{Reference Type}: Journal Article {Title}: Isolation, Purification, and Identification of Bacitracin-producing Bacillus licheniformis from Fresh Feces of Healthy Pigs. {Author}: Tang Y;Hao N; {Journal}: J Vis Exp {Volume}: 0 {Issue}: 207 {Year}: 2024 May 31 {Factor}: 1.424 {DOI}: 10.3791/66777 {Abstract}: Bacillus licheniformis and bacitracin have a huge application market and value in the fields of medicine, chemistry, aquaculture, agricultural, and sideline products. Therefore, the selection of B. licheniformis with high production of bacitracin is of great importance. In this experimental protocol, Bacillus with a high yield of bacitracin was isolated, purified, and identified from the fresh feces of healthy pigs. The inhibitory effect of secondary metabolite bacitracin on Micrococcus luteus was also tested. Thin-layer chromatography and high-performance liquid chromatography were used for the qualitative and quantitative detection of bacitracin. The physiological and biochemical characteristics of B. licheniformis were determined by relevant kits. The phylogenetic relationships of B. licheniformis were determined and constructed using gene sequence detection. This protocol describes and introduces the standard isolation, purification, and identification process of B. licheniformis from animal fresh feces from multiple perspectives, providing a method for the large-scale utilization of B. licheniformis and bacitracin in factories.