Journal of Bioremediation & Biodegradation

Abstrait

Stabilizing Role of Nanodiamonds on the Amaranth Transformation in Model Biofilters

Irina Schneider, Mihaela Beluhova and Yana Topalova

The present article is focused on studying the first phase of a model dye biodegradation, the reduction of the azo bond, and the following amaranth decolorization. This phase is speed-limiting, i.e. it defines the speed of the whole process. The process is with a periodic regime of feeding and is simulated in reactors of the “biofilter’ type in the presence of trivial organic matter (peptone and yeast extract). In the first part of the studies the dynamics of the amaranth and the organic matter (measured as TOC) is followed as well as the decolorization effectiveness and the effectiveness of decreasing concentration of the organic matter. The spatial and temporal distribution of important groups of microorganisms in depth of the inert carrier has been followed, which take part in the biotransformation of the azo dye. The azoreductase activity of the immobilized community is studied. The second part of the article investigates the modulation effect of nanodiamonds on the residual concentration of amaranth and organic matter, as well as on the effectiveness of their biotransformation. The obtained results showed that the medium layer of the inert carrier in the biofilter has the most favorable conditions for carrying out the reduction of the azobond. The key groups of microorganisms in the biofilm which carry out the process are: the anaerobic heterotrophs; the anaerobic azo degraders, the bacteria from genus Pseudomonas and Acinetobacter. Nanodiamonds have a stimulating effect on the technological parameters of the system. It is expressed in maintaining a stable biofilm with a high activity, maintaining an optimal flow of the system and increasing the effectiveness of amaranth decolorization and organic matter removal.