Assessment of Physiological Traits in Cyanobacteria Isolated From Rice Agroecosystems for Biofertilizer Applications

ABSTRACT Cyanobacteria are photosynthetic prokaryotes recognized for their varying pigment composition and capacity to adapt to different ecological situations. Even though they are significant, there aren't many studies comparing native cyanobacterial strains in terms of their ability to be used as biofertilizers. This study comparatively evaluated the physiological characteristics of seven cyanobacterial strains ( Nostoc sp., Anabaena sp., Westiellopsis sp., Oscillatoria sp., Tolypothrix sp., Calothrix sp., and Phormidium sp.) isolated from paddy fields in different regions of Uttar Pradesh (Meerut, Muzaffarnagar, and Haridwar regions). The examined parameters included photosynthetic pigments‐ chlorophyll, carotenoids, phycobiliproteins‐Phycocyanin (PC), Phycoerythrin (PE), and Allophycocyanin (APC), Total Soluble Protein (TSP), and carbohydrates. Cultures were cultivated in BG‐11 medium, and samples were analyzed at 7th, 14th, 21st, and 28th days of incubation for examination via spectrophotometer. The findings indicated substantial interstrain differences. Anabaena sp. demonstrated the highest levels of chlorophyll, carotenoids, proteins, and carbohydrates on Day 14, while Tolypothrix sp. had the greatest concentrations of APC and PE. The strain‐specific variations underscore the metabolic diversity of paddy field cyanobacteria. This thorough comparison of physiological data sheds light on the adaptation mechanisms of cyanobacteria and their potential uses as natural biofertilizers and in biotechnological applications.