteria-producers. Improving the efficiency of the biosurfactants production is highly dependent on rational approaches to the target products isolation. In this regard, there is an increasing need for rational, scientifically substantiated methods for their isolation and purification. Therefore, the aim of the presented work was to determine the optimal extractants for the isolation of rhamnolipid surfactants – metabolites of bacteria of Pseudomonas sp. PS-17 strain. For this purpose, the extraction process of rhamnolipids from the post fermentative cultural liquid supernatant has been investigated. The optimal extractants were selected among 13 organic solvents of different nature. Processing of the obtained experimental data by the method of multi-parameter equations of linearity of free energies (modified Koppel-Palm equation) made it possible to establish the relationship between the physicochemical properties of the extractants and amounts of the biosurfactants which were isolated from cultural liquid supernatant. It was shown that the data on the rhamnolipids extraction are adequately associated with the physicochemical characteristics of the solvents using a six-parameter linear equation. It was determined that the polarizability and molar volume are the main properties of solvents that affect the extraction process. The best extractants for the rhamnolipids isolation from cultural liquid supernatant of the Pseudomonas sp. PS-17 strain are the ethers. It can be explained by the presence of a lone pair of the electrons of oxygen in its molecule. The obtained results of the study are of scientific interest for isolation of the important and perspective biotechnological products – surface-active substances.