Hydrocarbon-oxidizing Microorganisms Research Articles

Hydrocarbon-Oxidizing Bacteria of the Bottom Ecotopes of the Barents and Pechora Seas

Microorganisms capable of degrading hydrocarbons are regular components of natural microbial communities and play an important role in self-purification of marine environments from oil contamination. High-throughput sequencing of the 16S rRNA gene V4 variable region was used to analyze microbial communities of the Barents and Pechora seas and of the microcosms with a spectrum of hydrocarbon substrates: oil, n-nonane, n-undecane, and phenanthrene. The Barents Sea communities of hydrocarbon-oxidizing microorganisms were characterized by predominance of the genera Pseudoalteromonas, Pseudomonas, Porticoccus, and Oleispira, while those of the Pechora Sea contained members of the genera Rhodococcus, Dietzia, Sphingorhabdus, and Hyphomonas. Pure cultures of these microorganisms were shown to utilize the major oil hydrocarbons: n-alkanes, cycloalkanes, and aromatic compounds.

Бактерии-деструкторы с ростстимулирующими свойствами для использования в экологической

A topical research trend in ecological biotechnology is the search and study of microorganisms-destructor resistant to additional pollutants and growth-stimulating to remediant-plants. Four strains of hydrocarbon-oxidizing microorganisms isolated from soil samples were identified on the basis of cultural-morphological, physiological-biochemical properties and a comparative analysis of the gene encoding 16S rRNA. The bacteria Acinetobacter calcoaceticus UOM 22 and UOM 29, A. courvalinii UOM 35 showed a significant degree of oil biodegradation in a liquid medium at 24 and 8 °C (93.0–95.6% and 78.4–81.1%, respectively). In the same conditions these indicators were 44.8 and 33.7%, respectively for strain Rhodococcus erythropolis UOM 33. All microorganisms grew in the presence of aromatic hydrocarbons (including polycyclic hydrocarbons), were resistant to NaCl (5–7%) and lead ions (1.00–1.25 g/L). They were capable of nitrogen fixation and inorganic phosphate dissolution, indole-3-acetic acid synthesis (150–1416 ng/ml of culture liquid) and hydrolytic enzyme lipase production. We found that A. calcoaceticus UOM 22 and A. courvalinii UOM 35 strains increased the barley seeds germination by 8.6 and 10.5%, as well as A. calcoaceticus UOM 29 and A. courvalinii UOM 35 stimulated the barley root growth by 16.3 and 18.1% respectively. The results of the experiments indicate the possibility of using A. calcoaceticus UOM 22 and UOM 29, and A. courvalinii UOM 35 strains for cleaning oil-contaminated soils, including in combination with remediant-plants.

Effectiveness of biogeosorbents based on mineral carriers for treatment oil-contaminated soil

Methods for cleaning oil-contaminated areas include the use of sorbents, the effectiveness of which is enhanced by the immobilization of hydrocarbon-oxidizing microorganisms on their surface. Biogeosorbents are obtained on the basis of mineral raw materials (analcime- and glauconite-containing rocks and thermally activated vermiculite) and hydrocarbon-oxidizing bacteria of the genera Pseudomonas and Microbacterium extracted from contaminated soils of the Murmansk region. The number of immobilized bacteria on the studied carriers remains high throughout 9 months of storage, and the bacterial film on the surface of mineral carriers persists for 12 months of storage in an air-dry state. When storing biogeosorbents, no special conditions or additional preparation are required before use. Mineral carriers have a stimulating effect on the height of seedlings and the length of roots of test plants. When biogeosorbents are added, the number of bacteria capable of microbiological transformation of petroleum products increases, and the degree of soil purification from petroleum hydrocarbons at the initial stage (during the first 30 days) increases. The most effective is the introduction of thermally activated vermiculite and glauconite-containing rock with immobilized hydrocarbon-oxidizing bacteria. The use of a biogeosorbent based on thermally activated vermiculite can reduce the cleaning time to 20–22 months, and based on glauconite-containing rock – up to 17 months, while without treatment this period will be at least 29 months.

