EFFECT OF Pb2+ IONS ON THE SYNTHESIS OF THE EXOPOLYSACCHARIDE COMPLEX BY GORDONIA RUBRIPERTINCTA
DOI:
https://doi.org/10.31861/biosystems2026.01.196Keywords:
Gordonia rubripertincta, lead ions, exopolysaccharides, bioremediation, heavy metalsAbstract
Today, the issue of biosphere contamination with heavy metal salts is one of the key challenges for the safety and preservation of ecosystems. Among these, lead is particularly notable as a toxic metal that enters water and soil on a massive scale through industrial emissions, mineral extraction, and the consequences of armed conflicts. Lead does not degrade over time but accumulates continuously in the environment. High concentrations of this metal have a detrimental effect on living organisms. Conventional physicochemical approaches to soil and water detoxification typically require significant financial investment and are accompanied by the generation of hazardous secondary waste, which complicates their disposal. In light of this, bioremediation technologies based on the ability of specific microorganisms to accumulate or neutralize ecotoxicants are emerging as a promising alternative. Bacteria capable of surviving in extreme conditions are of particular interest.
This study investigated the effect of lead loading (specifically, lead ions at concentrations up to 0.6 mg/L) on the adaptive responses of the actinobacterium G. rubripertincta.
It was found that the bacteria exhibit extremely high tolerance to lead ions. The presence of the toxicant at concentrations up to 600 μg/L does not inhibit culture growth, ensuring stable biomass accumulation and colony formation. At the same time, a dose-dependent intensification of exopolysaccharide synthesis was observed. At the maximum toxic load, the concentration of cell-bound exopolysaccharides increased by nearly 1.5-fold, and that of free exopolysaccharides by 5-fold. The extracellular exometabolites of the studied microorganism appear to form a reliable protective barrier that ensures intensive binding and immobilization of Pb2+on the cell surface. An assessment of the dynamics of this process showed that when 6 μg/L and 60 μg/L of the toxicant were introduced into the medium, the bacteria removed 66% and 76% of the lead, respectively. The results confirm the high bioremediation potential of G. rubripertincta under conditions of severe chemical stress. In particular, the identified mechanisms of microbial adaptation open up promising prospects for the development of effective new-generation biopreparations. Such environmentally safe preparations can be successfully applied for the full restoration of agricultural soils and the purification of industrial wastewater from heavy metal ions. Further fundamental research will logically focus on a detailed study of the genetic determinants of metal resistance in this valuable strain and the optimization of conditions for its large-scale cultivation.
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