Evaluation of Bile Salt Hydrolases, Cholesterol-Lowering Capabilities, and Probiotic Potential of Enterococcus faecium Isolated From Rhizosphere

Abstract

Bile salt hydrolase (BSH) activity, hypo-cholesterolemic effect, and probiotic properties have been reported for <i>Enterococcus</i> strains isolated from animal and human gut and fermented foods but not for strains isolated from environmental niches, like aquatic and terrestrial plants, soil, and water. The present study is the first report on isolation of <i>Enterococcus faecium</i> from rhizospheric soils that harbor the <i>bsh</i> gene, remove cholesterol <i>in vitro</i>, and possess essential and desirable probiotic attributes. Fifteen samples were collected from different sites located in northern, southern, and central regions of India, of which five yielded pure colonies that were named LR2, LR3, ER5, LR13, and VB1. These were identified by 16S rRNA gene sequencing as <i>E. faecium</i> and evaluated for BSH activity, cholesterol-lowering potential <i>in vitro</i>, and probiotic properties. Our results indicated that all the strains were capable of surviving the harsh conditions of the gastrointestinal tract and did not harbor any of the virulence genes. Though all strains showed the presence of <i>bsh</i> and potential for cholesterol removal, <i>E. faecium</i> strain LR13 showed a remarkable cholesterol removal capability and vancomycin susceptibility and possessed most of the desirable and essential attributes of a probiotic. Hence, it seems to be a fairly promising probiotic candidate that needs to be further evaluated in <i>in vivo</i> studies, especially for its hypo-cholesterolemic potential.