Mutants of Lactobacillus plantarum ML11-11 deficient in co-aggregation with yeast exhibited reduced activities of mixed-species biofilm formation

Abstract

Lactic acid bacteria (LAB) mutants deficient in interspecies co-aggregation with yeast were spontaneously derived from Lactobacillus plantarum ML11-11, a significant mixed-species biofilm former in static cocultures with budding yeasts. These non-co-aggregative mutants also showed significant decreases in mixedspecies biofilm formation. These results suggest the important role of co-aggregation between LAB and yeast in mixed-species biofilm formation. Cell surface proteins obtained by 5M LiCl extraction from the wildtype cells and non-co-aggregative mutant cells were analyzed by SDS-PAGE. There was an obvious difference in protein profiles. The protein band at 30 kDa was present abundantly in the wild-type cell surface fraction but was significantly decreased in the mutant cells. This band assuredly corresponded to the LAB surface factors that contribute to co-aggregation with yeasts. © 2012 W. S. Maney & Son Ltd.