Efficient selection of new Limnospira platensis strains (spirulina) for biomass and high-value molecule production

Limnospira platensis is the most widely cultivated cyanobacterium worldwide, valued by the food industry for its high content of useful compounds like protein, long-chain polyunsaturated fatty acids, vitamins, carotenoids, phenolics, and other antioxidants. Its rapid cellular multiplication capacity makes it a highly promising source for sustainable biomass production and synthesis of commercially valuable compounds. Growing food industry interest has stimulated studies on optimizing culture parameters such as culture medium composition, temperature, and light to maximize biomass and the synthesis of high-value molecules. Given the demonstrated diversity in production yields, we hypothesized that different L. platensis strains would exhibit varying growth and productivity rates under specific conditions, allowing for selection of the most promising strains for specific industrial applications. In this study, from a previous study of 85 french L. platensis strains (Roussel et al. 2025), we selected 17 strains to assess the combined impact of genotype and light quality on growth rate, biomass production, and high-value molecule concentrations. The selected strains were cultured in a modified Zarrouk Spirulina medium at 30°C, under white or red light at 200 µmol photons m ^− 2 s ^− 1 and a 22:2 h light-dark photoperiod. Results indicate significant variability across tested strains and light conditions. Notably, the L. platensis PMC 1246.20 strain, exhibited exceptional performance, achieving some of the highest recorded growth rates and production of biomass, phycobiliproteins and carotenoids. This selection experiment demonstrates the critical importance of strain-specific optimization of culture conditions for scaling up production to industrial levels.