Bacterial degradation of dyes is interesting and holds good promise as a viable treatment process. Coupling of anaerobic dye decolourization with aerobic amine degradation is a way to acieve complete minzeralization of textile dyes. To achieve this goal, studies are currently in progress to use anaerobic bio film reactors with different carriers or upflow anaerobic sludge blanket reactors (UASB) coupled to aerobic stirred tank reactors.

Azo dyes are known to be persistent to biodegradation under aerobic conditions. Under anaerobic conditions the azo linkage can be reduced which leads to decolorization but also results in formation of aromatic amines. These amines are generally not further degraded and will accumulate under anaerobic conditions. Mineralization of aromatic amines is more common by aerobic bacteria and therefore, aerobic conditions could be used as next step to degrade the accumulated aromatic amines. A shift from anaerobic to aerobic conditions can thus be a solution to achieve complete degradation dyes.