Title: The analysis of antimicrobial peptides production of lactic acid bacteria

Biography:

Inga Burneikiene is a PhD student in Vilnius University. She works as junior assistant in Department of Microbiology & Biotechnology, Life Sciences Center, Vilnius University.

Abstract

Microorganisms such as molds, yeast and bacteria can cause a lot of loses in food industry and agricultures. So, researchers are looking for new more effective and environmentally friendly ways to control of growth of bacteria and fungi. Lactic acid bacteria (LAB) and their supernatants are quite promising tools in this area. During the fermentation process, lactic acid bacteria produce variety of anti-microbial agents, such as organic acid, carbon dioxide, ethanol, hydrogen peroxide, diacetyl as well as bacteriocins (John et al. 2007). They contribute to extend the expiration date of foods by using above mentioned anti-microbial agents as natural bio-preservatives and bacteriocins are also a great alternative to common antibiotics to which bacteria gain resistance. In our study we used lactic acid bacteria cultures newly isolated from different sources: sour cow and gout milk, pickled vegetables, bread sourdough. The genetic analysis of LAB isolates allowed to group them into different strains and confirmed that they have bacteriocin-encoding genes in their genomes. 16s rDNA sequencing showed that strains belong to Lactobacillus sp., Lactococcus sp., Pediococcus sp. and Leuconostoc sp. The analysis of an influence of aerobic and anaerobic conditions on the growth and antimicrobial activity against two sensitive strains (Pseudomonas aeruginosa (ATCC 27853) and Staphylococcus epidermidis (ATCC 12228)) of LAB isolates in 37 °C temperature showed that a biomass growth depends on bacteria isolate, not on growth’s conditions, and the highest antimicrobial activity was determined in the stationary growth phase and it correlated with biomass quantity.