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Effect of cations on the activity of NADP+-dependent glutamate dehydrogenase in Acinetobacter calcoaceticus IMV B-7241, Rhodococcus erythropolis IMV Ac-5017 and Nocardia vaccinii IMV B-7405 grown on industrial waste
(2021) Pirog, Tatiana; Paliichuk, Olesia; Lutsay, Dariya; Kliuchka (Nykytyuk), Lilia; Shevchuk, Tetiana
Introduction. It is studied the activity of NADP+-dependent glutamate dehydrogenase in the presence of mono- and divalent cations (potential activators of this key enzyme of surface-active aminolipids biosynthesis) in A. calcoaceticus IMV B-7241, R. erythropolis IMV Ac-5017 and N. vaccinii IMV B-7405 during cultivation on waste of biodiesel production and sunflower oil waste. Materials and methods. Cultivation of strains was performed in liquid mineral media using as substrates: refined and waste (after frying potato) sunflower oil, refined glycerol and waste of biodiesel production. NADP+-dependent (EC 1.4.1.4) glutamate dehydrogenase activity in cell-free extracts was analyzed for glutamate formation during oxidation of NADPH at 340 nm. Monovalent (Na+, K+) and divalent (Mg2+, Ca2+, Zn2+) cations in the form of salts of NaCl, KCl, MgSO4 × 7H2O, CaCl2 and ZnSO4 × 7H2O were added to the reaction mixture, as well as into the medium for strains cultivation. Results and discussion. Calcium cations were found to be activators of NADP+-dependent glutamate dehydrogenase activity in R. erythropolis IMV Aс-5017 and N. vaccinii IMV B-7405 grown on refined and waste sunflower oil: in the presence of 1–5 mmol Ca2+ in the mixture, the activity of the enzyme increased 1.3–2 times compared with that without these cations. The increase in the concentration of CaCl2 to 0.2−0.4 g/l in oil-containing medium of strains IMV Ac-5017 and IMV B-7405 cultivation was accompanied by an increase in NADP+-dependent glutamate dehydrogenase activity by 1.3–1.5 times compared with that on basic medium. When additional quantity of CaCl2 (0.1−0.2 g/l) was introduced into the medium with purified glycerol for the cultivation of A. calcoaceticus IMV B-7241, an increase in NADP+-dependent glutamate dehydrogenase activity was observed by almost 2.5−3 times compared with those for strain IMV B-7241 on the basic medium. There was no impact of activating cations magnesium, zinc, potassium and sodium on NADP+-dependent glutamate dehydrogenase activity of all strains grown on oil-containing substrates and glycerol of different degrees of purification. Conclusion. The results demonstrate the possibility to increase activity of key enzymes of the biosynthesis of the desired product: the composition of the medium should be modified by changing the content of enzymes’ activators.
Practically valuable properties of the surfactant synthesized by Rhodococcus genus actinobacteria
(2020) Pirog, Tatiana; Petrenko, Natalia; Skrotska, Oksana; Paliichuk, Olesia; Shevchuk, Tetiana; Iutynska, Galyna
Currently, microbial surfactants are the objects of intense research because of their surface-active and emulsifying properties, high antimicrobial, anti-adhesive activity, and ability to destroy biofilms. The review provides current literature data on the properties of surfactants synthesized by Rhodococcus genus actinobacteria, determining their practical significance. The researchers’ interest in the surfactants of Rhodococcus bacteria is primarily due to their key role in the destruction of xenobiotics (aliphatic, heterocyclic and polycyclic aromatic hydrocarbons). Information on the antimicrobial and anti-adhesive activity of surfactants of Rhodococcus genus bacteria remains scarce at present, while the immunomodulatory properties of these products of microbial synthesis are studied more actively than for other microbial surfactants known in the world. The data of our experimental studies on the practically valuable properties of surfactants synthesized by Rhodococcus erythropolis IMV Ac-5017 are presented. Unlike surfactants of other representatives of Rhodococcus genus bacteria, surfactants of IMV As-5017 strain are multifunctional preparations. Because in addition to the high efficiency of the destruction of oil pollution, including complex with heavy metals, surfactants are characterized by high antimicrobial and anti-adhesive activity, including the ability to destroy biofilms.