Propionibacteria also have probiotic potential

Abstract

Propionibacteria were first described by the end of the nineteenth century and named some years later by Orla-Jensen (1909) who proposed the genus Propionib acterium for referring to bacteria that produce propionic acid as their main fermentation endproduct. Based on habitat of origin, they are conventionally divided into "classical or dairy" and "cutaneous" microorganisms which mainly inhabit dairy/silage environments and the skin/intestine of human and animals, respectively. Historically, the economic relevance of Propionib acterium has been related to the industrial application of classical species as dairy starters for cheeses manufacture and as biological producers of propionic acid. However, propionibacteria also display probiotic potential. Over the last two decades, the ability of these microorganisms to improve the health of humans and animals by being used as dietary microbial adjuncts has been extensively demonstrated. Both in vitro and in vivo studies revealed that propionibacteria are able to modulate in a favorable way gut physiology, microbiota composition and immunity. Much of these health benefits could be related to the ability of propionibacteria to remain in high numbers in the gastrointestinal tract by surviving the adverse environmental conditions and adhering to the intestinal mucosa. In addition, other promising properties like the production of nutraceuticals and relevant biomolecules such as vitamins B and K, conjugated linoleic acid (CLA), exopolysaccharides (EPS), trehalose, bifidogenic factors, bacteriocins, etc have been reported. In recent years, the availability of genome sequences of different propionibacteria species have allowed to deep insight into the metabolism and physiology of these microorganisms and became a useful tool for selecting appropriate strains for technological, functional or probiotic applications. In the present chapter, we review exhaustively the evidences that support the potential of propionibacteria to be used as probiotic supplements for human and animal nutrition. Besides the positive results on health obtained by us and others, the hardiness and adaptability of propionibacteria to both technological and physiological stresses encourage their usage for designing new functional foods.