Aggregation, adhesion and efficacy studies of probiotic candidate Pediococcus acidilactici NCDC 252: a strain of dairy origin.

Aggregation and adhesion capability and survival efficacy of candidate probiotic strain Pediococcus acidilactici NCDC 252 under simulated gastric, intestinal and vaginal conditions was studied. The strain exhibited strong autoaggregation phenotype and coaggregation with other Lactic acid bacteria (LAB) and E. coli. The adhesion studies of NCDC 252 to pig's intestinal epithelial cells showed its adhesive ability. Aggregation and adhesiveness were related through cell surface proteins as removal/extraction of surface proteins resulted in altered aggregation and no adhesiveness. Cell surface proteins were analysed by SDS-PAGE and also in silico analysed from its genome. SDS-PAGE analysis of cell surface proteins of NCDC 252 revealed two potential proteins of approximately 74.3 and 53.6 kDa to be involved in host-probiotic interaction. Removal of cell surface proteins by LiCl-treatment (5 mol l-1) resulted in loss of aggregation and adhesiveness. Further survival of NCDC 252 under simulated gastrointestinal and vaginal conditions in terms of high viable counts confirmed its efficacy for its survival under gut and urogenital conditions. These observations suggest that it can be used further in functional foods, nutraceuticals and in combating urogenital infections. As NCDC 252 was able to survive in intestinal conditions, interaction of its cell surface proteins with intestinal mucins was studied in silico by docking. Highest affinity of adhesion was observed for MUC3B. In conclucion, NCDC 252, exhibited aggregation phenotype and adhesion capability. Survivability of NCDC 252 under simulated conditions and its interaction with human mucins confirms its efficacy to be used as probiotic.