https://dspace.univ-guelma.dz/jspui/handle/123456789/3 2026-10-08T19:48:55Z https://dspace.univ-guelma.dz/jspui/handle/123456789/19494 Optimization of Microalgal Biomass Production Parameters, Agroecological and Nutritional Interests: The Case of Spirulina HAKIM, Djihane ArthrospiraPlatensis, commonly known as Spirulina, is a filamentous cyanobacterium recognized for its high nutritional value and its capacity to produce bioactive compounds of significant biotechnological interest. Rich in proteins, essential amino acids, vitamins, minerals, and pigments such as phycobiliproteins, Spirulina has been largely studied as a sustainable resource for food, pharmaceutical, and agro-industrial applications. Among its pigments, C-phycocyanin is of particular interest due to its antioxidant, anti-inflammatory, and antimicrobial properties. This study focused on optimizing the abiotic culture parameters of ArthrospiraPlatensis to enhance biomass and C-Phycocyanin (C-PC) production, and to evaluate the antibacterial potential of its aqueous extract. Laboratory cultures were conducted for 30 days, varying temperature, pH, light intensity, and light quality. The results identified the combination of 30°C, pH 10, 5000 Lux, and White light as the optimal conditions, offering the best trade-off with a dry biomass of 0.50 g/L and a C-PC yield of 18.75%. The C-PC extracted under optimal conditions achieved a purity ratio of 0.97, qualifying it as "Food-Grade." Regarding the bioactivity of spirulina, the extract demonstrated broad-spectrum bactericidal activity (MBC/MIC Ratio = 2) against four pathogenic strains. The strongest activity in agar diffusion was recorded against MRSA (Methicillin-resistant Staphylococcus aureus) with an inhibition zone of 32 mm. Concurrently, Gram-negative strains (S. typhi and E. coli) showed the highest physiological sensitivity (MIC of 12.5 and 25 mg/mL, respectively). This study confirms the potential of A. Platensis as a sustainable, nutritive source of high-quality and effective antimicrobial agents against multidrug-resistant bacteria. Also emphasizes the relevance of Spirulina cultivation within a broader agroecological and sustainability framework, offering promising perspectives for future large-scale production and biotechnological applications. 2026-07-14T00:00:00Z https://dspace.univ-guelma.dz/jspui/handle/123456789/19046 Seed Borne diseases BENDJEDID, SAMIRA 2026-03-08T00:00:00Z https://dspace.univ-guelma.dz/jspui/handle/123456789/19045 Phytopathology: Biological and Molecular Bases BENDJEDID, SAMIRA 2026-03-08T00:00:00Z https://dspace.univ-guelma.dz/jspui/handle/123456789/19032 CLIMATOLOGY Bennacer, Leila 2026-02-25T00:00:00Z