Molecular identification of native lactic acid bacteria isolated from curd samples with probiotic potential

Abstract

Fermented foods are high in nutrient content than any other category of foods due to the presence of live microorganisms called probiotics. Its application in manufacturing of dairy foods and role in different types of disease prevention ranks it as the most exuberant. The aim of the present study was to isolate and identify lactic acid bacteria from native curd samples collected from dairy farms of Odisha state of India and explore its probiotic potential. Three morphologically distinct bacterial strains were isolated using MRS agar plates. The biochemical study confirmed that all the isolates were gram-positive. The molecular approaches were used to analyze the taxonomical diversity of isolates. 16 S rRNA sequencing was carried out and the bacterial isolates were taxonomically classified as Lactobacillus sp., Lactobacillus plantarum, Lactobacillus casei with NCBI Gene bank accession number [MG573071], [MG573072] and [MG573073] respectively. Further, the isolated bacterial strains were screened for their acid and bile tolerance competence as a principal criterion for probiotic. Among the isolates Lactobacillus casei (MG573073) was found to be highly tolerant of low pH and bile salts, posed strongest cell surface hydrophobicity of 75%. However, the maximum zone of inhibition was observed against Amoxilline/clavunic acid 44mm. The cell growth was found higher in presence of 2% inulin with cell viability 9.11 log 10 CFU/ml. In conclusion, based on the obtained results, Lactobacillus casei can act as a suitable probiotic candidate.