Introduction: Textile industry is a water consumer which produce enormous volume of harmful dyes and chemicals into water. therefore, finding cost effective, efficient and ecofriendly approaches are essential.in this review we try to present studies on the bacterial bioreactors to biodegrade the groups of azo dyes family And some consortium do to the fact that in some cases only one strain of bacteria is not sufficient.
Methods: one of the most Practical dye in textile industry is azo family. Wide color range, Ease of utilize, strong attachment to the material fibers, qualified colors and proper energy consumption makes azo dyes one of textile industry s favorite dyes family with the chromophoric azo group. The resistance of Complex aromatic structure of azo dyes family gives them High toxicity level which threatens human health and the environment. Therefore, the proper, cost efficient and ecofriendly approach to eliminating these contaminants are necessary.
Bacteria as Microorganisms which produce oxidoreductive enzymes are one of the Eco friendly bioreactors for dyes biodegradation.
Results: Using bacterial tools to biodegrade Azo family dyes has been taken into consideration by groups of researchers.
D.C. Kalyani et al. studied Pseudomonas sp. SUK1. Strain as one of Pseudomonas species, and its effect on textile dyes. they announced that Pseudomonas sp. SUK1. Can biodegrade 52% of the Reactive Red 2 from sulfonated azo dye family in the vast range. contrary to previous studies On P. luteola, P. mirabilis, K. rosea and Pseudomonas sp. evaluate the product toxicity and announced the change of the Reactive Red 2 into a non-toxic product under Pseudomonas sp. SUK1 treatments.
Samta Saroj et al. studied a group of azo dyes family (Acid Red 183 (AR 183), Direct Red 75 (DR 75) and Direct Blue 15 (DB 15)) at 95–100% biodegradation level by Penicillium oxalicum SAR-3. they announced that manganese peroxidase presence implied enzymatic activity in decolorizing process.
Muhammad Ikram et al. announced that a list of bacteria such as orand Clostridium sp., Bacteroides sp., Sphingomonas xenophaga BN6, Butyrivibrio sp., Eubacterium sp., are decolorizing azo dyes in anaerobic conditions. they announced that decolorization of reactive red 22 dye by Pseudomonas luteola as well as P. luteola biofilm in 89% level. they also announced that S. arlettae strain decolorized four members of azo dyes family at 97% level.
In another study Manjinder Singh Khehra et al, researched on a bacterial consortium that contains Pseudomonas sp. Stenotrophomonas sp. and Bacillus sp. as a biodegradation treatment of synthetic dye (Acid Red 88) in the anoxic-aerobic conditions. they resulted in 98% decolorization and 95% chemical oxygen demand (COD) removal.
In another study HeFang et al. introduced A microbial consortium obtained from a Pseudomonas 1-10 and white-rot fungus 8-4. They designed this consortium for Direct Fast Scarlet 4BS decolorization as a water-soluble dye from azo family. the result Show that the Pseudomonas 1-10 treatment, in three condition of incubating- (a)continuous static incubation, (b)continuous shaking incubation, (c)static incubation then change to shaking incubation- presents 90%, 65% and 84% biodegrading effects respectively. On the other hand, the consortium treatment presents almost 100% biodegrading effect.
Conclusion: textile industries pollution is a considerable Issue nowadays. The original and synthetic dye diffusion into water makes human health threats and environmental hazard. and the massive amount of this diffusion demands an urgent solution. Bacterial treatments are cost effective, ecofriendly and efficient approaches to dyes degradation. The different studies on bacterial decolorization treatment show us The success of some strains as biodegradation tools of textile dyes although different kinds of bacterial consortiums present more prominent results.