The strain Gordonia polyisoprenivorans 135 is able to utilize a wide range of aromatic compounds. The aim of this work was to study the features of genetic organization and biotechnological potential of the strain G. polyisoprenivorans 135 as a degrader of aromatic compounds. The study of the genome of the strain 135 and the pangenome of the G. polyisoprenivorans species revealed that some genes, presumably involved in PAH catabolism, are atypical for Gordonia and belong to the pangenome of Actinobacteria. Analyzing the intergenic regions of strain 135 alongside the “panIGRome” of G. polyisoprenivorans showed that some intergenic regions in strain 135 also differ from those located between the same pairs of genes in related strains. The strain G. polyisoprenivorans 135 in our work utilized naphthalene (degradation degree 39.43%) and grew actively on salicylate. At present, this is the only known strain of G. polyisoprenivorans with experimentally confirmed ability to utilize these compounds.

The self-purification capacity of oil-contaminated soils is largely determined by the metabolic activity of autochthonous oil-oxidizing microorganisms. This study examined three strains of actinobacteria, which are hydrocarbon degraders, isolated from oil-contaminated sierozem soil at the Daulet Asia landfill (Southern Kazakhstan). Functional gene analysis was conducted (genome completeness > 98%, and contamination < 3%), and the phenotypic properties of these bacterial strains were studied to assess their potential for bio- and phytoremediation technologies in the sharply continental arid climate of the Aral Sea region. The isolated strains Rhodococcus kroppenstedtii K18 and MF2 and Kocuria rosea K1 grow on oil (12–22% oil loss after 10 days of cultivation in liquid mineral salt medium) and diesel fuel and can utilize hexadecane and benzoate as the sole source of carbon and energy. Furthermore, Rhodococcus K18 and MF2 utilize dodecane and eicosane, while K. rosea K1 utilizes phenol and gentisate. A significant decrease in surface tension (to 31.4 mN/m) observed during cultivation of strains K18 and MF2 on minimal salt medium indicates the secretion of surfactants that increase the bioavailability of hydrophobic substrates. The studied strains possess a number of properties that promote plant growth: they produce auxins, solubilize calcium hydroxyapatite, and protect plants from infection by the phytopathogenic microorganisms Fusarium oxysporum and Pectobacterium wasabiae. Actinobacteria are compatible when co-cultivated, as no mutual growth inhibition was observed. This study expands our understanding of typical bacterial representatives of desert soil, and this may contribute to the development of bioremediation approaches for the restoration of disturbed biotopes under extreme environmental conditions.

The efficiency of bioremediating oil-contaminated serozem (gray desert soil) of Southern Kazakhstan was investigated in the study. The first stage involved choosing hydrocarbon-degrading microorganisms suitable for the bioremediation of this desert soil. The second stage assessed the bioremediation potential of the selected microorganisms in laboratory microcosms. The final stage was a field trial experiment investigating oil removal under conditions of in situ natural attenuation, biostimulation (application of NPK fertilizer Nitroammophoska), reintroduction of indigenous oil-degrading microorganisms isolated from soils of the Aral Sea region and bioaugmentation using degrader strains from the laboratory collection. Additionally, the resulting native desert soil microbiomes were compared. Results showed that natural attenuation of the desert soil occurred over two months (with 68.5% of hydrocarbons removed), while biostimulation, reintroduction, and bioaugmentation were—as expected—also effective, achieving 89.4–97.0% oil removal. In the contaminated soil during the spring season, a significant increase in the proportion of Gammaproteobacteria within the soil microbiome was observed, with Alphaproteobacteria and Bacilli also representing significant fractions.