Interaction between Lactobacillus kefir and Saccharomyces lipolytica isolated from kefir grains: evidence for lectin-like activity of bacterial surface proteins

MARINA ALEJANDRA GOLOWCZYC; PABLO MOBILI; GRACIELA LILIANA GARROTE; MARÍA DE LOS ANGELES SERRADELL; ANALÍA GRACIELA ABRAHAM; GRACIELA LILIANA DE ANTONI

Journal of Dairy Research

Cambridge University Press

Lugar: Cambridge, England; Año: 2009 vol. 76 p. 111 - 116

0022-0299

Several microbial interactions involving yeast and lactobacilli have been suggested in fermentedproducts. Co-aggregation between Lactobacillus kefir and yeast Saccharomyces lipolyticaisolated from kefir grains was studied by scanning electron microscopy and aggregation assays.Six out of twenty Lb. kefir strains were able to co-aggregate with Sacch. lipolytica CIDCA 812and showed thermolabile non-covalently bound surface molecules involved in this interaction.Co-aggregation inhibition after Lb. kefir pre-treatment with 5 M-LiCl or 20 g SDS/l showed thatbacterial S-layer proteins play an important role in this interaction. Presence of different sugar(mannose, sucrose and fructose) or yeast pre-treatment with sodium periodate inhibited coaggregation between Lb. kefir and Sacch. lipolytica. Co-aggregating Lb. kefir strains were alsoable to agglutinate with human red blood cells and they lost this ability after treatment with5 M-LiCl. These results and the capacity of purified S-layer proteins of Lb. kefir to haemagglutinate, strongly suggest that a lectin-like activity of bacterial surface proteins (S-layer) mediates the aggregation with yeast cells.