Heavy Metals as a Factor Increasing the Functional Genetic Potential of Bacterial Community for Polycyclic Aromatic Hydrocarbon Biodegradation.

Justyna Staninska-Pięta,Wojciech Juzwa,Jacek Nowak,Jakub Czarny,Paweł Cyplik,Łukasz Wolko,Agnieszka Piotrowska-Cyplik

doi:10.3390/molecules25020319

Abstract

The bioremediation of areas contaminated with hydrocarbon compounds and heavy metals is challenging due to the synergistic toxic effects of these contaminants. On the other hand, the phenomenon of the induction of microbial secretion of exopolysaccharides (EPS) under the influence of heavy metals may contribute to affect the interaction between hydrophobic hydrocarbons and microbial cells, thus increasing the bioavailability of hydrophobic organic pollutants. The purpose of this study was to analyze the impact of heavy metals on the changes in the metapopulation structure of an environmental consortium, with particular emphasis on the number of copies of orthologous genes involved in exopolysaccharide synthesis pathways and the biodegradation of hydrocarbons. The results of the experiment confirmed that the presence of heavy metals at concentrations of 50 mg·L−1 and 150 mg·L−1 resulted in a decrease in the metabolic activity of the microbial consortium and its biodiversity. Despite this, an increase in the biological degradation rate of polycyclic aromatic hydrocarbons was noted of 17.9% and 16.9%, respectively. An assessment of the estimated number of genes crucial for EPS synthesis and biodegradation of polycyclic aromatic hydrocarbons confirmed the relationship between the activation of EPS synthesis pathways and polyaromatic hydrocarbon biodegradation pathways. It was established that microorganisms that belong to the Burkholderiales order are characterized by a high representation of the analyzed orthologs and high application potential in areas contaminated with heavy metals and hydrocarbons.

Highlights

Hydrocarbon compounds are currently considered as one of the most significant power sources for human activities
Strong inhibition was noted in the case of the biodegradation of the aromatic hydrocarbon fraction of diesel oil
The studies indicate that the consortium with high potential for the biodegradation of hydrocarbons was highly sensitive to heavy metals

Summary

Introduction

Hydrocarbon compounds are currently considered as one of the most significant power sources for human activities. Due to the high ecotoxicity of hydrocarbon compounds and their adverse impact on human health, increasing attention has been paid to the development of remediation technologies of contaminated. Bioremediation methods are characterized by low process costs and allow for the complete mineralization of xenobiotics. They do not significantly affect the natural environment and are effective for the removal of low concentrations of pollutants [1,9]. The difficulty in optimizing this technology due to the high impact of environmental factors is the main limiting factor in terms of efficiency [2,9,11,12,13]

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Results

Discussion

Conclusion