A Study on Probiotic Properties of Bacteria Isolated From Selected Yoghurt (Comilla) and Poultry Faeces (Comilla and Pabna)

Abstract

Probiotic bacteria are a heterogeneous group found widely in nature. They colonize in gastrointestinal and urogenital tracts of humans and animals and are present in foods. The objectives of the present research work were isolation, identification, study of probiotic properties and in vivo mice trial of isolated bacteria. Three isolates of Lactobacillus acidophilus, two isolates of Lactobacillus brevis, one isolate of Lactobacillus delbrueckii and two isolates of Streptococcus thermophilus were isolated from four yoghurt samples. Two Streptococcus spp., one Lactobacillus spp. and one Bifidobacterium spp. were isolated from poultry samples. All isolated bacteria were gram positive, endospore negative, catalase negative, non-motile and showed bile salt hydrolase activity. In this study sixteen carbohydrates were used to construct carbohydrate fermentation profile of the isolated bacteria. Isolated probiotic bacteria showed NaCl tolerance activity against 1-8% NaCl and few showed 9% NaCl tolerance. They also showed artificial gastric acid resistance at low pH (pH 2.2) and favorable pH (pH 6.6) after 24 hours of incubation at 37°C. Isolated bacteria were capable to survive in 0.05%, 0.1%, 0.3% and 0.6% bile salt at 2, 4 and 24 hours of incubation at 37°C respectively. The isolates showed excellent phenol tolerance activities and were capable to survive in 0.1%, 0.2% and 0.3% of phenol and moderate growth at 0.4% phenol after 24 hours of incubation at 37°C. In mouse trial, the treatment group with maximum quantity of yoghurt supplement showed as significant body weight gain, decreased blood cholesterol level, antibiotic resistance and pathogenic organisms inhibition activities.