Lactic Acid Bacteria Isolated from Human Feces of Vegetarian and Non-Vegetarians

ABSTRACT: The human microbiota is currently receiving significant attention, and the studies have shown that the changes to this microbiome can lead to extensive consequences. The gut microbiota’s diversity and composition can be influenced by dietary choices. Human faeces are the solid waste material excreted as the residual product following the digestion of food within the small intestine. This waste contains a significant number of viruses, bacteria, fungi, actinomycetes, and other microorganisms. Lactic acid bacteria (LAB) are prevalent and perform a significant function in immunity and metabolism. This study involved the processing of faecal samples from both vegetarian and non-vegetarian sources to isolate various LAB. Lactococcus spp., Bifidobacterium spp., Leuconostoc spp., Lactobacillus spp., Enterococcus spp., and Pediococcus spp. were isolated from both samples, although the percentages differ in each case. In vegetarian samples, Lactobacillus species were predominant (35%), followed by Lactococcus (24%), Bifidobacterium (20%), Enterococcus (9%), Pediococcus (7%), and Leuconostoc (5%). Conversely, non-vegetarian samples showed a higher proportion of Lactobacillus (44%), Leuconostoc (15%) and Enterococcus (18%), with lower percentages of Lactococcus (9%) and Bifidobacterium (7%) while Pediococcus (7%) remained unaffected. The higher population of Bifidobacterium in vegetarian suggest greater happiness of vegetarians than non-vegetarians as the bacterium is known to reduce depression and increase happiness. The processes of isolation, characterisation, and biochemical identification were conducted using Gram's staining, oxidase test, catalase test, and fermentation of sugar. The most effective isolates were determined through the evaluation of various probiotic characteristics, their antimicrobial properties, and their sensitivity to antibiotics. This study highlights the impact of dietary habits on the formation and probiotic functions of microbiota of gut. A diet of vegetarian appears to encourage a higher prevalence and diversity of LAB that display advantageous probiotic traits.