Isolation and Identification of Potential Probiotic Bacteria from Cattle Farm Soil in Dibrugarh District

摘要

Several studies have been done to isolate probiotic bacteria from different sources. In this present study, an attempt was made to isolate, screen and identify potential probiotic bacteria from cattle farm soil in Dibrugarh district, Assam, India. At the level of screening, the result showed the isolates designated as DUA4, DUD3 and DUE2 showed a percent survival rate of 75.36, 69.14 and 52.36 respectively at a pH of 2.5. Similarly survival rate of the same isolates in 0.5% bile salt condition was found to be 117.17%, 144.59% and 118.10% for the isolates DUA4, DUD3 and DUE2 respectively. Antimicrobial activity of the isolates towards the indicator organisms tested showed that DUA4 inhibited gram positive organisms while DUD3 showed activity against both gram positive and gram negative bacteria. All the three isolates showed activity against L. monocytogenes. Autoaggregation ability of the isolates DUA4, DUD3 and DUE2 was found to be 44.15%, 54.11% and 9.42% respectively. The adhesion ability of the isolates DUD3, DUA4 and DUE2 to xylene was 61.78%, 45.37% and 14.83% respectively. Antimicrobial susceptibility test of the isolates showed that the isolates are in general sensitive to antibiotics tested. Phenotypic and genotypic analysis based on the 16S rRNA gene sequence of the isolates DUA4, DUD3 and DUE2 resulted in the identification and designation of the isolate DUA4 as Bacillus spp., DUD3 as Enterococcus faecium and DUE2 as Enterobacter sp. In conclusion, the study has indicated the possibility of isolating potential probiotic bacterial strains from cattle farm soil.