Cleaning up the environment after chemical spills could be made easier thanks to Argentinean scientists who have developed a material that encapsulates pollutant-destroying microorganisms inside it. 

Removing organic pollutants from water after a chemical leak or cleaning up industrial waste water remains a challenge. One solution is to use microorganisms to break up organic pollutants, however, this risks releasing foreign or genetically modified organisms into the environment. These microorganisms can rapidly grow, deplete vital nutrients and cause further damage. Now, Sara Bilmes and colleagues at the University of Bunenos Aires, have developed a material that could help break up organic pollutants without releasing the microorganisms. 

The material is based on an alginate bead which surrounds a silica hydrogel. The hydrogel houses the filamentous fungus Stereum hirsutum which produces enzymes capable of breaking up organic pollutants. The pores of the hydrogel are designed to control the transport of toxic substances from the polluted surroundings, which controls the level of toxicity experienced by the fungus and prevents it being killed, explains Bilmes. Also, as the fungus is encapsulated inside the material, it cannot escape into the environment. 

The team demonstrated the usefulness of their hydrogel-fungi system by degrading malachite green (an organic dye), although in principle the system could be tailored to a wide range of organic pollutants. 'Choosing the right microorganism, this platform can be used for sensing and destroying any contaminant,' claims Bilmes. 

Thibaud Coradin, an expert in biotechnological applications of sol-gel materials at Collège de France in Paris, welcomed the research. 'This remarkably simple methodology occurs at low cost and in environment-friendly conditions,' he says. 'It combines the biocompatibility of biomacromolecular hosts with the structural stability and flexibility of sol-gel materials. This work represents a significant step towards in-field applications of the sol-gel cell encapsulation technology.'

Russell Johnson 

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