Nutragenomics of probiotic bile salt hydrolases

Abstract

The bile salt hydrolysis is one of the most important metabolic activities that are exhibited by enteric bacteria colonizing in the Gl tract of humans and animals. The BSH active probiotic strains such as Bifidobacterium animalis-ssp-lactis are commercially used as probiotic yogurts and capsule forms that may bring about a lowering of serum cholesterol levels (hypocholesterolemic effects). However, the hypocholesterolemic mechanism of probiotics based on the BSH hypothesis has not been sufficiently elucidated and its high activity that produces toxic bile salts may cause colon cancer and few undesirable diseases. Thus, further studies are warrant whether the BSH activity of probiotics is beneficial or detrimental to the host. We reviewed the available literature and our own data on the biochemical, molecular, physiological aspects, and potential applications of the BSH. Many probiotics contain multiple bsh genes that may confer some advantage on the strains, as each BSH may have different bile tolerance and adaptation, thereby ensuring maxima survival under constantly changing stress environments. Multiple BSHs may have other roles in hydrolyzing bile salts to be used as an energy source or as an enhanced defence to membrane-damaging compounds.