PAHs distribution and cultivable PAHs degraders'biodiversity in soils and surface sediments of the impact zone of the Novocherkassk thermal electric power plant (Russia)

摘要

The qualitative and quantitative composition of polycyclic aromatic hydrocarbons (PAHs) pollutants at 13 points of the impact zone of the Novocherkassk thermal electric power plant (NchPP) has been determined. This territory has been polluted with emissions from brown coal combustion for several decades. A total of 200 isolates from PAH-degrading bacteria were selected from the soils and surface sediments, heavily contaminated with PAHs. Taxonomic identification of isolates was carried out by sequencing of the 16S rRNA genes and by MALDI-TOF analysis of protein spectra. Soil cultivable PAH-degrading microorganisms were represented by six species of four genera of actinobacteria (Arthrobacter, Rhodococcus, Oerskovia and Isoptericola). Surface sediments cultivable PAH degraders were represented by six species of the genus Pseudomonas. R. erythropolis was the most numerous of soil isolated strains. The studied soils heavily contaminated with PAHs display low biodiversity of cultivable PAH-degrading bacteria and do not have a connection between the quantity of PAHs in the soil samples and taxonomic variety of PAH degraders. Cultivable PAH degraders were represented in the soils exclusively by Gram-positive bacteria, and in the surface sediments only by Gram-negative bacteria.