Optimization of the composition of natural sugar-containing mediums for biosynthesis of lysine by microbial producers

Lysine is an amino acid that is necessary for humans and animals for nutrition and is used in physiological processes. Currently, lysine production is large-scale. It is obtained by hydrolysis of waste from poultry processing plants using microbiological synthesis. The raw materials for the production of lysine are molasses, corn extract, sunflower meal, bran, meat and bone meal and fish meal, rapeseed. An important criterion for finding a reduction in the cost of Llysine production is the development of nutrient media for cultivating producers capable of maximizing the yield of amino acids. In this work, a study was conducted to optimize a nutrient-rich sugar-containing medium for the cultivation of microbial producers of amino acids Corynebacterium, Brevibacterium and Bacillus. Optimization of nutrient media was carried out by the Box-Wilson method using a complete factor experiment with varying the concentration factors of the nutrient medium: peptone, yeast extract, reducing substances. Microbial producers of amino acids were used as objects of research - Corynebacterium glutamicum B-1085, Corynebacterium glutamicum B-11609, Bacillus subtilis B- 4828, Bacillus subtilis AJ11779, Brevibacterium flavum B- 11404, Brevibacterium flavum B-11635. To select productive microbial lysine producers, bacterial strains were screened on an optimized nutrient medium with peptone, yeast extract, and wheat straw fermentolysate as a source of reducing substances. It has been established that a promising lysine–producing strain is C. glutamicum B-1085. As a result of the conducted studies, the composition of the culture medium Corynebacterium glutamicum B-1085 was determined: peptone – 20.4 g/l; yeast extract – 6.7 g/l; wheat straw fermentolysate – 28.2 g/l. The lysine concentration in the final product was 11.9 g/l.