Molecular identification of Lactic Acid Bacteria strains isolated from Chal in Golestan province and study of antifungal activity of Lactobacillus brevis and Enterococcus faecium isolates against Penicillium chrysogenum

The aim of this study was to identify the LAB strains isolated from Chal by the molecular method and to study antifungal activity of Lactobacillus brevis and Enterococcus faecium isolates as a biological preservative against Penicillium chrysogenum. The LAB isolates were identified using PCR technique with universal primers of LAB, sequencing of PCR products and comparing the sequencing results with the data available in NCBI. The antifungal effects were determined using overlay method to investigate the potential application of tested isolates as a biological preservative agent. Analysis of 16S rDNA gene sequences revealed two strains as L. brevis, one E. hirae and one E. faecium. The results of antifungal activity showed that both isolates of L. brevis and E. faecium had a strong inhibitory effect against P. chrysogenu so that the growth inhibition, after 48 hours, for strain C6 was more than the other strains. All treatments showed significant differences (P0.05) between treatments samples. Inhibitory percentage of both strains of L. brevis (C6 and C17) against P. chrysogenum was stronger than the strain of E. faecium (C8) against the mold. All treatments showed significant differences (P0.05) between the treatments samples. According to the results from present work can conclude that the tested isolates have a potential ability to prevent the microbial spoilage, in foods such as cheese that susceptible to spoil with P. chrysogenum, as natural and safe bio-preservative.