Karpenko I. Biotechnology of rhamnolipid surface-active products of the strain Pseudomonas sp. PS-17 and their application for oil-bearing plants

The dissertation thesis is devoted to the development of the biotechnology of microbial synthesis of the surface-active substances by the strain Pseudomonas sp. PS-17 and their application in cultivation of oil-bearing plants. The effectiveness of the application of cost-beneficial substrates (Used frying oil and waste from production of sunflower oil - phosphatide concentrate) was established for the synthesis of rhamnolipid surfactants by the strain Pseudomonas sp. PS-17 when applied alone and in combination with glycerol. It was shown that the use of combined substrates contributed to increased yields of rhamnolipids if compared to the media with monosubstrates. When using a mixture of glycerol and used frying oil or phosphatide concentrate as carbon sources the final concentration of rhamnolipids can be increased on 18-39%. The developed approaches of the synthesis of rrhamnolipid surfactants will enable the decrease of the overall cost of biosurfactant production if compared with the cost of the production on glycerol alone. The process of rhamnolipid surfactant separation were optimized: enzymatic hydrolysis (using protease C enzyme) of post-fermentative culture liquid, precipitation of rhamnolipid biocomplex (RBC) from culture liquid supernatant (CLS) by adjusting temperature regime. Optimum solvents for the extraction of rhamnolipids from culture liquid supernatant were determined using the method of linear multiparameter equations. A simultaneous action of the synthesized rhamnolipid surfactants on the growth of oil-bearing plants was established. It was shown that the effect of the biosurfactants on microorganisms and plants via changes in their physiological and biochemical characteristics. The possibility of application of the obtained biosurfactants in agriculture as plant growth regulators was established. The process flow and equipment diagrams of industrial production of rhamnolipid surfactants of Pseudomonas sp. PS-17 using a vortex bioreactor were deployed, 5 forms of rhamnolipid products for practical use in cropping were obtained.