engleski

Bacteria immobilized on natural zeolitized tuff are able to survive in the conditions of extreme pH

The bacteria in the form of biofilm are more adapted to survive environmental stresses. We prepared biofilm by immobilizing phosphate-accumulating bacterium Acinetobacter junii, a heterotrophic bacteria normally present in activated sludge, on the particles of natural zeolitized tuff. The obtained bioparticles had thick biofilm with number of immobilized bacteria 2.2±0.12×109 CFU g-1. To test the survival of such bacteria in harsh conditions of wastewater treatment plants, such as unfavourable pH, the bioparticles were introduced in reactors containing simulated wastewater of extreme pH values, namely, 2, 3, 4 and 5 during 24h. The bacteria immobilized on bioparticles showed great resistance to unfavourable pH. The bacteria were viable in the biofilm, but also detaching from the biofilm and continued its growth in the media as planktonic cells. At pH 4 the survival of bacteria was 82% of starting number as opposed to the control reactors where survival was 0%. At pH 3, there were 38% of bacterial cells able to survive, while at pH 2 no viable cells were present in the reactors after the incubation. The results proved that bacteria immobilized on natural zeolitized tuff are able to survive the extreme conditions of wastewater treatment plants such as 24h disturbances of pH. This way the survival of bacterial population is enabled while the system upsets are fixed and bioparticles could serve as seeds for regeneration of bacterial population in the treatment plant.

bacteria; immobilization; pH; wastewater; zeolite

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