The metabolic diversity of soil microbial community in the petroleum exploitation area of Northern Shaanxi, China

In order to explore the changes of soil chemical properties and microbial metabolic diversity under different petroleum pollution levels, conventional soil detection technology and Biolog® technology were used to study the soil chemical properties and microbial community characteristics of the clean soil in the north Shaanxi oilfield under four different petroleum pollution gradients. The results showed that the soil after petroleum pollution had higher total organic carbon content, higher carbon nitrogen ratio and lower total nitrogen content. Petroleum had a significant effect on the metabolic capacity of soil microbial communities from carbon sources and their utilization patterns. There were significant differences in microbial community metabolism in petroleum-contaminated soils at different concentrations, with a decreasing trend with increasing contamination. At the same time, the microbial activity that could utilize carboxylic acid compounds and polymers was higher in the contaminated soil, while the microbial activity that utilized amino acids and carbohydrates was higher in the clean soil. With the increase of pollutant concentration, the metabolic pattern of soil microbial community to carbon sources changed from sugar-based to polymers-based. This indicates that oil pollution has changed the use of some preferred carbon sources by soil microorganisms, and long-term pollution will stabilize the carbon sources available to microorganisms and promote the development of microbial communities that prefer polymeric substances as carbon sources. This provides theoretical guidance and data support for the bioremediation and treatment of petroleum-contaminated soil in loess hilly areas.