Dyes-decolorizing potential of fungi strain BUK_BCH_BTE1 locally isolated from textile industry effluents: Characterization and LC-MS analysis of the metabolites

Abstract

Textile industry wastewater contains azo dye leftovers, which have a deleterious impact on most environmental systems. Because of safety and cost considerations, biological waste treatment is the best alternative. The goal of the study was to isolate and characterized fungus that could decolorize and use azo dye (Congo red) as a single carbon source. After serial dilution on mineral salt media, the fungus was isolated using the pour plating procedure. Based on gene sequencing of ITS1 and ITS2 ribosomal RNA region and molecular phylogenetic analysis the strain was identified as Aspergillus quadrilineatus with the accession number OK178927. Temperature, pH, substrate concentration, incubation period, inoculum size, and the influence of interacting heavy metals in Mineral Salt Medium were all investigated during the characterization process Congo red is used as the sole carbon source. This fungal isolate grew and decolorized Congo red best at 400 μɡ/ml substrate concentration, 30 °C temperature, 5.0 pH, an inoculum size of 200 μL, and a 72-h incubation time. The isolate was shown to withstand up to 6 ppm of Zink (Zn), Chromium (Cr), and Cupper (Cu), with Iron (Fe) and Arsenic (Ar) showing the most inhibition. Comparing Congo red's metabolites to a standard database of organic substances. LC/MS analyses of the intermediate compounds produced during Congo red decolorization revealed the formation of Isamine blue, p-bromo-N-(2-naphthyl)-benzenesulfonamide, 4-acetomido-N,N-dicyclohexyl-3-nitrobenzene, and azobenzene-2-sulfenyl bromide as metabolites in the fungal biodegradation of Congo red. The isolate might be a good candidate for bioremediation.

Keywords

• Dyes
• Decolorization
• Fungi strain
• Textile industry effluents
• Metabolites