Evaluation of the safety of immobilized microorganisms Lysobacter sp. on inorganic media

It is known that the immobilization of microorganisms on carriers of various nature increases their safety. The aim of the study was to identify a rational inorganic carrier for the immobilization of Lysobacter sp. Inorganic matrices: sodium carboxymethylcellulose technical brand "KMC 85/500"; colloidal silicon dioxide in the form of a commercial preparation "Polysorb"; sodium form of montmorillonite from the Podgorenskoye deposit, Voronezh region. The immobilization of bacterial cells was carried out by adding Lysobacter sp. solid sterile carrier with constant mechanical stirring in the ratio "carrier:biomass", equal to 1:(2-4), at T=30°C; subjected to freeze drying at T=-40-45°C for 24 hours to a moisture level of 3-7%. Survival of microorganisms Lysobacter sp. after immobilization on solid carriers: the samples were suspended in Petri dishes using molten agar, incubated for 24 hours and the number of colony forming units was determined by the method of serial dilutions. After three months of storage of lyophilizates, the following results were obtained: lyophilization of the bacterial culture of Lysobacter sp. without immobilization on the matrix leads to a decrease in safety to 37.5%; cell immobilization on sodium carboxymethyl cellulose allows to increase safety up to 65%; for colloidal silicon dioxide - up to 50%; when immobilized on the mineral montmorillonite, not only the preservation of microorganisms is manifested, but also an increase in the number of cells by 18%. Thus, it has been established that the mineral montmorillonite is a promising material for the immobilization of bacterial cells in order to obtain biocompositions based on them, since a positive trend in the preservation of bacterial cells has been revealed.