Microbiota Composition of Buffalo Colostrum and Characterization of Potential Probiotic Bacteria With High Exopolysaccharide Production and Cholesterol Assimilation Capacity

Abstract

Colostrum microbiota is diverse and rich in beneficial bacteria with potential probiotic properties. The current study investigates the buffalo colostrum from Turkey, assessing its cultivable microbial diversity and conducting a metagenomic analysis. The metagenomic analysis of Day 2 colostrum shows a diverse bacterial composition, dominated by Bacteroidota (49.75%) and Firmicutes (44.934%), followed by Proteobacteria (5.11%) and Actinobacteriota (1.50%). Bifidobacterium spp., Lactobacillus acidophilus, and Lactococcus spp. were counted above 7.00 log CFU/mL in culturable microbiota. Thirty-six lactic acid bacteria (LAB) strains were selected, with 14 strains showing positive bile salt hydrolase (BSH) activity with glycocholic acid (GCA) and taurocholic acid (TCA) and resistance to bile salts and acidic conditions (survival in pH 2 medium and 0.3% (w/v) bile salt). These strains were identified with high scores (> 1.80 genus levels) by MALDI-TOF MS and exhibited cholesterol assimilation ranging from 49.21% to 68.22% and exopolysaccharide (EPS) production from 7.9 to 12.4 mg/L. L. acidophilus PB4, grouped as high cholesterol assimilation and EPS production capacity, was well-characterized for safety through whole-genome sequencing (WGS) analysis using the Illumina NovaSeq platform and assigned an average nucleotide identity (ANI) value of 99.1%. The findings from this study could advance research on the potential of probiotic microorganisms and probiotic food products derived from them in lowering cholesterol risk.