Polycyclic aromatic hydrocarbons (PAHs) pose a real threat towards all elements of the ecosystem due to their toxic properties. One of the methods reducing PAHs from the environment is bioremediation, including bioaugmentation. Bioaugmentation consists in introducing microorganisms capable of effective recultivation ground into contaminated areas. This kind of microorganisms (microbial consortia), are often isolated from places permanently contaminated with organic compounds due to their high potential for biodegradation. Genetic assays based on Next Generation Sequencing (NGS) indicate that K52 consortium obtained from crude oil contaminated site of eastern Carpathians is characterized by a high diversity of population with dominance of Pseudomonas genus. Polycyclic aromatic hydrocarbons (naphthalene, phenanthrene and fluorene) used throughout the currently described experiments were biodegradable both in the individual systems, and in the mixture, but the degree of biodegradation depended on the type of PAH. The most susceptible to biodegradation is naphthalene in the concentration of 20 mg/l, which undergoes completely decomposed after six days of experiments. In the system with initial concentration of 50 mg/l, biodegradation of naphthalene reached almost 80% after eight days. The results of flow cytometry confirm that the difficulties in PAHs decomposition increasing with amount of aromatic rings.