Isolation, selection, and evaluation of characteristics of potential Bacillus strains for probiotic products

Abstract

In the human digestive tract, there resides a very large number of microorganisms, including more than 400 different species of bacteria. Probiotics are defined as live bacteria that when introduced into the body in sufficient quantities will produce beneficial health effects. Probiotics (commonly known as digestive enzymes) are not drugs but are classified as nutritional supplements. In this study, we aim to investigate the probiotic properties of 2 strains of Bacillus bacteria isolated from fecal samples of healthy people, without the use of antibiotics or probiotic products for at least 1 month. The basic properties investigated include the hemolytic ability of bacteria, tolerance to artificial gastric acid and bile salt, and sensitivity to antibiotics. Out of a total of 72 isolates, 2 potential Bacillus strains were selected that did not cause hemolysis, were able to survive and survive in the harsh environment of the digestive system, and were sensitive to antibiotics commonly used for humans. On that basis, we initially evaluated the safety and potential application of these 2 strains to probiotic products.