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Biotechnological potential of the Acinetobacter genus bacteria
(2021) Pirog, Tatiana; Lutsay, Dariya; Muchnyk, Faina
Until recently, there were rare scientific reports on the biotechnological potential of non-pathogenic bacteria of the Acinetobacter genus. Although the first reports about the practically valuable properties of these bacteria date back to the 70s and 80s of the twentieth century and concerned the synthesis of the emulsan bioemulsifier. In the last decade, interest in representatives of the Acinetobacter genus as objects of biotechnology has significantly increased. The review presents current literature data on the synthesis by bacteria of this genus of high-molecular emulsifiers, low-molecular biosurfactants of glyco- and aminolipid nature, enzymes (lipase, agarase, chondroitinase), phytohormones, as well as their ability to solubilize phosphates and decompose various xenobiotics (aliphatic and aromatic hydrocarbons, pesticides, insecticides). Prospects for practical application of Acinetobacter bacteria and the metabolites synthesized by them in environmental technologies, agriculture, various industries and medicine are discussed. The data of own experimental studies on the synthesis and biological activity (antimicrobial, anti-adhesive, ability to destroy biofilms) of biosurfactants synthesized by A. calcoaceticus IMV B-7241 strain and their role in the degradation of oil pollutants, including complex ones with heavy metals, are presented. The ability of A. calcoaceticus IMV B-7241 to the simultaneous synthesis of phytohormones (auxins, cytokinins, gibberellins) and biosurfactants with antimicrobial activity against phytopathogenic bacteria allows us to consider this strain as promising for practical use in crop production to increase crop yields.
Synergistic effect of surfactants of Nocardia vaccinii IMV B-7405 and essential oils on Candida genus yeast
(2022) Pirog, Tatiana; Kliuchka (Nykytyuk), Lilia; Shevchuk, Tetiana; Muchnyk, Faina
The increase in the number of resistant strains of Candida genus representatives, capable of forming biofi lms on various surfaces, stimulates the search for new, alternative methods of combating them, one of which is the use of compounds of natural origin, such as essential oils. However, at the same time, their concentration should be minimal, which is due to the ability of essential oils to cause severe damage of the human’s central nervous system and aspiration pneumonia. This leads to the necessity of searching for new methods to reduce the concentration of essential oils and at the same time to preserve their properties, in particular, by their use in a mixture with other antimicrobial agents, which can be microbial surfactants. Previously, it was found that the degree of yeast biofi lm destruction under the action of Nocardia vaccinii IMV B-7405 surfactants dependson the nature of the growth substrate and is the highest in the presence of preparations synthesized on purified glycerol. Aim. To study the synergism of antifungal activity and the role in the destruction of biofilms of a mixture of Nocardia vaccinii IMV B-7405 surfactants synthesized on glycerol of different quality and essential oils. Methods. N. vaccinii IMV B-7405 was grown in a medium containing purified glycerol or waste from biodiesel production at a concentration of 2% (v/v) as carbon sources. The surfactants were extracted from the supernatant of cultural liquid by a modified Folch mixture. The antimicrobial activity of essential oils, surfactants, and their mixtures was determined by the index of the minimum inhibitory concentration. To assess the synergistic effect of a mixture of surfactants with essential oils, the fractional inhibitory concentration index was used. The degree of biofi lm destruction (%) was determined as the difference between the cell adhesion in untreated and treated with surfactants, essential oil, or their mixture wells of the polystyrene microplates. Results. It was found that the surfactants synthesized by N. vaccinii IMV B-7405 on both purifi ed glycerol and waste from biodiesel production showed synergistic antifungal activity in mixtures with cinnamon and lemongrass essential oils. Thus, the minimum inhibitory concentrations against Candida albicans D-6, Candida utilis BVS-65, and Candida tropicalis RE-2 of a mixture of surfactants synthesized on purified glycerol with cinnamon and lemongrass essential oils were 1.8—7.5 and 3.7— 15 μg/mL, respectively, and were lower than in the case of using surfactants (30-60 μg/mL), cinnamon or lemongrass essential oil (156—312 μg/mL) alone. The use of a mixture of surfactants obtained on waste from biodiesel production and cinnamon or lemongrass essential oils made it possible to reduce the minimum inhibitory concentrations of the latter against studied yeast test cultures by 14—56 times. At the same time, the index of fractional inhibitory concentration did not exceed 0.5, which indicates the synergism of the antifungal activity of the mixture of these compounds. The destruction of Candida yeast biofi lms under the action of surfactants synthesized on both purified glycerol and waste from biodiesel production in a mixture with cinnamon or lemongrass essential oils reached 60—67 and 67—77%, respectively, which is an average of 25—35% higher compared to the use of each monopreparation separately. Conclusions. The results presented in this paper confirm the previously obtained data that N. vaccinii IMV B-7405 surfactants, synthesized on both traditional substrates and toxic industrial wastes, have antimicrobial and antiadhesive synergistic action with essential oils, which allows us to consider them as potential components of the so-called «antifungal locks» in the fight against of Candida genus representatives.