Diversity of active bacterial communities in the disposal sites of liquid waste of a chemical enterprise

The composition and taxonomic structure of the phylum Actinobacteria were studied on the example of technosols formed on the territory of the former tailings of liquid waste of a chemical enterprise in the floodplain of the Vyatka River. The diversity of actinobacteria in soil samples taken from three spatially remote monitoring sites (SG, SU1 and SU2), differing in the complex of physico-chemical properties and the nature of the vegetation cover, was studied. The results were compared with the background soil (BS) - alluvial soil selected on the territory of the Nurgush State Nature Reserve. The studies were carried out using high-performance sequencing using Illumina technology and the culture method (seeding). The culture method revealed representatives of the genera Streptomyces, Micromonospora, Streptospo-rangium and a number of oligospore forms in the actinobacterial complexes. The total number of actinomycetes in the samples of technosols varied from 2.4 center dot 104 to 1.8 center dot 105 CFU/g, and in the background soil was 8.5 center dot 103 CFU/g. Families of actinomycetes established by the seeding method were also detected using the amplicon sequencing of the V4 section of the 16S rRNA gene, but the molecular method made it possible to identify a number of other taxa in the studied samples, including those that do not have cultured representatives or are not yet classified. Using amplicon sequencing, it was found that representatives of the phylum Actinobacteria in samples of technogenically disturbed soils are absolute dominants in relative abundance in the total bacterial diversity. The proportion of actinobacteria in disturbed soils ranges from 33 to 41%, while in the background soil it is only 22%. Actinobacteria in the samples of technosols were represented by the families Micromonosporaceae, Micrococcaceae, Nocardioidaceae, Microbacteriaceae, Thermomonosporaceae, Pseudonocardiaceae, Actinosynnemataceae, and Intrasporangiaceae, etc. The taxonomic spectrum of actinobacteria in the BS sample was similar to technosols, but the proportion of taxa was different. The results obtained will be used in further studies of soil actinobiota in connection with changes in ecosystems disrupted by human economic activity, and are also of interest for the search and isolation of natural strains of actinobacteria for biotechnology purposes.