PHYSIOLOGICAL APPROACH TO EXTRACELLULAR POLYSACCHARIDE PRODUCTION BY LACTOBACILLUS-RHAMNOSUS STRAIN C83

Extracellular polysaccharide production was studied by growing strain C83 of Lactobacillus rhamnosus in a chemically defined medium containi ng various carbon sources (glucose, fructose, mannose or maltose) at d ifferent concentrations. Mannose or a combination of glucose + fructos e were by far the most efficient carbon sources. An optimization of gr owth medium composition led to an improvement in both growth and EPS p roduction. When the strain nas cultured at a lower temperature the EPS production increased. A temperature shift, at the end of the exponent ial growth phase, did not enhance the EPS production. The EPS synthesi s by strain C83 was growth-related. The isolated slime had a sugar com position, as shown by three different methods, of glucose and galactos e with a ratio of 1:1.