Biodecolourization of dye-contaminated textile effluents using Bacillus cereus N27

Abstract

This study examined the potentials of Bacillus cereus N27 to decolourize textile effluents. The determined physicochemical parameters of the effluents were temperature, pH, total dissolved solids (TDS), total suspended solids (TSS), dissolved oxygen (DO), biological oxygen demand (BOD) and chemical oxygen demand (COD) using standard techniques. The Bacillus cereus N27 was isolated from textile effluent contaminated soil samples in Challawa, Kano state, Nigeria and were characterized and identified based on cultural, biochemical and molecular techniques. The Bacillus cereus N27 was used for the biodecolourization study. The 3 ml broth culture of Bacillus cereus N27 was inoculated into medium comprising 2 g of yeast extract, 2 g of glucose, 2.8 g of lactose broth in 50 ml of different concentrations of the effluent (0%, 5%, 10%, 30%, 50%, 70%, 90% and 100 %) and were incubated for 30 days at 37^oC. The growth of the Bacillus cereus N27 was compared with corresponding McFarland standards. The rate of biodecolourization was determined using spectrophotometer at 600 nm. The effects of temperature (30^oC, 35^oC, 40^oC, 45^oC) and pH (4, 6, 8, and 10) on the decolourisation potential of the isolates was also determined. The results obtained for the physicochemical study were temperature (33.5^oC), pH (6.10), BOD (0.13 mg/L), COD (123.5 mg/L). DO (0.162 mg/L), TSS (310 mg/L), TDS (465.5 mg/L). The optimum biodecolourization temperature was 35^oC with 72.2% rate of biodecolourization after 30 days while pH 6 was optimum for the biodecolourization. The results obtained in the study suggest that Bacillus cereus can be used to develop an effective biological treatment system for the wastewaters contaminated with textile effluent.

Keywords: Textile effluent, dye, biodecolourization,Bacillus cereus.