CONICET | Buscador de Institutos y Recursos Humanos

Lactic acid bacteria (LAB), widely used as starter cultures for the fermentation of a large variety of foods, can improve the safety, shelf life, nutritional value, flavour and overall quality of the fermented products. In this regard, the selection of strains delivering health-promoting compounds (nutraceuticals) is now the main goal of several studies. Among these studies, vitamin production by LAB has recently gained attention of the scientific community. Although most LAB are auxotrophic for several vitamins, it is now known that certain strains have the capability to synthesize B-group vitamins. Humans cannot synthesize most vitamins and they have to be provided exogenously. Although most essential vitamins are present in a variety of foods, vitamin deficiencies still exist in many countries. Thus, LAB are the ideal candidates to deliver vitamins, among other specific compounds into foods. Certain fermented milks have shown high levels of B-group vitamins due to LAB biosynthesis. Folate biosynthesis by yogurt starter cultures can increase the natural folate levels in this product. These folates do not cause dangerous side-effects, such as masking of B12 deficiencies, as does folic acid, the chemical form of folates commonly used in food fortification. Although little is currently known about riboflavin (vitamin B2) production by LAB, the genes involved in their biosynthesis have been identified in several species. Cobalamin (vitamin B12), a complex corrin compound, was found to be produced by certain strains of Lactobacillus reuteri, particularly CRL1098, a probiotic microorganism. These microorganisms use this vitamin to catabolize glycerol and to produce reuterin, a well-known antimicrobial compound. Since most LAB are recognized as probiotics, their capacity to produce B-group vitamins could be useful for the design of novel functional foods able to prevent vitamin deficiencies by enhancing the nutritional value of the product.