Isolation and selection of potential Bacillus subtilis strain for producing probiotics

Abstract

The study was conducted at the Faculty of Animal Husbandry and Veterinary Medicine, Hue University of Agriculture and Forestry, Hue University to detect the potential strains of Bacillus subtilis (B. subtilis) for producing probiotics for animal husbandry. A total of 27 pure colonies having the morphological characteristics similar to Bacillus were isolated. The results of biochemical examination showed that there were B. subtilis (3/27 strains), B. pumilis (4/27 strains), B. lichenifomis (2/27 strains), B. coagulans (3/27 strains), B. spharicus (3/27 strains) and Bacillus sp. (12/27 strains) identified. Bacteria belonging to the B. subtilis, B. pumilis and B. sphaericus genus had the ability
to ferment sugars without producing gas, but only B. subtilis had the ability to break down starch and proteins. Three strains (B4, B17 and B23) that were tested biochemically, they were all as B. subtilis, B23 strains was chosen for sequencing the 16S ribosomal RNA gene, as a result the
similarity level of B23 and B. subtilis strain H1 was 100%. The surveyed result on the growth curve of B. subtilis - B23 showed that the growth reached the maximum number after 10 to 14 hrs. in the static culture conditions with the rate of seeding 1%. The B. subtilis-B23 strain has many potential valuable biological properties for research on creating probiotics for animal husbandry.