Find in Library

In order for a strain to be considered a probiotic or suitable plant bioprotective agent, it must have proven antimicrobial activity against pathogenic bacteria and phytopathogenic fungi. <i>Bacillus amyloliquefaciens</i> M exhibited significantly high antifungal activity against pathogenic fungi of the genera <i>Aspergillus</i>, <i>Penicillium</i>, <i>Fusarium</i>, and <i>Sclerotinia</i>; yeasts of the genera <i>Candida</i> and <i>Saccharomyces</i>; as well as high antibacterial activity against pathogens of the genera <i>Escherichia</i>, <i>Salmonella</i>, <i>Staphylococcus</i>, <i>Listeria</i>, <i>Pseudomonas</i>, and <i>Bacillus</i>. The manifested antimicrobial activity was influenced by the composition of the growth medium. The antifungal activity of the strain was investigated at growth temperatures of 30 °C and 37 °C, and at different pH values in aerobic and anaerobic cultivation, under static and dynamic culturing conditions. High antifungal activity was observed at the 24th h on both growth media (LBG broth and MPB broth) at pH = 6 and pH = 7 in aerobic and anaerobic cultivation. <i>Bacillus amyloliquefaciens</i> M produced antibiotic substances at pH > 5.0, and the antibiotic substances were either secreted into the medium or associated with the cell surface. Four compounds with different antifungal activity and different R_f values were registered through thin-layer chromatography (R_f1 = 0.47; R_f2 = 0.55; R_f3 = 0.67; and R_f4 = 0.75), two of the compounds were ninhydrin-positive. <i>Bacillus amyloliquefaciens</i> M was cultured in a bioreactor with stirring, and the parameters of the growth kinetics and the sporulation kinetics have been modeled. A spore concentrate of <i>Bacillus amyloliquefaciens</i> M has been obtained. In further research, the efficiency of the concentrate as a plant bioactive agent will be tested.