Diversity and Metabolic Potential of a PAH-Degrading Bacterial Consortium in Technogenically Contaminated Haplic Chernozem, Southern Russia

Abstract

Polycyclic aromatic hydrocarbons (PAHs) are chemically recalcitrant carcinogenic and mutagenic compounds with primarily anthropogenic origin. The investigation of the effects of emissions from energy enterprises on soil microbiomes is of a high priority for modern soil science. In this study, metagenomic profiling of technogenic contaminated soils was carried out based on bioinformatic analysis of shotgun metagenome data with PAH-degrading genes identification. The use of prokaryotic consortia has been often used as one of the bio-remediation approaches to degrade PAHs with different molecular weight. Since the process of PAH degradation predominantly includes non-culturable or yet-to-be cultured species, metagenomic approaches are highly recommended for studying the composition and metabolic abilities of microbial communities. In this study, whole metagenome shotgun sequencing of DNA from two soils with varying PAH levels was performed. In the control site, the total content of 12 priority PAHs was 262 µg kg−1. The background soil levels in the polluted site for PAHs with 3 or more rings exceeded this, at 800 µg kg−1. The abundance of genes and taxa associated with PAH degradation in these two sites were estimated. Despite differences in PAH concentrations up to 1200 µg kg−1, individual and operon-organized PAH degradation genes were almost equally abundant and diverse in pristine and highly contaminated areas. The most numerous taxa in both spots were actinobacteria from Terrabacteria group. In addition to well-known PAH degraders such as Gordonia and Rhodococcus, genes corresponding to the PAH degradation were found in Azoarcus, Burkholderia and Variovorax. The data shows non-specificity and multifunctionality of metabolic pathways encoded in the genes of PAH-degrading microorganisms.

Complete Genome Sequence of Gordonia polyisoprenivorans 135, a Promising Degrader of Aromatic Compounds

“…Polycyclic aromatic hydrocarbons (PAHs) are chemically stable carcinogenic and mutagenic compounds of crude oil ( 1 ). The ability to utilize PAHs is characteristic for many Actinobacteria members, but not many strains of the genus Gordonia are currently known to possess this property.…”

Nano-Enhanced Microbial Remediation of PAHs Contaminated Soil

“…Crude oils are one of the major sources of PAHs which are also the main pollutants of soil and water bodies (S. Kumari et al, 2018)). Hence, the merging of nanotechnology with microbial remediation enhances the PAHs remediation potential by several times without producing toxic by-products such as carbon monoxide, metabolites like, 9-fluorenone, dibenz[a,h]anthracene, which inhibits enzymes and cellular activity, and prevents the degradation of other PAHs in the system during incomplete bioremediation (Muralidharan et al, 2021;Delegan et al, 2022). Biodegradation of crude oils by strain B. licheniformis has been reported to be enhanced by the amendment of two different types of NPs such as Fe 2 O 3 NPs and Zn 5 (OH) 8 C l2 NPs (El-Sheshtawy & Ahmed, 2017).…”

Profile distribution of polycyclic aromatic hydrocarbons in coastal soils of the Lower Don and Taganrog Bay, Russia

“…In this case, pedogenic PAHs are firmly bound to the highly aromatic soil organic matter (Aemig et al, 2016). In this regard, PAHs in the lower soil horizons become less labile, making them inaccessible to microbial degraders (Delegan et al, 2022;Ren et al, 2018). In addition, the activity of PAH-degrading microorganisms is predominantly observed in the most aerated 0-20 cm layer, which also does not favour the biodegradation of pollutants deep in the soil profile (Mazarji et al, 2022;Ren et al, 2018).…”