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

Abstract Limnospira platensis is the most widely cultivated cyanobacterium worldwide and is valued by the food industry for its high content of useful compounds like peptides, amino acids, 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 growth medium composition, growth temperature, and light to maximize biomass and the production of high-value biomolecules. Given the demonstrated genomic diversity within each species of cyanobacterium, we hypothesised that different L. platensis strains would exhibit varying genomic and phenotypic characteristics, resulting in strain-specific biomolecule production, growth and productivity rates. In the context of Access and Benefit-Sharing under the 1992 Convention on Biological Diversity, the selection of French L. platensis strains for local industrial applications requires a large-scale isolation process followed by a selection protocol. The novel aspects of this study include the isolation and characterization of a large number (n = 85) of French L. platensis strains and a multistage workflow procedure involving several steps to select the most promising strains for industrial culture in France. The L. platensis PMC 1246.20 strain (from Camargue, France) exhibited exceptional performance, achieving some of the highest recorded growth rates as well as the highest biomass, phycobiliproteins and carotenoids production when cultured under red light. These selection experiments highlight the importance of identifying the optimal strain-specific culture conditions when selecting L. platensis strains for scaling up production to industrial levels.