Abstract: Main factors affecting exo-polysaccharides(EPS) synthesis by Lactobacillus bulgaricus,such as culture temperature,pH,inoculation amount and carbon sources,were discussed. Higher yield of EPS can be achieved under the conditions of culture temperature 40 ℃,pH 6,inoculation amount 2% and glucose used as carbon source. The EPS has some biological functions,can endow mice with strong stamina and resistance to anoxia by gavage,and also can promote growth of Lactobacillus acidophilus.

Key words: Lactobacillus bulgaricus, exo-polysaccharide, biological characteristics, polysaccharides synthesis