Pollution of the hydrosphere with petroleum products at railway transport facilities

On railway transport, a large amount of water is used for production needs, respectively, domestic wastewater contaminated with petroleum products is formed.For water purifi cation in modern conditions, oil traps or oil traps are used. They are designed for cleaning ground, thawed, rainwater, water from washing rolling stock, washing components and parts before repair in electroplating workshops or sites, when washing and refueling batteries, fi lter regeneration, when purging and washing steam boilers, washing inspection ditches and washing overalls.As a result of man-made disasters on railway transport, there may be pollution of water bodies, as a result of which there is a violation of the integrity of ecological systems and the death of living organisms.To eliminate the consequences of pollution of water bodies, JSC “Russian Railways” uses mechanical, chemical and biological methods of water purifi cation. Additionally, it is advisable to use modern types of sorbents. The choice of a method for cleaning reservoirs depends on many factors, the most important of which are the volume and scale of pollution.A number of bacterial preparations have been created in Russia that are successfully used to clean water bodies and shorelines from oil pollution.Voronezh State University, with the cooperation of VEGA-eco LLC, is developing a biological product of the genus Acinetobacter (B-2838, B-5064 and B-3780), which is capable of refi ning oil.The drug “Devoroil” is used to clean oil-contaminated sites at railway enterprises. It includes an association of cells of hydrocarbon-oxidizing microorganisms and additives that activate the process of biodegradation of oil. The working time of the drug “Devoroil” is 2-3 months.Today, there are 25 known species of bacteria and fungi that decompose hydrocarbons.These organisms work in a complex and participate in the biochemical carbon cycle in nature, being powerful tools in the fi eld of environmental microbiology.As a result of the development of scientifi c and technological progress, it becomes possible to create new technologies in the fi ght against man–made disasters.

Influence of a Hydrocarbon Biodestructor on the Growth and Content of Phytohormones in Secale cereale L. Plants under Petroleum Pollution of the Soil

The phytoremediation of soil contaminated with petroleum depends on the association of plants with rhizosphere bacteria capable of promoting plant growth and destroying petroleum hydrocarbonates. In the present work, we studied the effects of “Lenoil” biological product containing bacteria Pseudomonas turukhanskensis IB 1.1, capable of destroying petroleum hydrocarbons on Secale cereale L plants, which previously proved to be resistant to the weak oil pollution of gray forest soil and to the composition of microorganisms in their rhizosphere. The composition of microorganisms in the rhizosphere of rye roots was studied, morphometric parameters of shoots and roots of rye plants were estimated, and hormone concentration was immunoassayed under conditions of 4% petroleum pollution of the soil. Addition of petroleum to the soil increased the content of oligonitrophilic (by 24%) and hydrocarbon-oxidizing (by 33%) microorganisms; however, the content of cellulolytic (by 12.5 times) microorganisms in the rhizosphere decreased. The use of Lenoil led to a further increase in the number of cellulolytic (by 5.6 times) and hydrocarbon-oxidizing (by 3.8 times) microorganisms and a decrease in the number of oligonitrophilic (by 22.7%) microorganisms in the rhizosphere. Under petroleum pollution, the content of auxins (IAA), zeatin riboside, zeatin nucleotide, and zeatin decreased, while the content of abscisic acid (ABA) increased in the shoots of rye plants. Lenoil treatment led to an eight-fold increase in the IAA content in the roots and a decrease in the ABA content in the aerial part and in the roots. It was shown for the first time that the treatment of petroleum-contaminated soil with “Lenoil” increased root mass due to the development of lateral roots, concurrent with high root IAA content. Petroleum pollution increased the deposition of lignin and suberin in the roots, which strengthened the apoplastic barrier and, thus, reduced the infiltration of toxic components. The deposition of suberin and lignin decreased under ”Lenoil” treatment, indicating a decrease in the concentration of toxic petroleum components in the soil degraded by the bacteria. Thus, the biological preparation reduced the growth-inhibiting effect of petroleum on rye plants by increasing the content of growth-stimulating phytohormones (IAA and cytokinins) and reducing the content of ABA, justifying the importance of further study of relevant hormones for the improvement of phytoremediation.

