Evaluation of the Antimicrobial Effect of Kefiran Extract against Some Plant Pathogenic Bacteria

Abstract

Kefir; is a fermented milk product which is produced by granules containing a wide variety of microorganisms such as lactic acid bacteria, acetic acid bacteria and yeasts. It is traditionally consumed in many countries. It has been shown in many studies that the polysaccharide structure surrounding the granules which is composed mainly of kefiran molecule has antimicrobial effect against various pathogens as well as many health promoting effects. In this study, 24 h fermented kefir was used with two types of kefir granules for production of kefiran extract. One of them is being sold commercially and the other was collected from private households in a different region of Turkey. Kefiran extraction was carried out from matured kefir granules using three different temperatures, 80°C, 90°C and 100°C. Also, the protein contents of the extracted solutions were determined by Bradford method. Protein content of the extract solutions obtained were measured as 0.001 g/ml. The antibacterial effect of 0.05, 0.1, 1 and 2 mg of this extract against several plant pathogenic bacterial strains belonging to genus Pseudomonas, Xanthomonas, Erwinia ve Clavibacter was investigated in vitro for the first time. For this purpose, two methods, disc diffusion method and spreading method were used. The AN and SD kefir supernatants used as the positive controls in the experiments showed an average of 13-17 mm and 10-14 mm inhibition zones on the isolates, respectively, but the antibacterial effect of kefiran extracts was not observed.