فهرست نشریات علمی دسترسی آزاد ایران

Cyanobacteria are valuable producers of phycobiliproteins, water-soluble pigments with fluorescent, antioxidant, and bioactive properties, widely used as natural colorants and functional bioactive compounds. This research employed a definitive systematic design to systematically evaluate the effects of multiple environmental and nutritional factors, including nitrogen and phosphorus availability, salinity, carbon sources (glucose and acetate), and light/dark cycles (24:0 and 16:8 hours), on the production of phycobiliproteins, namely phycocyanin, allophycocyanin, phycoerythrin, and total phycobiliproteins in Nostoc muscorum. Chlorophyll a and phycobiliprotein levels were monitored over a 30-day period across 14 experimental runs. Among them, run 8 characterized by high nitrate (1000 mg/L) and phosphate (40 mg/L), low salinity (0.5% NaCl), low glucose (0.25%), absence of acetate, and a 16:8 h light/dark cycle, achieved the highest levels of chlorophyll a (5.02 ± 0.55 µg mg-1dw), phycocyanin (23.38 ± 1.35 µg mg-1dw), allophycocyanin (8.35 ± 0.44 µg mg-1dw), phycoerythrin (37.86 ± 1.45 µg mg-1dw), and total phycobiliproteins (69.59 ± 2.03 µg mg-1dw). Nitrogen exerted the strongest influence on total phycobiliproteins production (p = 0.0099), followed by phosphorus (p = 0.0154) and salinity (p = 0.0105). Glucose supplementation enhanced pigment synthesis under nutrient-replete conditions, whereas higher acetate concentrations showed an inhibitory effect. Photoperiod significantly affected chlorophyll a content (p < 0.05), with a 16:8 h light/dark cycle generally promoting higher accumulation, although its effect on total phycobiliproteins production was not significant (p = 0.1879). Overall, these findings provide a solid framework for optimizing cultivation conditions to maximize phycobiliprotein production in N. muscorum, and endorsing their application as natural antioxidant pigments and bioactive compounds in industrial biotechnology applications.