Efficiency of sorption-biological treatment of oil-polluted coastal areas in the Euro-Arctic region

A biotechnology based on sorption-biological treatment for the restoration of the Arctic coastal areas after oil spills was proposed. A hydrocarbon-oxidizing microbial preparation based on microfungi (Penicillium janthinellum, Penicillium simplicissimum) and bacteria (Pseudomonas fluorescens, Pseudomonas putida) was created. Granular activated carbon, thermoactivated vermiculite, and peat were used as sorbents. The sorbents are concentration centers for microorganisms, prevent the spread of hydrocarbons, and improve the condition of the polluted substrate by optimizing the water-air regime. After treatment, sorbents are not removed from the soil. As a result of laboratory studies at +10°C, the hydrocarbon content in the polluted coastal sand was reduced by 44-60%, and in the coastal soil by 25-68% after three months. This technology can be used at the final stage of coastal areas cleaning, as well as the only method of cleaning in highly sensitive areas. The use of aboriginal hydrocarbon-oxidizing microorganisms, typical of most coastal substrates of the Euro-Arctic region, excludes changes in the structure of the microbial community in these areas. The adaptation of these microorganisms to extreme climatic conditions allows biological treatment to be carried out with high efficiency in the Subarctic and Arctic.

Groups of Geomicrobiological Indicators Are Spread across Gas-Hydrate and Non-Gas-Hydrate Areas in the Northern Part of the Sea of Japan.

The bioindication of oil and gas fields is a field of geomicrobiology that is mainly devoted to the detection of hydrocarbon-oxidizing microbial indicator species or functional genes in total DNA. However, it appears promising to use the physiological properties of microorganisms detection deposit type of hydrocarbons, in particular their ability to oxidize hydrocarbons under aerobic and anaerobic conditions. In this study, the most promising approach in this area was the method used for assessing the anaerobic degradation of hydrocarbons. When comparing molecular genetics and cultured methods of bioindication, it can be concluded that molecular biomarkers of functional genes for the anaerobic destruction of hydrocarbons (masD) make it possible to separate areas with traditional and gas-hydrate types of deposits. Using cultured methods, we found that representatives of the Nocardiaceae family of the phylum Actinomycetota were tied to the areas where gas hydrates were found. The ability of aerobic and facultative anaerobic hydrocarbon-oxidizing microorganisms to anaerobically utilize hydrocarbons was determined with cultured methods. For the first time, this ability was revealed for the genera Stenotrophomonas, Psychrobacter, Micrococcus and Peribacillus. The wide distribution of this ability that we found in strains isolated from both study regions suggests its prominent role in the destruction of hydrocarbons in marine sediments.

Влияние углеводородокисляющих штаммов Serratia grimesii и Bacillus sp.3 на микроценоз моллюсков и компоненты экосистем под воздействием нефтяного загрязнения

