METHOD OF CULTIVATION OF BRADYRHIZOBIUM JAPONICUM RZ300 SOYBEAN NODULATE BACTERIA Russian patent published in 2023 - IPC C05F11/00 

FIELD: biotechnology.

SUBSTANCE: claimed invention relates to a method of obtaining microbiological preparations by cultivating an osmotically stable strain of nodule bacteria of soybeans with the addition of carbohydrate osmoprotectors and polymeric film formers to the culture to further increase the resistance of cells to desiccation and obtain a rhizobial inoculant for soybeans, effective in preliminary treatment of the seeds. The method is implemented by cultivating an osmotically stable strain of Bradyrhizobium japonicum RZ300 soybean root nodule bacteria to obtain a liquid rhizobial inoculant for soybeans, including successive steps: sterilization of a liquid nutrient medium of the following composition: 10.0 g/l of mannitol; 0.5 g/l of yeast extract; 0.1 g/l of monosodium glutamate; 0.4 g/l of disubstituted potassium phosphate; 0.2 g/l of sodium chloride; 0.1 g/l of magnesium sulphate, water, aseptic introduction of seed culture of Bradyrhizobium japonicum RZ300 nodule strain in the amount of 2% of the volume of the sterilized liquid nutrient medium, deep cultivation of the target microorganism for 7 days at a temperature of 28–30°C, mechanical stirring at a speed of 100–150 rpm, aeration intensity from 0.7 to 1 liter of air/liter of liquid nutrient medium per minute, with aseptic introduction into the culture on the 7th day of growing sterilized solutions of the trehalose osmoprotector in an amount of 5–15% from the volume of the culture and the polymeric film-forming agent polyvinylpyrrolidone in the amount of 5–10% of the culture volume.

EFFECT: method makes it possible to obtain a high efficiency of nodule formation with their subsequent nitrogen-fixing activity, provided due to the symbiotic activity of viable bacteria applied as an inoculant to seeds several days before sowing.

3 cl