CHEMICAL MUTAGENESIS OF THE LYSINE-PRODUCING STRAIN Brevibacterium sp. IMV B-7447

The aim of the work was to obtain a producer strain with increased lysine accumulation using the chemical mutagenesis method. Methods. To achieve the goal, we used the method of treating the lysine-producing strain with the chemical mutagen N-methyl-N-nitro-N-nitrosoguanidine, cultivating the resulting clone and determining the accumulation of lysine in flasks and a bioreactor. Results. The optimal concentrations and duration of mutagen action for the production of mutant microorganisms were found. Сlones with the maximum lysine accumulation were selected. Mutagenesis was carried out consecutively three times. As a result, lysine-producing strain Brevibacterium sp. IMV B-7796 auxotrophic regarding leucine and threonine with maximum accumulation of the target amino acid was obtained. Conclusions. The lysine producer Brevibacterium sp. IMV B-7796 was obtained, which produced 65.0 g/dm3 of lysine in a bioreactor under conditions of periodic cultivation with feeding. The Brevibacterium sp. IMV B-7796 strain was proposed as a basis for the creation of a genetically modified strain with increased accumulation of lysine for further use in industrial lysine technology.