[Special traits of decomposition of azo dies by anaerobic microbial communities].

We present the results of an investigation into the special traits of conversion of azo dies golden yellow, acid orange, methyl orange, and methyl red under anaerobic conditions in comparison to aerobic conditions. In the presence of oxygen, only methyl red underwent decomposition, while under oxygen-free conditions, all remaining substances were fully discolored under the action of a methanogenous consortium of organisms. The products of reduction of the azo bond are determined in the case of each die.