Biotechnology production of medium for cultivation and lyophilization of lactic acid bacteria

Abstract

The aim of our work was to develop a medium for the cultivation of lactic acid bacteria and to select the optimal protective mediums for the freeze-drying of lactic acid bacteria. The objects of research were cultures of microorganisms Lactobacillus plantarum 7 and Lactobacillus casei 27 isolated, selected and stored in the National Scientific Center Institute of Experimental and Clinical Veterinary Medicine (NSC "IECVM", Kharkiv). Cultivation of lactobacilli was carried out on medium MRS and Blaurock for 24-72 hours at the temperature of 37 °C. To develop nutrient media for the cultivation of lactobacilli, the selected components in the main composition of the medium: lactose, sodium phosphate disubstituted, sodium citrate. As components of the protective medium, solutions of sucrose, gelatinase, sodium acetate, and aerosol® were used. Because of the studies, the optimal composition of the nutrient medium was determined (lactose 1.2 %, sodium phosphate disubstituted 0.3 %, and sodium citrate 0.6 %) for the cultivation of lactic acid bacteria on which bacteria grow and actively accumulate a significant number of viable cells from 7.1 to 8.2 × 106 CFU/cm3. In the various cultivation regimes of lactobacilli, pH 7.0 is optimal, and the temperature of the inoculum incubation is 37±0,5 °C. An alternative protective medium is added with the addition of 10 % sucrose, 1.0 % gelatinase and 3.0 % aerosil, which ensures the viability of viable cells after lyophilization of strains of L. plantarum 7 and L. casei 27, respectively, 96 % and 97 %. A culture medium was proposed (lactose 1.2 %, sodium phosphate disubstituted 0.3 %, sodium citrate 0.6 %) for cultivation of lactobacilli on which bacteria grow and actively accumulate a significant number of viable cells (7.1-8.2) × 106 CFU/cm3). Under different temperature regimes and pH of the medium, the best is that it has a pH of 7.0 and the incubation of the inoculum passes at a temperature of 37 ± 0.5 °C. The maximum preservation of viable cells after lyophilization of strains L. plantarum 7 and L. casei 27, respectively, 96 % and 97 % were observed using a protective medium supplemented with 10 % sucrose, 1.0 % gelatose and 3.0 % aerosil. The addition of protective media according to the given formulation with the freeze-drying of lactic acid bacteria and the proposed drying regime have technological advantages and ensure the preservation of the basic biological properties of microorganisms.