Reducing Pollution, Restoring Balance: The Microbiology of Sulfur-Reducing Bacteria in Textile Wastewater Treatment

The textile industry releases large volumes of harmful chemicals, including residual dyes and xenobiotics-synthetic or foreign compounds not naturally produced or expected in living systems, such as dyes, surfactants, and pesticides. These pollutants contribute to environmental toxicity, mutagenicity, and carcinogenicity. While physicochemical treatments are commonly employed for dye and heavy metal removal, bioremediation using microorganisms offers a sustainable and eco-friendly alternative. Diverse microbial groups, including bacteria, fungi, and microalgae, can degrade textile pollutants through specialized metabolic pathways. However, biodegradation efficiency is often influenced by dye toxicity, environmental stress, and microbial diversity. Sulfate-reducing bacteria (SRBs) have emerged as promising agents for bioremediation due to their metabolic versatility. SRBs reduce sulfate to hydrogen sulfide (H₂S), which reacts with heavy metals to form insoluble metal sulfides, enabling their effective removal from wastewater. SRBs are also capable of decolourizing textile dyes-particularly azo dyes and, to a lesser extent, anthraquinone, triphenylmethane, and sulfur dyes-thereby enhancing their capacity for pollutant degradation and heavy metal removal. Understanding the role of SRBs requires a thorough knowledge of the sulfur cycle, including biogeochemical pathways, reduction mechanisms, and the genes and enzymes involved. Sulfur itself holds significant importance in agriculture and industry, further emphasizing the relevance of SRBs in environmental remediation. This review underscores the significance of sulfur, key features of the sulfur cycle, and the physiological roles of SRBs in degrading textile pollutants, positioning them as vital contributors to sustainable wastewater treatment strategies.