Obtaining mixed liquor culture using with the aim of biological treatment of wastewaters of the petrochemical industry

In the last five decades, besides numerous products which makes daily life easier, there have been paved the way for many environmental problems with flourishing of industries depending on the promptly soaring in science and technology. Particularly, negative effects of industrial wastes which could be named anthropogenic wastes on environment are jeopardized ecological balance, human and animal health. Discharging of the industrial wastes to environment with incompleted treatment or without treatment is caused to negative effects on ecosystem members. Important industries, especially, plastics, pharmeceutical, petroleum industries are the main sources such environmental problems. Most of the produced wastes are xenobiotics, accumulated in nature and caused toxic effect on living beings. Therefore, they must mainly be removed and treated. Wastes of the petroleum industry are hazardous compounds and they mostly consist of xenobiotic hydrocarbons. One group of those are polyaromatic hydrocarbons (PAHs) which necessary to remove. 16 PAHs which determined by US EPA frequently found in areas contaminated with petroleum compounds and derivatives. In this doctoral, thesis some kind of laboratory experiments were carried out and summarized as follows; removal of hydrocarbon compounds named as terephthalic acid (TPA), acenaphthane (ace), fluorene (flu), fluoranthene (flr), anthracene (ant) and pyrene (pyr) via microbiological ways, determination of removal efficiencies, constructing inoculum liquor with bacterial consortium, evaluation of removal efficiencies of inoculum liquor in industrial wastewaters, monitoring of the selected microorganisms with qPCR during bioaugmentation and biodegradation and investigation of expression levels of genes which codes primer enzymes involved in bacterial PAH bioremediation. In this context, 13 microorganisms were obtained which use the target hiydrocarbons as a sole carbon and energy sources. These microorganism were molecular biologically identified. Bacterial strains belong to Acinetobacter sp., Aeromonas media, Arthrobacter nicotianae, Arthrobacter protophormiae, Burkholderia cepacia, Chryseobacterium sp, Pseudomonas sp., Pseudomonas fluorescens, Raoultella planticola genus and species. An inoculum liquor was prepared with isolated microorganisms and tried in aged activated sludge system in completely stirred tank bioreactor (CSTR). Biodegradation states and removal efficiencies were determined of TPA (50 mg/L), Ace, Flu, Flr and Ant (20 mg/L). According to this, % removal rates of hydrocarbons which obtained from effluent determined as 82,3 %; 100 %; 100 %; 100 % and 75.4 % respectively. Primer prob sets were used peculiar to isolated microorganisms and bacterial monitoring was carried out using Real time PCR. Accordingly, during the 55 days biodegradation period amount of copy DNA of microorganisms was stable and between 105 – 106 copy DNA/ 50µl. Optimized PAH RHDα gene region for Gram negative bacteria was used in gene expression experiments. For this, Livak, Pfaffl and BestKeeper methods were used and compared to evaluate expression levels. Keywords: Microbial PAH biodegradation, bioaugmentation, bioremediation, activated sludge system, petrochemical industry.