*Article* **Absence of Cyanotoxins in Llayta, Edible Nostocaceae Colonies from the Andes Highlands**

**Alexandra Galetovi´c 1, Joana Azevedo 2, Raquel Castelo-Branco 2, Flavio Oliveira 2, Benito Gómez-Silva <sup>1</sup> and Vitor Vasconcelos 2,3,\***


Received: 8 April 2020; Accepted: 5 June 2020; Published: 9 June 2020

**Abstract:** Edible Llayta are cyanobacterial colonies consumed in the Andes highlands. Llayta and four isolated cyanobacteria strains were tested for cyanotoxins (microcystin, nodularin, cylindrospermopsin, saxitoxin and β-N-methylamino-L-alanine—BMAA) using molecular and chemical methods. All isolates were free of target genes involved in toxin biosynthesis. Only DNA from Llayta amplified the *mcy*E gene. Presence of microcystin-LR and BMAA in Llayta extracts was discarded by LC/MS analyses. The analysed Llayta colonies have an incomplete microcystin biosynthetic pathway and are a safe food ingredient.

**Keywords:** cyanobacteria; cyanotoxins; Llayta; microcystin; *Nostoc*

**Key Contribution:** No known cyanotoxins were found in naturally collected Llayta and isolated *Nostoc* strains using molecular and chemical methods.
