Semidefined Media for the Exopolysaccharide (EPS) Production by Lactobacillus helveticus ATCC 15807 and Evaluation of the Components that Interfere with the EPS Quantification

TORINO, MARÍA INÉS; SESMA, FERNANDO; FONT DE VALDEZ, GRACIELA

MILCHWISSENSCHAFT-MILK SCIENCE INTERNATIONAL

A V A AGRARVERLAG

Año: 2000 vol. 55 p. 314 - 316

0026-3788

Growth and EPS production by Lactobacillus he/veticus ATCC 15807 was evaluated in semi-defined media. Lactose (as carbon source) and CaCI2 proved to be the major stimulating factors for an optimal EPS synthesis while the highest specific EPS yield was obtained when CaCI2 and MnS04 were the only salts added to the medium. Both EPS and cell growth were slightly aftected by the nitrogen source. The analysis of the interference components (EPS.eq) in uninoculated media revealed an overestimation in EPS of ea. 76% due to beef extract and yeast extract, and of 64% due to the presence of peptone. Nevertheless, in fermented cultures, the level of interference may be lower since nitrogen compounds are used by the microorganism during growth and residuallactose showed to be easily removed by dialysis before EPS quantification.