Screening and selection of probiotic Lactobacillus strains of Indian gut origin based on assessment of desired probiotic attributes combined with principal component and heatmap analysis

Abstract Selection of candidate probiotic strains for functional efficacy studies in cell line and animal models is an important challenge which requires a platform of basic information about their phenotype and genotype identity in relation to their probiotic attributes. Hence, in the current study, the probiotic isolates of human origin previously identified using PCR or 16S rRNA gene sequencing were characterized for probiotic phenotypes using FAO/WHO or ‘ICMR-DBT′ guidelines for evaluation of probiotics in food. Finally, the candidate probiotic strains were selected by subjecting their probiotic phenotypic data (acid tolerance, bile tolerance, cell surface hydrophobicity, aggregation, co-aggregation and antimicrobial activity) to multivariate principal component analysis and heatmap visualization. Out of the fourteen isolates, which included two L. casei (LbS2 and LbS6), four L. plantarum (A1, A3, A5 and A9) and eight L. fermentum (A2, A6, A7, A8, A10, LbS4, Ad05 and Ad06), a total of nine probiotic Lactobacillus isolates viz. A1, A2, A5, A6, A8, A9, Ad06, LbS2, LbS4 were finally selected as candidate probiotic strains.