Oksana A. Aref’eva, Candidate of biological sciences, associate professor of the sub-department of natural and technosphere safety, Yuri Gagarin State University of Saratov (77 Politekhnicheskaya street, Saratov, Russia), E-mail: email@example.com
Lubov N. Ol’shanskaya, Doctor of chemical sciences, professor, professor of the sub-department of natural and technosphere safety, Yuri Gagarin State Technical University of Saratov (77 Politekhnicheskaya street, Saratov, Russia), E-mail: firstname.lastname@example.org
Renat Sh. Valiev, Candidate of biological sciences, assistant of the sub-department of medical and biological disciplines, Saratov Medical University “Reaviz” (10 Verkhny rynok street, Saratov, Russia), E-mail: email@example.com
Background. Chlorella sorokiniana is used for the production of biofuels and the release of biologically active substances. Biomass can be grown in low-energy and economical conditions. The purpose of this work is to assess the influence of the cultivation’s conditions of microalgae Ch. sorokiniana in the open air and the effect of a constant magnetic field in laboratory conditions on the reproduction, growth and development of microalgae.
Materials and methods. Population growth was assessed by the optical density of the chlorella suspension and further counting in the Goryaev chamber for the number of million cells per ml. For statistical analysis of the experimental results, we used the R version 3.4.0 software environment. In this work, we compared the quantitative indicators of reproduction, as well as the sizes of chlorella cells after and without the effects of constant magnetic field (CMF). Regression analysis was carried out to assess the dependence of the growth rate of chlorella on the air temperature.
Results. Visually (under a microscope), it was revealed that the growing population in a bioreactor placed in the open air has a larger proportion of elongated cells (young cells) and a smaller proportion of rounded cells (old cells). Intensive growth and development of cells occurs in July and August with a minimum of cloudy days. The optimal temperature regime for constant renewal of chlorella cells was reached at 27–30 ºС. When analyzing the influence of CMF with a strength of 2 kA/m on the growth and reproduction of chlorella in laboratory conditions, an intensive growth of cells was revealed during the first 3 days of cultivation. The increase in biomass increased 3–4 times and reached 7,5 million cells/ml. When exposed to CMF with a strength of 0,5 and 1,0 kA/m, no increase in cell concentration was observed during the entire cultivation period.
Conclusions. As a result of the work done, it was found that exposure to constantly high temperatures (30–36 ºС) in open air without additional aeration is an unfavorable factor for the development of Ch. sorokiniana. The optimal temperature regime for constant renewal, growth and development of chlorella cells in natural conditions was achieved at 27–30 ºС. In the course of studies carried out in laboratory conditions, the maximum increase in chlorella cells was revealed when exposed to CMF with a voltage of 2 kA/m during the first 3 days of cultivation, after which a stabilization phase was observed. It has been shown that the use of a magnetic field promotes cell aggregation.
microalgae, chlorella, Chlorella sorokiniana, cultivation, biomass, constant magnetic field
1. Dvoretsky D.S., Dvoretsky S.I., Peshkova E.V. Optimization of the Process of Cultivation of Microalgae Chlorella Vulgaris Biomass with High Lipid Content for Biofuel Production. Chemical Engineering Transactions. 2015;43:361–366.
2. Politaeva N.A., Atamanyuk I.V., Smyatskaya Y.A. [et al.]. Waste-free technology of Shlorella sorokiniana microalgae biomass usage for lipids and sorbents production. Izvestiya vysshikh uchebnykh zavedeniy. Ser.: Khimiya i Khimicheskaya tekhnologiya = University proceedings. Series: Chemistry and chemical technology. 2018;61(12): 137–143.
3. Bogdanov N.I. Chlorella: Green food all year round. Kombikorma = Combined feed. 2004;3:66–72. (In Russ.)
4. Piligaev A.V., Sorokina K.N., Bryanskaya A.B. [et al.]. Investigation of the biodiversity of microalgae in Western Siberia for use in the production of third-generation biofuel. Vavilovskiy zhurnal genetiki i selektsii = Vavilovsky journal of genetics and selection. 2013;17(2):359–367. (In Russ.)
