| Summary: | Background. An important task of modern biotechnology is the development of rational technologies for the microbial synthesis of microbial surfactants, in particular, the increasing of the effectiveness of methods for the isolation and purification of microbial surfactants.
Objective. The aim of the paper is to determine the optimal extracting agent for the surface-active trehalose lipids – metabolites of the R. erythropolis Au-1 strain.
Methods. Bacteria were grown on Goodwin's nutrient medium with hexadecane as the source of carbon. The trehalose lipids were isolated from the culture liquid via a single extraction with various solvents and followed by evaporation of the solvent in vacuum. 13 solvents of different nature were used, namely: aliphatic (hexane, n-octane) and aromatic (benzene, toluene) hydrocarbons, halogen derivatives of hydrocarbons (1,2-dichloroethane, chloroform, carbon tetrachloride), alcohols (t-butanol, isobutanol, pentanol-2), ethers (diethyl ether) and esters (ethyl acetate, n-butyl acetate). By chemical nature, some of these solvents are non-polar (hexane, octane, benzene, toluene, and carbon tetrachloride), and the rest are polar. The amounts of obtained biosurfactant were determined by the gravimetric method, calculating the mass of trehalose lipids which were transferred from the aqueous phase to 1 mole of extracting agent. The experimental data were processed by the method of linear multiparameter equations.
Results. The distribution of the surface-active trehalose lipids of the R. erythropolis Au-1 strain between the aqueous phase (culture liquid) and solvents of different nature was studied. Processing the experimental data by the method of linear multiparameter equations allowed establishing the relationship between the physicochemical characteristics of the extractants and the amount of biogenic surfactants which were transferred from the culture liquid. It was determined that the solvents with high polarizing ability to substrate molecules are the optimal extractants for the isolation of trehalose lipids.
Conclusions. Based on the experimental and calculated data, the extraction of the surface-active trehalose lipids – metabolites of the R. erythropolis Au-1 strain was optimized. The biosurfactants are polar compounds due to the presence of OH-group in the molecule structure. It is founded that the trehalose lipids are better extracted by solvents with higher polarizing ability. This is confirmed both experimentally and by the multiparameter equations.
|
|---|
