Evaluation of the microorganisms consortium efficiency to cleaning soils polluted by oil products in the Kola North conditions
Microscopic fungi and bacteria that are active oil hydrocarbons destructors were isolated from the soils of the Kola Peninsula (Al-Fe humus podzols). Microorganisms consortium efficiency (bacteria Pseudomonas fluorescens, P. putida, P. baetica, Microbacterium paraoxydans and fungi Penicillium commune, P. canescens st.1, P. simplicissimum st.1) for soil purification from oil products in field model experiment was estimated. Diesel fuel in the amount of 10 L/m2 was inserted as contaminator. Variants of the experiment were: soil without oil product (OP) as control, OP + bacterial consortium, OP + fungal consortium, OP + bacterial and fungal consortium. The residual content of oil hydrocarbons in the soil was determined by IR spectrometry methods with the AN-2 analyzer. Oil destructive native microorganisms consortium accelerate the oil product decomposition by 10-20% and are advised for environment post-cleaning from oil hydrocarbons. The bacterial-fungi consortium demonstrated the best result: during 120 days oil products content was reduced by 82%, oil products decomposition rate after 30 and 120 days was maximum as compared to other experiment scenarios. The soils of the Kola Peninsula are predominately acid soils, therefore, the efficiency of biopreparations based on fungi will likely be higher than that of bacterial preparation. Soil oil-oxidizing microorganisms changed the abundance, species composition and community structure of indigenous microorganisms. So, P. canescens, being a part of the consortium became the dominant species in the purified soil. The micromycetes involved in the consortium have different levels of phytotoxicity. Being an active decomposer of the oil products, the species P. commune displays these properties least of all, suppressing the Triticum aestivum seeds growth by 24%, and Lepidium sativum seeds by 29%. Consequently, this species may be a promising one for the biological product creation, and may be advised for use in bioremediation of soils contaminated by the oil products.