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Документ Industrial wastes as substrates for synthesis of surfactants with antiadhesive activity by Rhodococcus erythropolis IMV Ac-5017(2022) Pirog, Tatiana; Kliuchka, Igor; Kliuchka (Nykytyuk), LiliaMicrobial surfactants can affect the degree of microorganism’s adhesion to different surfaces and lead to biodegradation of the already formed biofilms. They are also non-toxic to the environment. These properties allow to use the microbial surfactants in medicine and food industry.Документ Application of surface-active substances produced by Rhodococcus erythropolis IMB Aс-5017 for post-harvest treatment of sweet cherry(2022) Pirog, Tatiana; Stabnikov, Victor; Antoniuk, SvitlanaIntroduction. The aim of the present study was testing of the supernatant of Rhodococcus erythropolis ІМВ Ас-5017 with different concentration of surface-active substances (SAS) for treatment of sweet cherry for shelf-life extension. Materials and methods. R. erythropolis ІМВ Ас-5017 were grown in the medium with ethanol. Supernatant with concentration of SAS from 0.1 to 0.5 g/L was used for the treatment of sweet cherry fruit. Concentration of SAS in supernatant was determined by weight method. The total number of heterotrophic bacteria and fungi were determined by the plate dilution method. Results and discussion. The treatment of sweet cherries with a supernatant containing 0.5 g/L SAS diminished the numbers of bacteria and fungi on the fruit’s surface by 10 and 5 times, respectively, in comparison with cherries washed with water. The treatment of sweet cherries with supernatant containing 0.2 g/L SAS diminished the numbers of bacteria and fungi on the fruit’s surface by 5 and 3 times, respectively; treatment with supernatant containing 0.1 g/L diminished the numbers of bacteria and fungi by 2 times in comparison with cherries washed with water. The treatment with supernatant with concentration SAS 0.5 g/L was most effective. Treated with supernatant sweet cherries fruits did not show signs of decay even on 7th day of storage, while untreated or washed with water fruits lost moisture, fruit’s skin became wrinkled, cracks and decayed areas appeared on it. Content of fungal cells on the surface of sweet cherry pretreated with supernatant with concentration of SAS from 0.1 to 0.5 g/L and after that contaminated with spore’s suspension of Aspergillus niger Р-3 were by 2 – 11 times lower than on the surface of fruits washed with water after 5 days of incubation. The possibility of multiple usage of supernatant was shown. Application of supernatant with concentration of 0.5 g/L resulted in decrease of bacterial concentration after first usage by 10 times, after second usage it was diminished by 5 times and after third usage it was diminished by 3 times, meanwhile concentration of fungi decreased by 9, 5 and 4 times after I, II, and III usage of supernatant. Conclusion. Surface-active substances synthesized by Rhodococcus erythropolis IMB Ac-5017 could be used for treatment of sweet cherry to extend their shelf life.Документ Scaling of the process of biosynthesis of surfactants by Rhodococcus erythropolis ek-1 on hexadecane(2011) Pirog, Tatiana; Ignatenko, SergeyPeculiarities of synthesis of surface-active substances (SAS) are studied at periodical cultivation of Rhodococcus erythropolis EK-1 in the AK-210 fermenter on medium containing n-hexadecane. Maximum indicators of SAS synthesis (concentration of extra cellular SAS is 7.2 g/l; factor of emulsification of the cultural liquid 50%; SAS yield from the substrate 50%) have been observed at 60–70% concentration of dissolved oxygen from the saturation level with aerial oxygen (pH 8.0) fractional supply of the substrate by portions each being 0.3–0.4% every 5–6 h to a final volume concentration of 2.4% and with the use of 10% inoculate grown until mid-exponential phase on the medium with 1.0 vol % of n-hexadecane. Implementation of the process of SAS biosynthesis with the fermentation equipment provided the possibility to increase almost two-fold the amount of the synthesized SAS and reduce 3.5-fold the time of cultivation of the producer strain compared with the growth in flasks at shake-flask propagator.Документ Peculiarities of C2-Metabolism and Intensification of the Synthesis of Surface-Active Substances in Rhodococcus erythropolis EK-1 Grown in Ethanol(2008) Pirog, Tatiana; Korzh, Yuliya; Shevchuk, Tetiana; Tarasenko, D.Oxidation of ethanol, acetaldehyde, and acetate in Rhodococcus erythropolis EK-1, producer of surface-active substances (SAS), is catalyzed by N,N-dimethyl-4-nitrosoaniline (DMNA)-dependent alcohol dehydrogenase, NAD+/NADP+-dependent dehydrogenases (optimum pH 9.5), and acetate kinase/acetyl-CoAsynthetase, respectively. The glyoxylate cycle and complete tricarboxylic acid cycle function in the cells of R. erythropolis EK-1 growing on ethanol; the synthesis of phosphoenolpyruvate (PEP) is provided by the two key enzymes of gluconeogenesis, PEP carboxykinase and PEP synthetase. Introduction of citrate (0.1%) and fumarate (0.2%) into the cultivation medium of R. erythropolis EK-1 containing 2% ethanol resulted in the 1.5- and 3.5-fold increase in the activities of isocitrate lyase and PEP synthetase (the key enzymes of the glyoxylate cycle and gluconeogenesis branch of metabolism, respectively) and of lipid synthesis, as evidenced by the 1.5-fold decrease of isocitrate dehydrogenase activity. In the presence of fumarate and citrate, the indices of SAS synthesis by strain R. erythropolis EK-1 grown on ethanol increased by 40–100%. Окисление этанола у штамма Rhodococcus erythropolis ЭК-1 – продуцента поверхностно-активных веществ (ПАВ), осуществляется 4-нитрозо-N,N-диметиланилин (НДМА)-зависимой алкогольдегидрогеназой, окисление ацетальдегида – НАД+- и НАДФ+-зависимыми дегидрогеназами с оптимумом рН 9.5, окисление ацетата – ацетаткиназой и ацетил-КоА-синтетазой. При росте на этаноле в клетках R. erythropolis ЭК-1 функционирует как глиоксилатный цикл, так и полный цикл трикарбоновых кислот, синтез фосфоенолпирувата (ФЕП) обеспечивается двумя ключевыми ферментами глюконеогенеза – ФЕП-карбоксикиназой и ФЕП-синтетазой. Внесение в среду культивирования R. erythropolis ЭК-1, содержащую 2 % этанола, цитрата (0.1 %) и фумарата (0.2 %) сопровождалось усилением глюконеогенеза, что подтверждается повышением в 1.5 и 3.5 раза активности изоцитратлиазы и ФЕП-синтетазы (ключевых ферментов глиоксилатного цикла и глюконеогенетической ветви обмена веществ соответственно), а также синтеза липидов, о чем может свидетельствовать снижение в 1.5 раза активности изоцитратдегидрогеназы. В присутствии фумарата и цитрата показатели синтеза ПАВ штаммом R. erythropolis ЭК-1 на этаноле повышались на 40–100 %.