Screening of Lipid-Lowering Acid Bacteria from Traditional Koumiss to Develop a New Probiotic Starter Culture

With obesity posing a growing global health burden, probiotic interventions are gaining attention as potential therapeutic strategies. This study moves beyond conventional single-strain approaches by developing a rationally designed multi-strain consortium sourced from the under-explored microbial niche of traditional koumiss. Sixteen lactic acid bacterial strains were isolated and screened using key in vitro lipid-lowering indicators. Two high‑performing strains, Lactobacillus plantarum SR6 and Enterococcus faecalis SM5, were selected and formulated into a 1:1 composite (SR6‑SM5). The composite not only exhibited synergistically enhanced functional properties-including strong gastrointestinal tolerance, with a survival rate of over 95.7% in gastric juice and over 76% in intestinal juice, high adhesion potential (hydrophobicity 93.00 ± 0.25%; auto-aggregation 90.58 ± 0.31%), notable antioxidant activity (ABTS⁺ and DPPH· scavenging rates > 87%), and antibacterial effects-but also demonstrated a comprehensive safety profile with no hemolytic, cytotoxic, or acute oral toxicity observed in mice. By integrating efficacy, safety, and probiotic suitability into a single tailored consortium, this work provides a novel, functionally enhanced probiotic candidate with strong potential for further development in obesity‑related functional foods.