STUDY OF THE ANTAGONISTIC ACTION NATURE OF STRAINS OF LACTOBACILLUS PLANTARUM TO OPPORTUNISTIC AND PHYTOPATHOGENIC MICROORGANISMS

Aim. To study the nature of the antagonistic action of the strains Lactobacillus plantarum, isolated from fermented foods, to determine their ability to produce hydrogen peroxide and the dependence of the spectrum of antagonistic activity against opportunistic and phytopathogenic microorganisms from the presence of glucose and Tween-80 in culture medium. Methods. The ability of the strains L. plantarum to synthesize hydrogen peroxide was studied on MRS medium, which comprised horseradish peroxidase and tetramethylbenzidine. Antagonistic activity was determined by the deferred antagonism using the medium: the basic MRS, MRS without glucose, MRS without Tween-80. Result. Among 109 used strains only three (2.75%) produced hydrogen peroxide. The absence of glucose in the medium had practically no effect on the antagonistic activity of the strains of L. plantarum against Shigella flexneri, Staphylococcus epidermidis and Candida albicans and inhibitory effect had about of 75% the strains. The antagonistic activity retained 53–68% of strains L. plantarum against other test cultures. The antagonistic activity against Clavibacter michiganensis was very dependent of the presence of tween-80 and not dependent – against Pseudomonas aeruginosa (26% retained activity and 92% of the strains, respectively). For other test cultures inhibitory effect on the medium without Tween-80 retained 67–88% of strains of L. plantarum. Conclusions. Lactic acid and hydrogen peroxide are not the major factors of antagonistic activity in the most examined L. plantarum strains in this study. Antagonistic action spectrum dependence of the presence of glucose or Tween-80 in the culture medium, may be indicative synthesis of bacteriocin-like substances with a broad or narrow spectrum of action. The spectrum of antagonistic activity is strainspecific and differs with against opportunistic and phytopathogenic microorganisms.