The role of divalent iron cations in the growth, adhesive properties and extracellular adaptation mechanisms of Propionibacterium sp

Abstract

The present study aims to examine PAB culture, synthesizing a significant number of iron-containing enzymes and capable of adhesion. Results show that increased iron concentration increased enzymes activity in all strains studied. An increase of iron ions level increasing up to 0.50-0.60 mg/ml leads to a 1.3-fold and 2-dold increase of catalase and SOD activity respectively, peroxidase activity was virtually unchanged. Optimal iron ions Fe²⁺ doses to ensure active PAB growth were determined. Of all the cultures studied P. fredenreichii subsp. shermanii AC-2503 has high adhesion: AAI = 5.1; MAI = 5.60; erythrocyte involvement rate = 87%. It was shown that certain iron ion concentrations increased the specific growth rate of PAB (P. freudenrichii subsp. freudenrichii AC-2500 (0.3 mg/ml) and other strains (0.4 mg/ml). A further increase in the iron ions concentration slows bacterial growth, while excessive content inhibits metabolism, including defense mechanisms that offset the negative effects of the metal. Our subsequent studies will focus on the effect of other metal ions on the metabolism of bacteria, mainly lactic acid bacteria, which are important biotechnological objects of the industry similar to propionic acid bacteria.

Keywords: Activity of catalase; Adhesiveness; Extracellular metabolites; Iron ions Fe2+; Peroxidase; Propionic acid bacteria; SOD.

Fig. 1

Adhesion properties of cultures were studied according to MAI (Microbial Adhesion Index) and AAI (Average Adhesion Index).

Fig. 2

Effect of Fe²⁺ ions on the activity of catalase (a) and superoxide dismutase (b) in different strains of propionic acid bacteria.