Biodegradation of Basic Yellow Auramine- O Dye using Staphylococcus sp. Isolated from Textile Industry Effluent

Due to the increased use of synthetic dyes in various industries, there is an increased disposal of wastewater containing harmful dyes. These, in turn, have affected plants, animals, and humans. The physical and chemical methods of dye decolorization have failed to degrade the synthetic dyes in industrial effluents completely. The microbial decolorization is better due to its versatility, dynamic metabolism, and potential machinery of enzymes. This study aimed to degrade basic yellow dye auramine O by bacteria isolated from textile industry effluent. In this regard, five bacterial strains were isolated and screened from a soil sample taken from textile industry effluent. The initial physical and biochemical characterization of the bacterial isolates 1 and 2 indicated catalase test-positive, starch test-negative, motility agar test-negative, gram staining test-positive, and morphology-bacillus. The bacterial isolates 3, 4, and 5 indicated oxidase test-negative, urease test-positive, gram staining test-negative, and morphology-staphylococcus. All the isolates were further subjected to a screening test, where isolate 5 showed maximum dye decolorization of 98.9% in 96 h. The biodegradation of dye was optimized for different values of initial pH (4-10), inoculum size (2% -10%), initial dye concentration (50 mgL-1 to400 mgL-1), carbon source (glucose, fructose, xylose, starch and lactose) and nitrogen source (peptone, ammonium sulphate, yeast extract, ammonium nitrate and urea). Maximum dye decolorization was observed for initial dye concentration of 200 mgL-1, initial pH of 6, inoculum size of 10%, yeast extract as nitrogen source, and glucose as carbon source. Therefore, dye degradation by bacteria can be used as a potential method for auramine O dye treatment.