Considerations to Avoid the Overestimation of Exopolysaccharides Produced by Lactic Acid Bacteria

TORINO, MARÍA INÉS; FONT DE VALDEZ, GRACIELA

Methods in Biotechnology

Humana Press Inc

Lugar: New Jersey; Año: 2004; p. 96 - 102

Lactic acid bacteria (LAB) producing exopolysaccharide (EPS) are of commercial interestespecially because of their ?food-grade? nature and their application as starter cultures in thefood industry. Milk has been commonly used as a culture medium for EPS production.However, the isolation of polysaccharides from coagulated milks is tedious, time-consumingand includes the risk of degrading the polymer during manipulation. When a complexmedium is used, the isolated EPS is always heavily contaminated with other mediumcomponents (the so-called EPS reacting material) like beef extract, peptones and yeast extract,which remain after dialysis. Thus, the amount of EPS determined in complex media isoverestimated. In order to avoid this problem, some practical considerations are given, as wellas evidences of the interference between the EPS reacting material (ERM) and the EPSproduced by starter cultures.