Bivalved molluscs are natural filter feeders of the aquatic environment due to their physiological characteristics. Passing sea water containing emulsified oil through them, they bind its droplets in pseudofeces, thereby accel-erating water self-purification. Mussels prove to be resistant to oil pollution. Experiments have shown that in aquariums with mussels the content of petroleum hydrocarbons decreases faster than in the tanks without mussels. The interaction of mussels with oil has been studied in detail. It has been established that when passing through the body 
 of mussels the group composition of oil products changes. Oil resignification is noted, which is also observed during its natural weathering. Currently, for the post-purification of natural ecosystems from oil pollution, the method of introducing active hydrocarbon-oxidizing microorganisms is widely used, often with the simultaneous incoming of additional biogenic elements, the so-called bioaugmentation. In this regard, the study of the interaction of oil-oxidizing microorganisms and molluscs is of practical and scientific interest. The aim of the work was to study the interaction 
 of hydrocarbon-oxidizing microorganisms on molluscs Unio and other components of the microecosystem when modeling the process of oil pollution. A study was made of river water, soil and molluscs Unio from model microecosystems for contamination by saprophytic and hydrocarbon-oxidizing microflora with the additional introduction of hydrocarbon-oxidizing microorganisms – Serratia grimesii and Bacillus sp.3 under conditions of Caspian oil pollution.The values of the bacterial composition of saprophytic and hydrocarbon-oxidizing microflora obtained in the experiment suggest that the processes of restoration and reclamation of a water body take place due to the structural and functional organization of ecosystems and communities.

СКРИНИНГ УГЛЕВОДОРОДОКИСЛЯЮЩИХ МИКРООРГАНИЗМОВ, ОБЛАДАЮЩИХ УСТОЙЧИВОСТЬЮ К ТЯЖЕЛЫМ МЕТАЛЛАМ И ХЛОРИДУ НАТРИЯ

In the process of extraction of hydrocarbon raw materials, in addition to mechanical disturbance of the soil cover, it is chemically contaminated with hydrocarbons and heavy metals contained in oil and oilfield wastewater, mainly of sodium chloride composition. Combined pollution has a more pronounced adverse effect on plants and soil biocenosis than each pollutant alone and leads to a very rapid loss of soil fertility. The aim of this work was to screen for new strains of hydrocarbon-oxidizing microorganisms resistant to elevated concentrations of sodium chloride and heavy metals. Isolation of strains of microorganisms from samples of technogenically contaminated soils from the territory of the Republic of Bashkortostan was carried out by the method of enrichment cultures on a liquid mineral medium of Raymond with oil. The hydrocarbon-oxidizing activity of the isolates was determined by the degree of destruction of the aliphatic oil fraction by the gas chromatographic method after extraction with hexane. The resistance of strains to the presence of sodium chloride and heavy metals (Zn, Co, Cd, Cu, Pb, Ni) was established by their growth on meat-peptone agar with various concentrations of NaCl or salts of these metals. Of the 14 isolated strains, 6 were selected, most actively growing on a solid medium with oil. The highest abundance and the most significant hydrocarbon-oxidizing activity during cultivation in a liquid medium with oil was found in strain 22 (the degree of oil biodegradation was 93.0%). All microorganisms were halotolerant and grew at 5 and 7% sodium chloride in the medium, but cultures 11 and 41, which withstood a NaCl concentration of 10%, turned out to be the most resistant to salinity. Strains 33.1 and 33.2 had the highest resistance to the action of metals. Lead and zinc were the least toxic to microorganisms. The results obtained should be considered preliminary, and the isolates themselves need further research with a view to their possible application in ecobiotechnology.

Effect of remediation techniques on petroleum removal from and on biological activity of a drought-stressed Kastanozem soil.

Many petroleum extraction and refinement plants are located in arid climates. Therefore, the remediation of petroleum-polluted soils is complicated by the low moisture conditions. We ran a 70-day experiment to test the efficacy of various combining of remediation treatments with sorghum, yellow medick, and biochar to remove petroleum from and change the biological activity of Kastanozem, a soil typical of the dry steppes and semideserts of the temperate zone. At normal moisture, the maximum petroleum-degradation rate (40%) was obtained with sorghum-biochar. At low moisture, the petroleum-degradation rate was 22 and 30% with yellow medick alone and with yellow medick - sorghum, respectively. Biochar and the biochar-plant interaction had little effect on soil remediation. Both plants promoted the numbers of soil microbes in their rhizosphere: yellow medick promoted mostly hydrocarbon-oxidizing microorganisms, whereas sorghum promoted both hydrocarbon-oxidizing and total heterotrophic microorganisms. Low moisture did not limit microbial development. In the rhizosphere of sorghum, dehydrogenase and urease activities were maximal at normal moisture, whereas in the rhizosphere of yellow medick, they were maximal at low moisture. Peroxidase activity was promoted by the plants in unpolluted soil and was close to the control values in polluted soil. Biochar and the biochar-plant interaction did not noticeably affect the biological activity of the soil.

