Biodegradation of Congo Red Dye using Textile Effluent

The diazo dye Congo red (C.I. No. 22120, Direct red 28, MF: C₃₂H₂₂N₆Na₂O₆S₂ and FW: 696.66 g·mol⁻¹) which is the sodium salt of benzidinediazo-bis-1-naphthylamine-4-sulfonic acid, used in this study was supplied by Sigma-Aldrich (St. Louis, MO, USA). RTE was collected from Mahesh Textile Processors (Ichalkaranji, MS, India) in an airtight plastic can, passed through Whatman grade No. 1 filter paper to remove large suspended matter and stored in a refrigerator at 4 ± 1 °C until further use. Veratryl alcohol, catechol, methyl red, 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), nicotinamide adenine dinucleotide (NADH), dichlorophenol indophenol (DCIP), glucose, yeast extract and peptone were purchased from HiMedia Laboratories Pvt. Ltd. (Mumbai, MS, India). All of the chemicals used in this study were of analytical grade, unless otherwise mentioned. WB medium was prepared, the pH adjusted to 7.5 with with 0.1 N NaOH or 0.1 N HCL and used as growth medium for the biodegradation of dye and textile effluent [22 (link)].