The wide spectrum of oil industry activities caused soil contaminants, as environmental concern in many areas of the world. Bioremediation of oily soils, as biological approach done by bacteria and fungi, is very important to eliminate this pollution. In this study four different metagenomic protocols for DNA extraction has been tested in order to sequence and identify the native bacterial species involved in remediation of oily soils. In this regard, 3 manual methods and a soil DNA extraction kit are used. In manual protocol, physical processes including the addition of silica beads and freezing samples by liquid nitrogen, chemical methods such as treating the lysozyme, and lysis buffer and proteinase K as biochemical methods were utilized for optimal extraction. Quality and quantity of the extracted DNA analyzed using Agarose gel electrophoresis and Picodrop respectively. Then, the 16S rdna gene of bacteria amplified through universal primer for preparing a genomic library by PCR. Results showed that the highest concentration and quality of extracted DNA was obtained by protocol D which was about 135 μg/ul and 260/230 = 2.2 respectively. Moreover, 500 bp fragment amplified perfectly by using DNA extracted through protocol D in the PCR test. Therefore, protocol D can be used as an appropriate and effective way in order to study the microbial population of oily soils using direct extraction of DNA.

石油工业的广泛活动引起土壤污染物，这是世界许多地区对环境的关注。作为细菌和真菌的生物方法，油性土壤的生物修复对消除这种污染非常重要。在这项研究中，已经测试了四种用于DNA提取的宏基因组学方案，以便测序和鉴定与修复油性土壤有关的天然细菌种类。在这方面，使用了3种手动方法和土壤DNA提取试剂盒。在手动操作中，物理过程包括最佳方法，包括通过液氮添加硅胶珠和冷冻样品，化学方法（如溶菌酶），裂解缓冲液和蛋白酶K作为生化方法。分别使用琼脂糖凝胶电泳和Picodrop分析提取的DNA的质量和数量。然后，通过通用引物扩增细菌的16S rdna基因，通过PCR制备基因组文库。结果显示，通过方案D获得的提取DNA的最高浓度和质量分别为约135μg/ ul和260/230 = 2.2。此外，通过在PCR测试中使用通过方案D提取的DNA，可以完美扩增500 bp片段。因此，协议D可以用作通过直接提取DNA来研究油性土壤微生物种群的一种合适而有效的方法。结果显示，通过方案D获得的提取DNA的最高浓度和质量分别为约135μg/ ul和260/230 = 2.2。此外，通过在PCR测试中使用通过方案D提取的DNA可以完美扩增500 bp片段。因此，协议D可以用作通过直接提取DNA来研究油性土壤微生物种群的一种合适而有效的方法。结果显示，通过方案D获得的提取DNA的最高浓度和质量分别为约135μg/ ul和260/230 = 2.2。此外，通过在PCR测试中使用通过方案D提取的DNA可以完美扩增500 bp片段。因此，协议D可以用作通过直接提取DNA来研究油性土壤微生物种群的一种合适而有效的方法。