Monospecific renaming within the cyanobacterial genus Limnospira (Spirulina) and consequences for food authorization

Abstract

Aims: The cyanobacterial genus, Limnospira (anc. Arthrospira Stizenberger ex Gomont 1892), commonly called “Spirulina”, is widely used for commercial purposes because of its high protein content and beneficial probiotic metabolites. Thus, the taxonomy of this genus is important because of its consequences for food applications. Methods and results: We constructed a database with formation on all Limnospira strains plus new ones from 72 new French isolates. We used a polyphasic approach (phylogenetic, phylogenomic, presence or absence of coding DNA sequences, morphological, and ultrastructure analyses) to confirm that the species A. platensis belonged to the genus Limnospira (L. platensis Gomont comb. nov. Basionym. Arthrospira platensis Gomont 1892) and that the genus Limnospira was monospecific, only represented by L. platensis. Conclusions: This study highlighted the large intra-specific diversity of L. platensis, independent of the affiliations of the phylogenetic clades or geographical location of the habitats and the subsequent physiological and metabolic plasticity. Significance and impact of study The cyanobacterial genus, Limnospira (anc. Arthrospira), commonly called “Spirulina” is monospecific and the authorization for food applications should be extended to all Limnospira taxa, including the previously named L. platensis, L. fusiformis, L. indica, and L. maxima.