Erratum to: New Biocomposite Materials Based on Hydrocarbon-Oxidizing Microorganisms and Their Potential for Oil Products Degradation

An Erratum to this paper has been published: https://doi.org/10.1134/S0026261722300142

СКРИНИНГ УГЛЕВОДОРОДОКИСЛЯЮЩИХ МИКРООРГАНИЗМОВ ДЛЯ БИОРЕМЕДИАЦИИ ПОЧВ, ЗАГРЯЗНЕННЫХ НЕФТЬЮ И НЕФТЕПРОДУКТАМИ

Accidents with oil and petroleum product spills pose a serious threat to environmental safety and human health. To date, measures to eliminate the effects of pollution have mainly been reduced to the use of physical and chemical methods, which are characterized by high cost and many restrictive factors. Microbiological reclamation is a promising approach to solving the problem of cleaning environmental objects from oil pollution. The purpose of this work was to isolate native microflora from the deposits of viscous and ultra-viscous oil to form an association that contributes to the degradation of heavy oil. As a result of screening of hydrocarbon-oxidizing microorganisms, 6 highly active isolates were selected from the bottomhole zones of oil wells of the Bashkir tier of deposits of the Republic of Tatarstan. It has been established that they take part in the oxidation and biological degradation of heavy oil with a specific density of 0.89-0.91 g/cm3. In the experiment with monocultures, the transformation of oil did not exceed 34%, but under the influence of the association, the value of the indicator reached 52%. Under the influence of the association of microorganisms, a significant decrease in the viscosity of oil was noted. The data obtained indicate the prospects for further study of the hydrocarbon-oxidizing ability of the selected microorganisms and the use of this association as the basis of biological products for the elimination of oil and petroleum product spills, rehabilitation of the environment.

New Biocomposite Materials Based on Hydrocarbon-Oxidizing Microorganisms and Their Potential for Oil Products Degradation

New Biocomposite Materials Based on Hydrocarbon-Oxidizing Microorganisms and Their Potential for Oil Products Degradation

Influence of biological product’s carriers on the biological properties of oil-contaminated sod-podzolic soil

The article shows the effect of organomineral fertilizers and various disintegrants-carriers of oil-oxidizing biological product of a new generation on the biological indicators of sod-podzolic soil heavily polluted with oil (up to 10%), and on the decomposition rate of oil in it. Sawdust, lowland peat, barley straw, vermiculite, flax shover and lignin were studied as carriers of a bioproduct that showed positive effects during the 2019 growing season. Lignin showed the largest number of heterotrophs, the sawdust – hydrocarbon-oxidizing microorganisms. The introduction of the bioproduct with carriers contributed to the restoration of the enzymatic activity of the contaminated soil. Low-lying peat and flax shover had the greatest positive effect on this indicator. Improvement of biological properties of oil-contaminated soil by carriers of the bioproduct has sharply increased its efficiency in the decomposition of oil in it. The biolproduct in combination with flax shover, lignin and straw reduced the content of oil products as much as possible (by 9.9–10.9 mg/kg or 40.2–44.3%). Organomineral fertilizers also significantly improved the biological properties of oil-contaminated soils and reduced the residual oil content in them by 13.0 mg/kg or 52.8%.

The Effectiveness of Biostimulation, Bioaugmentation and Sorption-Biological Treatment of Soil Contaminated with Petroleum Products in the Russian Subarctic.

