Production and characterization of antibacterial compounds produced by Pediococcus damnosus and Pediococcus...

The broad-spectrum antibacterial activity exhibited by three Pediococcus strains isolated from beer was preliminarily characterized. Factors affecting the production rate of bacterial inhibitors were screened and the effects of simultaneous cultivation of Lactococcus and Pediococcus on the production of inhibitory substances were studied. The antibacterial activity against a range of Gram-negative test organisms was not affected by catalase or proteolytic enzymes and was extremely thermotolerant. Production of the inhibitors was maximal between pH 6 and pH 7. A growth medium containing unhopped end-fermented wort was beneficial for the production of inhibitors, particularly by the Pediococcus damnosus strain, and anaerobic growth conditions were preferable. The antagonistic activity against the Gram-negative test organism Salmonella infantis could be demonstrated after an incubation period of only 2 d if the Pediococcus and Lactococcus strains were incubated simultaneously as a mixed population.