Resistance and functional profiling of tannery effluent bacterial communities

The contamination of soil and aquatic ecosystems with heavy metals has become a significant global concern due to its detrimental effects on agricultural productivity, environmental integrity, and human health. Tannery operations-especially those involving chromium salts, dyes, and other finishing agents-are major contributors to this problem, releasing a variety of heavy metals into wastewater. These effluents contaminate surrounding soils and water bodies, particularly in regions where untreated or poorly treated wastewater is used for irrigation or discharged into the natural ecosystems. Several bacterial strains, isolated from these effluents impacted by prolonged exposures in these environments, have demonstrated varying levels of tolerance to heavy metals. In addition to metal tolerance, many of these strains exhibit the capacity to produce extracellular enzymes, which enable them to degrade complex organic substrates-including various forms of tanned leather waste. This study aims to isolate, characterize, and evaluate naturally occurring bacteria from tannery effluents that demonstrate both heavy metal detoxification potential and leather-degrading enzyme production. It was elucidated that tannery effluents harbor metabolically versatile bacterial communities with high tolerance to heavy metals and antibiotic resistance, particularly among Gram-negative species. These bacteria also produced diverse extracellular enzymes that enabled degradation of complex organic wastes, including tanned leather waste. Enhanced hydroxyproline release further confirmed their ability to break down chemically treated substrates. Such multi-functional microbes could be employed in the -treatment of tannery waste, offering a sustainable solution for reducing environmental pollution and recovering value-added biomaterials from solid leather waste.