Aim: Evaluate accumulation of capsule polysaccharide by Streptococcus pneumoniae 19A strain in semisynthetic nutrient medium including various amino acid sources.
Materials and methods: Comparative evaluation of the production of capsule polysaccharide by the strain belonging to one of the most widespread S. pneumoniae serotype (19A) was performed by using rocket immunoelectrophoresis. The bacteria were cultivated in semisynthetic liquid nutrient media of varying composition.
Results: Among 4 sources of nitrogen (aminopeptide, acid and pancreatic hydrolysate of casein, soy peptone) added to salt nutrient medium supplemented with glucose and vitamins, casein and soy peptone were shown to promote the maximum synthesis of capsule polysaccharide independently of the cultivation time. Supplementation of the medium with sulfates of iron, zinc and manganese, as well as pH decrease to acid values significantly reduced the level of capsule polysaccharide in the culture liquid. The maximum growth of bacteria was observed at 11 hours after the start of cultivation in a 10 L volume fermenter in semisynthetic nutrient medium with soy peptone. Accumulation of capsule polysaccharide in the culture liquid continued to the end of the observation period (24 hours) and by the end of the process reached 193 mcg/ml.
Conclusion: Further study of influence of vitamins, carbohydrates, CO2 concentration on the synthesis of high molecular capsule polysaccharide by bacteria belonging to various pneumococcus serotypes is reasonable.