# Use of biosurfactants, microorganism-destructors, and plants for eco-friendly bioremediation technologies on oil-contaminated soils

## TL;DR

This study explores eco-friendly methods to clean up oil-contaminated soil using microbes, biosurfactants, and plants, achieving significant reductions in oil contamination.

## Contribution

The study introduces an integrated bioremediation approach combining specific microbes, biosurfactants, and plants for oil-contaminated soil cleanup.

## Key findings

- Combined use of microbial preparation D, RBC, and CaO2 reduced oil contamination to 1.3%.
- Soil dehydrogenase activity increased up to 2.7 times with sorghum, microbial preparation D, and RBC.
- Phytotoxicity of the soil decreased by 3.7 times after bioremediation.

## Abstract

Soil contamination by oil products is a significant problem that affects the environment, agriculture, economy, and human health, and requires effective solutions. The study aimed to develop effective methods of bioremediation of oil-contaminated soils using microbial preparation D (a mixture of Rhodococcus sp. and Gordonia sp. – a consortium of autochthonous hydrocarbon-degrading micro-organisms), a rhamnolipid biocomplex (RBC), the oxidant calcium peroxide (CaO2), and plant remediants.

Bioremediation processes were carried out on oil-contaminated clay soil (initial contamination – 9.5%) over 1.5 years. First, the soil was treated with microbial preparation D and CaO2. After 14 days, field peas or sorghum were sown, with seeds treated using an RBC solution. Hydrogen peroxide content and lipid peroxidation index in plants, as well as soil dehydrogenase activity, were determined by spectrophotometry. Additionally, soil phytotoxicity was assessed using test plants, and the residual content of oil products was quantified.

The best effect was achieved with the combined use of microbial preparation D, RBC, and CaO2: the degree of oil contamination in the soil decreased to 1.3%; with microbial preparation D, plants, and RBC, contamination decreased to 1.4–1.6% (compared to the initial 9.5%). The maximum value of dehydrogenase activity was recorded when sorghum, microbial preparation D, and RBC were applied, 2.7 times higher than in the control. After bioremediation, the phytotoxicity of oil-contaminated soils (in test plants) decreased on average by 3.7 times compared to the control.

The effectiveness of the integrated use of hydrocarbon-degrading microorganisms, field peas, sorghum, RBC, and CaO2 in bioremediation of oil-contaminated soils was established.