Promising Strains of Hydrocarbon-Oxidizing Pseudomonads with Herbicide Resistance and Plant Growth-Stimulating Properties for Bioremediation of Oil-Contaminated Agricultural Soils

Abstract

Nowadays, large areas of agricultural land are contaminated with chemical plant-protection products. Agricultural soils are also susceptible to oil pollution as a result of accidents on oil pipelines. Bioremediation of such soils from oil with the help of hydrocarbon-oxidizing bacteria is hindered by the presence of additional pollutants such as herbicides. In this work, seven strains of Pseudomonas were isolated and identified, which showed differences in ability of oil biodegradation (32.7–77.3%). All strains showed resistance to herbicides based on 2,4-D and substances from the class of imidazolinones, possessed phosphate-solubilizing and nitrogen-fixing activity, and produced indolyl-3-acetic acid (305–1627 ng/mL culture liquid). They stimulated the growth of barley and clover in soil with oil, as well as the growth of clover in soil with herbicide. In a vegetative experiment (duration 30 days, initial oil content in soil 2% wt., herbicide based on imazethapyr 0.002% wt.) of barley plants and P. alcaligenes UOM 10 or P. frederiksbergensis UOM 11, oil degradation was 48.1–52.7%, the same strains and clover plants, 37.9–38.6%. The studied bacteria have the potential to be used in the bioremediation of oil-contaminated agricultural soils, including in combination with phytomeliorant plants.