Surface properties of Lactobacillus and Leuconostoc isolates from homemade cheeses showing auto-aggregation ability

Ten lactobacilli and one leuconostoc showing auto-aggregation ability were isolated from artisanal cheeses. Furthermore, non-aggregation strains were isolated from the same cheese sample, if existed. The analysis of factor(s) possibly involved in auto-aggregation was performed. The pretreatment of cells with proteinase K resulted in the disappearance of auto-aggregation ability. Moreover, cells also lost aggregation ability after three-times, successive washing in distilled water. Testing the ability of strain Lactobacillus paracasei subsp. paracasei BGSJ2-8 and its aggregation-deficient derivative BGSJ2-81 to co-aggregate with Listeria innocua ATCC33090, Escherichia coli ATCC25922 or Salmonella typhimurium TR251 showed that strain BGSJ2-8 co-aggregated with these strains, but derivative BGSJ2-81 was not. However, the treatment of L. paracasei subsp. paracasei BGSJ2-8 with proteinase K prior to co-aggregation tests resulted in losing co-aggregation ability. Surface properties of selected strains were analyzed by MATS (microbial adhesion to solvents) method. It was noticed that the strains with auto-aggregation ability were highly hydrophobic in comparison with aggregation-deficient ones. Comparative analyses of the surface features of strain L. paracasei subsp. paracasei BGSJ2-8 and its derivative BGSJ2-81 revealed notable difference.