Determining the role of microelements for the synthesis of antifungal metabolites of the antagonistic Bacillus velezensis strain

Aim. To study the structure of bacteria exometabolites of the Bacillus velezensis BZR336g strain using the GC×GC‐MS method when cultivated on nutrient media differing in the content of microelements.

Material and Methods. The object of the study is the B. velezensis BZR336g bacterium strain. It shows promise for the development of a biopreparation on its basis for protecting plants against phytopathogenic fungi. Exometabolites were isolated from the liquid culture and their metabolomic profile was analysed with the GC×GC‐MS method using a LECO Pegasus BT‐4D device.

Results. Among the identified compounds one can see the precursors of biologically active metabolites of bacteria of the strain B. velezensis BZR336g. Analysis of the total accumulation of fatty acids and their analogs, as well as of amino acids and peptides, by B. velezensis BZR336g bacteria on nutrient media differing in the content of metal ions, shows that Co²⁺ ions in combination with Mn²⁺ and Zn²⁺ ions play an important role in inducing their synthesis. The presence of the Co²⁺ ion in the nutrient medium has the greatest influence on the synthesis of peptide components. If it is removed from the nutrient medium, the amount of amino acids and peptides decreases by almost two times. Benzene compounds can act as precursors of aromatic hydrocarbons, which are also of interest in the analysis of bacterial metabolism, since they have antimicrobial activity.

Conclusions. The number of compounds that are precursors of lipopeptide metabolites depends on the content of metal ions in the nutrient medium. This fact may vary depending on the combination in which the metals are present.

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