VIABILITY AND BIOLOGICAL PROPERTIES OF BAKER'S YEAST SACCHAROMYCES CEREVISIAE AND ACETOBACTER XYLINUM WHEN PRESERVED BY LYOPHILIZATION

Abstract

Freeze-drying is a common method of preservation in the storage collection of microorganisms. This method is very convenient for storage and transport and it helps the microorganisms survive in the long-term period. In this paper, we studied some conditions to improve the method of freeze-dried on yeast’s baker Saccaromyces cerevisae and bacteria fermented cellulose Acetobacter xylinum. During storage, evaluating viability and their biological properties, the results showed that after freeze-drying, the survival rate of bacteria is 12 %, yeast is 2,96 %, after 2 years of storage, the survival of bacteria remained at high rate 3*106CFU/ml and yeast is 106CFU/ml. Biological characteristics of two strains have decreased but not at a considerable rate. The most efficient protectant of freeze-drying is skim milk.