Broad-spectrum anti-yeast activity of natural lactic acid bacteria from Chinese traditional fermented food

Lactic acid bacteria (LAB) with wide spectrum inhibitory activity against pathogenic and spoilage yeast were isolated and their inhibitory properties were analyzed. Forty-six presumptive LAB were isolated from seven Chinese traditional fermented food samples. Fourteen typical pathogenic and spoilage yeast were used as indicators. By overlay method and microtitre plate well assay, three Lactobacillus plantarum strains, two Weissella cibaria strains and one Enterococcus faecium strain with excellent anti-yeast activity were selected. Through HPLC analysis, lactic, acetic and phenyllatic acid were measured in the cell-free culture supernatants (CFSs) of anti-yeast positive LAB. By GC-MS detection, cyclic dipeptides were found in CFSs of L. plantarum AT4 and W. cibaria AT6, the latter produced cyclo(Gly-Leu), cyclo(Phe-Pro) and cyclo(Gly-Pro). The variety of cyclic dipeptides in CFS was speculated to decide the inhibitory spectrum against yeast indicators. High inhibitory rate and favorable bioactive spectrum afford the selected LAB strains greatly candidates for bio-control and biopreservation against pathogenic and spoilage yeast.