EFFECT OF CULTURE MEDIA, SUGAR SOURCE AND pH ON THE GROWTH OFLactobacillus delbrueckii subsp. delbrueckii CRL 1461, A POTENTIALLY PROBIOTIC TO PREVENT BOVINE METRITIS

OTERO, M. CLAUDIA; ESPECHE, M. CAROLINA; NADER-MACÍAS, M. ELENA

España

Congreso; 2nd FEMS Congress of European Microbiologists; 2006

Lactobacillus delbruekii subsp. delbruekii CRL 1461 isolated from bovine vagina was previously selected by its capability to autoaggregate, to adhere to bovine vaginal epithelial cells and to inhibit the growth of pathogenic microorganisms that cause metritis. The application of this microorganism in a probiotic product requires the evaluation of technological properties. A complete factorial design of 2x32 was used to study the effect of culture media (LAPTg and MRS broths without sugar), carbon source (glucose, lactose or both) and pH (5.5, 6.5 and 7.5) on the growth (increase of biomass and growth rate) and lactic acid production. The growth was determined spectrophotometrically (OD540nm) at 37ºC and the organic acids quantified by HPLC. The higher increase of biomass and growth rate was obtained in MRS broth when both sugars were present and at initial pH 5.5. In LAPTg medium no significant differences  were observed in the growth parameters from glucose or the mixture glucose-lactose. When the initial pH was 6.5 or lower, the growth parameters were not affected in this medium. The optimal condition for the lactic acid production was: LAPTg with glucose and pH 7.5. These results will allow optimizing the conditions of biomass and lactic acid production by using a low cost substrate, as whey protein concentrate, with high lactose concentration.