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CNAA / Theses / 2021 / July /

Biotechnologies for obtaining spirulina-based preparations with high selenium and germanium content

Author: Djur Svetlana
Degree:doctor of biology
Speciality: 03.00.23 - Biotechnology
Scientific adviser: Valeriu Rudic
doctor habilitat, professor, Institute of Microbiology and Biotechnology of the ASM
Institution: Institute of Microbiology and Biotechnology of the ASM


The thesis was presented on the 29 July, 2021
Approved by NCAA on the 4 October, 2021


Adobe PDF document1.12 Mb / in romanian


CZU 573.6+602.3 : 582.232.2+579.222.4

Adobe PDF document 5.90 Mb / in romanian
180 pages


Arthrospira platensis CNMN-CB-11, spirulina, biomass, preparations and supplements, organic selenium, organic germanium


The thesis consists of an introduction, four chapters, conclusions and recommendations, bibliography list with 332 references. It comprises 122 pages of the main text, 24 figures, 20 tables and 3 annexes. The results were published in 22 scientific papers.

Aim: Development of biotechnologies for obtaining preparations with a high content of selenium and/or germanium based on biomass of cyanobacterial strain Arthrospira platensis CNMN-CB-11.

Objectives: To establish the effect of some inorganic compounds of Se (IV), inorganic and organic compounds of Ge (IV) on biomass production and accumulation of selenium and germanium by cyanobacterial strain Arthrospira platensis CNMN-CB-11; to assess the changes in the content of major biologically active components (proteins, phycobiliproteins, carbohydrates, lipids) in the composition of biomass on background of selenium and germanium accumulated by spirulina; to elaborate proceedings for spirulina cultivation under conditions that ensure the production of biomass with high content of biotransformed selenium and germanium; to develop technological schemes for one-stage production of preparations and supplements containing selenium and/or germanium as an effective component.

Scientific novelty: The compounds Se (IV) and Ge (IV) have been selected, and their concentration limits and optimal parameters ensuring the maximum level of selenium and germanium accumulation by cyanobacterial strain Arthrospira platensis CNMN-CB-11, which do not affect productivity, biochemical composition and safety aspects (confirmed by the MDA test) of biomass production. The bioorganic nature of selenium and germanium accumulated in spirulina biomass was demonstrated by the high level of distribution of these elements in biologically active fractions (amino acids, oligopeptides, proteins, lipids and carbohydrates).

Solved scientific problem: scientific foundation of the capacity of cyanobacterium Arthrospira platensis CNMN-CB-11 strain to accumulate and biotransform selenium and germanium from chemical compounds that led to the elaboration of new proceedings for obtaining spirulina biomass enriched with selenium and/or germanium, which allowed one-stage production of new preparations with a high content of these biologically important elements.

Theoretical significance: New data have been accumulated about the action of chemical compounds Se (IV) and Ge (IV) on the productivity of cyanobacterium Arthrospira platensis CNMN-CB-11, as well as the level and conditions of selenium and germanium accumulation by this strain. Changes in biochemical composition, content of lipid oxidation products, and antioxidant activity of biomass in the process of selenium and germanium accumulation by spirulina were revealed.

Applicative value: There have been developed 3 new proceedings to obtain selenium and/or germanium enriched spirulina biomass. The technological schemes with a single manufacturing cycle for 9 new preparation variants with high selenium and/or germanium content were elaborated. Germanium selenide offers the opportunity to obtain biologically active raw materials containing increased quantities of both trace elements based on spirulina biomass.

Implementation of scientific results: the results were implemented at FICOTEHFARM SRL, Chisinau, Republic of Moldova (Implementation Acts No. 01-11/2017 and No. 02-11/2017 of 30.11.2017).