Lactobacillus plantarum CECT 9571 is a natural mutant riboflavin overproducer derived from the strain Lactobacillus plantarum CECT 9492, isolated from quinoa seeds in Maimará (Jujuy), Northwestern Argentina, and has been investigated for its high biotechnological potential in the frame of project Microandes that targeted traditional fermented Andean products of vegetal origin.