5. Sorokina K.N., Yakovlev V.A., Piligaev A.V. [et al.]. Potential application of microalgae as raw material for bioenergy. Kataliz v promyshlennosti = Industrial catalysis. 2012;2:63–72. (In Russ.)
6. Meshcheryakova Yu.V., Nagornov S.A. Obtaining raw materials for biodiesel fuel based on chlorella microalgae oil. Innovatsii v sel'skom khozyaystve = Agricultural innovation. 2013;3:39–41. (In Russ.)
7. Smyatskaya Yu.A., Politaeva N.A. Biogas production by fermentation of residual biomass of microalgae and duckweed. Butlerovskie soobshcheniya = Butlerov messages. 2019;60(12):146–151. (In Russ.)
8. Politaeva N., Smyatskaya Y., Slugin V. [et al.]. Effect of laser radiation on the cultivation rate of the microalga Chlorella sorokiniana as a source of biofuel. IOP Conference. Ser.: Earth and Environmental Science. 2018;115:012001.
9. Bogdanova A.A., Sukhovskiy N.A. Influence of different voltage and time of exposure to electrostatic field on morphological parameters CHLORELLA VULGARIS IFR No. S-111. Materialy dokladov: XXI Vseros. molodezh. nauch. konf. ekologii (posvyashch. 70-letiyu A. I. Taskaeva) = Proceedings of the 21st All-Russiany youth scientific conference of ecology (dedicated to the 70th anniversary of A.I. Taskaev). Syktyvkar: UrO RAN, 2014:372. (In Russ.)
10. Bogatina N.I., Sheykina N.V. The effect of magnetic fields on plants. Uchenye zapiski Tavricheskogo natsional'nogo universiteta imeni V. I. Vernadskogo. Ser.: Biologiya, khimiya = Scientific notes of Tavrida National V.I. Vernadsky University. Series: Biology, chemistry 2010;23(4):45–55. (In Russ.)
11. Ol'shanskaya L.N., Titorenko O.V., Eremeeva Yu.A. Effect of constant magnetic field and ultraviolet radiation on the growth of higher plants and phytoremediation of soil from oil products. Khimicheskoe i neftegazovoe mashinostroenie = Chemical and oil and gas engineering. 2015;5:43–45. ISSN 0023-1126. (In Russ.)
12. Olshanskaja L.N., Russkikh M.L., Arefeva O.A., Vlasova E.L. Intensification of heavy metal extraction from effluent by phytoremediation using electromagnetic radiation energy and NaCl additive. Chemical and Petroleum Engineering. 2013;49(7-8): 555–558.
13. R Core Team. R: A language and environment for statistical computing. R Foundation for Statistical Computing. Vienna, 2020. Available at: https://www.R-project.org/
14. Kobzar' A.I. Prikladnaya matematicheskaya statistika. Dlya inzhenerov i nauchnykh rabotnikov = Applied mathematical statistics. For engineers and scientists. Moscow: Fizmatlit, 2006:816. (In Russ.)
15. Bragazin A.A., Radaev A.A., Nizhegorodtsev A.A., Gelashvili D.B. Statistical analysis of the exterior features of working individuals of the honeybee breeds Apis Mellifer Karnitz Pohlmann and Apis Mellifer. Vestnik Nizhegorodskogo universiteta imeni N. I. Lobachevskogo = Bulletin of Lobachevsky State University of Nizhny Novgorod. 2012;2:119–122. (In Russ.)
16. Ob utverzhdenii Metodicheskikh ukazaniy po razrabotke normativov kachestva vody vodnykh ob"ektov rybokhozyaystvennogo znacheniya, v tom chisle normativov predel'no dopustimykh kontsentratsiy vrednykh veshchestv v vodakh vodnykh ob"ektov rybokhozyaystvennogo znacheniya: prikaz Federal'nogo agentstva po rybolovstvu ot 4 avgusta 2009 g. № 695 [s izm. i dop.]. = On approval of guidelines on developing water quality standards for fishery water basins, including the standards of maximum permissible concentration of hazardous substances in waters of fishery water basins: the order of the Federal Agency for Fishery of 04.08.2009 No. 695 [amended and supplemented]. Available at: https://www.base.garant.ru (In Russ.)