Influence of different substrate limitations on the yield, composition andmolecular mass of exopolysaccharides produced by Lactococcus lactis subsp cremoris in continuous cultures

The type of substrate limitation had a remarkable influence on the molecula r mass of exopolysaccharides (EPS) produced by Lactococcus lactis subsp. cr emoris NIZO B40 and NIZO B891. Under glucose/energy limitation the molecula r mass was much smaller than under leucine or phosphate limitation, resulti ng in a marked decrease of the intrinsic viscosity of this EPS. The sugar c omposition of EPS produced by both strains, and the phosphate content of EP S produced by NIZO B40, were not affected by the type of nutrient limitatio n. Both strains produced comparable amounts of EPS under leucine and glucos e limitation, but the efficiency of EPS production was highest under glucos e limitation. The EPS yields of the phosphorylated B40 EPS as well as the u nphosphorylated B891 EPS were reduced, with about 40% under conditions of p hosphate limitation.