Study the Effect of Colored and White LED Light Radiation on the Biological Activity of Desmonostoc alborizicum Cultivated Under Modified BG-110 Medium Composition

The present effort intends to evaluate the influence of different wavelengths of LED lights on the biological activity of cyanobacterial species of the native toxic Iranian cyanobacteria strain Desmonostoc alborizicum strain 1387 cultivated under abiotic stresses for 30 days. The phycobiliproteins, dry weight, specific growth rate, and cell doubling time were measured. Furthermore, an assessment was conducted on phytochemical substances such as phenolic, flavonoid, and tannin levels, as well as defense enzymes and antioxidant activity. Additionally, the cytotoxic evaluation was conducted using the MTT test and GC–MC analysis. The results of the concentration and purity of pigments showed that the highest amount belonged to blue light (470 lx) and red light (660 lx). Biomass and SGR amounts were the greatest under white light conditions. Based on antioxidant activity, blue light showed the highest activity by the DPPH method. Phenolic and flavonoid contents were lower under blue light conditions, while they showed a higher amount in other treatments without significant differences. The results of the measurement of catalase and glutathione s-transferase enzymes had higher activity when studied in strains grown under green light (520 lx), while white light showed the highest activity for the SOD enzyme. The findings of gas chromatography demonstrated that 3-methylbutanal, 2-methylbutanal, 2-methylpropanol, and 3-methyl-1-butanol were higher in the red light condition. In conclusion, the results of this study showed that red and blue light treatments had a significant effect on the biological activity of Desmonostoc alborizicum cultivated under nitrogen and sulfur stress.