Degradation of polyaromatic hydrocarbons by microorganisms isolated from different environments

Polyaromatic hydrocarbons (PAHs) are toxic, mutagenic and carcinogenic compounds that are released to the environment as a result of negligence and mistakes made during their use, spilling of oil and disposal of fossil fuels before they are completely burned. Accumulation and long-term persistence of PAHs in the environment affect the environment and biological balance. Biodegradation is the most important and fundamental mechanism for the removal of PAHs from the environment. Various chemical compounds are used by microorganisms as energy and carbon sources and converted into different biological products. In this study, bacteria was isolated from water and soil samples taken from Sinop and Ayancık ports. As a result of the isolation studies, it was determined that 3 isolates had high degradation ability among 46 isolates. Among the 3 isolates determined at different pyrene concentrations, 13 isolates with the best growth were selected and a biodegradation rate of 73% was found at 80 ppm pyrene concentration. According to the results of 16S rRNA sequence analysis, this isolate was determined to be Pseudomonas hydrolytica. With this species, optimization studies were carried out using the taguchi method. The levels that affect biodegradation are temperature, pH and salinity; As the best biodegradation rate, it was determined that the temperature value was 31oC, the pH was 6, the pyrene concentration was 1g/L and the salinity was 0.1g/L. As a result of anaerobic treatability studies of pyrene in batch reactor, high COD removal was obtained in the medium containing 20 and 40 ppm pyrene with sludge samples taken from different environments. As a result of the toxicity test performed with these samples, it was observed that the toxic effect decreased after treatment at 20 and 40 ppm pyrene concentrations. As a result, eliminating PAHs that cause problems in the environment and reducing pollution by using microorganisms with biodegradation capability creates a potential for bioremediation studies of PAHs.