Promoters are essential regulatory elements that determine the likelihood and efficiency of gene transcription in prokaryotic and eukaryotic cells. They are characterized by the presence of conserved regions, which may differ from consensus sequences and significantly affect transcription efficiency and expression levels. Mutations in the promoter region can result in complete transcription suppression or weakened transcription. Conversely, SNPs that lead to increased gene expression are less likely. Strong and weak promoters can be distinguished. This study focuses on the structural and functional characteristics of weak and strong gum operon promoters involved in xanthan biosynthesis in various Xanthomonas campestris strains, such as M28, B1459, and B-100. Comparative analysis of Gum operon annotations in X. campestris M28 and X. camp. pv.Campestris B1459 was analyzed. The B-100 strain served as a reference, due to its availability of a complete genetic annotation for the gum operon. It is worth noting that six promoter regions for the gumB, -D, -E, -H, -J, and -K genes were identified in the above-mentioned strains. The promoter regions and operon genes in strains B-100, M28, and B1459 demonstrate a high degree of similarity (100% for the five analyzed promoters), while small differences were observed in the promoter region of the gumJ gene compared to the reference strain B-100 (98.7% identity). As a result of bioinformatics analysis, genetic annotations for strains M28 and B1459 were generated, including the coordinates of genes and SNPs, as well as the percentage of identity relative to the reference sequence.