Microbiome profile of soil and rhizosphere plants growing in traditional oil mining land in Wonocolo, Bojonegoro, Indonesia

Traditional oil mining poses negative effects on the environment through pollution with crude oil. One of the traditional mining sites in Wonocolo, Bojonegoro, Indonesia was reported to contaminate the surrounding area with a high level of crude oil. Therefore, this study aims to examine the microbiome profiles of contaminated soil and the rhizosphere of naturalized plants growing at the sites. It was conducted in Wonocolo, Bojonegoro to obtain an insight into the possible remediation efforts of using indigenous hydrocarbon-degrading bacteria and naturalized plants as in situ remediation agents. The results showed that the soil located close to the oil well-contained a high level of crude oil at 24.8%, and exhibited a distinct microbiome profile compared to those located further which had lower crude oil contamination of 14.15, 10.89, and 4.9%. Soil with the highest level of crude oil contamination had a comparatively higher relative abundance of <i>assA</i>, an anaerobic alkene-degrading gene. Meanwhile, the rhizosphere of the two naturalized plants, <i>Muntingia calabura</i>, and <i>Pennisetum purpureum</i>, exhibited indifferent microbiome profiles compared to the soil. They were found to contain less abundant hydrocarbon-degrading genes, such as C230, PAH-RHD-GP, <i>nahAc</i>, <i>assA</i>, and <i>alkB</i> suggesting that these naturalized plants might not be a suitable tool for in-situ remediation. This study provides information on the microbiome profile of soil and rhizosphere crude oil contaminated sites. The rhizosphere of growing plants in the crude-oil contaminated site exhibited a similar microbiome profile as in soil, with a lower relative abundance of hydrocarbon-degrading genes. Commonly, most inhabitant plants of the contaminated site have great potential as a phytoremediator agent, however, two largely abundant species were found to possess low potential.