The effectiveness of different bioremediation methods (biostimulation, bioaugmentation, the sorption-biological method) for the restoration of soil contaminated with petroleum products in the Russian Subarctic has been studied. The object of the study includes soil contaminated for 20 years with petroleum products. By laboratory experiment, we established five types of microfungi that most intensively decompose petroleum hydrocarbons: Penicillium canescens st. 1, Penicillium simplicissimum st. 1, Penicillum commune, Penicillium ochrochloron, and Penicillium restrictum. One day after the start of the experiment, 6 to 18% of the hydrocarbons decomposed: at 3 days, this was 16 to 49%; at 7 days, 40 to 73%; and at 10 days, 71 to 87%. Penicillium commune exhibited the greatest degrading activity throughout the experiment. For soils of light granulometric composition with a low content of organic matter, a more effective method of bioremediation is sorption-biological treatment using peat or granulated activated carbon: the content of hydrocarbons decreased by an average of 65%, which is 2.5 times more effective than without treatment. The sorbent not only binds hydrocarbons and their toxic metabolites but is also a carrier for hydrocarbon-oxidizing microorganisms and prevents nutrient leaching from the soil. High efficiency was noted due to the biostimulation of the native hydrocarbon-oxidizing microfungi and bacteria by mineral fertilizers and liming. An increase in the number of microfungi, bacteria and dehydrogenase activity indicate the presence of a certain microbial potential of the soil and the ability of the hydrocarbons to produce biochemical oxidation. The use of the considered methods of bioremediation will improve the ecological state of the contaminated area and further the gradual restoration of biodiversity.

Intensification of the biotreatment processes of natural and waste water, contaminated with spent lubricating oils with sorbents of various nature

Biodegradation of spent lubricating oils (mineral, semisynthetic, synthetic) was investigated in natural and waste water of consortia of hydrocarbon-oxidizing microorganisms (HOM) under the influence of sorbents of various nature. It was found that the effectiveness of the latter’s action on the biotreatment processes of water from oils is determined by the size of particles, concentration, formation of active contact surface of phases by them and their participation in neutralization of contaminants. In direct use of sorbents without HOM, are purified 7 to 19.6 % oils. This is achieved within 10-14 days of contact. The joint use with HOM of inert materials (river sand, coal powder, polyethylene chips, etc.), in the same contact times, water is neutralized from lubricating oils from 44.9 to 63.7 % observed under the influence of HOM only. At the same time, with buckwheat, oats, wheat and barley husks with the same level of pollution, the purification of water from lubricating oils reaches 93.7 %. It is related to the simultaneous participation of these sorbents in the formation of a highly active surface for immobilizing contaminants and microflora, to provide stimulating activity of the latter by involving products associated with these materials in oxidative processes.

IDENTIFICATION OF HYDROCARBON-OXIDIZING MICROORGANISMS ISOLATED FROM OIL-CONTAMINATED SOILS OF SOUTH KAZAKHSTAN

Currently, one of the main sources of environmental pollution is oil and oil products. To solve the problems of soil cleaning, methods of biological reclamation have recently been successfully used, which are based on the activation of microbiological destruction of oil and oils products. The use of mixed strains of microorganisms allows the complete utilization of oil and oil products. The use of active hydrocarbon-oxidizing microorganisms in the cleaning of oil-contaminated objects is a promising and effective method. The aim of the work is to identify hydrocarbon-oxidizing microorganisms isolated from oil-contaminated soils of South Kazakhstan. From the oil-contaminated soils of South Kazakhstan, 5 active strains of hydrocarbon-oxidizing microorganisms have been isolated and identified, which can be promising for the disposal of oil-containing waste. Cultural-morphological and taxonomic features of microorganisms were revealed. Identification of the isolated cultures by molecular genetic characteristics were assigned to different physiological groups: Pseudomonas thivervalensis КМА4.1, Devosia neptuniae RMA7, Glutamicibacter arilaitensis MMA4, Aspergillus flavus Mach1, Penicillium chrysogenum Mach2. A phylogenetic analysis of the studied strains was carried out.

