Engineered Bacteria for Environmentally Friendly Cleaning of Rocket Fuel Contaminated Soil

Russian scientists have developed a soil decontamination technology for a highly toxic component of rocket fuel using the bacteria Bacillus subtilis KK1112 and hardy forage plants. This advancement aims to restore polluted areas near space launch sites and missile testing grounds, as reported by РИА Новости from the Russian Science Foundation (RSF).

The toxic substance in question, asymmetric dimethylhydrazine (also known as heptyl), forms compounds upon oxidation that can cause DNA mutations, posing risks to living organisms. As part of the fuel can contaminate the soil during rocket launches, researchers are actively seeking methods to cleanse these affected areas. The RSF notes that the most efficient degradation of heptyl and its oxidation products occurs in the presence of plants and diverse soil microorganisms.

«It is known that asymmetric dimethylhydrazine and its dangerous oxidation byproducts break down more rapidly in environments populated by plants and a rich diversity of soil microorganisms. Therefore, scientists believe that by carefully selecting bacterial strains and plant species, effective consortia can be established that will efficiently cleanse soils contaminated with rocket fuel components,» stated RSF in their announcement.

Researchers from the Moscow Institute of Physics and Technology, the Russian Biotechnological University, and the All-Russian Research Institute of Agricultural Biotechnology have developed a strain of Bacillus subtilis KK1112 that can withstand extremely high concentrations of heptyl (up to 200,000 times above permissible limits) and convert it into safe compounds.

The developed formulation was applied to seedlings of widely available and resilient forage grasses, including smooth brome (Bromus inermis), hybrid alfalfa (Medicago varia), and meadow timothy (Phleum pratense).

The researchers grew samples in water containing heptyl solution and in its absence for one week. Toxicity levels were then assessed using bacterial luminescent biosensors. It was found that Bacillus subtilis KK1112 was most effective in detoxifying the pollutant when used with smooth brome seedlings.

«In essence, we have created a natural cleaning system where bacteria and plants work together to break down hazardous compounds and restore soil fertility. This is an eco-friendly and cost-effective solution to a significant environmental issue,» commented Sergey Bazhenov, the project’s lead and senior researcher at the Moscow Institute of Physics and Technology’s Scientific Research Center for Molecular Mechanisms of Aging and Age-related Diseases.

According to him, this development opens up new possibilities for rehabilitating areas damaged by rocket launches. Similar consortia could be identified for addressing other industrial pollutants, and their effectiveness can be measured using biosensors.

The study showed that the bacteria not only cleaned the environment but also protected the seedlings from harmful substances, allowing them to develop normally even in contaminated conditions. In fact, in the absence of microorganisms, asymmetric dimethylhydrazine inhibited root growth and above-ground parts of the plants by 60 percent, an effect that was not observed with the addition of Bacillus subtilis. This suggests that the strain developed by the authors could be used as a probiotic for plants in agricultural settings, as reported by RSF.

Moreover, the strains used by the scientists are capable of thriving in dry and saline soils, indicating their potential for application in arid regions where space launch activities occur.

The results of the research, supported by a grant from the Russian Science Foundation (RSF), have been published in the Bioremediation Journal.