Isolation of Degraded Bacteria and Fungi of Petroleum Hydrocarbons from Two Polluted Soil under Remediation with Maize Plant

Abstract

Soil contaminated by petroleum hydrocarbons (PHCs) is a global severe environmental problem, especially if we consider that Iraq has been subjected to several wars and the widespread use of generators to provide electrical energy. In addition to oil extraction sites, gas manufacturing sites, refineries, and ammunition waste sites. Therefore, the need to know the best ways to treat these polluted soils has been increased. For this purpose, this study was conducted to isolate bacteria and fungi from contaminated and non-polluting soils that synergism with plant for remediation of oil-contaminated soil. The study was carried out in the plastic shade scale, and seeds were cultivated in plastic pots filled with 12 kg of soil. The experiment was laid out in Completely Randomized Block Design (CRBD) with three replications. Each replication comprised the following treatments randomly: AL-Daura power station soil planted with maize, AL-Daura oil refinery soil planted with maize, AL-Daura oil refinery soil unplanted (abiotic stress), AL-Daura oil refinery soil sterilized unplanted (treated with AgNO₃ (biotic stress)), in addition to control soil planted with maize. The total number of bacteria and fungi and hydrocarbon (HCs)-degrading microorganisms were evaluated during phytoremediation by cultured in a proper media agar. The rhizospheric bacterial and fungal count of the planted soil increased at the end of the experiment. Totally, the study obtained 11 pure bacterial isolates and 7 pure fungal isolates that could grow on Bushnell Hass (BH) agar medium containing crude oil. Current study suggested that the used of maize plants played an important role in stimulation the microorganisms. They were increased the number of microorganisms. Also, the petroleum degraders microbial increased in the oil-contaminated soil and the non-contaminated soil. The microbial degraders are found in the entire treatments.