Biodegradation of aromatic chloroderivatives from contaminated water

Polychlorinated biphenyls PCBs, are a group of chemicals now considered among the most hazardous pollutants in the world. The presence of these extremely stable compounds in trace concentrations in water have been linked to an increased risk in frequency of cancer. PCBs were used for production of various industrial capacitors, pesticides and herbicides over a number of years; and still appear in ground and water. Existing multistep water purification processes for PCBs and other chlorinated contaminants are expensive mostly due to usage of different chemicals.

Bioremediation processes utilising bacteria represents an alternative to existing chemical methods. Immobilisation of bacteria on a substrate reveals many benefits over free bacteria systems, such as higher biomass content, high metabolic activity, resistance to toxic chemicals, allowing continuous process operating and avoiding the biomass- liquid separation requirements.

The immobilised bacteria can be reused several times opening opportunities for developing cost-effective processes for wastewater treatment. In this project we apply a cutting-edge technology to the development of the direct cross-linking of the bacteria cells into a 3D-structured macroporous, highly permeable system. This system is used for selective and efficient purification of contaminated water from aromatic chloro derivatives (chlorophenols etc.). Advantages of the novel system are: one step immobilisation, high density of immobilised cells; no diffusion restriction of contaminant to the cells and possibility to exploit the system as a flow through bioreactor. This is an inter- and intra-disciplinary proposal involving the combination of knowledge and expertise in microbiology, cryotechnology, organic, polymer, physical, analytical, environmental and surface chemistry. The project intends to solve sophisticated problems of Environmental remediation through combination of microbiology and polymer chemistry.

The project aimed to develop and apply a new technology, for the direct cross-linking of the bacteria cells into a 3D structured macroporous, highly permeable system that will be used for selective and effective purification of contaminated water from organic compounds. The performance of developed materials was assessed on the real systems under the guidance of the ENVIROCENTRUM, Slovakian SME specialising in bioremediation.

The chemical cross-linking of bacteria under cryoconditions into a 3D structured bacterial cells structure is a highly novel process. The development of 3D structured bacterial cells systems gives new possibilities for easy immobilisation of the bacteria cells and developing novel methods to deal with complex contaminants, which are difficult to remove from the environment. It is expected that proposed bioreactor will provide direct flow through of the contaminated water, which opens opportunities to design novel systems and approaches in the treatment of water.

The outcome of this project built the strong foundations for creation of immobilised alive bacteria cells bioreactor that could also usefully utilised in other areas of chemistry and biotechnology. The understanding of formation mechanism of 3D structured bacterial cells in cryoconditions may lead to better understanding of cryopreservation process of cells and tissue and probably discovery of new cryoprotectors.