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SÎRBU, Tamara; MOLDOVAN, Cristina; ŢURCAN (OLAN), Olga; BURTSEVA, Svetlana; BYRSA, Maxim; BATYR, Ludmila; SLĂNINĂ, Valerina. Study on the action of nanoparticles of Fe3O4 and Fe0 on microorganisms. In: Achievements and perspectives of modern chemistry. 9-11 octombrie 2019, Chişinău. Chisinau, Republic of Moldova: Tipografia Academiei de Ştiinţe a Moldovei, 2019, p. 191. ISBN 978-9975-62-428-2.
|Achievements and perspectives of modern chemistry 2019|
Conferința "International Conference "Achievements and perspectives of modern chemistry"" |
Chişinău, Moldova, 9-11 octombrie 2019
Metal nanoparticles are currently used in various areas. It has been a significant increase in the number of phytotechnology research, NP use of Fe, also affecting the microbial population, microalgae and cyanobacteria. The results obtained previously within the IMB of Moldova have shown that iron-based nanoparticles can enhance the activity of microorganisms as well as the efficiency of soil bioremediation processes of POPs (Persistent organic pollutants) by: (a) the radical reduction of the number of manipulations necessary to remedy the polluted soil, (b) reducing the 3-fold processing time required to decompose the pollutant into the soil, and (c) increasing the degree of pollutant mineralization in soil by 4 times. Because the strains of microorganisms selected as potential POPs have a well-outlined perspective for use in various polluted soil bioremediation processes and technologies, there is a clear need to preserve and conserve these strains. As a subject of study were: (1) - 3 strains of microorganisms from CNMN selected as potential POPs destroyers: Penicillium sp.11; Streptomyces sp. 205 and Bacillus sp. 2; (2) Fe3O4 and Fe(0) nanoparticles, synthesized in Solid State Structures Laboratory of the Institute of Electronic Engineering and Nanotechnology "D. Ghiţu ", to whom we thank. To obtain the biological material subjected to lyophilization the strains were grown in glass tubes, Penicillium sp. 11 and Streptomyces sp. 205 on Czapek agar medium with glucose for 714 days at t°= +30°C and +27°C, respectively, and the strain Bacillus sp. 2 for 48 hours to +35°C. For lyophilization strains were used in the stationary growth phase. As a protective medium served: Penicillium sp. 11 strain - skimmed milk + 7% glucose; Streptomyces sp. 205 - 2.5% gelatin + 7.5% glucose; Bacillus sp. 2 - skimmed milk + 12% sucrose (control medium) and their variants, using as a supplement NPof Fe3O4 and Fe(0) in concentration (mg/L): 1; 5; 10. The lyophilization was carried out on freeze-drier „LABCONCO” FreeZone Plus 6 Liter Cascade Console Freeze Dry System (SUA), at a condenser temperature of -88 ... -94°C in vacuum 6-7 Pa, the pre-freezing temperature for Penicillium sp. 11 and Streptomyces sp. 205 was -50°C, and for the strain Bacillus sp. of -20°C for 12 hours. The titre of the suspension subjected to lyophilization and the viability of the cultures after lyophilization were determined. The culture viability was calculated according to the formula c% = (logUFCml-1fin / logUFCml-1in) × 100%, where logUFC mL-1in is the logarithm of the number of colony forming units before lyophilization, logUFC mL-1fin - logarithm of the number of colony forming units after lyophilization or preservation and c - viability of the strains in percent. The results obtained in this study have shown that the use of both nanomagnetite and nanoparticles of Fe(0) in concentrations of 1 - 10 mg/L in the protective medium for the lyophilization of the nano-bioremediating potential strains: Penicillium sp. 11, Streptomyces sp. 205 and Bacillus sp. 2 did not result in essential changes in strain viability, so it varies within the control up to 3-5% and can not be recommended as lyoprotectors for freeze-drying and longterm maintenance of the studied strains.