Abstract

Culture collections of microalgae preserve viable material for conservation, research and biotechnology pur-poses; however, in the absence of routine authenticity checking, the strains deposited may become inexact references or inadequate starting material for a commercial development. The edible cyanobacteria Arthrospira/ Limnospira is recognized as one of the most important industrially cultivated microalgae. Arthrospira/Limnospira strains have been frequently confused and incorrectly denoted as Spirulina, therefore, an accurate taxonomic identification of strains available in culture collections worldwide is imperative. In this study, eleven strains, originally designated as Arthrospira/Limnospira or Spirulina in three microalgae culture collections, were analyzed using their ITS sequence to verify their taxonomic classification. Phylogenetic analysis showed that there were misclassified strains in these collections: seven strains were grouped in one of the two genetic clusters previously described for Arthrospira, while remaining strains were grouped within Spirulina genus, forming two well-supported not previously described genetic clusters. Morphological characterization of Arthrospira strains showed typical characters of the genus; while their physiological and biochemical characterization showed intraspecific variability in growth attributes and pigments, proteins, lipids and fatty acids contents.