Selection of Riboflavin Overproducing Strains of Lactic Acid Bacteria and Riboflavin Direct Quantification by Fluorescence.

Riboflavin (vitamin B ₂ ) is a vitamin of the B group involved in essential biological pathways, including redox reactions and the electron transport chain. Some lactic acid bacteria (LAB) can synthesize riboflavin and this capability is strain-dependent. In the last years, a growing interest has focused on the selection of riboflavin-overproducing food-grade LAB for the vitamin biofortification of fermented foods, as well as for the formulation of innovative functional products.In this chapter we report fast and inexpensive techniques in order to (1) screen LAB isolates able to produce riboflavin from different matrices, (2) select spontaneous roseoflavin-resistant riboflavin overproducing strains, and (3) quantify vitamin B ₂ in culture media by fluorescence detection.These protocols could be useful to select new overproducing strains and/or species from different ecological niches, as well as to optimize the conditions for vitamin bioproduction.