LOW–TEMPERATURE STORAGE AND THE VIABILITY PRESERVATION OF STREPTOMYCES

The most effective way to store microorganisms of different taxonomic groups is at low temperatures from minus 12°C to minus 150°C. The present research features the influence of low temperature (minus 12°C and 18°C) on the viability of collection strains of actinomycetes Streptomyces lucensis VKPM Ac-1743 and Streptomyces violaceus VKPM Ac-1734, producers of glycosidase inhibitors. The strains were stored without a cryoprotector in a 15% glycerol solution and 0.9% sodium chloride aqueous liquid. The research objective was to check their ability to keep their inhibitor activity against pancreatic amylase during corn starch hydrolysate fermentation. The experiment made it possible to determine the titer (CFU in 1 cm3 of the initial inoculum) and inhibitory activity against pancreatic α-amylase. It was revealed that Streptomyces lucensis and Streptomyces violaceus strains in cell initial concentrations of 107 and 108 CFU/cm3 maintained high viability level during four months conservation in 15% glycerol solution and 0.9% sodium chloride aqueous solution at the temperatures of minus 12 °C and minus 18 °C. Most cells survived at the conservation in a 15% glycerol solution at minus 18 °C. The inhibitor activity level in cultural liquid was higher in Streptomyces lucensis and Streptomyces violaceus strains kept in 15% glycerol solution at low the temperatures than in those kept in a 0.9% sodium chloride solution. The cultures kept in a 15% glycerol solution at minus 18 °C had higher inhibitor activity indicators 2600 ± 200 IU/cm3 . The research proved that low-temperature storage of Streptomyces produces no negative effect on the viability and biosynthetic activity of the cultures.