توصيف المجتمعات الجرثومية المعزولة من ترب سورية ملوثة بالديوكسينات

الملخص EN

Dioxins are one of the most dangerous and toxic environmental contaminants, belong to persistent organic pollutants, which known for their resistance to degradation process, helped by their stable chemical structure, which Leads to their bioaccumulation and biomagnification threatened the health of living organisms, thus affecting the Ecosystem safety.

Soils are an essential store of dioxin compounds and a source of their spread within the environment, Besides, the microorganisms endemic to these polluted soils are exposed to high levels of dioxins, which affects their biological diversity and their genetic and functional characteristics.

Therefore, the research aimed to highlight the reality of local soils and the possibility of their contamination with dioxins, in addition to characterization of the bacterial communities endemic to these contaminated soils in search of strains characterized by their ability to biodegrade environmental toxins, including dioxins.

Seven soil sampling sites were selected as a source of dioxins emission.

The results of the study showed that the soils of Site C near the Homs Refinery were the most polluted, while the soils of Al-Moadamyeh site A1, A2, A3, and D Al-Suwayda polluted with emissions from waste burning; the level of pollution was medium, and the lowest level of dioxin contamination was recorded in each of the soil samples for the Deir al-Asafir site B Contaminated with industrial and local wastewater,and samples of the site of Maadamiyat al-Sham A4 collected from agricultural land.

Bacterial communities which isolated from contaminated soils were characterized molecularly by 16srRNA sequencing, The results of the biological abundance of the bacterial species within the studied sites showed that the genus Bacillus followed by the genus Pseudomonas and Acinetobacter was the most abundant by 37.38%, 21.49%, and 14.10%, respectively.

Due to the coexistence of these bacterial species in polluted soils, it was necessary to search their genome for genes responsible for the biodegradation pathways of these pollutants.

The results of molecular detection of the two genes Cytochrome P450 (CYPBM3) and angular dioxygenase (AD) indicated the presence of 22 bacterial strains that have the AD gene, and 14 container strains on the CYPBM3 gene.

Finally, the evaluation of the biological ability of the bacterial strains to grow was carried out in the presence of the most toxic compound tetrachlorodibenzo-p-dioxin “2,3,7,8-TCDD”.