Production of extracellular polysaccharides by Lactobacillus delbrueckii ssp. bulgaricus NCFB 2772 grown in a chemically defined medium

Lactobacillus delbrueckii ssp. bulgaricus NCFB 2772 produced an extracellular polysaccharide when grown in a chemically defined medium with glucose or lactose as the substrate carbohydrate. The isolated extracellular polysaccharide had a sugar composition of glucose, galactose and rhamnose in a ratio of 1:6.8:0.7. The production of extracellular polysaccharides increased at higher temperatures, but the bacterium rapidly lost its polysaccharide producing ability at 47°C. Production of polysaccharides was growth‐related: no polysaccharide production was found after growth had ceased. An excess carbohydrate did not result in increased polysaccharide production.