Bioremediation Of Soil Of The Kola Peninsula (Murmansk Region) Contaminated With Diesel Fuel

This work focuses on the creation and use of associations of hydrocarbon-oxidizing microorganisms. Bioremediation of soils with the help of mixed cultural and associations of microorganisms provides wider adaptive possibilities than individual species. This is especially important in conditions of short northern summer. The results of field experiments showed that microbial associations based on indigenous microorganisms (bacteria Pseudomonas fluorescens, P. putida, P. baetica, Microbacterium paraoxydans and fungi Penicillium commune, P. canescens st. 1, P. simplicissimum st. 1) with mineral fertilizers reduced the content of total petroleum hydrocarbons in the Hortic Arthrosol soil of the Kola Peninsula by 82% over 120 days. Also, the microbial associations with mineral fertilizers had a positive effect on the physical properties of the soil, increasing its humidity. The bacterial-fungi associations changed the number, abundance and structure of the indigenous community of microorganisms. Penicillium canescens, which was included in the composition of fungi association, became dominant. During the rapid decomposition of hydrocarbons are released to the soil toxic intermediates or metabolites of the microbial oxidation of hydrocarbons. Hydrocarbon oxidizing microfungi suppressed the germination of test plant seeds to one degree or another. Penicillium commune fungal metabolites inhibited seed germination only by 29% for Lepidium sativum L. and 24% for Triticum aestivum L. This species can be used for bioremediation of petroleum contaminated soils.

Oxidation of a Mixture of Polyaromatic Hydrocarbons by a Mixed Culture of Hydrocarbon-Oxidizing Microorganisms

The possibility of biochemical oxidation of polyaromatic hydrocarbon mixtures (PAHs) by the mixed culture of hydrocarbon-oxidizing microorganisms (HOM) in a liquid medium and soil was investigated. The mixed HOM culture was represented by Pseudomonas stutzeri, Pseudomonas putida, Bacillus cereus, and Arthrobacter globiformis genera. It was shown that during HOM cultivation of the microorganisms under study in the liquid medium their number increases from 0.25·104 to 11·108 CFU/ml, which is accompanied by an increase in their oxygenase activity. All PAHs identified were subjected to oxidation from 11.3 to 100%. The results of experiments on biodegradation of PAHs under natural conditions have shown that for 60 days the total utilization of oil products in soils was on the average 65% of the initial contamination. This suggests the prospects for the use of the mixed HOM culture under study for effective biodegradation of PAHs polluting soil and waste waters.

CHEMICAL AND BIOLOGICAL INDICATORS FOR EVALUATION OF ARCTIC SOIL DEGRADATION AND ITS POTENTIAL TO REMEDIATION

In recent years, significant efforts have been made to accelerate the economic development of the Arctic zone, leading to intense environmental pollution of this region, accompanied by the significant impact of accumulated environmental damage in the region. The solution to these problems is difficult due to the remoteness of these areas and severe climatic conditions. Therefore, it is important to evaluate the potential for restoration of arctic soils. For this purpose, various indicators are used, including biological ones. In the analyzed arctic soil samples, high concentrations of petroleum hydrocarbons (up to 47,000 mg/kg) and chloride-ions (0.10–0.14 wt %) were established. Microbioassay demonstrated a presence of hydrocarbon-oxidizing microorganisms: Penicillium, Azotobacter chroococcum, Bacillus subtilis, Pseudomonas oleovorans. A low enzymatic activity and specific Arctic climate point out a low self-restoration ability of the soil, demonstrated the need for its remediation. The microbioassay with microbial strains identification and soil remediation methods suitable for the Arctic zone were recommended.