Phylogenetic Analysis of the Bacillus subtilis IFBG MK-2 Strain and Riboflavin Production by Its Induced Clones

The aim of this work was to study phylogenetic relationships between the new producer strain Bacillus subtilis IFBG MK-2 and the existing strains and increase the biosynthetic activity of this producer by mutagenesis. As a result of sequencing the 16S rRNA gene of the IFBG MK-2 strain, gene fragments with a total length of 1305 nucleotides have been obtained. Based on the 16S rRNA gene nucleotide sequences, a phylogenetic analysis was performed and a dendrogram was constructed using the Neighbor Joining method and the Kimura two-parameter model. It has been shown that the similarity between the sum of the 16S rRNA gene sequenced fragments of the IFBG MK-2 strain and the GenBank-deposited sequence of this gene of the B. subtilis IAM 12118 type strain reaches 99%. Based on the phylogenetic analysis, the IFBG MK-2 strain was identified as B. subtilis. Through induced mutagenesis, using UV radiation and subsequent stepwise selection, a mutant clone B. subtilis IFBG MK-1A providing for a 50% increase in riboflavin production compared with the original strain has been obtained.