Review Article
Year: 2023 | Month: June | Volume: 10 | Issue: 6 | Pages: 443-462
DOI: https://doi.org/10.52403/ijrr.20230657
A Review of Bacterial Degradation of Azo Dyes
Hassan Alzain1, Victor Kalimugogo1, Karim Hussein1, Mona Karkadan1
1Environmental Protection Organization, Saudi Aramco, Al-Midra Tower, Dhahran 31311, Kingdom of Saudi Arabia
Corresponding Author: Hassan Alzain
ABSTRACT
Biodegradation of synthetic dyes using different bacteria is becoming an accepted approach for treating Azo dye wastewater to mitigate many environmental problems. Azo dye has a negative impact on the environment by increasing biochemical oxygen demand (B.O.D.) and chemical oxygen demand (C.O.D.). The Biodegradation of azo dyes by different bacteria was evaluated. Biodegradation of synthetic dyes not only results in the decolorization of the dyes but also in the disintegration of the dye molecules into smaller and simpler parts. Decolorization of the dye arises when the chromophoric center of the dye is slashed. Various microorganisms, including fungi, bacteria, yeasts, and algae, have been used to decolorize and Degradation of synthetic dyes. Bacterial decolorization is usually faster than fungal decolourization. It is well known that bacteria degrade azo dyes reductively under anaerobic circumstances to colorless aromatic amines, which are carcinogenic compounds. These colorless aromatic amines must also be degraded because they may be toxic, mutagenic, and carcinogenic to humans and animals Bacteria are capable of removing dyes by adsorption and absorption. Biosorption rates are directly matched with the composition of heteropolysaccharides and the cell wall lipids. Dead cells are more useful in Biosorption than living cells because they do not need nutrients and can be stockpiled for a long time. The azoreductases are considered to be the most potent group of enzymes active in the Biodegradation of synthetic azo dyes. They accomplish the reductive cleavage of synthetic azo dyes bonds. Laccases enzymes become more interesting and have more focus recently due to their ability in generating much lower toxic aromatic amines. Laccases do not need other cofactors. Many factors affecting the process are temperature, pH, salinity, dye concentration, and Bioremediation in aerobic and anaerobic environments.
Keywords: Biodegradation, azo dyes, biochemical oxygen demand (B.O.D.), chemical oxygen demand (C.O.D.), bacterial enzymes and Bacterial Laccases enzymes.
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