Probiotic attributes of riboflavin over-producing lactic acid bacteria strains

Riboflavin plays a crucial role in human cell metabolism as precursor of coenzymes flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) (Capozzi et al., 2012). In this study, the riboflavin production of Lactobacillus plantarum and Lactobacillus fermentum strains was investigated in chemically defined medium (CDM) (Russo et al., 2014) and in a co-cultures system of lactobacilli and human intestinal epithelial cells (Russo et al., 2012). Both strains showed the ability to over-produce riboflavin respect to the control strains. The strains displayed a significant ability to survive to an in vitro gastrointestinal transit, an aptitude to form biofilm on abiotic surface, a strong capability to adhere on intestinal cells and to contrast the adhesion of Escherichia coli O157:H7. Furthermore, both strains showed antimicrobial activity on agar plate against three human pathogenic bacteria, i.e. Escherichia coli O157:H7, Listeria monocytogenes and Salmonella enterica. Resistance to major antibiotics and potential hemolytic activity confirmed the safety assessment. This study aims to demonstrate the combination of probiotic features and riboflavin over-production by the investigated Lactobacillus plantarum and Lactobacillus fermentum strains and their potential application as endogenousriboflavin producers that couldenrichedthe riboflavin content both in novel fermented food and in situ in the host intestine.