The Reduction of Azo Dye Carmoisine from Synthetic Desizing Stage Effluent by Klebsiella quasipneumoniae GT7

The removal of the azo dye carmoisine from a synthetic dye wastewater medium, which contained starch and had a similar composition to the effluent from the de-sizing stage, was investigated by Klebsiella quasipneumoniae GT7. The measurements of dye concentration by spectrophotometry and starch concentration by the Anthrone method revealed that the anaerobic process at a temperature of 30 °C and pH 7, with an initial concentration of 50 mg/l of carmoisine, resulted in a decrease of approximately 96 % in the initial dye concentration within 48h. This was accompanied by a decrease of approximately 30 to 35 % in the initial starch concentration (1870 mg/l). Thin layer chromatography (TLC) showed that the bacteria degraded the carmoisine dye, which was removed during the anaerobic process, into its constituent aromatic amines. The continuation of the process under aerobic conditions, with and without re-inoculation of bacteria at the beginning of the aerobic stage, revealed that until day 23, aromatic amine molecules were not degraded and there was no significant reduction in the amount of dye or starch remaining from the anaerobic stage.