Production of Thermostable phycocyanin in Spirulina

This study focuses on enhancing the thermal stability of phycocyanin, a valuable blue pigment from Spirulina, widely used as a natural dye and protein supplement. While phycocyanin degrades at temperatures above 45–50ºC, thermostable variants exist in thermophilic microalgae such as Galdieria sulphuraria, though these strains are difficult and costly to cultivate. To overcome this, thermostable phycocyanin genes from G. sulphuraria were cloned and introduced into commercial Spirulina using Agrobacterium-mediated transformation. Validation confirmed successful gene integration and protein expression in Spirulina, but not in Chlorella vulgaris.The recombinant Spirulina produced thermostable phycocyanin that retained 74.3% stability at 55ºC compared to 45.3% in the wild type. It also showed slightly higher biomass productivity (7.2% increase) and greater phycocyanin yield (1.0 g/L vs. 0.7 g/L). Importantly, the foreign gene remained stably integrated without antibiotic selection for several months. These findings demonstrate that genetically engineered Spirulina can serve as a cost-effective platform for producing thermostable phycocyanin with improved yield and stability, addressing limitations of current production methods.