Evaluation of the Ecological Potential of Microorganisms for Purifying Water with High Iron Content

The ability of a number of microorganisms isolated from highly magnetic soil of the city Mednogorsk to oxidize Fe (II) under conditions of periodic cultivation in a liquid medium was studied. Among the studied microorganisms, two microbial isolates with maximum growth characteristics and iron-oxidizing activity were selected and identified: Bacillus megaterium 69.3 and B. megaterium 69.5. Individual levels of metal resistance of the isolates were determined: maximum tolerated concentration (MTC) for Fe (II) of the isolates B. megaterium 69.3 and B. megaterium 69.5 was 1200 mg L-1, minimum inhibitory concentration (MIC) was 1800 mg L-1. Both microbial isolates actively oxidized Fe (II) by reducing its high concentration in the medium (1.19 g L-1) by 33 and 39% during 14 days of culturing. Total increase in the biomass of B. megaterium 69.3 and B. megaterium 69.5 after 14 days of culturing was 15.3 and 14.7 g L-1; the active parts of the biomass increased 8.7- and 6.9-fold compared to the inoculum dose, respectively. These microbial isolates could be used in future in the biotechnological process of water purification with increased/high levels of Fe (II).

Automated summary

The study investigated the ability of microorganisms isolated from highly magnetic soil in the city of Mednogorsk to oxidize Fe (II) under liquid cultivation conditions. Two microbial isolates with the strongest iron-oxidizing activity were selected and identified, showing potential for future use in biotechnological processes for water purification.