# Postbiotic production, aggregation properties, binding potential, antioxidants capacity, and functional characterization of the lead Enterococcus faecium probiotic strains

## TL;DR

This study explores the probiotic potential of six Enterococcus faecium strains, highlighting their stress tolerance, antioxidant activity, and ability to produce postbiotics.

## Contribution

The study provides a comprehensive functional characterization of E. faecium strains, including their postbiotic production and antioxidant properties.

## Key findings

- Selected E. faecium strains showed significant probiotic potential with stress tolerance and postbiotic production.
- Strains exhibited antioxidant activity and free radical scavenging abilities.
- Two strains produced slime and all tolerated digestive stress, indicating potential for food and biotech applications.

## Abstract

The emergence and applications of probiotic species across industries are growing rapidly, requiring the isolation, identification, and robust characterization of new strains. Enterococcus faecium, a dominant species of the genus Enterococcus, is widely distributed and has a prominent role in biotechnological applications. The probiotic potential of E. faecium is well established, and various strains have been commercially available. In this study, we aimed to provide a strategic road map to explore the probiotic potential, postbiotic production, antioxidant activities, aggregation properties, and functional characterization of the selected E. faecium strains (n = 6) isolated locally. All selected strains demonstrated significant probiotic potential, with stress tolerance, aggregation, and postbiotic production. They were free from biogenic amines while exhibiting notable free radical scavenging and reducing activities. Additionally, their ability to adhere to fibrinogen and mucin indicates enhanced potential for mucosal colonization, competitive exclusion of pathogens, and improved host interaction. All strains tolerated digestive stress, two strains (E. faecium Se142 and E. faecium F25) produced slime, and all exhibited antioxidant activity. The influence of digestive enzymes on enterocins, the production of arginine hydrolases, and the impact of glycine, arginine, and glucose on their growth performance reflected positive attributes. These attributes indicate their potential as ideal candidates for developing new probiotic formulations, with intended food and biotechnological applications. In the future, genomic and in vivo validation studies are warranted.