Preliminary investigation on some characteristics of indigenous B. subtilis strains isolated from healthy Vietnamese for application in probiotic production

Abstract

The concept of probiotics is becoming increasingly widespread today due to applied research and the diversity of probiotic products. In this study, we cultured, isolated, and identified B. subtilis strains from stool samples of healthy individuals and evaluated the probiotic properties of the obtained strains. The evaluation experiments were conducted based on the Generally Recognised As Safe (GRAS) guidelines of the U.S. Food and Drug Administration (FDA). This is an important standard used by food and pharmaceutical companies to assess the probiotic characteristics and safety of bacterial strains, including hemolytic activity, antibiotic susceptibility, tolerance to gastric acid, and bile salts. Study results selected a non-hemolytic B. subtilis strain, designated as B. subtilis Eramic26 (Eramic26). This strain exhibited completely distinct colony morphology compared to hemolytic B. subtilis strains. Additionally, we assessed its susceptibility to commonly used antibiotics in humans, its survival and persistence in the human gastrointestinal tract: The results showed that Eramic26 adapts well to the human digestive system, does not exhibit resistance to critical antibiotics, and meets the safety standards according to the GRAS guidelines.