Comparative and Kinetic Studies on Microbial Decolorization of Azo Dyes By Pseudomonas Aeruginosa and Pseudomonas Putida

ntroduction: Microbial decolorization in removing chromophores is investigated as an effective and potential method to be applied in textile industries. The type of dyes and degraders determines efficiency of the process. Biodegraders such as bacteria are environmentally biocompatible and cost effective which their application in deco-lorization is extending day to day. Pseud-omonas bacteria are known as one of the most powerful degrader bacteria that can be applied to decolorize textile wastewater. In this study، four different azo dyes including Acid Blue 113 (AB-113)، Basic Red 46 (BR-46)، Direct Blue 151 (DB-151)، Direct Brown 2 (DB-2)، and a mixture of the four dyes (Mix) were subjected to biodegradation using Pseudomonas aeruginosa (P. aeruginosa)، and Pseudomonas putida (P. putida) at pH 7. 2 and 30 °C condition. P. aeruginosa completely deco-lorized AB-113 in all initial dye concen-trations، BR-46 in the concentrations of 0. 1 and 0. 2 g/L and DB-2 in the concentrations of 0. 1، 0. 2 and 0. 5 g/L. P. putida completely decolorized AB-113 in the concentrations of 0. 1 and 0. 2 g/L، DB-2 in the conce-ntrations of 0. 1 and 0. 2 g/L. The mixture of four dyes was also completely decolorized in the concentration of 0. 1 g/L by P. putida. Decolorization processes followed first and second order kinetics with respect to dye concentration. The higher calculated rate constants of first and second order were observed in low dye concentrations. Discussion & Results of the study represented that various strains of Pseudomonas are differently able to degra-de azo dyes in different concentrations that can be used based on the components and concentrations of dyes.