Karışık Mikrobiyal Kültür ile Petrol Biyoyıkımının Araştırılması

Abstract

This study aimed petroleum biodegradation with Bacillus cereus ATCC 14579, Bacillus subtilis ATCC 6633, Bacillus tequilensis NR104919, Bacillus axarquiensis NR115929, Klebsiella oxytoca ATCC 13182, Klebsiella pneumoniae ATCC 13883, Proteus mirabilis ATCC 29906 and Pannonibacter phragmitetus NR_028009.1 strains from Hacettepe University Environmental Biotechnology Laboratory Culture Collection, which were isolated from an oil field. Petroleum biodegradation rates were determined to be 85% for Pannonibacter phragmitetus NR_028009.1, 81% for Bacillus axarquiensis NR115929, 80% for Klebsiella pneumoniae ATCC 13883 and 65% for Bacillus tequilensis NR104919. The mentioned strains were selected for the continuation of the study. In order to increase petroleum biodegradation, these strains were brought together in double and triple groups to form ten different consortium groups. It was determined that five of these consortia had petroleum biodegradation rate above 75%. The consortium of Klebsiella pneumoniae ATCC 13883, Bacillus axarquiensis NR115929, Pannonibacter phragmitetus NR_028009.1 had the highest petroleum biodegradation rate (88%). In order to determine the optimal physiological conditions for petroleum biodegradation for the potential consortium, effect of different pH, incubation conditions, temperature and incubation time were investigated and it was determined that maximum petroleum biodegradation was obtained with pH 7.0, 150 rpm shaking speed, 25°C temperature and 7 days of incubation. Furthermore, above 78% petroleum biodegradation rate was observed in the pH range of 4.0-8.0 and the temperature range of 25-35°C. In the continuation of the study, higher petroleum biodegradation rate in a shorter time was aimed with the culture supernatant obtained using determined optimal conditions from Klebsiella pneumoniae ATCC 13883, Bacillus axarquiensis NR115929, Pannonibacter phragmitetus NR_028009.1 consortium. For this purpose, petroleum biodegradation was investigated at different supernatant concentrations and incubation times. It was observed that there was no significant increase in petroleum biodegradation with an increase in the concentration of culture supernatant. In this regard, effective petroleum biodegradation was observed even at 20% supernatant concentration. Petroleum biodegradation rates of Klebsiella pneumoniae ATCC 13883, Bacillus axarquiensis NR115929, Pannonibacter phragmitetus NR_028009.1 consortium and culture supernatant in different concentrations were compared. In this respect, it was determined that the petroleum biodegradation obtained with this consortium after 7 days was comparable to the petroleum biodegradation obtained with 30% supernatant concentration after 60 hours. In the last stage of the study, the maximum petroleum biodegradation of Klebsiella pneumoniae ATCC 13883, Bacillus axarquiensis NR115929, Pannonibacter phragmitetus NR_028009.1 consortium and culture supernatants were determined by GC analysis. When the results obtained were evaluated, 87% petroleum biodegradation after 7 days with the potential consortium, 84% after 84 hours with 50% supernatant concentration and 75% after 60 hours with 30% supernatant concentration was observed.