Scientists from Tula State University, together with colleagues from the Postovsky Institute of Organic Synthesis of the Ural Branch of the Russian Academy of Sciences, have figured out how to extend the service life of biofilters for wastewater treatment. The technology could also find applications in the cryopreservation of cellular tissues. This was reported to RT in the press service of the Ministry of Education and Science of Russia. The results are published in the journal Polymers.

One of the ways to purify wastewater from toxic impurities is biological - special microorganisms are able to feed on substances harmful to humans, decomposing them to safe compounds.

However, a whole set of toxic compounds, including heavy metals, may be present in industrial effluents. Microorganisms can decompose only a part of these substances, while other toxins inhibit the activity of living "filters". As a result, the operating time of biofilters is markedly reduced, and the cleaning efficiency is reduced.

Scientists have found an approach to solving this problem - a special shell of biocompatible silicon composites is able to protect microorganisms from negative effects. It shelters beneficial microorganisms from exposure to heavy metal ions and UV radiation, but at the same time does not interfere with their vital activity. The authors of the work borrowed the idea from nature - diatoms already use such protection. These single-celled organisms, over millions of years of evolution, have learned to form mineralized shells of silica (silicon dioxide) on their surface. "Armor" allows algae to survive in adverse conditions.

The authors of the work synthesized hybrid compounds of silicon dioxide and organic polymer - silicon polyethylene glycolates. In the presence of water, they form special hydrogels on the surface of microorganisms. The coating protects microorganisms used to purify water from external influences and prolongs the life of the biological filter.

  • Diatoms
  • © Micro Discovery

"The organosilicate shells formed on the surface of methylotrophic yeast create a comfortable habitat for packaged cells, on the one hand, and protect living microorganisms from environmental stressors, on the other hand, which is important not only for the development of industrial wastewater treatment technologies, but also for the development of new biocatalysts for biotechnological production," the head of the scientific group, Doctor of Chemical Sciences, explained to RT. Head of the Department of Biotechnology of Tula State University Olga Ponamoreva.

Scientists have already tested new biofilters to purify water from methanol. In 90 minutes, the filter purified water by 60% of this toxic compound to humans.

According to experts, the new technology can also be used in the development of biocatalysts for biotechnological production. In addition, the technology of encapsulating living cells in a composite hydrogel can be adapted for cryopreservation of tissues and organs for medical purposes.