Exploring the influence of light conditions on the antifungal, antioxidant, and cytotoxic potential of N. persica A1387

Environmental factors significantly influence the growth, metabolism, and bioactive compound synthesis of cyanobacteria, with light playing a critical role. This study evaluated the effects of red, blue, and white light at various intensities (45, 80, 120, and 200 W) on the growth rate, biomass dry weight, cell doubling time, antioxidant activity, antifungal activity, and cytotoxicity of Neowestiellopsis persica A1387 under two photoperiod conditions (16:8 L:D and 24:0 L:D). White light significantly enhanced the growth rate and biomass production. The biomass dry weight under white light was 1.5–1.6 times higher than red light and 2–2.2 times higher than under blue light across both photoperiod conditions. Furthermore, the average specific growth rate under white light was 1.06 times higher than under red light and 1.13 times higher than under blue light for both treatments. In contrast, blue light had the most pronounced effect on antioxidant activity, increasing it by 1.01–1.02 times compared to red light and 1.21–1.22 times compared to white light, as measured by the ABTS method. No significant differences (p > 0.05) were observed in antifungal activity against Candida albicans and Aspergillus niger or in cytotoxicity against MCF-7 cells under different light treatments. GC-MS analysis identified 3-methylbutanal and 2-methylbutanal as the most abundant volatile compounds across all treatments. In conclusion, white light is optimal for growth and biomass production, while blue light enhances antioxidant activity, demonstrating their potential for optimizing bioactive compound production. • White light significantly enhanced the growth rate and biomass dry weight of Neowestiellopsis persica A1387. • Blue light notably increased the antioxidant activity of Neowestiellopsis persica A1387. • GC-MS assay revealed, the highest amounts of volatile compounds were 3-methylbutanal and 2-methylbutanal.